Suzuki Outboards Workshop Manual - Motoren - Dynamic DNS ...

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Transcript

OUTBOARD
WORKSHOP
SERVICE MANUAL
ALL MOTORS
2 TO 225 HP
YEARS
1988 TO 2003
CONTENTS
HOW TO USE THIS MANUAL 1·2
BOATING SAFETY 1·4
SAFETY IN SERVICE 1·12
TOOLS AND EQUIPMENT 2·2
TOOLS 2·5
FASTENERS, MEASUREMENTS AND CONVERSIONS 2·14
ENGINE MAINTENANCE 3·2
BOAT MAINTENANCE 3·8
TUNE-UP 3·12
WINTER STORAGE CHECKLIST 3·35
SPRING COMMISSIONING CHECKLIST 3·35
FUEL AND COMBUSTION 4·2
FUEL SYSTEM 4·3
TROUBLESHOOTING 4·7
CARBURETOR SERVICE 4·11
REED VALVE SERVICE 4·25
FUEL PUMP SERVICE 4·27
ELECTRONIC FUEL INJECTION 4·32
UNDERSTANDING AND TROUBLESHOOTING
ELECTRICAL SYSTEMS 5·2
BREAKER POINTS IGNITION (MAGNETO IGNITION) 5·7
CAPACITOR DISCHARGE IGNITION (CDI) SYSTEM 5·11
ELECTRONIC IGNITION 5·38
CHARGING CIRCUIT 5·39
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IGNITION AND ELECTRICAL WIRING DIAGRAMS 5·52
OIL INJECTION SYSTEM 6·2
COOLING SYSTEM 6·11
OIL INJECTION WARNING SYSTEMS 6·14
OVERHEAT WARNING SYSTEM 6·17
ENGINE MECHANICAL 7-2
POWERHEAD RECONDITIONING 7-32
LOWER UNIT 8-2
LOWER UNIT OVERHAUL 8-6
JET DRIVE 8-51
MANUAL TILT 9-2
GAS ASSISTED TILT 9-2
POWER TILT 9-3
POWER TRIM/TILT 9-6
REMOTE CONTROL BOX 10·2
TILLER HANDLE 10-7
HAND REWIND STARTER 11-2
OVERHEAD TYPE STARTER 11-2
BENDIX TYPE STARTER 11·10
GLOSSARY 11-13
INDEX 11·17
SUPPLEMENT: DTSY AND ADDITIONAL INFORMATION 12·2
ON MOST OTHER MODELS, INCLUDING UPDATED
CARBURETOR AND IGNITION SPECIFICATIONS
CONTENTS
GLOSSARY
MASTER INDEX
SUPPLEMENT
HOW TO USE THIS MANUAL 1-2
CAN YOU DO IT? 1-2
WHERE TO BEGIN 1-2
AVOID ING TROUBLE 1-2
MAINTENANCE OR REPAIR? 1-2
D IRECTIONS AND LOCATIONS 1-2
PROFESSIONAL HELP 1-2
PURCHASING PARTS 1-3
AVOIDING THE MOST COMMON
M ISTAKES 1-3
BOATING SAFETY 1-4
REGULATI ONS FOR YOUR BOAT 1-4
DOCUMENTING OF VESSELS 1-4
REGISTRATION OF BOATS 1-4
NUMBERING OF VESSELS 1-4
SALES AND TRANSFERS 1-4
HULL IDENTIFICATION
NUMBER 1-4
LENGTH OF BOATS 1-4
CAPACITY INFORMATION 1-4
CERTIFICATE OF COMPLIANCE 1-4
VENTILAT ION 1-5
VENTILATION SYSTEMS 1-5
REQUIRED SAFETY EQUIPMENT 1-5
TYPES OF FIRES 1-5
FIRE EXTINGU ISHERS 1-5
WARNING SYSTEM 1-7
PERSONAL FLOTATION
DEVICES 1-7
SOUND PRODUCING DEVIC ES 1-9
VISUAL DISTRESS SIGNALS 1-9
EQUIPMENT NOT REQUIRED BUT
RECOMMENDED 1-10
SECOND MEANS OF
PROPULSION 1-10
BAILING DEVICES 1-10
FIRST AID KIT 1-10
ANCHORS 1-10
VHF-FM RADIO 1-11
TOOLS AND SPARE PARTS 1-11
COURTESY MARINE
EXAMINATIONS 1-11
SAFETY I N SERVICE 1-12
DO'S 1-12
DON'TS 1-12
1 -2 G ENERAL I N FORMAT ION AN D BOAT ING SAFETY
HOW TO USE THIS MANUAL
This manual is designed to be a handy reference guide to maintaining and
repairing your Suzuki 2-stroke outboard. We strongly believe that regardless of
how many or how few years experience you may have, there is something new
waiting here for you.
This manual covers the topics that a factory service manual (designed for
factory trained mechanics) and a manufacturer owner's manual (designed more
by lawyers these days) covers. it wi l l take you through the basics of maintaining
and repairing your outboard, step-by-step, to help you understand what the fac­
tory trained mechanics already know by heart. By using the information in this
manual, any boat owner should be able to make better informed decisions about
what they need to do to maintain and enjoy their outboard.
Even if you never plan on touching a wrench (and if so, we hope that you wi l l
change your mind), this manual wi l l st i l l help you understand what a mechanic
needs to do in order to maintain your engine.
Can You Do lt?
If you are not the type who is prone to taking a wrench to something, NEVER
FEAR. The procedures in this manual cover topics at a level virtually anyone wi l l
be able to handle. And just the fact that you purchased this manual shows your
interest in better understanding your outboard.
You may find that maintaining your outboard yourself is preferable in most
cases. From a monetary standpoint, it could also be beneficial. The money spent
on hauling your boat to a marina and paying a tech to service the engine could
buy you fuel for a whole weekend's boating. If you are unsure of your own
mechanical abi l ities, at the very least you should fully understand what a marine
mechanic does to your boat. You may decide that anything other than maintenance
and adjustments should be performed by a mechanic (and that's your call), but
know that every time you board your boat, you are placing faith in the mechanic's
work and trusting him or her with your well-being, and maybe your life.
it should also be noted that in most areas a factory trained mechanic wi l l
command a hefty hourly rate for off site service. This hourly rate is charged
from the time they leave their shop to the time they return home. The cost sav­
ings in doing the job yourself should be readi ly apparent at this point.
Where to Begin
Before spending any money on parts, and before removing any nuts or bolts,
read through the entire procedure or topic. This will give you the overal l view of
what tools and supplies wi l l be requ i red to perform the procedure or what ques­
tions need to be answered before purchasing parts. So read ahead and plan
ahead. Each operation should be approached logically and a l l procedures thor­
oughly understood before attempting any work.
Avoiding Trouble
Some procedures in this manual may require you to "label and disconnect
. . . " a group of l i nes, hoses or wires. Don't be lu l led into thinking you can
remember where everything goes - you won't. If you reconnect or install a part
incorrectly, things may operate poorly, if at a l l . If you hook up electrical wiring
incorrectly, you may i nstantly learn a very, very expensive lesson.
A piece of masking tape, for example, placed on a hose and another on its
fitting wi l l allow you to assign your own label such as the letter "A", or a short
name. As long as you remember your own code, the l i nes can be reconnected
by matching letters or names. Do remember that tape wi l l dissolve when satu­
rated in fluids. If a component is to be washed or cleaned, use another method
of identification. A permanent felt-tipped marker can be very handy for marking
metal parts; but remember that flu ids will remove permanent marker.
SAFETY is the most important thing to remember when performing mainte­
nance or repairs. Be sure to read the i nformation on safety in this manual.
Maintenance or Repair?
Proper maintenance is the key to long and trouble-free engine life, and the work
can yield its own rewards. A properly maintained engine performs better than one
that is neglected. As a conscientious boat owner, set aside a Saturday morning, at
least once a month, to perform a thorough check of items which could cause prob­
lems. Keep your own personal log to jot down which services you performed, how
much the parts cost you, the date, and the amount of hours on the engine at the
time. Keep all receipts for parts purchased, so that they may be referred to in case
of related problems or to determine operating expenses. As a do-it-yourselfer, these
receipts are the only proof you have that the required maintenance was performed.
In the event of a warranty problem, these receipts wi l l be invaluable.
it's necessary to mention the difference between maintenance and repair.
Maintenance includes routine inspections, adjustments, and replacement of
parts that show signs of normal wear. Maintenance compensates for wear or
deterioration. Repair impl ies that something has broken or is not working. A
need for repair is often caused by lack of maintenance.
For example: draining and refi l l ing the engine oil is maintenance recommended
by all manufacturers at specific intervals. Failure to do this can allow internal cor­
rosion or damage and impair the operation of the engine, requiring expensive
repairs. While no maintenance program can prevent items from breaking or wear­
ing out, a general rule can be stated: MAINTENANCE IS CHEAPER THAN REPAIR.
Oirections and locations
• See Figure 1
Two basic rules should be mentioned here. Fi rst, whenever the Port side of
the engine (or boat) is referred to, it is meant to specify the left side of the
engine when you are sitting at the helm. Conversely, the Starboard means your
right side. The Bow is the front of the boat and the Stern is the rear.
Most screws and bolts are removed by turning counterclockwise, and tightened
by turning clockwise. An easy way to remember this is: righty-tighty; lefty-loosey.
Corny, but effective. And if you are really dense (and we have all been so at one
time or another), buy a ratchet that is marked ON and OFF, or mark your own.
STERN -- AFT
(REAR)
04701G10
Fig. 1 Common terminology used for reference designation on boats
of all size. These terms are used though out the manual
Professional Help
Occasionally, there are some things when working on an outboard that are
beyond the capabi l ities or tools of the average Do-lt-Yourselfer (DIYer). This
shouldn't include most of the topics of this manual, but you wil l have to be the
judge. Some engines require special tools or a selection of special parts, even
for basic maintenance.
Tal k to other boaters who use the same model of engine and speak with a
trusted marina to find if there is a particular system or component on your
engine that is difficult to maintain. For example, although the technique of valve
adjustment on some engines may be easily understood and even performed by
a DIYer, it might require a handy assortment of shims in various sizes and a few
hours of disassembly to get to that point. Not having the assortment of shims
handy might mean multiple trips back and forth to the parts store, and this
might not be worth your time.
G ENERAL I NFORMAT ION AND BOATING SAFETY 1 -3
You wi l l have to decide for yourself where basic maintenance ends and where
professional service should begin. Take your time and do your research first
(starting with the information in this manual) and then make your own decision.
If you real ly don't feel comfortable with attempting a procedure, DON'T DO IT If
you've gotten into something that may be over your head, don't panic. Tuck your
tail between your legs and call a marine mechanic. Marinas and independent
shops will be able to finish a job for you. Your ego may be damaged, but your
boat will be properly restored to its fu l l running order. So, as long as you
approach jobs slowly and careful ly, you real ly have nothing to lose and every­
thing to gain by doing it yourself.
Purchasing Parts
• See Figures 2 and 3
When purchasing parts there are two things to consider. The first is qual ity
and the second is to be sure to get the correct part for your engine. To get qual­
ity parts, always deal directly with a reputable retailer. To get the proper parts
always refer to the information tag on your engine prior to cal l ing the parts
counter. An incorrect part c.an adversely affect your engine performance and fuel
economy, and wi l l cost you more money and aggravation in the end.
Just remember, a tow back to shore wi l l cost p lenty. That charge is per hour
from the time the towboat leaves their home port, to the time they return to their
home port. Get the picture .. . $$$?
So who should you call for parts? Well, there are many sources for the parts you
wil l need. Where you shop for parts will be determined by what kind of parts you
need, how much you want to pay, and the types of stores in your neighborhood.
Your marina can supply you with many of the common parts you require.
Using a marina for as your parts supplier may be handy because of location
(just walk right down the dock) or because the marina special izes in your partic­
ular brand of engine. In addition, it is always a good idea to get to know the
marina staff (especially the marine mechanic).
The marine parts jobber, who is usually l isted in the yellow pages or whose
name can be obtained from the marina, is another excellent source for parts. In
addition to supplying local marinas, they also do a sizeable business in over­
the-counter parts sales for the do-it-yourselfer.
Almost every community has one or more convenient marine chain stores.
These stores often offer the best retail prices and the convenience of one-stop
shopping for a l l your needs. Since they cater to the do-it-yourselfer, these stores
Fig. 2 By far the most important asset in purchasing parts is a
knowledgeable and enthusiastic parts person
05001P01
04971P12
Fig. 3 Parts catalogs, giving application and part number informa­
tion, are provided by manufacturers for most replacement parts
are almost always open weeknights, Saturdays, and Sundays, when the jobbers
are usually closed.
The lowest prices for parts are most often found in discount stores or the
auto department of mass merchandisers. Parts sold here are name and private
brand parts bought in huge quantities, so they can offer a competitive price. Pri­
vate brand parts are made by major manufacturers and sold to large chains
under a store label.
Avoiding the Most Common Mistakes
There are 3 common mistakes in mechanical work:
1 . Incorrect order of assembly, disassembly or adjustment. When taking
something apart or putting it together, performing steps in the wrong order usu­
ally just costs you extra time; however, it CAN break something. Read the entire
procedure before beginning disassembly. Perform everything in the order in
which the instructions say you should, even if you can't immediately see a rea­
son for it. When you're taking apart something that is very intricate, you might
want to draw a picture of how it looks when assembled at one point in order to
make sure you get everything back in its proper position. When making adjust­
ments, perform them in the proper order; often, one adjustment affects another,
and you cannot expect satisfactory results un less each adjustment is made only
when it cannot be changed by another.
2. Overtorquing (or undertorquing). Whi le it is more common for over­
torquing to cause damage, undertorquing may allow a fastener to vibrate loose
causing serious damage. Especia l ly when deal ing with aluminum parts, pay
attention to torque specifications and util ize a torque wrench in assembly. If a
torque figure is not available, remember that if you are using the right tool to
perform the job, you wi l l probably not have to strain yourself to get a fastener
tight enough. The pitch of most threads is so s l ight that the tension you put on
the wrench wil l be multiplied many times in actual force on what you are tight­
ening.
3. Crossthreading. This occurs when a part such as a bolt is screwed into a
nut or casting at the wrong angle and forced. Crossthreading is more likely to
occur if access is difficult. lt helps to clean and lubricate fasteners, then to start
threading with the part to be installed positioned straight in . Always start a fas­
tener, etc. with your fingers. If you encounter resistance, unscrew the part and
start over again at a different angle until it can be inserted and turned several
times without much effort. Keep in mind that some parts may have tapered
threads, so that gentle turning wil l automatically bring the part you're threading
to the proper angle, but only if you don't force it or resist a change in angle.
Don't put a wrench on the part until it has been tightened a couple of turns by
hand. If you suddenly encounter resistance, and the part has not seated fully,
don't force it. Pull it back out to make sure it's clean and threading properly.
1 -4 G ENERAL I N FORMAT ION AND BOAT ING SAFETY
BOATING SAFETY
In 1 971 Congress ordered the U .S. Coast Guard to improve recreational
boating safety. In response, the Coast Guard drew up a set of regulations.
Beside these federal regulations, there are state and local laws you must fol­
low. These sometimes exceed the Coast Guard requirements. This section dis­
cusses only the federal laws. State and local laws are avai lable from your local
Coast Guard. As with other laws, "Ignorance of the boating laws is no excuse."
The rules fall into two groups: regulations for your boat and requi red safety
equipment on your boat.
Regulations For Your Boat
Most boats on waters within Federal jurisdiction must be registered or docu­
mented. These waters are those that provide a means of transportation between
two or more states or to the sea. They also include the territorial waters of the
Un ited States.
DOCUMENTING OF VESSELS
A vessel of five or more net tons may be documented as a yacht. In this
process, papers are issued by the U.S. Coast Guard as they are for large ships.
Documentation is a form of national registration. The boat must be used solely
for pleasure. Its owner must be a U.S. citizen, a partnership of U.S. citizens, or a
corporation contro l led by U.S. citizens. The captain and other officers must also
be U.S. citizens. The crew need not be.
If you document your yacht, you have the legal authority to fly the yacht
ensign. You also may record b i l ls of sale, mortgages, and other papers of title
with federal authorities. Doing so gives legal notice that such instruments exist.
Documentation also permits preferred status for mortgages. This gives you
additional security and aids financing and transfer of title. You must carry the
original documentation papers aboard your vessel. Copies wi l l not suffice.
REGISTRATION OF BOATS
If your boat is not documented, registration in the state of its principal use is
probably required. If you use it mainly on an ocean, a gulf, or other simi lar
water, register it in the state where you moor it.
If you use your boat solely for racing, it may be exempt from the requirement
in your state. States may also exclude dinghies. Some require registration of
documented vessels and non-power driven boats.
All states, except Alaska, register boats. In Alaska, the U.S. Coast Guard issues
the registration numbers. If you move your vessel to a new state of principal use, a
valid registration certificate is good for 60 days. You must have the registration
certificate (certificate of number) aboard your vessel when it is in use. A copy wil l
not suffice. You may be cited if you do not have the original on board.
NUMBERING OF VESSELS
A registration number is on your registration certificate. You must paint or
permanently attach this number to both sides of the forward half of your boat.
Do not display any other number there.
The registration number must be clearly visible. lt must not be placed on the
obscured underside of a flared bow. If you can't place the number on the bow,
place it on the forward half of the hu l l . If that doesn't work, put it on the super­
structure. Put the number for an inflatable boat on a bracket or fixture. Then,
firmly attach it to the forward half of the boat. The letters and numbers must be
plain block characters and must read from left to right. Use a space or a hyphen
to separate the prefix and suffix letters from the numerals. The col or of the char­
acters must contrast with that of the background, and they must be at least three
inches high.
In some states your registration is good for only one year. In others, it is
good for as long as three years. Renew your registration before it expires. At
that time you wil l receive a new decal or decals. Place them as requi red by state
law. You should remove old decals before putting on the new ones. Some states
require that you show only the current decal or decals. If your vessel is moored,
it must have a current decal even if it is not in use.
If your vessel is lost, destroyed, abandoned, stolen, or transferred, you must
inform the issuing authority. If you lose your certificate of number or your
address changes, notify the issuing authority as soon as possible.
SALES AND TRANSFERS
Your registration number is not transferable to another boat. The number
stays with the boat unless its state of principal use is changed.
HULL IDENTIFICATION NUMBER
A Hull Identification Number (HIN) is l i ke the Vehicle Identification Number
(VIN) on your car. Boats bui lt between November 1 , 1 972 and July 31 , 1 984
have old format HINs. Since August 1 , 1 984 a new format has been used.
Your boat's HIN must appear in two places. If it has a transom, the primary num­
ber is on its starboard side within two inches of its top. If it does not have a tran­
som or if it was not practical to use the transom, the number is on the starboard
side. In this case, it must be within one foot of the stern and within two inches of
the top of the hul l side. On pontoon boats, it is on the aft crossbeam within one foot
of the starboard hul l attachment. Your boat also has a duplicate nurnber in an unex­
posed location. This is on the boat's interior or under a fitting or item of hardware.
LENGTH OF BOATS
For some purposes, boats are classed by length. Required equipment, for
example, differs with boat size. Manufacturers may measure a boat's length i n
several ways. Officially, though, your boat is measured along a straight l ine from
its bow to its stern. This l i ne is paral lel to its keel.
The length does not include bowsprits, boomkins, or pulpits. Nor does it
include rudders, brackets, outboard motors, outdrives, diving p latforms, or
other attachments.
CAPACITY INFORMATION
t See Figure 4
Manufacturers must put capacity plates on most recreational boats less than
20 feet long. Sailboats, canoes, kayaks, and inflatable boats are usually exempt.
Outboard boats must display the maximum permitted horsepower of their
engines. The p lates must also show the al lowable maximum weights of the peo­
ple on board. And they must show the al lowable maximum combined weights of
people, engines, and gear. In boards and stern drives need not show the weight
of their engines on their capacity p lates. The capacity plate must appear where it
is clearly visible to the operator when underway. This information serves to
remind you of the capacity of your boat under normal c i rcumstances. You
should ask yourself, "Is my boat loaded above its recommended capacity" and,
"Is my boat overloaded for the present sea and wind conditions?" If you are
stopped by a legal authority, you may be cited if you are overloaded.
BAHAMA INDUSTRiES, INC.
. -��·.t'�l,NI� Sl: AIII AHEIM, .CAI...If. 92807 •
04701P20
Fig. 4 A U .S. Coast Guard certification plate indicates the amount of
occupants and gear appropriate for safe operation of the vessel
CERTIFICATE OF COMPLIANCE
Manufacturers are required to put compl iance p lates on motorboats greater
than 20 feet in length. The p lates must say, "This boat," or "This equipment
G ENERAL I N FORMATION AND BOAT ING SAFETY 1 -5
compl ies with the U. S. Coast Guard Safety Standards in effect on the date of
certification." Letters and numbers can be no less than one-eighth of an inch
high. At the manufacturer's option, the capacity and compl iance plates may be
combined.
VENTILATION
A cup o f gasol ine spil led in the bi lge has the potential explosive power o f 15
sticks o f dynamite. This statement, commonly quoted over 20 years ago, may be
an exaggeration, however, i t i l l ustrates a fact. Gasoline fumes in the b i lge o f a
boat are highly explosive and a serious danger. They are heavier than air and
will stay in the bilge until they are vented out.
Because of this danger, Coast Guard regulations require ventilation on many
power boats. There are several ways to supply fresh air to engine and gasol ine
tank compartments and to remove dangerous vapors. Whatever the choice, it
must meet Coast Guard standards.
,.. The following is not intended to be a complete discussion of the regu­
lations. lt is l imited to the majority of recreational vessels. Contact your
local Coast Guard office for further information.
General Precautions
Ventilation systems will not remove raw gasol ine that leaks from tanks or fuel
l ines. If you smel l gasol ine fumes, you need immediate repairs. The best device
for sensing gasol ine fumes is your nose. Use it! If you smel l gasol ine in an
engine compartment or elsewhere, don't start your engine. The smaller the com­
partment, the less gasol ine it takes to make an explosive mixture.
Ventilation for Open Boats
In open boats, gasol ine vapors are dispersed by the air that moves through
them. So they are exempt from ventilation requirements.
To be "open," a boat must meet certain conditions. Engine and fuel tank
compartments and long narrow compartments that join them must be open to
the atmosphere." This means they must have at least 1 5 square inches of open
area for each cubic foot of net compartment volume. The open area must be in
d i rect contact with the atmosphere. There must also be no long, unventi lated
spaces open to engine and fuel tank compartments into which flames cou ld
extend.
Ventilation for All Other Boats
Powered and natural ventilation are required in an enclosed compartment
with a permanently installed gasol ine engine that has a cranking motor. A com­
partment is exempt if its engine is open to the atmosphere. Diesel powered
boats are also exempt.
VENTILATION SYSTEMS
There are two types of venti lation systems. One is "natural venti lation." In it,
air circulates through closed spaces due to the boat's motion. The other type is
"powered ventilation . " In it, air is circu lated by a motor driven fan or fans.
Natural Ventilation System Requirements
A natural ventilation system has an air supply from outside the boat. The air
supply may also be from a venti lated compartment or a compartment open to
the atmosphere. Intake openings are required. In addition, i ntake ducts may be
requi red to d i rect the ai r to appropriate compartments.
The system must also have an exhaust duct that starts in the lower third of the
compartment. The exhaust opening must be into another venti lated compartment
or into the atmosphere. Each supply opening and supply duct, if there is one,
must be above the usual level of water in the bilge. Exhaust openings and ducts
must also be above the bilge water. Openings and ducts must be at least three
square inches in area or two inches in diameter. Openings should be placed so
exhaust gasses do not enter the fresh air intake. Exhaust fumes must not enter
cabins or other enclosed, non-ventilated spaces. The carbon monoxide gas in
them is deadly.
Intake and exhaust openings must be covered by cowls or similar devices. These
registers keep out rain water and water from breaking seas. Most often, intake registers face forward and exhaust openings aft. This aids the flow of air when the boat is
moving or at anchor since most boats face into the wind when anchored.
Power Ventilation System Requirements
• See Figure 5
Powered ventilation systems must meet the standards of a natural system.
They must also have one or more exhaust blowers. The b lower duct can serve
as the exhaust duct for natural ventilation if fan blades do not obstruct the air
flow when not powered. Openings in engine compartment, for carburetion are in
addition to ventilation system requirements.
04891P17
Fig. 5 Typical blower and duct system to vent fumes from the engine
compartment
Required Safety Equipment
Coast Guard regulations requ i re that your boat have certain equipment
aboard. These requirements are min imums. Exceed them whenever you can.
TYPES OF FIRES
There are four common c lasses of fires:
• Class A-fires are in ordinary combustible materials such as paper or wood.
• Class B-fires involve gasol i ne, o i l and grease.
• Class C-fires are electrical.
• Class D-fires involve ferrous metals
One of the greatest risks to boaters is fire. This is why it is so important to
carry the correct number and type of extinguishers on board.
The best fire extinguisher for most boats is a C lass B extinguisher. Never
use water on C lass B or Class C fires, as water spreads these types of fires.
You should never use water on a C lass C fire as it may cause you to be elec­
trocuted.
FIRE EXTINGUISHERS
• See Figure 6
If your boat meets one or more of the following conditions, you must have at
least one fire extinguisher aboard. The conditions are:
• I nboard or stern drive engines
• C losed compartments under seats where portable fuel tanks can be stored
• Double bottoms not sealed together or not completely fi l led with flotation
materials
• C losed living spaces
• Closed stowage compartments in which combustible or flammable materi­
als are stored
1 -6 G ENERAL I NFORMAT ION AND BOATI NG SAFETY
04701P29
Fig . 6 An approved fire extinguisher should be mounted close to the
operator for emergency use
• Permanently installed fuel tanks
• Boat is 26 feet or more in length.
Contents of Extinguishers
Fire extinguishers use a variety of materials. Those used on boats usually
contain dry chemicals, Halon, or Carbon Dioxide (C03). Dry chemical extin­
guishers contain chemical powders such as Sod ium Bicarbonate-baking
soda.
Carbon dioxide is a colorless and odorless gas when released from an extin­
guisher. it is not poisonous but caution must be used in entering compartments
fil l ed with it. it wi l l not support life and keeps oxygen from reaching your lungs.
A fire-ki l l ing concentration of Carbon Dioxide is lethal. If you are i n a compart­
ment with a high concentration of C03, you wi l l have no difficu lty breathing. But
the air does not contain enough oxygen to support life. Unconsciousness or
death can resu it.
HALON EXTINGUISHERS
Some fire extingu ishers and 'bui lt-in' or 'fixed' automatic fire extinguish­
ing systems contain a gas cal l ed Halon. Like carbon d ioxide it is colorless
and odorless and wi l l not support l ife. Some Halons may be toxic if in­
haled.
To be accepted to the Coast Guard, a fixed Halon system must have an indi­
cator l ight at the vessel's helm. A green light shows the system is ready. Red
means it is being discharged or has been discharged. Warning horns are avail­
able to let you know the system has been activated. If your fixed Halon system
discharges, venti late the space thoroughly before you enter it. There are no
residues from Halon but it wi l l not support life.
Although Halon has excel l ent fire fighting properties, it is thought to deplete
the earth's ozone layer and has not been manufactured since January 1 , 1 994.
Ha ion extingu ishers can be refi l led from existing stocks of the gas until they are
used up, but high federal excise taxes are being charged for the service. If you
discontinue using your Halon extinguisher, take it to a recovery station rather
than releasing the gas into the atmosphere. Compounds such as FE 241 ,
designed to replace Halon, are now avai lable.
Fire Extinguisher Approval
Fire extinguishers must be Coast Guard approved. Look for the approval num­
ber on the nameplate. Approved extinguishers have the following on their labels:
"Marine Type USCG Approved, Size . . . , Type . . . , 1 62.208/," etc. In addi­
tion, to be acceptable by the Coast Guard, an extinguisher must be in serviceable
condition and mounted in its bracket. An extinguisher not properly mounted in
its bracket wi l l not be considered serviceable during a Coast Guard inspection.
Care and Treatment
Make certain your extinguishers are i n their stowage brackets and are not
damaged. Replace cracked or broken hoses. Nozzles should be free of obstruc­
tions. Sometimes, wasps and other i nsects nest inside nozzles and make them
inoperable. Check your extinguishers frequently. If they have pressure gauges,
is the pressure within acceptable l im its? Do the locking pins and sealing wires
show they have not been used since recharging?
Don't try an extinguisher to test it. Its valves wi l l not reseal properly and the
remaining gas wi l l leak out. When this happens, the extinguisher is useless.
Weigh and tag carbon dioxide and Halon extingu ishers twice a year. If their
weight loss exceeds 10 percent of the weight of the charge, recharge them.
Check to see that they have not been used. They should have been inspected by
a qualified person within the past six months, and they should have tags show­
ing al l inspection and service dates. The problem is that they can be partially
discharged whi le appearing to be ful ly charged.
Some Halon extinguishers have pressure gauges the same as dry chemical
extingu ishers. Don't rely too heavily on the gauge. The extinguisher can be par­
tially discharged and sti l l show a good gauge reading. Weighing a Halon extin­
guisher is the only accurate way to assess its contents.
If your dry chemical extinguisher has a pressure indicator, check it fre­
quently. Check the nozzle to see if there is powder in it. If there is, recharge it.
Occasionally invert your dry chemical extinguisher and hit the base with the
palm of your hand. The chemical in these extinguishers packs and cakes due
to the boat's vibration and pounding. There is a difference of opin ion about
whether hitting the base helps, but it can't hurt. it is known that caking of the
chemical powder is a major cause of failure of dry chemical extinguishers.
Carry spares in excess of the minimum requirement. If you have guests
aboard, make certain they know where the extinguishers are and how to use
them.
Using a Fire Extinguisher
A fire extinguisher usually has a device to keep it from being discharged
accidentally. This is a metal or plastic pin or loop. If you need to use your extin­
guisher, take it from its bracket. Remove the pin or the loop and point the nozzle
at the base of the flames. Now, squeeze the handle, and discharge the extin­
guisher's contents wh i le sweeping from side to side. Recharge a used extin­
guisher as soon as possib le .
If you are using a Halon or carbon dioxide extingu isher, keep your hands
away from the discharge. The rapidly expanding gas wi l l freeze them. If your fire
extinguisher has a horn, hold it by its handle.
legal Requirements for Extinguishers
You must carry fire extingu ishers as defined by Coast Guard regulations.
They must be firmly mounted in their brackets and immediately accessible.
A motorboat less than 26 feet long must have at least one approved hand­
portable , Type B-1 extinguisher. If the boat has an approved fixed fire extin­
guishing system, you are not required to have the Type B-1 extinguisher. Also, if
your boat is less than 26 feet long, is propelled by an outboard motor, or
motors, and does not have any of the first six conditions described at the begin­
ning of this section, it is not required to have an extinguisher. Even so, it's a
good idea to have one, especially if a nearby boat catches fire, or if a fire occurs
at a fuel dock.
A motorboat 26 feet to under 40 feet long, must have at least two Type B-1
approved hand-portable extinguishers. it can, instead, have at least one Coast
Guard approved Type B-2. If you have an approved fire extinguishing system,
only one Type B-1 is required.
A motorboat 40 to 65 feet long must have at least three Type B-1 approved
portable extinguishers . it may have, instead, at least one Type B-1 plus a Type
B-2. If there is an approved fixed fire extinguishing system, two Type B-1 or one
Type B-2 is required.
G ENERAL I N FORMAT ION AND BOAT ING SAFETY 1 -7
WARNING SYSTEM
Various devices are available to alert you to danger. These include fire,
smoke, gasoline fumes, and carbon monoxide detectors. If your boat has a gal­
ley, it should have a smoke detector. Where possible, use wired detectors.
Household batteries often corrode rapidly on a boat.
You can't see, smel l , nor taste carbon monoxide gas, but it is lethal. As little
as one part in 1 0,000 parts of air can bring on a headache. The symptoms of
carbon monoxide poisoning-headaches, dizziness, and nausea-are l ike sea
sickness. By the time you realize what is happen ing to you, it may be too late to
take action. If you have enclosed living spaces on your boat, protect yourself
with a detector. There are many ways in which carbon monoxide can enter your
boat.
PERSONAL FLOTATION DEVICES
Personal Flotation Devices (PFDs) are commonly called l ife preservers or life
jackets. You can get them in a variety of types and sizes. They vary with their
intended uses. To be acceptable, they must be Coast Guard approved.
Type I PFDs
A Type I life jacket is also called an offshore life jacket. Type I life jackets wi l l
turn most unconscious people from facedown to a vertical or sl ightly backward
position. The adult size gives a min imum of 22 pounds of buoyancy. The chi ld
size has at least 11 pounds. Type I jackets provide more protection to their
wearers than any other type of life jacket. Type I l ife jackets are bulkier and less
comfortable than other types. Furthermore, there are only two sizes, one for
chi ldren and one for adults.
Type I life jackets will keep their wearers afloat for extended periods in rough
water. They are recommended for offshore cruising where a delayed rescue is
probable .
Type 1 1 PFDs
• See Figure 7
A Type !I life jacket is also called a near-shore buoyant vest. lt is an
approved, wearable device. Type !I l ife jackets wi l l turn some unconscious peo­
ple from facedown to vertical or sl ightly backward positions. The adult size
gives at least 1 5.5 pounds of buoyancy. The medium chi ld size has a min imum
of 1 1 pounds. And the small child and infant sizes give seven pounds. A Type 11
l ife jacket is more comfortable than a Type I but it does not have as much buoy­
ancy. lt is not recommended for long hours in rough water. Because of this,
Type l is are recommended for inshore and inland cruising on calm water. Use
them where there is a good chance of fast rescue.
04891P07
Fig. 7 Type 11 approved flotation devices are recommended for
inshore and inland cruising on calm water. Use them where there is
a good chance of fast rescue
Type I l l PFDs
Type Ill life jackets or marine buoyant devices are also known as flotation
aids. Like Type lis, they are designed for calm inland or close offshore water
where there is a good chance of fast rescue. Their min imum buoyancy is 1 5.5
pounds. They wi l l not turn their wearers face up.
Type I l l devices are usually worn where freedom of movement is necessary.
Thus, they are used for water ski ing, small boat sail ing, and fishing among
other activities. They are available as vests and flotation coats. Flotation coats
are useful in cold weather. Type I l ls come in many sizes from small chi ld
through large adult.
Life jackets come in a variety of colors and patterns-red, b lue, green,
camouflage , and cartoon characters . From a safety standpoint, the best color
is br ight orange. l t is easier to see i n the water, especially if the water is
rough.
Type IV PFDs
• See Figures 8 and 9
Type IV ring life buoys, buoyant cushions and horseshoe buoys are Coast
Guard approved devices called throwables. They are made to be thrown to peo­
p le in the water, and should not be worn. Type IV cushions are often used as
04891P09
Fig. 8 Type IV buoyant cushions are made to be thrown to people in
the water. If you can squeeze air out of the cushion, it is faulty and
should be replaced
04891P10
Fig. 9 Type IV throwables, such as this ring life buoy, are not
designed as personal flotation devices for unconscious people, non­
swimmers, or children
1 -8 G ENERAL I NFORMATIO N AND BOATI NG SAFETY
seat cushions. Cushions are hard to hold onto in the water. Thus, they do not
afford as much protection as wearable life jackets.
The straps on buoyant cushions are for you to hold onto either in the water
or when throwing them. A cushion should never be worn on your back. it wi l l
turn you face down in the water.
Type IV throwables are not designed as personal flotation devices for uncon­
scious people, non-swimmers, or children. Use them only in emergencies. They
should not be used for, long periods i n rough water.
Ring life buoys come in 18 , 20, 24, and 30 inch diameter sizes. They have
grab l i nes. You should attach about 60 feet of polypropylene l i ne to the grab
rope to aid in retrieving someone in the water. If you throw a ring, be careful not
to hit the person. Ring buoys can knock people unconscious
Type V PFDs
Type V PFDs are of two kinds, special use devices and hybrids. Special use
devices include boardsai l ing vests, deck suits, work vests, and others. They
are approved only for the special uses or conditions indicated on their labels.
Each is designed and intended for the particular appl ication shown on its labe l .
They do not meet legal requirements for general use aboard recreational boats.
Hybrid life jackets are inflatable devices with some bui lt-in buoyancy pro­
vided by plastic foam or kapok. They can be inflated orally or by cylinders of
compressed gas to give additional buoyancy. In some hybrids the gas is
released manual ly. In others it is released automatically when the life jacket is
immersed in water.
The inherent buoyancy of a hybrid may be insufficient to float a person
unless it is inflated. The only way to find this out is for the user to try it in the
water. Because of its l imited buoyancy when deflated, a hybrid is recommended
for use by anon-swimmer only if it is worn with enough inflation to float the
wearer.
If they are to count against the legal requirement for the number of life jack­
ets you must carry on your vessel , hybrids manufactured before February 8,
1 995 must be worn whenever a boat is underway and the wearer is not below
decks or in an enclosed space. To find out if your Type V hybrid must be worn
to satisfy the legal requirement, read its label. If its use is restricted it will say,
"REQUIRED TO BE WORN" in capital letters.
Hybrids cost more than other life jackets, but this factor must be weighed
against the fact that they are more comfortable than Type I , 11, or Ill life jackets.
Because of their greater comfort, their owners are more l ikely to wear them than
are the owners of Type I, 11, or I l l life jackets.
The Coast Guard has determined that improved, less costly hybrids can save
l ives since they wi l l be bought and used more frequently. For these reasons a
new federal regulation was adopted effective February 8, 1 995. The regulation
i ncreases both the deflated and inflated buoyancys of hybrids, makes them
available in a greater variety of sizes and types, and reduces their costs by
reducing production costs.
Even though it may not be required, the wearing of a hybrid or a life jacket is
encouraged whenever a vessel is underway. Like life jackets, hybrids are now
available in three types. To meet legal requirements, a Type I hybrid can be sub­
stituted for a Type I life jacket. Similarly Type 1 1 and I l l hybrids can be substi­
tuted for Type 11 and Type Ill life jackets. A Type I hybrid, when inflated, will turn
most unconscious people from facedown to vertical or sl ightly backward posi­
tions just l i ke a Type I life jacket. Type I and I l l hybrids function l i ke Type 11 and
Ill life jackets. If you purchase a new hybrid, it should have an owner's manual
attached which describes its life jacket type and its deflated and inflated buoyan­
cys. it warns you that it may have to be inflated to float you. The manual also
tells you how to don the life jacket and how to inflate it. it also tells you how to
change its inflation mechanism, recommended testing exercises, and inspection
and maintenance procedures. The manual also tells you why you need a l ife
jacket and why you should wear it. A new hybrid must be packaged with at least
three gas cartridges. One of these may already be loaded into the inflation
mechanism. Likewise, if it has an automatic inflation mechanism, it must be
packaged with at least three of these water sensitive elements. One of these ele­
ments may be instal led.
legal Requirements
A Coast Guard approved life jacket must show the manufacturer's name and
approval number. Most are marked as Type I , 11, I l l , IV, or V. All of the newer
hybrids are marked for type.
You are required to carry at least one wearable life jacket or hybrid for each
person on board your recreational vessel. If your vessel is 16 feet or more in
length and is not a canoe or a kayak, you must also have at least one Type IV on
board. These requirements apply to all recreational vessels that are propelled or
control led by machinery, sails, oars, paddles, poles, or another vessel . Sail­
boards are not required to carry life jackets.
You can substitute an older Type V hybrid for any required Type I, 11, or I l l life
jacket provided that its approval label shows it is approved for the activity the
vessel is engaged in, approved as a substitute for a l ife jacket of the type
required on the vessel, used as required on the labels, and used in accordance
with any requirements in its owner's manual, if the approval label makes refer­
ence to such a manual.
A water skier being towed is considered to be on board the vessel when
judging compl iance with legal requirements.
You are required to keep your Type I , 11, or I l l life jackets or equivalent
hybrids readily accessible, which means you must be able to reach out and get
them when needed. All life jackets must be in good, serviceable condition.
General Considerations
The proper use of a life jacket requires the wearer to know how it wi l l perform.
You can gain this knowledge only through experience. Each person on your boat
should be assigned a life jacket. Next, it should be fitted to the person who wi l l
wear it. Only then can you be sure that i t wi l l be ready for use in a n emergency.
Boats can sink fast. There may be no time to look around for a life jacket. Fit­
ting one on you in the water is almost impossible. This advice is good even if
the water is calm, and you intend to boat near shore. Most drownings occur in
in land waters within a few feet of safety. Most victims had life jackets, but they
weren't wearing them.
Keeping life jackets in the plastic covers they came wrapped in and in a
cabin assures that they wi l l stay clean and unfaded. But this is no way to keep
them when you are on the water. When you need a life jacket it must be readi ly
accessible and adjusted to f i t you. You can't spend t ime hunting for it or learn­
ing how to fit it.
There is no substitute for the experience of entering the water whi le wearing a
life jacket. Ch i ldren, especially, need practice. If possible, give, your guests this
experience. Tel l them they should keep their arms to their sides when jumping
in to keep the life jacket from riding up. Let them jump in and see how the life
jacket responds. Is it adjusted so it does not ride up? Is it the proper size? Are
all straps snug? Are chi ldren's life jackets the right sizes for them? Are they
adjusted properly? If a ch i ld's life jacket fits correctly, you can l ift the chi ld by
the jacket's shoulder straps and the chi ld's chin and ears will not slip through.
Non-swimmers, ch i ldren, handicapped persons, elderly persons and even pets
should always wear life jackets when they are aboard. Many states require that
everyone aboard wear them in hazardous waters.
Inspect your lifesaving equipment from time to time. Leave any questionable
or unsatisfactory equipment on shore. An emergency is no time for you to con­
duct an inspection.
Indel ibly mark your l ife jackets with your vessel's name, number, and cal l ing
port. This can be important i n a search and rescue effort. it could help concen­
trate effort where it will do the most good.
Care of life Jackets
Given reasonable care, life jackets last many years. Thoroughly dry them
before putting them away. Stow them in dry, wel l ventilated places. Avoid the
bottoms of lockers and deck storage boxes where moisture may col lect. Air and
dry them frequently.
Life jackets should not be tossed about or used as fenders or cushions. Many
contain kapok or fibrous g lass material enclosed in plastic bags. The bags can rup­
ture and are then unserviceable. Squeeze your life jacket gently. Does air leak out? If
so, water can leak in and it wil l no longer be safe to use. Cut it Up so no one wil l
use it, and throw it away. The covers of some l ife jackets are made of nylon or poly­
ester. These materials are plastics. Like many plastics, they break down after
extended exposure to the u ltraviolet light in sunl ight. This process may be more
rapid when the materials are dyed with bright dyes such as "neon" shades.
Ripped and badly faded fabric are clues that the covering of your life jacket is
deteriorating. A simple test is to pinch the fabric between your thumbs and fore­
fingers. Now try to tear the fabric. If it can be torn, it should definitely be
destroyed and discarded. Compare the colors in protected places to those
exposed to the sun. If the colors have faded, the materials have been weakened.
A fabric covered life jacket should ordinarily last several boating seasons with
normal use. A life jacket used every day in di rect sunl ight should probably be
replaced more often .
G ENERAL I N FORMAT ION AND BOATING SAFETY 1 -9
SOUND PRODUCING DEVICES
All boats are required to carry some means of making an efficient sound sig­
nal. Devices for making the whistle or horn noises required by the Navigation
Rules must be capable of a four second blast. The blast should be audib le for at
l east one-half mi le . Athletic whistles are not acceptable on boats 1 2 meters or
longer. Use caution with athletic whistles. When wet, some of them come apart
and loose their "pea." When this happens, they are useless.
If your vessel is 12 meters long and less than 20 meters, you must have a power
whistle (or power horn) and a bell on board. The bell must be in operating condi­
tion and have a minimum diameter of at least 200 mm (7.9 inches) at its mouth.
VISUAL D ISTRESS SIGNALS
• See Figure 1 0
Visual D istress Signals (VDS) attract attention to your vessel if you need
help. They also help to guide searchers in search and rescue situations. Be sure
you have the right types, and learn how to use them properly.
it is i l legal to fire flares_ improperly. In addition, they cost the Coast Guard
and its Auxil iary many wasted hours in fruitless searches. If you signal a dis­
tress with flares and then someone helps you, p lease let the Coast Guard or the
appropriate Search And Rescue Agency (SAR) know so the distress report wi l l
be canceled.
Recreational boats less than 16 feet long must carry visual distress signals
on coastal waters at n ight. Coastal waters are:
• The ocean (territorial sea)
• The G real Lakes
• Bays or sounds that empty into oceans
• Rivers over two mi les across at their mouths upstream to where they nar­
row to two mi les.
04701G09
Fig. 10 Internationally accepted distress signals
Recreational boats 1 6 feet or longer must carry VDS at all times on coastal
waters. The same requirement applies to boats carrying six or fewer passengers
for hire. Open sailboats less than 26 feet long without engines are exempt in the
daytime as are manually propelled boats. Also exempt are boats in organized
races, regattas, parades, etc. Boats owned in the United States and operating on
the high seas must be equipped with VDS.
A wide variety of signal ing devices meet Coast Guard regulations. For
pyrotechnic devices, a minimum of three must be carried. Any combination can
be carried as long as it adds up to at l east three signals for day use and at least
three signals for night use. Three day/n ight signals meet both requirements. If
possible, carry more than the legal requirement.
,..The American flag flying upside down is a commonly recognized dis­
tress signal. lt is not recognized in the Coast Guard regulations, though.
In an emergency, your efforts would probably be better used in more
effective signaling methods.
Types of VDS
VDS are divided into two groups; daytime and n ighttime use. Each of these
groups is subdivided into pyrotechnic and non-pyrotechnic devices.
DAYTIME NON-PYROTECHNIC SIGNALS
A bright orange flag with a black square over a black circle is the simplest
VDS. it is usable, of course, only in daylight. it has the advantage of being a con­
tinuous signal. A mirror can be used to good advantage on sunny days. it can
attract the attention of other boaters and of aircraft from great d istances. M irrors
are available with holes in their centers to aid in "aiming." In the absence of a
mirror, any shiny object can be used. When another boat is in sight, an effective
VDS is to extend your arms from your sides and move them up and down. Do it
slowly. If you do it too fast the other people may think you are just being friendly.
This simple gesture is seldom misunderstood, and requires no equipment.
DAYTIME PYROTECHNIC DEVICES
Orange smoke is a useful daytime signal. Hand-held or floating smoke flares
are very effective in attracting attention from ai rcraft. Smoke flares don't last
long, and are not very effective in h igh wind or poor vis ib i l ity. As with other
pyrotechn ic devices, use them only when you know there is a possib i l ity that
someone wi l l see the display.
To be usable, smoke flares must be kept dry. Keep them in airtight containers and
store them in dry places. If the "striker" is damp, dry it out before trying to ignite the
device. Some pyrotechnic devices require a forceful "strike" to ignite them.
All hand-held pyrotechnic devices may produce hot ashes or slag when
burn ing. Hold them over the side of your boat in such a way that they do not
burn your hand or drip into your boat.
Nighllime Non-Pyrotechnic Signals
An electric distress l ight is available. This l ight automatically flashes the
international morse code SOS d istress signal ( • • • • • • ) . Flashed four to six
times a minute, it is an unmistakable d istress signal. it must show that it is
approved by the Coast Guard. Be sure the batteries are fresh. Dated batteries
give assurance that they are current.
Under the Inland Navigation Rules, a high intensity white l ight flashing 50-70
times per minute is a distress signal. Therefore, use strobe l ights on i n land
waters only for distress signals.
Nighttime Pyrotechnic Devices
• See Figure 1 1
Aerial and hand-held flares can b e used at night o r in the daytime. Obviously,
they are more effective at n ight.
Currently, the serviceable life of a pyrotechnic device is rated at 42 months
from its date of manufacture. Pyrotechnic devices are expensive. Look at their
dates before you buy them. Buy them with as much time remaining as possible.
Like smoke flares, aerial and hand-held flares may fail to work if they have
been damaged or abused. They wi l l not function if they are or have been wet.
Store them in dry, airtight containers in dry places. But store them where they
are read ily accessible.
Aerial VDSs, depending on their type and the conditions they are used in,
may not go very high. Again, use them only when there is a good chance they
wi l l be seen.
1 -1 0 G ENERAL I N FORMAT ION AND BOAT ING SAFETY
04701P17
Fig. 11 Moisture protected flares should be carried onboard any
vessel for use as a distress signal
A serious disadvantage of aerial flares is that they burn for only a short time.
Most burn for less than 10 seconds. Most parachute flares burn for less than 45
seconds. If you use a VDS in an emergency, do so careful ly. Hold hand-held
flares over the side of the boat when in use. Never use a road hazard flare on a
boat, it can easily start a fire. Marine type flares are carefu l ly designed to lessen
risk, but they sti l l must be used carefu l ly.
Aerial flares should be given the same respect as firearms since they are
firearms! Never point them at another person. Don't a l low children to play with
them or around them. When you fire one, face away from the wind. Aim it down­
wind and upward at an angle of about 60 degrees to the horizon. If there is a
strong wind, aim it somewhat more vertically. Never fire it straight up . Before
you discharge a flare pistol , check for overhead obstructions. These might be
damaged by the flare. They might deflect the flare to where it wil l cause damage.
Disposal of VDS
Keep outdated flares when you get new ones. They do not meet legal require­
ments, but you might need them sometime, and they may work. lt is i l legal to
fire a VDS on federal navigable waters un less an emergency exists. Many states
have similar laws.
Emergency Position Indicating Radio Beacon (EPIRB)
There is no requirement for recreational boats to have EPIRBs. Some com­
mercial and fishing vessels, though, must have them if they operate beyond the
three mile limit. Vessels carrying six or fewer passengers for hire must have
EPIRBs under some circumstances when operating beyond the three mile limit.
If you boat in a remote area or offshore, you should have an EPIRB. An EPIRB
is a small (about 6 to 20 inches high), battery-powered, radio transmitting
buoy-like device. lt is a radio transmitter and requires a license or an endorse­
ment on your radio station license by the Federal Communications Commis­
sion (FCC). EPIRBs are activated by being immersed in water or by a manual
switch.
Equipment Not Required But Recommended
Although not required by law, there are other pieces of equipment that are
good to have onboard.
SECOND MEANS OF PROPULSION
• See Figure 1 2
All boats less than 1 6 feet long should carry a second means o f propulsion.
A paddle or oar can come in handy at times. For most small boats, a spare
trolling or outboard motor is an excel lent idea. If you carry a spare motor, it
should have its own fuel tank and starting power. If you use an e lectric tro l ling
motor, it should have its own battery.
04701P33
Fig. 1 2 A typical wooden oar should be kept onboard as an auxiliary
means of propulsion. lt can also function as a grab hook for some­
one fallen overboard
BAILING DEVICES
All boats should carry at least one effective manual bailing device in addition
to any instal led electric bilge pump. This can be a bucket, can, scoop, hand oper­
ated pump, etc. If your battery "goes dead" it wil l not operate your e lectric pump.
FIRST AID KIT
• See Figure 1 3
All boats should carry a first aid kit. l t should contain adhesive bandages,
gauze, adhesive tape, antiseptic, aspirin, etc. Check your first aid kit from time
to time. Replace anything that is outdated. lt is to your advantage to know how
to use your first aid kit. Another good idea would be to take a Red Cross first
aid course.
ANCHORS
• See Figure 1 4
Al l boats should have anchors. Choose one of suitable size for your boat.
Better sti l l , have two anchors of different sizes. Use the smaller one in calm
Fig. 13 Always carry an adequately stocked first aid kit on board for
�he safety of the crew and guests
G ENERAL I NFORMATIO N AND BOATI NG SAFETY 1 -1 1
04891P14
Fig. 14 Choose an anchor of sufficient weight to secure the boat
without dragging. In some cases separate anchors may be needed
for different situations
water or when anchoring for a short time to fish or eat. Use the larger one when
the water is rougher or for overnight anchoring.
Carry enough anchor line of suitable size for your boat and the waters in
which you wi l l operate. If your engine fails you, the first th ing you usually
should do is lower your anchor. This is good advice in shallow water where you
may be driven aground by the wind or water. it is also good advice in windy
weather or rough water. The anchor wi l l usually hold your bow into the waves.
VHF-FM RADIO
Your best means of summoning help in an emergency or in case of a break­
down is a VHF-FM radio. You can use it to get advice or assistance from the
Coast Guard. In the event of a serious i l lness or injury aboard your boat, the
Coast Guard can have emergency medical equipment meet you ashore.
TOOLS AND SPARE PARTS
• See Figures 1 5 and 1 6
Carry a few tools and some spare parts, and learn how to make minor
repairs. Many search and rescue cases are caused by minor breakdowns that
boat operators could have repaired. If your engine is an inboard or stern drive,
carry spare belts and water pump impel lers and the tools to change them.
Courtesy Marine Examinations
One of the roles of the Coast Guard Auxil iary is to promote recreational boat­
ing safety. This is why they conduct thousands of Courtesy Marine Examina­
tions each year. The auxil iarists who do these examinations are well-trained and
knowledgeable in the field.
These examinations are free and done only at the consent of boat owners. To
pass the examination, a vessel must satisfy federal equipment requ i rements and
certain additional requirements of the coast guard auxil iary. If your vessel does
not pass the Courtesy Marine Examination, no report of the failure is made.
Instead , you will be told what you need to correct the deficiencies. The examiner
wi l l return at your convenience to redo the examination.
If your vessel qualifies, you will be awarded a safety decal. The decal does
not carry any special privileges, it simply attests to your interest in safe boating.
04701P34
Fig. 15 A flashlight with a fresh set of batteries is handy when
repairs are needed at night. lt can also double as a signaling device
Fig. 16 A few wrenches, a screwdriver and maybe a pair of pliers
can be very helpful to make emergency repairs
1 -1 2 G ENERAL I N FORMAT ION AND BOAT ING SAFETY
SAFETY IN SERVICE
lt is virtually impossible to anticipate a l l of the hazards involved with mainte­
nance and service, but care and common sense wi l l prevent most accidents.
The rules of safety for mechanics range from "don't smoke around gasoline,"
to "use the proper tool(s) for the job." The trick to avoiding injuries is to
develop safe work habits and to take every possible precaution. Whenever you
are working on your boat, pay attention to what you are doing. The more you
pay attention to detai ls and what is going on around you, the less l ikely you wi l l
be to hurt yourself or damage your boat.
Do's
• Do keep a fire extinguisher and f i rst aid kit handy.
• Do wear safety g lasses or goggles when cutting, dri l l ing, grinding or pry­
ing, even if you have 20-20 vision. If you wear g lasses for the sake of vision,
wear safety goggles over your regular g lasses.
• Do shield your eyes whenever you work around the battery. Batteries con­
tain sulfuric acid. In case of contact with the eyes or skin , flush the area with
water or a mixture of water and baking soda, then seek immediate medical atten­
tion.
• Do use adequate ventilation when working with any chemicals or haz­
ardous materials.
• Do disconnect the negative battery cable when working on the electrical
system. The secondary ignition system contains EXTREMELY HIGH VOLTAGE.
In some cases it can even exceed 50,000 volts.
• Do follow manufacturer's directions whenever working with potentially
hazardous materials. Most chemicals and fluids are poisonous if taken inter­
nal ly.
• Do properly maintain your tools. Loose hammerheads, mushroomed
punches and chisels, frayed or poorly grounded e lectrical cords, excessively
worn screwdrivers, spread wrenches (open end), cracked sockets, or sl ipping
ratchets can cause accidents.
• Likewise, keep your tools clean; a greasy wrench can s l ip off a bolt head,
ruining the bolt and often harming your knuckles in the process.
• Do use the proper size and type of tool for the job at hand. Do select a
wrench or socket that fits the nut or bolt. The wrench or socket should sit
straight, not cocked.
• Do, when possible, pu l l on a wrench handle rather than push on it, and
adjust your stance to prevent a fal l .
• Do be sure that adjustable wrenches are tightly c losed on the nu t or bolt
and pul led so that the force is on the side of the fixed jaw. Better yet, avoid the
use of an adjustable if you have a fixed wrench that wi l l fit.
• Do strike squarely with a hammer; avoid glancing blows. But, we REALLY
hope you won't be using a hammer much in basic maintenance.
• Do use common sense whenever you work on your boat or motor. If a sit­
uation arises that doesn't seem right, sit back and have a second look. lt may
save an embarrassing moment or potential damage to your beloved boat.
Don'ts
• Don't run the engine in an enclosed area or anywhere else without proper
ventilation-EVER! Carbon monoxide is poisonous; it takes a long time to leave
the human body and you can bui ld up a deadly supply of it in your system by
simply breathing in a little every day. You may not realize you are slowly poi­
soning yourself.
• Don't work around moving parts wh i l e wearing loose clothing . Short
sleeves are much safer than long, loose sleeves. Hard-toed shoes with neo­
prene soles protect your toes and give a better grip on s l ippery surfaces.
Jewel ry, watches, large belt buckles, or body adornment of any kind is not
safe working around any vehicle. Long hair should be tied back under a
hat.
• Don't use pockets for tool boxes. A fall or bump can drive a screwdriver
deep into your body. Even a rag hanging from your back pocket can wrap
around a spinning shaft.
• Don't smoke when working around gasol i ne, cleaning solvent or other
flammable material.
• Don't smoke when working around the battery. When the battery is being
charged, it gives off explosive hydrogen gas. Actually, you shouldn't smoke any­
way. Save the cigarette money and put it into your boat!
• Don't use gasol ine to wash your hands; there are excellent soaps avai l­
able. Gasol ine contains dangerous additives which can enter the body through a
cut or through your pores. Gasoline also removes al l the natural o i ls from the
skin so that bone dry hands will suck up oil and grease.
• Don't use screwdrivers for anyth ing other than driving screws! A screw­
driver used as an prying tool can snap when you least expect it, causing
injuries. At the very least, you'l l ru in a good screwdriver.
TOOLS AND EQUIPMENT 2-2
SAFETY TOOLS 2-2
WORK GLOVES 2-2
EYE AND EAR PROTECTION 2-2
WORK CLOTHES 2-3
CHEMICALS 2-3
LUBRICANTS & PENETRANTS 2-3
SEALANTS 2-4
CLEANERS 2-4
TOOLS 2-5
HAND TOOLS 2-5
SOCKET SETS 2-5
WRENCHES 2-8
PLIERS 2-9
SCREWDRIVERS 2-9
HAMMERS 2-9
_
OTHER COMMON TOOLS 2-1 0
SPECIAL TOOLS 2-10
ELECTRONIC TOOLS 2-10
GAUGES 2-11
MEASURING TOOLS 2-12
M ICROMETERS & CALIPERS 2-12
DIAL INDICATORS 2-13
TELESCOPING GAUGES 2-13
DEPTH GAUG ES 2-13
FASTENERS, MEASUREMENTS AND
CONVERSIONS 2-14
BOLTS, NUTS AND OTHER THREADED
RETAINERS 2-14
TORQUE 2-15
STANDARD AND METRIC
MEASU REMENTS 2-15
SPECIFICATIONS CHARTS
C ONVERSION FACTORS 2-16
2-2 TOO LS AND EQU I PMENT
TOOlS AND EQUIPMENT
Safety Tools
WORK GLOVES
t See Figures 1 and 2
Unless you think scars on your hands are cool, enjoy pain and like wearing ban­
dages, get a good pair of work gloves. Canvas or leather are the best. And yes, we
realize that there are some jobs involving small parts that can't be done while wear­
ing work gloves. These jobs are not the ones usually associated with hand injuries.
A good pair of rubber gloves (such as those usually associated with dish
washing) or vinyl gloves is also a great idea. There are some l iqu ids such as
solvents and penetrants that don't belong on your skin. Avoid burns and rashes.
Wear these g loves.
And lastly, an option. I! you're tired of being greasy and dirty all the time, go
to the drug store and buy a box of disposable latex g loves l ike medical profes­
sionals wear. You can handle greasy parts, perform small tasks, wash parts, etc.
all without getting dirty! These g loves take a surprising amount of abuse without
tearing and aren't expensive. Note however, that it has been reported that some
people are allergic to the latex or the powder used inside some g loves, so pay
attention to what you buy.
EYE AND EAR PROTECTION
t See Figures 3 and 4
Don't begin any job without a good pair of work goggles or impact resistant
glasses! When doing any kind of work, it's a l l too easy to avoid eye injury
through this simple precaution. And don't just buy eye protection and leave it on
the shell. Wear it all the time! Things have a habit of breaking, chipping, splash­
ing, spraying, spl intering and !lying around. And, !or some reason, your eye is
always i n the way!
Fig. 1 Three different types of work gloves. The box contains latex gloves
04892P14
Fig. 2 Latex gloves come in handy when you are doing those messy
jobs
I! you wear vision correcting g lasses as a matter of routine, get a pair made
with polycarbonate lenses. These lenses are impact resistant and are avai lable at
any optometrist.
Often overlooked is hearing protection. Power equipment is noisy! Loud
noises damage your ears. it's as simple as that! The simplest and cheapest form
of ear protection is a pair of noise-reducing ear plugs. Cheap insurance !or your
ears. And, they may even come with their own, cute little carrying case.
More substantial, more protection and more money is a good pair of noise
87933518
04892P08
Fig. 3 Don't begin af!Y job without a good pair of work goggles or
impact resistant g lasses. Also good noise reducing earmuffs are
cheap insurance to protect your hearing
' . . . . . . . . ' . . . . . . . . . � . . . � . . .. . . . . · · : · · . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . ' . . . . . . . . . . . . . . . �· . . . . . . . . . . . . . . . . . . . . . ' ' . . . . . . . . . . . . . . . . . . . . . . . .
: i : i i ! ! � ; i ; ; � ·; ; ; ; � : : � � � ; i : : ; � i � � � f j � : . . . . � . . . � . . . . .
. . . . . . . � . . . . " .
" . . . . . . . . .. . � .
04892P28
Fig. 4 Things have a habit of breaking, chipping, splashing, spray­
ing, splintering and flying around. And, for some reason, your eye
is always in the way
reducing earmuffs. They protecUrom al l but the loudest sounds. Hopefu l ly
those are sounds that you'l l never encounter since they're usual ly associated
with disasters.
WORK CLOTHES
Everyone has "work clothes." Usually these consist of old jeans and a shirt
that has seen better days. That's fine. In addition, a denim work apron is a nice
accessory. it's rugged, can hold some spare bolts, and you don't feel bad wiping
your hands or tools on it . That's what it's for.
When working in cold weather, a one-piece, thermal work outfit is invaluable.
Most are rated to below zero (Fahrenheit) temperatures and are ruggedly con­
structed. Just look at what the marine mechanics are wearing and that should
give you a clue as to what type of clothing is good.
Chemicals
There is a whole range of chemicals that you'll find handy for maintenance
work. The most common types are, lubricants, penetrants and sealers. Keep
these handy on board. There are also many chemicals that are used for detai l ing
or cleaning.
TOOLS AND EQU I PM ENT 2-3
When a particular chemical i s not being used, keep i t capped, upright and i n
a safe place. These substances may b e flammable, may b e irritants o r might
even be caustic and should always be stored properly, used properly and han­
dled with care. Always read and follow a l l label d irections and be sure to wear
hand and eye protection!
LUBRICANTS & PENETRANTS
t See Figure 5
Anti-seize is used to coat certain fasteners prior to installation. This can be
especially helpful when two dissimilar metals are in contact (to he lp prevent
corrosion that might lock the fastener in place). This is a good practice on a lot
of different fasteners, BUT, NOT on any fastener which might vibrate loose caus­
ing a problem. I f anti-seize is used on a fastener, it should be checked periodi­
cally for proper tightness.
Lithium grease, chassis lube, si l icone grease or a synthetic brake caliper
grease can al l be used pretty much interchangeably. All can be used for coating
rust-prone fasteners and for faci l itating the assembly of parts that are a tight fit.
S i l icone and synthetic greases are the most versatile.
,.Silicone dielectric grease is a non-conductor that is often used to coat
the terminals of wiring connectors before fastening them. 11 may sound
odd to coal metal portions of a terminal with something that won't con­
duct electricity, but here is it how it works. When the connector is fas­
tened the metal-to-metal contact between the terminals will displace
the grease (allowing the circuit to be completed). The grease that is dis­
placed will then coat the non-contacted surface and the cavity around
the terminals, SEALING them from atmospheric moisture that could
cause corrosion .
Si l icone spray is a good lubricant for hard-to-reach places and parts that
shouldn't be gooped up with grease.
Penetrating oi l may turn out to be one of your best friends when taking
something apart that has corroded fasteners. Not only can they make a job eas­
ier, they can really help to avoid broken and stripped fasteners. The most fami l­
iar penetrating oi ls are L iqu id Wrench® and WD-40@ A newer penetrant, PB
Blaster® also works wel l . These products have hundreds of uses. For your pur­
poses, they are vital!
Before disassembl ing any part (especial ly on an exhaust system), check
the fasteners. If any appear rusted, soak them thoroughly with the penetrant
and let them stand wh i l e you do something e lse (for particularly rusted or
frozen parts you may need to soak them a few days in advance). This s imple
act can save you hours of ted ious work trying to extract a broken bo l t or
stud.
04892P09
Fig. 5 Antiseize, penetrating oil, lithium grease, electronic cleaner
and silicone spray. These products have hundreds of uses and
should be a part of your chemical tool collection
2-4 TOO LS AND EQU I PMENT
SEALANTS faces of each part to be joined, then a gasket is put in place and the parts are
assembled.
• See Figures 6 and 7
Sealants are an ind ispensable part for certain tasks, especial ly if you
are trying to avoid leaks. The purpose of sealants is to establ ish a leak­
proof bond between or around assembled parts. Most sealers are used in
conjunction with gaskets, but some are used instead of conventional gasket
material .
The most common sealers are the non-hardening types such as
Permatex®No.2 or its equ ivalents. These sealers are applied to the mating surFig. 6 Sealants are essential for preventing leaks
Fig. 7 On some engines, RTV is used instead of gasket material to
seal components
,.A sometimes overlooked use for sealants like RTV is on the threads of
vibration prone fasteners.
One very helpful type of non-hardening sealer is the "high tack" type. This
type is a very sticky material that holds the gasket in place wh i le the parts are
being assembled. This stuff is really a good idea when you don't have enough
hands or fingers to keep everyth ing where it should be.
The stand-alone sealers are the Room Temperature Vulcanizing (RTV) s i l i­
cone gasket makers. On some engines, this material is used instead of a gasket.
87933507
In those instances, a gasket may not be available or, because of the shape of the
mating surfaces, a gasket shouldn't be used. This stuff, when used in conjunc­
tion with a conventional gasket, produces the surest bonds.
RTV does have its l imitations though. When using this material, you wi l l
have a t ime l imit. lt starts to set-up within 1 5 minutes or so, so you have to
assemble the parts without delay. In addition, when squeezing the material out
of the tube, don't drop any glops into the engine. The stuff wi l l form and set and
travel around the o i l gal lery, possibly plugging up a passage. Also, most types
are not fuel-proof. Check the tube for a l l cautions.
CLEANERS
• See Figures 8 and 9
There are two types of c leaners on the market today: parts cleaners and hand
c leaners. The parts cleaners are for the parts; the hand c leaners are for you.
They are not interchangeable.
There are many good, non-flammable, biodegradable parts c leaners on the
market. These cleaning agents are safe for you, the parts and the environment.
Therefore, there is no reason to use flammable, caustic or toxic substances to
c lean your parts or tools.
As far as hand cleaners go, the waterless types are the best. They have
always been efficient at cleaning, but l eave a pretty smelly odor. Recently
87933018
Fig. 8 The new citrus hand cleaners not only work well, but they
smell pretty good too. Choose one with pumice for added cleaning
power
though, just about all of them have e l iminated the odor and added stuff that
actually smells good. Make sure that you pick one that contains lanol in or some
other moisture-replenishing additive. C leaners not only remove grease and o i l
but also sk in o i l .
TOOLS
t See Figure 1 0
Tools; this subject could f i l l a completely separate manual. The first thing
you wi l l need to ask yourself, is just how involved do you plan to get. If you
are serious about your maintenance you wi l l want to gather a quality set of
tools to make the job easier, and more enjoyable. BESIDES, TOOLS ARE
FUN! I !
Almost every do-it-yourselfer loves to accumulate tools. Though most find a
way to perform jobs with only a few common tools, they tend to buy more over
time, as money al lows. So gathering the tools necessary for maintenance does
not have to be an expensive, overnight proposition.
When buying tools, the saying "You get what you pay for . . " is absolutely
true! Don't go cheap! Any hand tool that you buy should be drop forged and/or
chrome vanadium. These two qual ities tel l you that the tool is strong enough for
the job. With any tool, go with a name that you've heard of before, or, that is
TCCX1P08
Fig. 1 0 Socket holders, especially the magnetic type, are handy
items to keep tools in order
TOO LS AND EQU I P M ENT 2-5
04892P12
Fig. 9 The use of hand lotion seals your hands and keeps dirt and
grease from sticking to your skin
�Most women will tell you to use a hand lotion when you're al l cleaned
up. lt's okay. Real men DO use hand lotion! Believe it or not, using hand
lotion before your hands are dirty will actually make them easier to
clean when you're finished with a dirty job. Lotion seals your hands,
and keeps dirt and grease from sticking to your skin.
recommended buy your local professional retai ler. Let's go over a list of tools
that you'll need.
Most of the world uses the metric system. However, some American-built
engines and aftermarket accessories use standard fasteners. So, accumu late
your tools accordingly. Any good DIYer should have a decent set of both U.S.
and metric measure tools.
�Don't be confused by terminology. Most advertising refers to "SAE
and metric", or "standard and metric." Both are misnomers. The Soci­
ety of Automotive Engineers (SAE) did not invent the English system of
measurement; the English did. The SAE likes metrics just fine. Both
English (U.S.) and metric measurements are SAE approved. Also, the
current "standard" measurement IS metric. So, if it's not metric, it's
U.S. measurement.
Hand Tools
SOCKET SETS
t See Figures 1 1 thru 1 7
Socket sets are the most basic hand tools necessary for repair and mainte­
nance work. For our purposes, socket sets come in three drive sizes: % inch,
% inch and 1f2 inch. Drive size refers to the size of the drive lug on the ratchet,
breaker bar or speed handle.
A % inch set is probably the most versati le set in any mechanic's tool box. i t
a l lows you to get into t ight places that the larger drive ratchets can't and gives
you a range of larger sockets that are sti l l strong enough for heavy duty work.
The socket set that you'll need should range in sizes from % inch through 1
inch for standard fasteners, and a 6mm through 1 9mm for metric fasteners.
You' l l need a good 1f2 inch set since this size drive lug assures that you won't
break a ratchet or socket on large or heavy fasteners. Also, torque wrenches with
a torque scale high enough for larger fasteners are usually 1f2 inch drive.
% inch drive sets can be very handy in tight places. Though they usually
dupl icate functions of the % inch set, % inch drive sets are easier to use for
smaller bolts and nuts.
As for the sockets themselves, they come in standard and deep lengths as
well as 6 or 1 2 point. 6 and 1 2 points refers to how many sides are in the
2-6 TOOLS AN D EQU I PM ENT
Fig. 1 1 A 3fs inch socket set i s probably
the most versatile tool in any mechanic's
tool box
Fig. 12 A swivel (U-joint) adapter (left), a
'14 inch-to-% inch adapter (center) and a
3fs inch-to-% inch adapter (right)
Fig . 13 Ratchets come in all s izes and
configurations from rigid to swivel-headed
04892P20
04892P15
Fig. 14 Standard length sockets (top) are
good for just about all jobs. However, some
bolts may require deep sockets (bottom)
Fig. 15 Hex-head fasteners retain many
components on modern powerheads.
These fasteners require a socket with a
hex shaped driver
04892P18
Fig. 1 6 Torx® drivers . . .
04892P19
Fig. 1 7 . . . and tamper resistant drivers are required to remove
special fasteners installed by the manufacturers
socket itself. Each has advantages. The 6 point socket is stronger and less
prone to sl ipping which would strip a bolt head or nut 1 2 point sockets are
more common, usually less expensive and can operate better in tight places
where the ratchet handle can't swing far.
Standard length sockets are good for just about al l jobs, however, some
stud-head bolts, hard-to-reach bolts, nuts on long studs, etc , require the deep
sockets.
Most manufacturers use recessed hex-head fasteners to retain many of the
engine parts. These fasteners require a socket with a hex shaped driver or a
large sturdy hex key. To help prevent torn knuckles, we would recommend that
you stick to the sockets on any tight fastener and leave the hex keys for I ighter
appl ications. Hex driver sockets are avai lable individually or in sets just l ike
conventional sockets.
More and more, manufacturers are using Torx® head fasteners, which were
once known as tamper resistant fasteners (because many people did not have
tools with the necessary odd driver shape). They are sti l l used where the manu­
facturer would prefer only knowledgeable mechanics or advanced Do-lt-Your­
sellers (D IYers) to work.
Torque Wrenches
• See Figure 1 8
I n most appl ications, a torque wrench can be used to assure proper installa­
tion of a fastener. Torque wrenches come in various designs and most stores
wi l l carry a variety to suit your needs. A torque wrench should be used any time
you have a specific torque value for a fastener. Keep in mind that because there
is no worldwide standardization of fasteners, the charts at the end of this section
are a general guideline and should be used with caution. If you are using the
right tool for the job, you shou ld not have to strain to tighten a fastener.
04892P30
Fig. 1 8 Three types of torque wrenches. Top to bottom: a 3fs inch
drive beam type that reads in inch lbs. , a '12 inch drive clicker type
and a % inch drive beam type
BEAM TYPE
• See Figures 1 9 and 20
The beam type torque wrench is one of the most popular styles in use. If
used properly, it can be the most accurate also. lt consists of a pointer attached
to the head that runs the length of the flexible beam (shaft) to a scale located
near the handle. As the wrench is pul led, the beam bends and the pointer indi­
cates the torque using the scale.
POINTER
BEA.M OR MEASURINC ELEMENT
TCCS1039
Fig. 1 9 Parts of a beam type torque wrench
04892P33
Fig. 20 A beam type torque wrench consists of a pointer attached to
the head that runs the length of the flexible beam (shall) to a scale
located near the handle
CLICK (BREAKAWAY) TYPE
• See Figures 21 and 22
Another popular torque wrench design is the click type. The c l icking mecha­
nism makes achieving the proper torque easy and most use ratcheting head for
ease of bolt installation. To use the c l ick type wrench you pre-adjust it to a
torque setting. Once the torque is reached, the wrench has a reflex signaling
feature that causes a momentary breakaway of the torque wrench body, sending
an impulse to the operator's hand.
Breaker Bars
• See Figure 23
Breaker bars are long handles with a drive lug. Their main purpose is to pro­
vide extra turning force when breaking loose tight bolts or nuts. They come in
all drive sizes and lengths. Always take extra precautions and use proper tech­
nique when using a breaker bar.
TOO LS AND EQU IPMENT 2-7
TCCS1040
Fig. 21 A click type or breakaway torque wrench-note this one has
a pivoting head
04892P32
Fig. 22 Selling the proper torque on a click type torque wrench
involves turning the handle until the proper torque specification
appears on the dial
90991P37
Fig. 23 Breaker bars are great for loosening large or stuck fasteners
2-8 TOOLS AND EQU I PM ENT
WRENCHES
• See Figures 24, 25, 26, 27 and 28
Basically, there are 3 kinds of fixed wrenches: open end, box end, and com­
bination.
Open end wrenches have 2-jawed openings at each end of the wrench. These
wrenches are able to fit onto just about any nut or bolt They are extremely ver­
sati le but have one major drawback. They can s l ip on a worn or rounded bolt
head or nut, causing bleeding knuckles and a useless fastener.
Box-end wrenches have a 360° circular jaw at each end of the wrench. They
INCHES DECIMAL
1 /8" . 1 25
3 / 1 6" . 1 87
1 /4" .250
5 / 1 6" .312
3/8" .375
7 / 1 6" .437
1 / 2" .500
9 / 1 6" .562
5/8" .625
1 1 / 1 6" .687
3/4" .750
1 3 / 1 6" .81 2
718" .875
----�1�5�/ 1�6�"----------�·�93�7 _________ (
1 '' 1 .00 -\·
Fig. 24 Comparison of U .S. measure and metric wrench sizes
Fig. 25 Always use a backup wrench to prevent rounding flare nut
fittings
come in both 6 and 12 point versions just l ike sockets and each type has the
same advantages and disadvantages as sockets.
Combination wrenches have the best of both. They have a 2-jawed open end
and a box end. These wrenches are probably the most versatile.
As for sizes, you'l l probably need a range similar to that of the sockets, about
% inch through 1 inch for standard fasteners, or 6mm through 1 9mm for metric
fasteners. As for numbers, you'll need 2 of each size, since, in many instances,
one wrench holds the nut whi l e the other turns the bolt On most fasteners, the
nut and bolt are the same size so having two wrenches of the same s ize comes
in handy.
l'l----------��--------�=----1--------��--------���---
DECIMAL MILLIMETERS
.1 1 8 3mm
. 1 57 4mm
.236 6mm
.354 9mm
.394 1 0mm
.472 1 2mm
.512 1 3mm
.590 1 5mm
.630 1 6mm
.709 1 8mm �·�!· ______ ___:_:....:.:_ _____ __.:__ __ _ .748 1 9mm
.787 20mm !!�-�___:::...:=:._____ .866 22mm
.945 24mm
.984 25mm
87933106
Fig. 26 Note how the flare wrench sides are extended to grip the fit­
ting tighter and prevent rounding
87933005
Fig. 27 Several types and sizes of adjustable wrenches
04892P21
Fig. 28 Occasionally you will find a nut which requires a particularly
large or particularly small wrench. Rest assured that the proper
wrench to fit is available at your local tool store
,..Although you will typically just need the sizes we specified, there are
some exceptions. Occasionally you will find a nut which is larger. For
these, you will need to buy ONE expensive wrench or a very large
adjustable. Or you can always just convince the spouse that we are talk­
ing about safety here and buy a whole (read expensive) large wrench set.
One extremely valuable type of wrench is the adjustable wrench. An
adjustable wrench has a fixed upper jaw and a moveable lower jaw. The lower
jaw is moved by turning a threaded drum. The advantage of an adjustable
wrench is its abi l ity to be adjusted to just about any size fastener.
The main drawback of an adjustable wrench is the lower jaw's tendency to
move sl ightly under heavy pressure. This can cause the wrench to s l ip if it is
not facing the right way. Pul l ing on an adjustable wrench in the proper direction
will cause the jaws to lock in place. Adjustable wrenches come in a large range
of sizes, measured by the wrench length.
PLIERS
• See Figure 29
Pl iers are simply mechanical fingers. They are, more than anything, an
extension of your hand. At least 3 pair of p l iers are an absolute necessity­
standard, needle nose and channel lock.
TOO LS AND EQU I PM ENT
Fig. 29 Pliers and cutters come in many shapes and sizes. You
should have an assortment on hand
2-9
TCCS1203
In addition to standard p l iers there are the s l ip-joint, multi-position p l iers
such as Channel Lock® pl iers and locking pl iers, such as Vise Grips®.
S l ip joint p l iers are extremely valuable in grasping oddly sized parts and fas­
teners. Just make sure that you don't use them instead of a wrench too often
since they can easily round off a bolt head or nut.
Locking p l iers are usually used for gripping bolts or studs that can't be
removed conventionally. You can get locking p l iers in square jawed, needle­
nosed and p ipe-jawed. Locking p l iers can rank right up behind duct tape as the
handy-man's best friend.
SCREWDRIVERS
You can't have too many screwdrivers. They come in 2 basic flavors, either
standard or Ph i l l ips. Standard blades come in various sizes and thicknesses for
all types of slotted fasteners. Phi l l ips screwdrivers come in sizes with number
designations from 1 on up, with the lower number designating the smaller size.
Screwdrivers can be purchased separately or i n sets.
HAMMERS
• See F igure 30
You always need a hammer for just about any kind of work. You need a ball­
peen hammer for most metal work when using drivers and other l ike tools. A
87933008
Fig. 30 Three types of hammers. Top to bottom: bal l peen, rubber
dead-blow, and plastic
2-1 0 TOOLS AND EQU I PM ENT
plastic hammer comes i n handy for hitting things safely. A soft-faced dead-blow
hammer is used for hitting things safely and hard. Hammers are also VERY use­
ful with non air-powered impact drivers.
OTHER COMMON TOOLS
There are a lot of other tools that every DIYer will eventual ly need (though
not all for basic maintenance). They include:
• Funnels (for adding fluid)
• Chisels
• Punches
• Files
• Hacksaw
• Portable Bench Vise
• Tap and Die Set
• Flashlight
• Magnetic Bolt Retriever
• Gasket scraper
• Putty Knife
• Screw/Bolt Extractors
• Prybar
Hacksaws have just one use-cutting things off. You may wonder why you'd
need one for something as simple as maintenance, but you never know. Among
other things, guide studs to ease parts installation can be made from old bolts
with their heads cut off.
A tap and die set might be something you've never needed, but you wi l l
eventually. it's a good rule, when everything is apart, to clean-up al l threads, on
bolts, screws and threaded holes. Also, you'll l i kely run across a situation in
which stripped threads wil l be encountered. The tap and die set wi l l handle that
for you.
Gasket scrapers are just what you'd think, tools made for scraping old gasket
material off of parts. You don't absolutely need one. O ld gasket material can be
removed with a putty knife or single edge razor blade. However, putty knives
may not be sharp enough for some really stubborn gaskets and razor blades
have a knack of breaking just when you don't want them to, inevitably sl icing the
nearest body part! As the old saying goes, "always use the proper tool for the
job". If you're going to use a razor to scrape a gasket, be sure to always use a
blade holder.
Putty knives really do have a use in a repair shop. Just because you remove
all the bolts from a component sealed with a gasket doesn't mean it's going to
come off. Most of the time, the gasket and sealer wi l l hold it tightly. Lightly driv­
ing a putty knife at various points between the two parts wi l l break the seal with­
out damage to the parts.
A small - 8-1 0 inches (20-25 centimeters) long - prybar is extremely
useful for removing stuck parts.
_.Never use a screwdriver as a prybar! Screwdrivers are not meant for
prying. Screwdrivers, used for prying, can break, sending the broken
shalt flying!
Screw/bolt extractors are used for removing broken bolts or studs that have
broke off flush with the surface of the part.
SPECIAL TOOLS
• See Figure 31
Almost every marine engine around today requires at least one special tool to
perform a certain task. In most cases, these tools are special ly designed to over­
come some unique problem or to fit on some oddly sized component.
When manufacturers go through the trouble of making a special too l , it is
usually necessary to use it to assure that the job will be done right. A special
tool might be designed to make a job easier, or it might be used to keep you
from damaging or breaking a part.
Don't worry, MOST basic maintenance procedures can either be performed
without any special tools OR, because the tools must be used for such basic
things, they are commonly avai lable for a reasonable price. lt is usually just the
low production, h ighly special ized tools (like a super thin 7-point star-shaped
Fig. 31 Almost every marine engine requires at least one special
tool to perform a certain task
socket capable of 1 50 ft. lbs. (203 Nm) of torque that is used only on the crank­
shaft nut of the l imited production what-dya-callit engine) that tend to be outra­
geously expensive and hard to find. Luckily, you wi l l probably never need such
a too l .
Special tools can be as inexpensive and s imp le as an adjustable strap
wrench or as compl icated as an ignition tester. A few common specially tools
are l isted here, but check with your dealer or with other boaters for help in
determining if there are any special tools for YOUR particular engine. There is
an added advantage in seeking advice from others, chances are they may have
already found the special tool you wi l l need, and know how to get it cheaper.
ELECTRONIC TOOLS
Battery Testers
The best way to test a non-sealed battery is using a hydrometer to
check the specific gravity of the acid. Lucki ly, these are usual ly i nexpensive
and are avai lable at most parts stores. Just be careful because the larger
testers are usually designed for larger batteries and may require more acid
than you wi l l be able to draw from the battery cel l . Smal ler testers (usually a
short, squeeze bu lb type) wi l l require less acid and should work on most
batteries.
Electronic testers are avai lable and are often necessary to tell if a sealed bat­
tery is usable. Lucki ly, many parts stores have them on hand and are wi l l ing to
test your battery for you.
Battery Chargers
• See Figure 32
If you are a weekend boater and take your boat out every week, then you wi l l
most l ikely want to buy a battery charger to keep your battery fresh. There are
many types avai lable, from low amperage trickle chargers to electronically con­
trolled battery maintenance tools which monitor the battery voltage to prevent
over or undercharging. This last type is especially useful if you store your boat
for any length of time (such as during the severe winter months found in many
Northern c l imates).
Even if you use your boat on a regular basis, you wi l l eventual ly need a bat­
tery charger. Remember that most batteries are shipped dry and in a partial
charged state. Before a new battery can be put into service it must be fil led and
properly charged. Failure to properly charge a battery (which was shipped dry)
before it is put into service wi l l prevent it from ever reaching a ful ly charged
state.
Fig. 32 The Battery Tender'" is more than just a battery charger,
when left connected, it keeps your battery fully charged
Digital Volt/Ohm Meter (DVOM)
• See Figure 33
Multi meters are an extremely useful tool tor troubleshooting electrical prob­
lems. They can be purchased in either analog or digital form and have a price
range to suit any budget. A multimeter is a voltmeter, ammeter and ohmmeter
(along with other features) combined into one instrument. lt is often used when
testing solid state ci rcuits because o! its high input impedance (usually 1 0
megaohms o r more). A brief description o! the multi meter main test !unctions
fol lows:
• Voltmeter-the voltmeter is used to measure voltage at any point in a cir­
cuit, or to measure the voltage drop across any part of a circuit. Voltmeters usu­
ally have various scales and a selector switch to allow the read ing of different
voltage ranges. The voltmeter has a positive and a negative lead. To avoid dam­
age to the meter, always connect the negative lead to the negative (-) side of the
circuit (to ground or nearest the ground side of the circuit) and connect the posiFig. 33 Multi meters are an extremely useful tool for troubleshooting
electrical problems
TOOLS AND EQU I PM ENT 2-1 1
tive lead to the positive (+) side of the circuit (to the power source or the nearest
power source). Note that the negative voltmeter lead wi l l always be black and that
the positive voltmeter wi l l always be some col or other than black (usually red).
• Ohmmeter-the ohmmeter is designed to read resistance (measured in
ohms) in a circuit or component. Most ohmmeters wi l l have a selector switch
which permits the measurement o! different ranges o! resistance (usually the
selector switch al lows the multipl ication o! the meter read ing by 1 0, 1 00, 1 , 000
and 1 0,000). Some ohmmeters are "auto-ranging" which means the meter itself
will determine which scale to use. Since the meters are powered by an internal
battery, the ohmmeter can be used like a self-powered test l ight. When the ohm­
meter is connected, current from the ohmmeter !lows through the circuit or
component being tested. Since the ohmmeter's internal resistance and voltage
are known values, the amount o! current !low through the meter depends on the
resistance of the circuit or component being tested. The ohmmeter can also be
used to perform a continu ity test tor suspected open c i rcuits. In using the meter
tor making continuity checks, do not be concerned with the actual resistance
read ings. Zero resistance, or any ohm reading, indicates continuity in the cir­
cuit. Infinite resistance indicates an opening in the circuit. A high resistance
reading where there should be none indicates a problem in the circuit. Checks
tor short circuits are made in the same manner as checks tor open circuits,
except that the circuit must be isolated from both power and normal ground.
Infinite resistance indicates no continuity, while zero resistance indicates a dead
short.
** WARNING
Never use an ohmmeter to check the resistance of a component o r
wire while there i s voltage applied to the circuit.
• Ammeter-an ammeter measures the amount of current flowing through a
circuit in un its called amperes or amps. At normal operating voltage, most cir­
cuits have a characteristic amount o! amperes, called "current draw" which can
be measured using an ammeter. By referring to a specified current draw rating,
then measuring the amperes and comparing the two values, one can determine
what is happening with in the circuit to aid in diagnosis. An open circuit, tor
example, will not allow any current to !low, so the ammeter reading wi l l be zero.
A damaged component or circuit will have an increased current draw, so the
reading wi l l be high. The ammeter is always connected in series with the circuit
being tested. All o! the current that normally !lows through the circuit must also
!low through the ammeter; it there is any other path tor the current to fol low, the
ammeter reading wi l l not be accurate. The ammeter itself has very little resis­
tance to current !low and, therefore, wi l l not affect the circuit, but it wi l l measure
current draw only when the circuit is closed and e lectricity is flowing. Excessive
current draw can blow !uses and drain the battery, whi le a reduced current draw
can cause motors to run slowly, l ights to dim and other components to not
operate properly.
GAUGES
Compression Gauge
• See Figure 34
An important element in checking the overal l condition o! your engine is to
check compression. This becomes increasingly more important on outboards
with high hours. Compression gauges are available as screw-in types and hold­
in types. The screw-in type is slower to use, but e l iminates the possibil ity o! a
faulty reading due to escaping pressure. A compression reading wi l l uncover
many problems that can cause rough runn ing. Normally, these are not the sort
of problems that can be cured by a tune-up.
Vacuum Gauge
• See Figures 35 and 36
Vacuum gauges are handy tor discovering air leaks, late ignition or valve
timing, and a number o! other problems.
2-1 2 TOO LS AND EQU I PM ENT
Fig. 34 Cylinder compression test results are extremely valuable
indicators of internal engine condition
Fig. 35 Vacuum gauges are useful for many diagnostic tasks includ­
ing testing of some fuel pumps
04892P25
Fig. 36 In a pinch, you can also use the vacuum gauge on a hand
operated vacuum pump
Measuring Tools
Eventually, you are going to have to measure something. To do this, you wi l l
need at l east a few precision tools in addition to the special tools mentioned
earlier.
MICROMETERS & CALIPERS
Micrometers and cal ipers are devices used to make extremely precise
measurements. The s imple truth is that you really won't have the need for
many of these items just for s imple maintenance. You wi l l probably want to
have at l east one precision too l such as an outside cal iper to measure rotors
or brake pads, but that should be sufficient to most basic maintenance pro­
cedures.
Should you decide on becoming more involved i n boat engine mechanics,
such as repair or rebui ld ing, then these tools will become very important. The
success of any rebui ld is dependent, to a great extent on the ability to check the
size and fit of components as specified by the manufacturer. These measure­
ments are made in thousandths and ten-thousandths of an inch.
Micrometers
• See Figure 37
A micrometer is an instrument made up of a precisely machined spindle
which is rotated in a fixed nut, opening and closing the distance between the
end of the spindle and a fixed anvil.
Outside micrometers can be used to check the thickness parts such shims or
the outside diameter of components l ike the crankshaft journals. They are also
used during many rebui ld and repair procedures to measure the diameter of
components such as the pistons. The most common type of micrometer reads
in 1!1 000 of an inch. M icrometers that use a vernier scale can estimate to 1/1 0
of an inch.
Inside micrometers are used to measure the distance between two paral le l
surfaces. For example, in powerhead rebui ld ing work, the inside mike measures
cylinder bore wear and taper. Inside mikes are graduated the same way as out­
side mikes and are read the same way as wel l .
Remember that an inside mike must be absolutely perpendicular to the work
being measured. When you measure with an inside mike, rock the mike gently
from side to side and tip it back and forth sl ightly so that you span the widest
part of the bore. Just to be on the safe side, take several readings. it takes a cer­
tain amount of experience to work any mike with confidence.
Metric micrometers are read in the same way as inch micrometers, except
that the measurements are in mi l l imeters. Each l i ne on the main scale equals 1
mm. Each fifth l i ne is stamped 5, 1 0, 1 5, and so on. Each l i ne on the th imble
scale equals 0.01 mm. it wi l l take a l ittle practice, but if you can read an inch
mike, you can read a metric mike.
Fig. 37 Outside micrometers can be used to measure the thickness
of shims or the outside diameter of a shaft
Gal ipers
• See Figures 38, 39 and 40
Inside and outside calipers are useful devices to have if you need to measure
something quickly and precise measurement is not necessary. Simply take the
reading and then hold the calipers on an accurate steel rule.
DIAL INDICATORS
• See Figure 41
A dial indicator is a gauge that utilizes a dial face and a needle to register
measurements. There is a movable contact arm on the dial indicator. When the
arms moves, the needle rotates on the dial. Dial indicators are calibrated to
show readings in thousandths of an inch and typically, are used to measure
end-play and run out on various parts.
Dial indicators are quite easy to use, although they are relatively expensive. A
variety of mounting devices are available so that the indicator can be used in a
number of situations. Make certain that the contact arm is always paral le l to the
movement of the work bein_g measured.
Fig. 38 Galipers, such as this dial caliper, are the fast and easy way
to make precise measurements
05002P06
Fig. 39 Galipers can also be used to measure depth . . .
TOO LS AND EQU I PM ENT 2-1 3
05002P05
Fig. 40 . . . and inside diameter measurements, usually to 0.001
inch accuracy
Fig. 41 Here, a dial indicator is used to measure the axial clearance
(end play) of a crankshaft during a powerhead rebuilding procedure
TELESCOPING GAUGES
• See Figure 42
A telescope gauge is used during rebui lding procedures (NOT usually basic
maintenance) to measure the inside of bores. it can take the place of an inside
mike for some of these jobs. Simply insert the gauge i n the hole to be measured
and lock the p lungers after they have contacted the walls. Remove the tool and
measure across the plungers with an outside micrometer.
DEPTH GAUGES
• See Figure 43
A depth gauge can be i nserted into a bore or other small hole to determine
exactly how deep it is. One common use for a depth gauge is measuring the
distance the piston sits below the deck of the block at top dead center. Some
outside calipers contain a built-in depth gauge so money can be saved by just
buying one tool.
2-1 4 TOO LS AND EQU I PM ENT
Fig. 42 Telescoping gauges are used during powerhead rebuilding
procedures to measure the inside diameter of bores
FASTENERS, MEASU REMENTS AND CONVERSIONS
Bolts, Nuts and Other Threaded Retainers
• See Figures 44, and 45
Although there are a great variety of fasteners found i n the modern boat
engine, the most commonly used retainer is the threaded fastener (nuts, bolts,
screws, studs, etc). Most threaded retainers may be reused, provided that they
are not damaged in use or during the repair.
P O Z I D R I V E P H I L L I P S R E C E S S
Fig. 43 Depth gauges are used to measure the depth of bore or
other small holes
TCCTIP02
... some retainers (such as stretch bolts or torque prevailing nuts) are
designed to deform when tightened or in use and should not be reused.
Whenever possible, we wi l l note any special retainers which should be
replaced during a procedure. But you should always i nspect the condition of a
retainer when it is removed and you should replace any that show s1gns of dam­
age. Check al l threads for rust or corrosion whi�h can increase the torqu� nec­
essary to achieve the desired clamp load for which that fastener was ongmally
selected. Additional ly, be sure that the driver surface of the fastener has not
C L U T C H R E C E S S
I N D E N T E D H E X A G O N H E X A G O N T R I M M E D H E X A G O N WAS H E R H EA D
TCCS1037
Fig. 44 Here are a few of the most common screw/bolt driver styles
04892P26
Fig. 45 Thread gauges measure the threads-per-inch and the pitch
of a bolt or stud's threads
been compromised by rounding or other damage. In some cases a driver sur­
face may become only partial ly rounded, allowing the driver to catch in only one
direction. In many of these occurrences, a fastener may be instal led and tight­
ened, but the driver would not be able to grip and loosen the fastener again .
(This could lead to frustration down the l ine should that component ever need to
be disassembled again).
If you must replace a fastener, whether due to design or damage, you must
always be sure to use the proper replacement. In al l cases, a retainer of the
same design, material and strength should be used. Markings on the heads of
most bolts wil l help determine the proper strength of the fastener. The same
material, thread and pitch must be selected to assure proper installation and
safe operation of the vehicle afterwards.
Thread gauges are avai lable to he lp measure a bolt or stud's thread. Most
part or hardware stores keep gauges avai I able to he I p you select the proper
size. In a p inch , you can use another nut or bolt for a thread gauge. If the
bolt you are replacing is not too badly damaged, you can select a match by
finding another bolt which will thread i n its place. If you find a nut which
threads properly onto the damaged bolt, then use that nut to help select the
replacement bolt. If however, the bolt you are replacing is so badly damaged
(broken or dri l led out) that its threads cannot be used as a gauge, you might
start by looking for another bolt (from the same assembly or a s imi lar loca­
tion) wh ich wi l l thread into the damaged bo lt's mounting. If so, the other bolt
can be used to select a nut; the nut can then be used to select the rep lace­
ment bolt.
TOO LS AND EQU I PM ENT 2-1 5
In al l cases, be absolutely sure you have selected the proper replacement.
Don't be shy, you can always ask the store clerk for help.
** WARN I N G
Be aware that when you find a bolt with damaged threads, you may
also find the nut or dri l led hole it was threaded into has also been
damaged. If this is the case, you may have to dri l l and tap the hole,
rep lace the nut or otherwise repai r the threads. NEVER try to force a
replacement bolt to fit into the damaged threads.
Torque
Torque is defined as the measurement of resistance to turning or rotating. i t
tends to twist a body about an axis of rotation. A common example of this
would be tightening a threaded retainer such as a nut, bolt or screw. Measuring
torque is one of the most common ways to help assure that a threaded retainer
has been properly fastened.
When tightening a threaded fastener, torque is applied i n three distinct areas,
the head, the bearing surface and the clamp load. About 50 percent of the mea­
sured torque is used in overcoming bearing friction. This is the friction between
the bearing surface of the bolt head, screw head or nut face and the base mate­
rial or washer (the surface on which the fastener is rotating). Approximately 40
percent of the applied torque is used in overcoming thread friction. This leaves
only about 1 0 percent of the applied torque to develop a useful clamp load (the
force which holds a joint together). This means that friction can account for as
much as 90 percent of the applied torque on a fastener.
Standard and Metric Measurements
Specifications are often used to help you determine the condition of various
components, or to assist you in their installation. Some of the most common
measurements include length (in. or cm/mm), torque (ft. lbs., inch lbs. or Nm)
and pressure (psi, in . Hg, kPa or mm Hg).
I n some cases, that value may not be conveniently measured with what is
available in your tool box. Lucki ly, many of the measuring devices which are
available today wi l l have two scales so Standard or Metric measurements may
easily be taken . If any of the various measuring tools which are available to you
do not contain the same scale as l isted in your specifications, use the accompa­
nying conversion factors to determine the proper value.
The conversion factor chart is used by taking the given specification and
multiplying it by the necessary conversion factor. For instance, looking at the
first l i ne, if you have a measurement in inches such as "free-play should be 2
in." but your ruler reads only in mi l l imeters, multiply 2 in. by the conversion
factor of 25.4 to get the metric equivalent of 50.8mm. Likewise, if the specifica­
tion was given only in a Metric measurement, for example in Newton Meters
(Nm), then look at the center column first. If the measurement is 1 00 Nm, multi­
ply it by the conversion factor of 0.738 to get 73.8 ft. lbs.
2-1 6 TOO LS AND EQU I PM ENT
C O NVE R S I O N FACTO R S
L E N GTH-D I STA N C E
Inches (in.) X 25.4 = Millimeters (mm) X .0394 = Inches
Feet (ft.) X .305 = Meters (m) X 3 .28 1 = Feet
Miles X 1 . 609 = Ki1ometers (km) X .0621 = Miles
VOLU M E
Cubic Inches (in3) X 1 6.387
·
= Cubic Centimeters X .06 1 = in3
IMP Pints (IMP pt.) x .568 = Liters (L) X 1 .76 = IMP pt.
IMP Quarts (IMP qt.) X 1 . 1 37 = Liters (L) X . 8 8 = IMP qt.
IMP Gallons (IMP gal.) X 4.546 = Liters (L) x .22 = IMP gal.
IMP Quarts (IMP qt.) X 1 . 20 1 = US Quarts (US qt.) X . 83 3 = IMP qt.
IMP Gallons (IMP gal.) X 1 .201 = US Gallons (US gal.) X .833 = IMP gal.
Fl. Ounces X 29.573 = Milliliters X .034 = Ounces
US Pints (US pt.) X .473 = Liters (L) X 2. 1 1 3 = Pints
US Quarts (US qt.) X .946 = Liters (L) X 1 .057 = Quarts
US Gallons (US gal.) X 3.785 = Liters (L) X .264 = Gallons
M ASS-WE I G H T
Ounces (oz.) X 28.35 = Grams (g) X .035 = Ounces
Pounds (lb.) X .454 = Kilograms (kg) X 2.205 = Pounds
P R ESS U R E
Pounds Per Sq. In. (psi) X 6.895 = Kilopascals (kPa) X . 1 45 = psi
Inches of Mercury (Hg) X .49 1 2 = psi X 2.036 = Hg
Inches of Mercury (Hg) X 3. 377 = Kilopasca1s (kPa) X .2961 = Hg
Inches of Water (H,O) X .07355 = Inches of Mercury X 1 3 .783 = H,O
Inches of Water (H20) X .03 6 1 3 = psi X 27.684 = H,O
Inches of Water (H,O) X .248 = Kilopascals (kPa) X 4.026 = H,O
TOR Q U E
Pounds-Force Inches (in-lb) X . 1 1 3 = Newton Meters (N · m) X 8.85 = in-lb
Pounds-Force Feet (ft-lb) X 1 . 356 = Newton Meters (N · m) X .738 = ft-lb
V E LOCITY
Miles Per Hour (MPH) X 1 . 609 = Kilometers Per Hour (KPH) X .62 1 = MPH
POWER
Horsepower (Hp) X . 745 = Kilowatts X 1 . 34 = Horsepower
F U E L CON S U M PTI O N *
Miles Per Gallon IMP (MPG) X .354 = Kilometers Per Liter (Km/L)
Kilometers Per Liter (Km/L) X 2.352 = IMP MPG
Miles Per Gallon US (MPG) X .425 = Kilometers Per Liter (Km/L)
Kilometers Per Liter (Km/L) X 2.352 = US MPG
*It is common to covert from miles per gallon (mpg) to liters/ 100 kilometers ( 1! 1 00 km), where mpg (IMP) x 1 / 100 km
= 282 and mpg (US) x 1/100 km = 235.
T E M P E R ATU R E
Degree Fahrenheit CF)
Degree Celsius CC)
= CC X 1 . 8) + 32
= CF - 32) X . 56
TCCS1044
ENGINE MAINTENANCE 3-2
SERIAL NUMBER IDENTIFICATION 3-2
2-STROKE O I L 3-2
O IL RECOMMENDATIONS 3-2
FILLING 3-2
LOWER UNIT 3-3
O I L RECOMMENDATIONS 3-3
DRAINING & FILLING 3-3
FUEL F ILTER 3-4
RELIEVING FUEL SYSTEM
PRESSURE 3-5
REMOVAL & I NSTALLATION 3-5
FUEL/WATER SEPARATOR 3-6
TRIM/TILT & PIVOT PO INTS 3-6
INSPECTION & LUBRICATION 3-6
PROPELLER 3-7 _
BOAT MAINTENANCE 3-8
INSIDE THE BOAT 3-8
F/BERGLASS HULLS 3-8
TRIM TABS, ANODES AND LEAD
WIRES 3-8
BATTERY 3-9
C LEANING 3-10
CHECKING SPECIF IC GRAVITY 3-10
BATTERY TERMINALS 3-11
BATTERY & CHARGING SAFETY
PRECAUTIONS 3-11
BATTERY CHARGERS 3-11
REPLACING BATTERY CABLES 3-12
TUNE-UP 3-12
I NTRODUCTION 3-12
TUNE- U P SEQUENCE 3-12
COMPRESSION CHECK 3-12
CHECKING COMPRESSION 3-12
LOW COMPRESSION 3-13
SPARK PLUGS 3-13
SPARK PLUG HEAT RANGE 3-13
SPARK PLUG SERVIC E 3-14
REMOVAL & INSTALLATION 3-14
READING SPARK PLUGS 3-14
INSPECTION & GAPPING 3-15
SPARK PLUG WIRES 3-17 -
TEST/ NG 3-17
REMOVAL & INSTALLATION 3-17
IGNITION SYSTEM 3-17
T IMING AND SYNCHRONIZATION 3-17
TIMING 3-17
SYNCHRONIZATION 3-17
PREPARATION 3-17
DT2 AND DT2.2 3-18
IGNITION TIMING 3-18
I D LE SPEED 3-19
DT4 3-19
IGN ITION T IMING 3-19
IDLE SPEED 3-19
DT6 AND DT8 3-19
IGNITION TIMING 3-19
IDLE SPEED 3-20
DT9.9 AND DT15 3-21
IGNITION TIMING 3-21
IDLE SPEED 3-21
DT20, DT25 AND DT30 3-22
IGNITION T IMING 3-22
THROTTLE L INKAGE
ADJUSTMENT 3-22
IDLE SPEED 3-22
DT35 AND DT 40 3-23
IGNITION TIMING 3-23
I D LE SPEED 3-25
THROTTLE L INKAGE 3-26
DT55 AND DT65 3-26
IGN ITION TIMING 3-26
IDLE SPEED 3-26
THROTTLE L INKAGE 3-27
DT75 AND DT85 3-29
IGN ITION T IMING 3-29
CARBURETOR L INKAGE
ADJUSTMENT 3-29
IDLE SPEED 3-29
DT90 AND DT1 00 3-30
IGNITION TIMING 3-30
CARBURETOR L INKAGE
ADJUSTMENT 3-30
IDLE SPEED 3-30
DT115 AND DT140 3-30
IGNITION T IMING 3-30
CARBURETOR L INKAGE 3-31
IDLE SPEED 3-32
DT150, DT175, DT200 3-32
IGNITION TIMING 3-32
CARBURETOR L INKAGE 3-32
IDLE SPEED 3-32
WINTER STORAGE CHECKLIST 3-35
SPRING COMMISSIONING
CHECKLIST 3-35
SPECIFICATIONS CHARTS
CAPAC ITIES 3-2
CARBURETOR IDLE AIR SCREW
SPECIF ICATION 3-33
TUNE U P SPECIFICATIONS
CHARTS 3-34
GENERAL ENGINE
SPECIFICATI ONS 3-38
SERIAL NUMBER
IDENTIFICATION 3-43
3-2 MAI NTENANCE
ENGINE MAINTENANCE
Serial Number Identification
Suzuki uses engine serial numbers and models numbers for identification
purposes. These numbers are stamped on plates riveted to the port side
trans�m. bracket or to th� starboard side of the support plate.
This mformat1on identifies the specific engine and will indicate to the
owner or service technician if there are any unique parts or if any changes
have been made to that particular model during its production run. The serial
and models number should be used any time you order replacement parts.
For more 1nformat1on, refer to the "Serial Number Identification" and the
"General Engine Specifications" charts at the end of this section.
2-Stroke Oil
OIL RECOMMENDATIONS
t See Figures 1 and 2
Use only Suzuki CC! oil or NMMA (National Marine Manufacturers
Association) certified 2�stroke lubricants. These oils are proprietary lubricants
des1gned to ensure opt1mal engine performance and to minimize combustion
Fig. 1 2·St�oke out�oard oils are proprietary lubricants designed to
ensure opt1mal engme performance and to minimize combustion
chamber deposits, avoid detonation and prolong spark plug life
Fig. 2 This scuffed piston is an example of what can happen when
the proper 2-stroke oil is not used. The outboard required a
complete overhaul
chamber deposits, avoid detonation and prolong spark plug l ife. If Suzuki
CCI oil or a NMMA certified lubricant is unavailable, use only 2-stroke
outboard oil.
.,. Remember, it is this oil, mixed with the gasoline that lubricates the
internal parts of the engine. Lack of lubrication due to the wrong mix or
improper type of oil can cause catastrophic powerhead failure.
FILLING
There are two methods of adding 2-stroke oil to an outboard. The first is
the pre-mix method used on outboards up to 6 horsepower and on some
commercial models. The second is the automatic oil injection method which
automatically injects the correct quantity of oil into the engine for all
operating conditions.
Pre·Mix
Mixing the engine lubricant with gasoline before pouring it into the tank is
by far the simplest method of lubrication for 2-stroke outboards. However
this method is the most messy and causes the most amount of harm to o
'
ur environment.
The most important part of filling a pre-mix system is to determine the
proper fuel/oil ratio. Most manufacturers use a 50:1 ratio (that is 50 parts of
fuel to 1 part of oil) or a 1 00:1 ratio. Consult your owners manual to
determine what the appropriate ratio should be for your engine.
The procedure itself is uncomplicated. Simply add the correct amount of
lubncant to your fuel tank and then fill the tank with gasoline. The order in
wh1ch you do th1s IS 1mportant because as the gasoline is poured into the fuel
tank it will mix with and agitate the oil for a complete blending.
If you are attempting to top off your tank, here is a general guideline to
determine how much oil to add. For three gallons of fuel you would add 4
ounces of oil to obtain a 1 00 : 1 ratio ; 8 ounces of oil to obtain a 50:1 ratio and
1 6 ounces of oil to obtain a 25:1 ratio.
Oil Injection
Most outboard manufacturers use a mechanically driven oil pump
mounted on the engine block that is connected to the throttle by way of a
linkage arm.
Model
DT2
DT2.2
DT4
DT5Y
DT6
DT8
DT9.9
DT15
DT20
DT25
DT30
DT35
DT40
DT55
DT65
DT75
DT85
DT90
DT100
DT115
DT140
DT150
DT175
DT200
DT225
Capacities
Injection Oil Lower Unit
Quart (Liter) Oz (m I)
PreMix 2.4(70)
PreMix 2.4(70)
PreMix 6.4(190)
Premix 6.4(190)
PreMix 1 1 .5(240)
PreMix 1 1 .5(240)
2.3(2.1) 5.7(170)
2.3(2.1) 5.7(170)
2.3(2.1) 10 .1(300)
2.1 (2.0) 7.8(230)
2.1(2.0) 7.8(230)
2.1 (2.0) 20.6(610)
2.1(2.0) 20.6(610)
3.2(3.0) 22(650)
3.2(3.0) 22(650)
2.4(2.3) 23.7(700)
2.4(2.3) 23.7(700)
4.8(4.5) 18.9(560)
4.8(4.5) 1 8.9(560)
6.3(6.0) 37.2(1 1 00)
6.3(6.0) 37.2(1 1 00)
9.5(9.0) 35.5(1050)
9.5(9.0) 35.5(1050)
9.5(9.0) 35.5(1050)
9.0(8.5) 35.5(1050)
Fuel Tank
Gal (Liter)
0.3(1.2)
0.3(1.2)
0.7(2.6)
0.7(2.8)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
6.3(24)
The system is powered by the crankshaft which drives a gear in the pump, cre­
ating o i l pressure. As the throttle lever is advanced to increase engine speed,
the l inkage arm also moves, opening a valve that al lows more oil to flow into
the oil pump.
Most mechanical-injection systems incorporate low-oi l warn ing alarms that
are also connected to an engine overheating sensor. Also, these systems may
have a built-in speed l imiter. This sub-system is designed to reduce engine
speed automatically when oi l problems occur. This important feature goes a
long way toward preventing severe engine damage in the event of an oi l injec­
tion problem.
The procedure for f i l l ing these systems is simple. On each powerhead there
is an auxiliary o i l reservoi r which holds the 2-stroke o i l . Simply f i l l the oil take
to the proper capacity.
,..11 is highly advisable to carry several spare bottles of 2-stroke oil with
you onboard.
For more information on the oil injection system refer to the "Lubrication and
Cooling" section of this manual.
lower Unit
t See Figures 3 and 4
Regular maintenance and inspection of the lower un it is critical for proper
operation and reliabil ity. A lower un it can quickly fail if it becomes heavily cont­
aminated with water, or excessively low on oi l . The most common cause of a
lower unit failure is water contamination.
Water in the lower unit is usually caused by fishing l i ne, or other foreign mate­
rial, becoming entangled around the propeller shaft and damaging the seal. If the
l ine is not removed, it wi l l eventually cut the propeller shaft seal and al low water to
enter the lower unit. Fishing l ine has also been known to cut a groove in the pro­
peller shaft if left neglected over time. This area should be checked frequently.
04703P10
Fig. 3 This lower unit was destroyed because the bearing carrier
was frozen due to lack of lubrication
MAI NTENANC E 3-3
04703P28
Fig. 4 Excellent view of rope and fishing line entangled behind the
propeller. Entangled fishing line can actually cut through the seal,
allowing water to enter the lower unit and lubricant to escape
OIL RECOMMENDATIONS
Use only Suzuki Outboard Motor Gear O i l or and equivalent high qual ity SAE
90 hypoid gear o i l . These o i ls are proprietary lubricants designed to ensure
optimal performance and to minimize corrosion in the lower unit.
,..Remember, it is this lower unit lubricant that prevents corrosion and
lubricates the internal parts of the drive gears. Lack of lubrication due
to water contamination or the improper type of oil can cause cata­
strophic lower unit failure.
DRAIN ING & FILLING
t See accompanying i l lustrations
** CAUTION
The EPA warns that prolonged contact with used engine oi l may
cause a number of skin d isorders, including cancer! You should
make every effort to min imize your exposure to used engine o i l .
Protective gloves shou ld be worn when changing the o i l . Wash your
hands and any other exposed skin areas as soon as possib le after
exposure to used engine o i l . Soajl and water, or waterless hand
cleaner should be used.
1 . Place a suitable container under the lower un it.
2. Loosen the oil level plug on the lower unit. This step is important! If the
oil level plug cannot be loosened or removed, the complete lower un it l ubricant
service cannot be performed.
,..Never remove the vent or filler plugs when the lower unit is hot.
Expanded lubricant will be released through the plug hole.
3. Remove the f i l l p lug from the lower end of the gear housing fol lowed by
the oi l level plug.
4. Allow the lubricant to completely drain from the lower unit.
3-4 MAI NTENAN C E
05003P11
Step 2 Step 3
,..If applicable, check the magnet end of the drain screw for metal
particles. Some normal wear is to be expected, but if there are signs of
metal chips or excessive metal particles, the gear case needs to be dis­
assembled and inspected.
5. Inspect the lubricant for the presence of a mi lky white substance, water
or metal l ic particles. If any of these conditions are present, the lower unit shou ld
be serviced immediately.
6. Place the outboard in the proper position for f i l l ing the lower unit. The
lower unit should not l ist to either port or starboard, and should be completely
vertical.
7. On smaller outboards, insert the lubricant tube into the oil drain hole at
the bottom of the lower unit, and squeeze lubricant until the excess begins to
come out the oil level hole.
8. On larger outboards, o i l should be injected, to f i l l the gear case through
the drain plug.
05003P27
Step 8
05003P12 05003P13
Step 4
9. Pump kits are available from marine manufacturers such as Rapiar®.
1 0. Using new gaskets, (washers) install the o i l level and vent plugs (if
applicable) first, then install the oi l fill plug.
1 1 . Place the used lubricant in a suitable container for transportation to an
authorized recycl ing station.
Step 9
Fuel Fi lter
• See Figures 5 and 6
The fuel filter is designed to keep particles of dirt and debris from entering
the carburetor(s) and clogging the internal passages. A small speck of dirt or
sand can drastically affect the abil ity of the carburetor(s) to deliver the proper
amount of air and fuel to enter the engine. If a filter becomes clogged, the flow
of gasoline wi l l be impeded. This could cause lean fuel mixtures, hesitation and
stumbl ing, and idle problems.
Regular replacement of the fuel filter will decrease the risk of blocking the
flow of fuel to the engine, which could leave you stranded on the water. Fuel fil­
ters are usually inexpensive, and replacement is a simple task. Change your fuel
filter on a regular basis to avoid fuel del ivery problems to the carburetor.
In addition to the fuel filter mounted on the engine, a filter is usually found
inside or near the fuel tank (with the exception of DT2 and DT2.2 ) . Because of the
large variety of differences in both portable and fixed fuel tanks, it is impossible to
give a detai led procedure for removal and installation. Most in-tank filters are sim­
ply a screen on the pick-up l i ne inside the fuel tank. Fi lters of this type usually
only need to be cleaned and returned to service. Fuel filters on the outside of the
tank are typically of the in l ine type, and are replaced by simply removing the
clamps, disconnecting the hoses, and instal l ing a new fi lter. When instal l ing the
new filter, make sure the arrow on the filter points in the direction of fuel flow.
Fig. 5 Typical fuel filter mounting location
05003P04
Fig. 6 A clogged fuel filter resulted in a lean fuel mixture at speed
and caused the burn hole in the top of the piston. This powerhead
required a complete overhaul
RELIEVING FUEL SYSTEM PRESSURE
On fuel injected engines, always relieve system pressure prior to disconnect­
ing any fuel system component, fitting or fuel l i ne.
** CAUTION
Exercise extreme caution whenever relieving fuel system pressure
to avoid fuel spray and potential serious bodi ly injury. Please be
advised that fue l under pressure may penetrate the skin or any part
of the body it contacts.
To avoid the possibil ity of fire and personal injury, always disconnect the
negative battery cable.
Always place a shop towel or cloth around the fitting or connection prior to
loosening to absorb any excess fuel due to spi l lage. Ensure that all fuel spi l lage
is removed from engine surfaces. Ensure that all fuel soaked clothes or towels
in suitable waste container.
1 . Remove the engine cover.
2. Place a wrench on both the service check bolt and fitting nut to prevent
the fitting from twisting and breaking oft.
3. Holding the service check bolt and fuel pressure check nut with both
wrenches, place a shop towel or equivalent material over the service check bolt.
4. Loosen the service check bolt approximately one turn slowly to relieve
the fuel pressure.
MAINTENANC E 3-5
5 . After relieving the fuel pressure, remove the service check bolt and
replace the 6mm seal ing washer with a new one. Tighten the service check bolt
to 9 ft. lbs. (12 Nm).
REMOVAL & INSTALLATION
• See Figures 7 and 8
** CAUTION
Observe all applicable safety precautions when working around
fue l . Whenever servicing the fuel system, a lways work in a well­
ventilated area. D o not a l low fue l spray or vapors to come in con­
tact with a spark or open flame. D o not smoke while working around
gasoline. Keep a dry chemical fire extinguisher near the work area.
Always keep fuel in a container specifically designed for fuel stor­
age; also, a lways properly seal fuel containers to avoid the possi­
bi l ity of fire or explosion.
1 . Remove the eng ine cover.
2. Locate the fuel filter in the engine pan.
3. Lift the fuel filter from the engine pan, and place a pan or clean rag
underneath it to absorb any spi l led fuel.
4. Sl ide the hose retaining c l ips oft the fi lter n ipple with a pair of p l iers and
disconnect the hoses from the filter.
5. Reinstall the hoses on the filter n ipples of the new fi lter. Make sure the
embossed arrow on the filter points in the direction of fuel flow.
6. Sl ide the c l ips on each hose over the filter n ipples.
7. Check the fuel filter installation for leakage by priming the fuel system
with the fuel l i ne primer bulb.
8. Once it is confirmed that there is no l eakage from the connections, place
the filter back to its proper position i n the engine pan.
9. Replace the engine cover.
05003G02
Fig. 7 Thoroughly clean the filter element in solvent
Pleasure market
Commercial market
05003G03
Fig. 8 Be sure to mount the filter in the proper direction. The arrow
on the filter (circled) indicates the direction of the flow of fuel
3-6 MAINTENANC E
Fuel/Water Separator
• See Figures 9 and 1 0
I n addition to the engine and in l ine fuel filters, there i s usually another filter
located in the fuel supply l ine. This is the fuel/water separator. i t is used to
remove water particles from the fuel prior to entering the engine or in l ine fi lter.
Water can enter the fuel supply from a variety of sources and can lead to poor
engine performance and ultimately, serious engine damage.
Because of the large variety of differences in both portable and fixed fuel
tanks, it is impossible to give a single procedure to cover all applications
04703P38
Fig. 9 A water separating fuel filter installed inside the boat on the
transom
04893P76
Fig. 10 A typical water separating fuel filter assembly ready to be
installed on the boat
Check with the boat manufacturer or the marina who rigged the boat to get the
specifics of your particular fuel fi ltration system.
Trim/Tilt & Pivot Points
I NSPECTION & LUBRICATION
• See Figures 1 1 , 12 and 13
The steering head and other pivot points of the outboard-to-engine mounting
components need periodic lubrication with marine grade grease to provide
smooth operation and prevent corrosion. Usual ly, these pivot points are easily
lubricated by simply attaching a grease gun to the fittings.
If the engine is used in salt water, the frequency of applying lubricant is usu­
ally doubled in comparison to operation in fresh water. Due to the very corrosive
nature of salt water, an anti-seize thread compound shou ld be used on a l l
exposed fasteners outside of the cowl ing to reduce the chance of them seizing
in place and breaking off when you try to remove them.
,..Rinsing off the engine after each use is a very good habit to get into,
not only does it help preserve the appearance of the engine, it virtually
eliminates the corrosive effects of operating in salt water.
05003P16
Fig. 1 1 The steering head . . .
05003P17
Fig. 12 . . . and steering tube both contain grease fittings which
should be lubricated regularly
05003P18
Fig. 13 Due to the very corrosive nature of salt water, some sort of
anti-seize type thread compound should be used on all exposed fas­
teners outside of the cowling to reduce the chance of them seizing
in place
Propel ler
t See Figures 14, 1 5 and 16
The propeller should be inspected regularly to be sure the blades are in good
condition. If any of the blades become bent or nicked, this condition wi l l set up
04703P27
Fig. 14 An appl ication of anti-seize on the propeller shall splines
will prevent the propeller from seizing on the shall and facilitate
easier removal for the next service
MAI NTENANC E 3-7
vibrations i n the motor. Remove and inspect the propeller. Use a fi le t o trim
nicks and burrs. Take care not to remove any more material than is absolutely
necessary.
Also, check the rubber and splines inside the propeller hub for damage. If
there is damage to either of these, take the propeller to your local marine dealer
or a "prop shop" . They can evaluate the damaged propeller and determine if it
can be saved by rehubbing.
Additional ly, the propeller should be removed each time the boat is hauled
from the water at the end of an outing. Any material entangled behind the pro­
peller should be removed before any damage to the shaft and seals can occur.
This may seem l ike a waste of time, but the small amount of time involved in
removing the propeller is returned many times by reduced maintenance and
repair, including the replacement of expensive parts.
04703P41
Fig. 15 A block of wood inserted between the propeller and the anti­
cavitation plate will prevent the propeller from turning while the nut
is being removed or installed
Fig. 16 Once the propeller nut and washer is removed, the propeller
can be removed by sliding it off the shall
3-8 MAI NTENAN C E
BOAT MAINTENANCE
Inside The Boat
• See Figure 17
The following points may be lubricated with an al l purpose marine lubricant:
• Remote control cable ends next to the hand nut. DO NOT over-lubricate
the cable
• Steering arm pivot socket
• Exposed shaft of the cable passing through the cable guide tube
• Steering l ink rod to steering cable
Fig. 17 Use only a good quality marine grade grease for lubrication
Fiberglass Hulls
• See Figures 18 , 19 and 20
Fiberglass reinforced plastic hu l ls are tough, durable, and h igh ly resistant to
impact. However, l ike any other material they can be damaged. One of the
advantages of this type of construction is the relative ease with which it may be
repaired. Because of its break characteristics, and the simple techniques used in
restoration, these hulls have gained popularity throughout the world. From the
most congested urban marina, to isolated lakes in wi lderness areas, to the
severe cold of far off northern seas, and in sunny tropic remote rivers of primi­
tive islands or continents, fiberglass boats can be found performing their dai ly
task with a min imum of maintenance.
A fiberglass hull has almost no internal stresses. Therefore, when the hul l is
broken or stove-in , it retains its true form. it wi l l not dent to take an out-of-shape
set. When the hul l sustains a severe blow, the impact wi l l be either absorbed by
deflection of the laminated panel or the blow wi l l result in a definite, localized
break. In addition to hull damage, bulkheads, stringers, and other stiffening
structures attached to the hu l l may also be affected and therefore, should be
checked. Repairs are usually confined to the general area of the rupture.
�The best way to care for a fiberglass hull is to wash it thoroughly,
immediately after hauling the boat while the hull is sti ll wet.
A fouled bottom can seriously affect boat performance. This is one reason
why racers, large and smal l , both powerboat and sail , are constantly giving
attention to the condition of the hul l below the waterl ine.
In areas where marine growth is prevalent, a coating of vinyl , anti-fou l ing
bottom paint should be applied. If growth has developed on the bottom, it can
be removed with a solution of Muriatic acid applied with a brush or swab and
then rinsed with clear water. Always use rubber gloves when working with Muri­
atic acid and take extra care to keep it away from your face and hands. The
fumes are toxic. Therefore, work in a well-venti lated area, or if outside, keep
your face on the windward side of the work.
Barnacles have a nasty habit of making their home on the bottom of boats
which have not been treated with anti-foul ing paint. Actually they wi l l not harm
the fiberglass hul l , but can develop i nto a major nu isance.
If barnacles or other crustaceans have attached themselves to the hu l l , extra
work wi l l be required to bring the bottom back to a satisfactory condition. First,
if practical, put the boat into a body of fresh water and allow it to remain for a
few days. A large percentage of the growth can be removed in this manner. If
this remedy is not possible, wash the bottom thoroughly with a high-pressure
fresh water source and use a scraper. Small particles of hard shel l may sti l l hold
fast. These can be removed with sandpaper.
Trim Tabs, Anodes and Lead Wires
• See Figures 21 thru 28
Check the trim tabs and the anodes (zinc). Replace them, i f necessary. The
trim tab must make a good ground inside the lower un it. Therefore, the trim tab
and the cavity must not be painted. In addition to trimming the boat, the trim tab
acts as a zinc e lectrode to prevent electrolysis from acting on more expensive
parts. it is normal for the tab to show signs of erosion. The tabs are inexpensive
and shou ld be replaced frequently.
Clean the exterior surface of the unit thoroughly. Inspect the finish for dam­
age or corrosion. Clean any damaged or corroded areas, and then apply primer
and matching paint.
Check the entire un it for loose, damaged, or missing parts.
An anode is attached across both clamp brackets. it also serves as protec­
tion for the coi l of hydraul ic hoses beneath the trim/tilt unit between the brack­
ets.
Lead wires provide good electrical continuity between various brackets which
might be isolated from the trim tab by a coating of lubricant between moving
parts.
SELSTK55
SELSTKOO
Fig. 18 In areas where marine growth is a
problem, a coating of anti-foul bottom
paint should be applied
Fig. 19 The best way to care for a fiber­
glass hull is to wash it thoroughly
Fig. 20 Fiberglass, vinyl and rubber care
products, such as those available from
Meguiar's are available to protect every
part of your boat
Fig. 21 What a trim tab should look like when it's in good condition
MAI NTENANC E 3-9
04703P08
Fig. 22 Such extensive erosion of a trim tab compared with a new
tab suggests an electrolysis problem or complete disregard for peri­
odic maintenance
05003P23
Fig. 24 . . . other types of anodes are
Fig. 23 Although many outboards use the
trim tab as an anode . . .
also used throughout the outboard, l ike
this one on the stern bracket . . .
04891P03 05003P22
Fig. 26 Anodes installed in the water
jacket of a powerhead provide added pro­
tection against corrosion
Fig. 27 Most anodes are easily removed
by loosening and removing their attaching
fasteners
Fig. 28 One of the many lead wires used
to connect bracketed parts. Lead wires are
used as an assist in reducing corrosion
Battery
Difficulty in starting accounts for almost half of the service required on boats
each year. A survey by Champion Spark Plug Company indicated that roughly
one th ird of al l boat owners experienced a "won't start" condition in a given
year. When an engine won't start, most people blame the battery when, in fact, it
may be that the battery has run down in a futile attempt to start an engine with
other problems.
Maintaining your battery in peak condition may be though of as either tune­
up or maintenance material . Most wise boaters wi l l consider it to be both. A
complete check up of the electrical system in your boat at the beginning of the
boating season is a wise move. Continued regular maintenance of the battery
wi l l ensure trouble free starting on the water.
A complete battery service procedure is included in the "Maintenance" sec­
tion of this manual. The fol l owing are a list of basic e lectrical system service
procedures that should be performed as part of any tune-up.
• Check the battery for solid cable connections
• Check the battery and cables for signs of corrosion damage
• Check the battery case for damage or e lectrolyte leakage
• Check the e lectrolyte level in each cel l
3-1 0 MAINTENAN C E
• Check to be sure the battery is fastened securely in position
• Check the battery's state of charge and charge as necessary
• Check battery voltage whi le cranking the starter. Voltage should remain
above 9.5 volts
• Clean the battery, terminals and cables
• Coat the battery terminals with dielectric grease or terminal protector
Batteries which are not maintained on a regular basis can fall victim to parasitic loads (small current drains which are constantly drawing current from the
battery). Normal parasitic loads may drain a battery on boat that is in storage
and not used frequently. Boats that have additional accessories with increased
parasitic load may discharge a battery sooner. Storing a boat with the negative
battery cable disconnected or battery switch turned off wi l l min imize discharge
due to parasitic loads.
CLEANING
Keep the battery clean, as a fi lm of dirt can help discharge a battery that is
not used for long periods. A solution of baking soda and water mixed into a
paste may be used for cleaning, but be careful to flush this off with c lear water.
,_Do not let any of the solution into the filler holes on non-sealed bat­
teries. Baking soda neutralizes battery acid and will de-activate a bat­
tery cell.
CHECKING SPECIFIC GRAVITY
The e lectrolyte f luid (sulfuric acid solution) contained in the battery cel ls wi l l
tel l you many things about the condition of the battery. Because the cel l plates
must be kept submerged below the fluid level in order to operate, maintaining
the fluid level is extremely important. In addition, because the specific gravity of
the acid is an indication of electrical charge, testing the f luid can be an aid in
determin ing if the battery must be replaced. A battery in a boat with a properly
operating charging system should require little maintenance, but careful , peri­
odic inspection should reveal problems before they leave you stranded.
** CAUTION
Battery electrolyte contains sulfuric ac id . I f you should splash any
on your skin or in your eyes, flush the affected area with plenty of
clear water. If it lands in your eyes, get medical help immediately.
As stated earlier, the specific gravity of a battery's e lectrolyte level can be used
as an indication of battery charge. At least once a year, check the specific gravity
of the battery. lt should be between 1 .20 and 1 .26 on the gravity scale. Most
parts stores carry a variety of inexpensive battery testing hydrometers. These can
be used on any non-sealed battery to test the specific gravity in each cel l .
Conventional Battery
• See Figures 29 and 3n
A hydrometer is required to check the specific gravity on all batteries that are
not maintenance-free. The hydrometer has a squeeze bulb at one end and a noz­
zle at the other. Battery e lectrolyte is sucked into the hydrometer unti l the float
or pointer is l ifted from its seat. The specific gravity is then read by noting the
position of the float/pointer. If gravity is low in one or more cells, the battery
shou ld be slowly charged and checked again to see if the gravity has come up.
Generally, if after charging, the specific gravity of any two cells varies more than
50 points (0.50), the battery should be replaced, as it can no longer produce
sufficient voltage to guarantee proper operation.
Check the battery electrolyte level at least once a month, or more often in hot
weather or during periods of extended operation. Electrolyte level can be checked
either through the case on translucent batteries or by removing the cell caps on
opaque-case types. The electrolyte level in each cell should be kept fi l led to the
split ring inside each cell, or the line marked on the outside of the case.
If the level is low, add only disti l led water through the opening unti l the level
is correct. Each cell is separate from the others, so each must be checked and
filled individually. Disti l led water should be used, because the chemicals and
minerals found in most drinking water are harmful to the battery and could sig­
nificantly shorten its life.
If water is added in freezing weather, the battery should be warmed to a l low
the water to mix with the e lectrolyte. Otherwise, the battery could freeze.
TCCA1P07
Fig. 29 On non-maintenance free batteries with translucent cases,
the electrolyte level can be seen through the case; on other types
(such as the one shown), the cell cap must be removed
04703P37
Fig. 30 The best way to determine the condition of a battery is to
test the specific gravity of the electrolyte with a battery tester
Maintenance-Free Batteries
• See Figure 31
Although some maintenance-free batteries have removable cell caps for
access to the e lectrolyte, the e lectrolyte condition and level is usually checked
using the bui lt-in hydrometer "eye". The exact type of eye varies between battery
manufacturers, but most apply a sticker to the battery itself explaining the pasLoc.tlon of Indicator on sealed battery
MAI NTENANC E 3-1 1
BATIERY TOP
DARKENED
INDICATOR
BATIERY TOP
DARKENED
INDICATOR
HO GREEN DOT
MAT If JUM,. STAnED
BATIERY TOP
UG!fl YELLO'W
OR BRIG!fl
INDICATOR,
HO GREEN DOT
00 NOT JUMP START
C heck the appearance of the charge Indicator on
top of the battery before attempting e jump start ; If
it's not green or dark, do not jump start the car
TCCS1253
Fig. 31 A typical sealed (maintenance-free) battery with a built-in hydrometer-note that the hydrometer eye may vary between manufacturers;
always refer to the battery's label
sible readings. When in doubt, refer to the battery manufacturer's instructions to
interpret battery condition using the bui lt-in hydrometer.
The readings from bui lt-in hydrometers may vary, however a green eye usu­
ally indicates a properly charged battery with sufficient fluid level. A dark eye is
normally an indicator of a battery with sufficient fluid, but one that may be low
in charge. In addition, a light or yellow eye is usually an indication that elec­
trolyte supply has dropped below the necessary level for battery (and hydrome­
ter) operation. In this last case, sealed batteries with an insufficient e lectrolyte
level must usually be discarded.
BATTERY TERMINALS
At least once a season , the battery terminals and cable clamps should be
cleaned. Loosen the clamps and remove the cables, negative cable first. On bat­
teries with top mounted posts, the use of a pul ler specially made for this pur­
pose is recommended. These are inexpensive and avai lable from most auto
parts stores.
Clean the cable clamps and the battery terminal with a wire brush, until al l
corrosion, grease, etc. , is removed and the metal is shiny. it is especially impor­
tant to c lean the inside of the clamp thoroughly (a wire brush is useful here),
since a small deposit of foreign material or oxidation there will prevent a sound
electrical connection and inhibit either starting or charg ing. it is also a good
idea to apply some dielectric grease to the terminal, as this will aid in the pre­
vention of corrosion.
After the clamps and terminals are clean, reinstall the cables, negative cable
last; Do not hammer the clamps onto battery posts. Tighten the clamps securely,
but do not distort them. Give the clamps and terminals a th in external coating of
grease after installation, to retard corrosion.
Check the cables at the same t ime that the terminals are c leaned. If the insu­
lation is cracked or broken, or if its end is frayed, that cable should be replaced
with a new one of the same length and gauge.
BATTERY & CHARGING SAFETY PRECAUTIONS
Always follow these safety precautions when charg ing or handling a battery.
1 . Wear eye protection when working around batteries. Batteries contain
corrosive acid and produce explosive gas a byproduct of their operation. Acid
on the skin should be neutralized with a solution of baking soda and water
made into a paste. In case acid contacts the eyes, flush with clear water and
seek medical attention immediately.
2. Avoid flame or sparks that could ignite the hydrogen gas produced by the
battery and cause an explosion. Connection and disconnection of cables to bat­
tery terminals is one of the most common causes of sparks.
3. Always turn a battery charger OFF, before connecting or disconnecting
the leads. When connecting the leads, connect the positive lead first, then the
negative lead, to avoid sparks.
4. When lifting a battery, use a battery carrier or lift at opposite corners of
the base.
5. Ensure there is good ventilation in a room where the battery is being
charged.
6. Do not attempt to charge or load-test a maintenance-free battery when the
charge indicator dot is indicating insufficient e lectrolyte.
7. Disconnect the negative battery cable if the battery is to remain in the
boat during the charging process.
8. Be sure the ignition switch is OFF before connecting or turning the
charger ON. Sudden power surges can destroy e lectronic components.
9. Use proper adapters to connect charger leads to batteries with non-con­
ventional terminals.
BATTERY CHARGERS
• See Figure 32
Before using any battery charger, consult the manufacturer's instructions for
its use. Battery chargers are e lectrical devices that change Alternating Current
(AC) to a lower voltage of Di rect Current (DC) that can be used to charge a
marine battery. There are two types of battery chargers-manual and auto­
matic.
90991P34
Fig. 32 Automatic battery chargers, l ike the Battery Tender" from
Deltran, have an important advantage-they can stay connected to
your battery for extended periods without the possibility of over­
charging
3-1 2 MAINTENAN C E
A manual battery charger must be physically disconnected when the battery
has come to a lu l l charge. If not, the battery can be overcharged, and possibly
fai l . Excess charging current at the end of the charging cycle will heat the e lec­
trolyte, resulting in loss of water and active material, substantially reducing bat­
tery life.
_.As a rule, on manual chargers, when the ammeter on the charger reg­
isters half the rated amperage of the charger, the battery is fully
charged. This can vary, and it is recommended to use a hydrometer to
accurately measure state of charge.
Automatic battery chargers have an important advantage-they can be left
connected (for instance, overnight) without the possib i l ity of overcharging the
battery. Automatic chargers are equipped with a sensing device to a l low the bat­
tery charge to taper off to near zero as the battery becomes fu l ly charged. When
charging a low or completely discharged battery, the meter will read close to lu l l
rated output. I f only partially discharged, the in itial reading may b e less than lu l l
rated output, a s the charger responds t o the condition o f the battery. As the bat­
tery continues to charge, the sensing device mon itors the state of charge and
reduces the charging rate. As the rate of charge tapers to zero amps, the charger
will continue to supply a few mi l l iamps of current-just enough to maintain a
charged condition.
TUNE-UP
Introduction
A proper tune-up is the key to long and trouble-free engine l ife, and the work
can yield its own rewards. Studies have shown that a properly tuned and main­
tained engine can achieve better fuel mileage than an out-of-tune engine. As a
conscientious boater, set aside a Saturday morning, say once a month, to check or
replace items which could cause major problems later. Keep your own personal
log to jot down which services you performed, how much the parts cost you, the
date, and the number of hours on the engine at the time. Keep all receipts for such
items as engine oil and filters, so that they may be referred to in case of related
problems or to determine operating expenses. As a do-it-yourseller, these receipts
are the only proof you have that the required maintenance was performed. In the
event of a warranty problem, these receipts wi l l be invaluable.
The efficiency, reliabi l ity, fuel economy and enjoyment available from engine
performance are al l d irectly dependent on having your outboard tuned properly.
The importance of performing service work in the proper sequence cannot be
over emphasized. Before making any adjustments, check the specifications.
Never rely on memory when making critical adjustments.
Before beginning to tune any engine, ensure the engine has satisfactory
compression. An engine with worn or broken piston rings, burned pistons, or
scored cylinder walls, wi l l not perform properly no matter how much time and
expense is spent on the tune-up. Poor compression must be corrected or the
tune-up will not give the desired results.
A practical maintenance program that is fol lowed throughout the year, is one
of the best methods of ensuring the engine wi l l give satisfactory performance.
As they say, you can spend a little time now or a lot of time later.
The extent of the engine tune-up is usually dependent on the time lapse
since the last service. A complete tune-up of the entire engine would entail
almost all of the work outlined in this manual. However, this is usually not nec­
essary in most cases.
In this section, a logical sequence of tune-up steps wi l l be presented in gen­
eral terms. If additional information or detailed service work is required, refer to
the section containing the appropriate instructions.
Each year higher compression ratios are bui lt into modern outboard engines
and the e lectrical systems become more complex. Therefore, the need for reli­
able, authoritative, and detailed instructions becomes more critical. The infor­
mation in this section wi l l lulli l l that requirement.
Tune-Up Sequence
During a major tune-up, a definite sequence of service work should be fol­
lowed to return the engine its maximum performance level. This type of work
should not be confused with troubleshooting (attempting to locate a problem
when the engine is not performing satisfactorily). In many cases, these two
areas wi l l overlap, because many times a minor or major tune-up wi l l correct
the malfunction and return the system to normal operation.
REPLACING BATTERY CABLES
Battery cables don't go bad very often, but l ike anything else, they can wear out.
If the cables on your boat are cracked, frayed or broken, they should be replaced.
When working on any e lectrical component, it is always a good idea to dis­
connect the negative (-) battery cable. This will prevent potential damage to
many sensitive e lectrical components
Always replace the battery cables with one of the same length, or you wi l l
increase resistance and possibly cause hard starting. Coat the battery posts with
a light film of dielectric grease, or a battery terminal protectant spray once
you've installed the new cables. If you replace the cables one at a time, you
won't mix them up.
_.Any time you disconnect the battery cables, it is recommended that
you disconnect the negative (-) battery cable first. This will prevent you
from accidentally grounding the positive (+) terminal when disconnect­
ing it, thereby preventing damage to the electrical system.
Before you disconnect the cable(s), first turn the ignition to the OFF position.
This will prevent a draw on the battery which could cause arcing. When the bat­
tery cable(s) are reconnected (negative cable last), be sure to check al l electrical
accessories are all working correctly.
The following l ist is a suggested sequence of tasks to perform during a tune­
up.
• Perform a compression check of each cylinder.
• Inspect the spark plugs to determine their condition. Test for adequate
spark at the p lug.
• Start the engine in a body of water and check the water f low through the
engine.
• Check the gear oi l in the lower unit.
• Check the carburetor adjustments and the need for an overhaul.
• Check the fuel pump for adequate performance and delivery.
• Make a general inspection of the ignition system.
• Test the starter motor and the solenoid, if so equipped.
• Check the internal wiring.
• Check the timing and synchronization.
Compression Check
Cylinder compression test results are extremely valuable indicators of inter­
nal engine condition. The best marine mechanics automatically check an
engine's compression as the first step in a comprehensive tune-up. Obviously, it
is useless to try to tune an engine with extremely low or erratic compression
readings, since a simple tune-up wi l l not cure the problem.
The pressure created in the combustion chamber may be measured with a gauge
that remains at the highest reading it measures during the action of a one-way valve.
This gauge is inserted into the spark plug hole. A compression test will uncover
many mechanical problems that can cause rough running or poor performance.
If the powerhead shows any indication of overheating, such as discolored or
scorched paint, inspect the cylinders visually through the transfer ports for pos­
sible scoring. lt is possible for a cylinder with satisfactory compression to be
scored sl ightly. Also, check the water pump. A faulty water pump may cause the
overheating condition.
CHECKING COMPRESSION
• See Figures 33, 34 and 35
Prepare the engine for a compression test as fol lows:
1 . Run the engine until it reaches operating temperature. If the test is per­
formed on a cold engine, the read ings wi l l be considerably lower than normal,
even if the engine is in perfect mechanical condition.
2. Label and disconnect the spark plug wires. Always grasp the molded cap
and pul l it loose with a twisting motion to prevent damage to the connection.
3. Clean all d irt and foreign material from around the spark plugs, and then
remove all the plugs. Keep them in order by cylinder for later evaluation.
4. Ground the spark p lug leads to the engine to render the ignition system
inoperative wh i le performing the compression check.
MAI NTENANC E 3-1 3
04702P02 Fig. 34 All spark plugs should be
04702P04
05003P26
Fig. 35 Crank the engine with the starter
through at least 4 complete strokes with
the throttle at the wide-open position, to
obtain the highest possible reading
Fig. 33 Removing the high tension lead.
Always use a twist and pull motion on the
boot to prevent damage to the wire
grounded while making compression
tests. this action will prevent placing an
extra load on the ignition coil
5. I nsert a compression gauge into the No. 1, top, spark plug opening.
6. Crank the engine with the starter through at l east 4 complete strokes with
the throttle at the wide-open position, to obtain the h ighest possible read ing.
Then record the reading.
7. Repeat the test and record the compression for each cylinder.
8. A variation between cylinders is far more important than the actual read­
ings. A variation of more than 1 5 psi (1 03 kPa), between cylinders indicates the
lower compression cylinder is defective. Not al l engines will exhibit the same
compression read ings. In fact, two identical engines may not have the same
compression. General ly, the rule of thumb is that the lowest cylinder should be
with in 25% of the highest (difference between the two read ings).
9. If compression is low in one or more cylinders, the problem may be
worn, broken, or sticking piston rings, scored pistons or worn cylinders.
LOW COMPRESSION
Compression read ings that are generally low indicate worn, broken, or stick­
ing piston rings, scored pistons or worn cylinders, and usually indicate an
engine that has a lot of hours on it. Low compression in two adjacent cylinders
(with normal compression in the other cylinders) indicates a blown head gasket
between the low-read ing cylinders. Other problems are possible (broken ring,
hole burned in a piston), but a blown head gasket is most l i kely.
A conventional compression check will only show secondary compression
readings and not primary crankcase compression. If there is an air leak in the
crankcase, this will cause insufficient fuel to be brought into the crankcase and
cylinder for normal operation . If it is a small leak, the powerhead will run poorly,
because the fuel mixture wi l l be too lean, and cylinder temperatures will be hot­
ter than normal.
Air leaks are possible around any seal, 0-ring, cylinder block mating surface,
or gasket surface. Always replace 0-rings, gaskets and seals when service work
has been preformed. If the powerhead is running poorly, spray soapy water on
the suspected sealing surface and look for bubbles to form, indicating an air
leak. The base of the powerhead and the lower crankshaft seal are impossible to
check in this manner, and wi l l need to be checked by another method, a
crankcase pressure test
To pressure test the crankcase, make up adapters to fit the carburetor mount­
ing studs. Into one adapter fit an air fitting, which wi l l accept a hand pump,
which is used for testing the lower unit. With the powerhead on the bench, place
some rubber gasket material over the exhaust, leaving the water passages open.
Using the hand pump, pressurize the crankcase to 5 psi.
Spray soapy water around the lower crankcase seal area and other seals and
gasket sealing surfaces looking for telltale bubbles. Also, if possible, pu l l a vac­
uum in the crankcase to check the seals in the opposite direction and watch for
a pressure drop.
Spark Plugs
t See Figure 36
Spark plug l i fe and efficiency depend upon the condition of the engine and
the combustion chamber temperatures to which the plug is exposed. These tem­
peratures are affected by many factors, such as compression ratio of the eng ine,
air/fuel mixtures and the type of normally placed on your engine.
Factory installed plugs are, in a way, compromise plugs, since the factory
has no way of knowing what typical loads your engine wi l l see. However, most
people never have reason to change their plugs
04702P05
Fig. 36 Damaged spark plugs. Notice the broken electrode on the
left plug. The electrode must be found and retrieved prior to return­
ing the powerhead to service
SPARK PLUG HEAT RANGE
t See F igure 37
Spark plug heat range is the abi l ity of the plug to dissipate heat. The longer
the insulator (or the farther it extends into the engine), the hotter the plug wi l l
operate; the shorter the insu lator {the closer the e lectrode is t o the block's cool­
ing passages) the cooler it wil l operate. A plug that absorbs little heat and
remains too cool wil l quickly accumulate deposits of oil and carbon since it is
not hot enough to burn them off. This leads to plug fouling and consequently to
misfiring. A plug that absorbs too much heat will have no deposits but, due to
the excessive heat, the e lectrodes will burn away quickly and might possibly
3-1 4 MAI NTENANC E
THE SHORTER
THE PATH. THE
FASTE R THE
HEAT IS 015-
SIPATED ANO
THE COOLER
THE PLUG
HEAVY LOADS.
HIGH SPEEDS
SHORT Insulator T o p
Fasl Heat Transfer
LOWER Heat Range
COLD PLUG
Fig. 37 Spark Plug heat range
THE LONGER
THE PATH. THE
SLOWER THE
HEAT IS DIS­
SIPATED AND
THE HOTTER
THE PLUG
SHORT T RIP
STOP-AND-GO
LONG Insulator T1p
Slow Heat Transfer
HIGHER Heat Range
H O T PLUG
TCCS1046
lead to pre-ignition or other ignition problems. Pre-ignition takes place when
plug tips get so hot that they glow sufficiently to ignite the air/fuel mixture
before the actual spark occurs. This early ignition wi l l usually cause a pinging
during heavy loads.
SPARK PLUG SERVICE
�New technologies in spark plug and ignition system design have
pushed the recommended replacement interval to every 1 OD hours of
operation (6 months). However, this depends on usage and conditions.
This holds true unless internal engine wear or damage cause plug foul­
ing. If you suspect this, you may wish to remove and inspect the plugs
before the recommended time.
Spark plugs should only require replacement once a season. The e lectrode
on a new spark plug has a sharp edge, but with use, this edge becomes
rounded by wear, causing the plug gap to increase. As the gap increases, the
p lug's voltage requirement also increases. it requires a greater voltage to jump
the wider gap and about two to three times as much voltage to fire a plug at
h igh speeds than at idle.
Tools needed for spark plug replacement include: a ratchet, short extension,
spark plug socket (there are two types; either 1¥16 inch or % inch, depending
upon the type of plug), a combination spark plug gauge and gapping too l , and a
can of penetrating o i l or anti-seize type grease for engines with aluminum
heads.
When removing spark plugs, work on one at a time. Don't start by remov­
ing the p lug wires all at once, because un less you number them, they may
become mixed up. Take a minute before you begi n and number the wires with
tape.
REMOVAL & INSTALLATION
1 . Disconnect the negative battery cable, and if the engine has been run
recently, allow the engine to thoroughly cool . Attempting to remove plugs from
a hot cylinder head could cause the plugs to seize and damage the threads in
the cylinder head. Especially on aluminum heads!
2. Carefu l ly twist the spark plug wire boot to loosen it, then pu l l the boot
using a twisting motion and remove it from the plug. Be sure to pu l l on the boot
and not on the wire, otherwise the connector located inside the boot may
become separated.
�A spark plug wire removal tool is recommended as it will make
removal easier and help prevent damage to the boot and wire assem­
bly.
3. Using compressed air (and safety glasses), blow debris from the spark
plug well to assure that no harmful contaminants are a l lowed to enter the com­
bustion chamber when the spark plug is removed. If compressed air is not
available, use a rag or a brush to clean the area. Compressed air is avai lable
from both an air compressor or from compressed air in cans available at pho­
tography stores.
�Remove the spark plugs when the engine is cold , if possible, to pre­
vent damage to the threads. If plug removal is difficult, apply a few
drops of penetrating oil to the area around the base of the plug, and
allow it a few minutes to work.
4. Using a spark p lug socket that is equipped with a rubber insert to prop­
erly hold the plug, turn the spark plug counterclockwise to loosen and remove
the spark plug from the bore.
** WARNING
Avoid the use of a flexible extension on the socket. Use of a flexible
extension may allow a shear force to be appl ied to the p lug . A
shear force could break the p lug off in the cylinder head, leading to
costly and frustrating repairs. In addition, be sure to support the
ratchet with your other hand-this will also help prevent the socket
from damaging the p lug .
Evaluate each cylinder's performance by comparing the spark condition.
Check each spark plug to be sure they are al l of the same manufacturer and
have the same heat range rating. Inspect the threads in the spark plug opening
of the block, and clean the threads before instal l ing the p lug.
When purchasing new spark p lugs, always ask the dealer if there has been a
spark plug change for the engine being serviced.
Crank the engine through several revolutions to blow out any material
which might have become dis lodged during c l eaning. Always use a new gas­
ket (if appl icable). The gasket must be fu l ly compressed on clean seats to
complete the heat transfer process and to provide a gas tight seal in the cyl in­
der.
5. Inspect the spark p lug boot for tears or damage. If a damaged boot is
found, the spark p lug boot and poss ib le the entire wire wi l l need replace­
ment.
6. Apply a th in coating of anti-seize on the thread of the plug. This is
extremely important on aluminum head engines.
7. Careful ly thread the p lug into the bore by hand. If resistance is felt
before the p lug completely bottomed, back the plug out and begin thread ing
again.
** WARNING
D o not use the spark plug socket to thread the p lugs. Always care­
fully thread the plug ilyiland or using an old p lug wire to prevent
the possib i l ity of crossthreading and damaging the cyl inder head
bore.
8. Carefully tighten the spark plug. If the plug you are insta l l ing is equipped
with a crush washer, seat the plug, then tighten to 1 0-15 ft. lbs. (1 4-20 Nm) or
about % turn to crush the washer. Whenever possible, spark plugs should be
tightened to the factory torque specification.
9 . Apply a smal l amount of s i l icone d ielectric compound to the end oi
the spark p lug lead or inside the spark p lug boot to prevent sticking, then
install the boot to the spark plug and push unti l it c l icks into place. The
c l ick may be felt or heard. Gently pull back on the boot to assure proper
contact.
READING SPARK PLUGS
• See Figures 38 thru 44
Your spark plugs are the single most valuable indicator of your engines inter­
nal condition. Study your spark plugs careful ly every time you remove them.
Compare them to i l lustrations shown to identify the most common plug condi­
tions.
Fig. 38 A normally worn spark plug should
have light tan or gray deposits on the fir­
ing tip (electrode)
TCCS2138
Fig. 41 An oil-fouled spark plug indicates
an engine with worn piston rings and/or
bad valve seals allowing excessive oil to
enter the combustion chamber
INSPECTION & GAPPING
TCCS2136
Fig. 39 A carbon-fouled plug, identified by
soft, sooty black deposits, may indicate an
improperly tuned vehicle. Check the air
cleaner, ignition components and the
engine control system.
TCCS2139
Fig . 42 This spark plug has been left in the
engine too long, as evidenced by the
extreme gap-Plugs with such an extreme
gap can cause misfiring and stumbling
accompanied by a noticeable lack of power
MAI NTENANC E 3-1 5
TCCS2137
Fig. 40 A physically damaged spark plug
may be evidence of severe detonation in
that cylinder. Watch that cylinder carefully
between services, as a continued detona­
tion will not only damage the plug, but
could also damage the engine
TCCS2140
Fig. 43 A bridged or almost bridged spark
plug, identified by the build-up between
the electrodes caused by excessive carbon
or oil build-upon the plug
Check spark plug gap before installation. The ground e lectrode (the L-shaped
one connected to the body of the plug) must be paral lel to the center e lectrode and
the specified size wire gauge must pass between the electrodes with a slight drag.
because the read ing may be inaccurate. A round-wire type gapping tool is the
best way to check the gap. The correct gauge shou ld pass through the e lectrode
gap with a slight drag. If you're in doubt, try a wire that is one size smaller and
one larger. The smaller gauge should go through easily, whi le the larger one
shouldn't go through at a l l .
Wire gapping tools usually have a bending tool attached. Use this tool to
adjust the side electrode unt i l the proper distance is obtained. Never attempt to
Always check the gap on new plugs as they are not always set correctly at the
factory. Do not use a flat feeler gauge when measuring the gap on a used plug,
3-1 6 MAINTENAN C E
Tracking Arc
High voltage arcs
between a fouling
deposit o n the
insulator tip and
spark pl ug shelL T h i s
ignites t h e fuel/a i r
mixture at some
point along the
insulator tip.
retarding the ignition
timing which causes
a power and fuel
loss.
Aashover
A dama ged spark
plug boot along with
dirt and moisture.
could perm i t the h i g h
voltage charge to
short over the
insulator to the spa rk
plug shell o r the
engi ne. A buttress
insulator design
helps prevent high
voltage flashover.
Bridged Electrodes
Fou ling deposits
between the
electrodes � g round
out� the high volt ag e
needed to fire the
spark plug. The arc
between the
e l ectrodes does not
occur and the fuel a ir
mixture is not
ignited . This causes a
power loss and
exhaust ing of raw
fue l .
( I
I I I I I
,
Fig. 44 Typical spark plug problems showing damage which may indicate engine problems
Wide Gap
Spark plug e lectrodes
are worn so that the
high voltage charge
cannot arc across the
electrodes. I m proper
gapping of electrodes
on new or �cleaned"
spark plugs cou ld
c a u s e a similar
condition. Fuel
remains unburned
a nd a power loss
result s .
Fouled Spark Plug
Deposits that have
formed on the
insulator tip may
become cond uct ive
and provide a
· shunt" path to t h e
shel l . This p revents
the h i g h volta ge from
arcing between the
electrodes. A power
and fuel loss is the
result .
Crack&d Insulator
A crack in the spark
plug insulator could
cause the hi g h
voltage charge to
" gro . md out." Here.
the spark does not
j u m p the electrode
g a p and the fuel a i r
mixture is not
ig nited . This causes a
power l oss and raw
fuel is exhausted.
TCCS201A
bend the center electrode. Also, be careful not to bend the side e lectrode too far
or too often as it may weaken and break off with in the engine, requiring removal
of the cylinder head to retrieve it.
Spark Plug Wires
TESTING
At every tune-up/inspection, visually check the spark plug wires for burns,
cuts, or breaks in the insulation. Check the boots on the coil and at the spark
plug. Replace any wire that is damaged.
Once a year, usually when you change your spark plugs, check the resistance
of the spark plug wires with an ohmmeter. Wires with excessive resistance wi l l
cause misfiring and may make the engine difficult to start. In addition worn
wires wi l l a l low arcing and misfiring in humid conditions.
Remove the spark plug wire from the engine. Test the wires by connecting
one lead of the ohmmeter to the coil end of the wire and the other lead to the
spark plug end of the wire. Resistance should measure approximately 7000
ohms per foot of wire.
When instal l ing a new set of spark p lug wires, replace the wires one at a time
so there will be no confusion. Coat the inside of the boots with dielectric grease
to prevent sticking. Install the boot firmly over the spark plug until it c l icks into
place. The c l ick may be felt or heard. Gently pu l l back on the boot to assure
proper contact. Route the wire the same as the original and install it in a simi lar
manner on the engine. Repeat the process for each wire.
REMOVAL & INSTALLATION
When insta l l ing a new set of spark plug wires, replace the wires one at a t ime
so there wi l l be no confusion. Coat the inside of the boots with dielectric grease
to prevent sticking. Install the boot firmly over the spark p lug until it c l icks into
place. The cl ick may be felt or heard. Gently pu l l back on the boot to assure
proper contact. Route the wire the same as the original and install it in a simi lar
manner on the engine. Repeat the process for each wire.
Ignition System
The electronic COl ignition system has become one of the most reliable
components on the modern outboard engine. There is very little maintenance
involved in the operation of the ignition and even less to repair if the component
fails. Most systems are sealed and there is no option other than to replace the
failed component.
I! is very important to narrow down the ignition problem and replace the cor­
reel component rather than just replace parts hoping to solve the problem. Elec­
tronic components can be very expensive and are usually not returnable. Please
refer to the "Ignition and Electrical" Section for more information on trouble­
shooting and repairing the COl ignition system.
Timing And Synchronization
TIMING
Timing and synchronization on an outboard engine is extremely important to
obtain maximum efficiency. The powerhead cannot perform properly and pro­
duce its designed horsepower output if the fuel and ignition systems have not
been precisely adjusted.
All units covered in this manual except those equipped with the Integrated
C ircuit ( IC) and Micro Link Ignition System, are equipped with a mechanical
advance type Capacitor Discharge Ignition (COl) system and use a series of l ink
rods between the carburetor and the ignition base p late assembly. At the time
the throttle is opened, the ignition base p late assembly is rotated by means of
the l ink rod, thus advancing the timing.
On the IC and Micro Link equipped models, the microcomputer decides
when to advance or retard the timing, based on input from various sensors.
Therefore, there is no l ink rod between the magneto control lever and the stator
assembly.
Many models have timing marks on the flywheel and COl base. A timing light
is normally used to check the ignition timing dynamically-with the powerhead
MAINTENANC E 3-1 7
operating. An alternate method is to check the static timing-with the powerhead
not operating. This second method requires the use of a dial indicator gauge.
Various models have unique methods of checking ignition timing. These dif­
ferences are explained in detail later in this section.
SYNCHRONIZATION
In simple terms, synchronization is timing the fuel system to the ignition. As
the throttle is advanced to increase powerhead rpm, the carburetor and the igni­
tion systems are both advanced equally and at the same rate.
Any time the fuel system or the ignition system on a powerhead is serviced
to replace a faulty part or any adjustments are made for any reason, powerhead
timing and synchronization must be carefu l ly checked and verified. For this rea­
son the timing and synchronizing procedures have been separated from al l oth­
ers and presented alone in this section.
Before making adjustments with the t iming or synchronizing, the ignition
system should be thoroughly checked and the fuel system verified to be in good
working order.
On the breaker point ignitions, synchronization is automatic once the point
gap and the piston travel or timing mark alignments are correct.
Models equipped with electronic ignitions are statically timed by al igning the
timing marks on the throttle cam or throttle stopper with timing marks on the
flywheel . In itial timing and timing advance are both set this way before using a
timing light to check the timing.
Before making adjustments with the timing or synchronizing, the ignition
system should be thoroughly checked and the fuel system verified to be in good
working order.
PREPARATION
Timing and synchronizing the ignition and fuel systems on an outboard
motor are critical adjustments. The following equipment is essential and is
called out repeatedly i n this section. This equipment must be used as described,
unless otherwise instructed by the equipment manufacturer. Naturally, the
equipment is removed following completion of the adjustments.
Suzuki also recommends the use of a test wheel instead of a normal pro­
pel ler in order to put a load on the engine and propeller shaft. The use of the
test wheel prevents the engine from excessive rpm.
The Synchronizing of the fuel systems on an outboard motor are critical
adjustments. The following equipment is essential and is called out repeatedly
in this section. This equipment must be used as described, unless otherwise
instructed by the equipment manufacturer. Naturally, the equipment is removed
following completion of the adjustments.
Dia l Indicator
Top dead center (TDC) of the No. 1 (top) piston must be precisely known
before the timing adjustment can be made. TDC can only be determined through
installation of a dial indicator into the No. 1 spark plug opening.
Timing Light
During many procedures i n this section, the timing mark on the flywheel
must be aligned with a stationary timing mark on the engine whi le the power­
head is being cranked or is running. Only through use of a timing l ight con­
nected to the No. 1 spark plug lead, can the timing mark on the flywheel be
observed whi le the engine is operating.
Tachometer
A tachometer connected to the powerhead must be used to accurately deter­
mine engine speed during idle and h igh-speed adjustment. Engine speed read­
ings range from 0 to 6,000 rpm in increments of 1 00 rpm. Choose a
tachometers with solid state e lectronic c i rcuits which e l iminates the need for
relays or batteries and contribute to their accuracy.
A tachometer is installed as standard equipment on most powerheads covered
in this manual. Due to local conditions, it may be necessary to adjust the carbure­
tor while the outboard unit is running in a test tank or with the boat in a body of
water. For maximum performance, the idle rpm should be adjusted under actual
operating conditions. Under such conditions it might be necessary to attach a
tachometer closer to the powerhead than the one installed on the control panel.
3-1 8 MAI NTENAN C E
Flywheel Rotation
The instructions may call for rotating the flywheel until certain marks are
aligned with the timing pointer. When the flywheel must be rotated, always move
the flywheel in the indicated direction. If the flywheel should be rotated in the
opposite direction, the water pump impel ler vanes would be twisted.
Should the powerhead be started with the pump tangs bent back in the wrong
direction, the tangs may not have time to bend in the correct di rection before
they are damaged. The least amount of damage to the water pump wi l l affect
cool ing of the powerhead.
Test Tank
Since the engine must be operated at various times and engine speeds dur­
ing some procedures, a test tank or moving the boat into a body of water, is
necessary. If insta l l ing the engine in a test tank, outfit the engine with an appro­
priate test propeller.
** CAUTION
Water must circulate through the lower unit to the powerhead any­
time the powerhead is operating to prevent damage to the water
pump in the lower un it. Just five seconds without water wi l l damage
the water pump impeller.
�Remember the powerhead will not start without the emergency tether
in place behind the kill switch knob.
** CAUTION
Never operate the powerhead above a fast id le with a flush attach­
ment connected to the lower un it. Operating the powerhead at a
high rpm with no load on the propeller shaft could cause the power­
head to runaway causing extensive damage to the unit.
DT2 and DT2.2
IGNITION TIMING
• See Figures 45, 46, 47 and 48
1 . Mount the engine in a test tank or move the boat to a body of water.
2. Remove the cowling and connect a tachometer to the powerhead.
3. Remove the flywheel.
4. Remove the spark plug.
5. Disconnect the magneto lead (usually white) from the connector and the
stator lead (usually black) from the connector.
�Before checking the ignition timing, make sure that the contact
point faces are in good condition. Sand and make parallel the two
faces by grinding with an oil stone if necessary and wipe the points
clean with solvent. Apply a small dab of grease to the breaker
shaft.
Bad Bad
Good
05003G04
Fig. 45 Check the condition of the points before setting the point gap
\
04707G19
Fig. 46 Measure the breaker point gap using a feeler gauge
A: Decreasing gap B: lncreasmg gap
04707G20
Fig. 47 Using a screwdriver, adjust the breaker point gap by rotating
the points
05003G05
Fig. 48 Remove the spark plug and install the dial indicator to measure the piston travel
6. Check and adjust the breaker point gap to 0.01 2-0.01 6 in . (0.3-0.4
mm) by moving the breaker base plate.
7. Install a dial indicator with a special adapter (09931 -001 1 2) in the spark
plug hole.
8. Rotate the flywheel c lockwise until the piston has reached TDC then
reset the indicator to zero.
9. Connect an ohmmeter between the magneto wire and a good engine
ground. A timing tester (09900-27003) can also be used.
1 0. Gently turn the rotor clockwise (with the tester turned on) until the ohm­
meter indicates continuity or the timing tester starts buzzing. Read the dial indi­
cator, this read ing is the piston travel and if the timing is set correctly, the
indicator should read: 0.032 in . (0.804 mm).
If the reading is not within specification, retime the ignition system as fol­
lows:
1 1 . Remove the flywheel magneto, loosen the screws securing the stator,
and manually turn the stator c lockwise to retard and counterclockwise to
advance the timing by the amount necessary to meet specification.
• If the correct gap cannot be obtained by adjustment, the points
should be replaced.
I DLE SPEED
t See Figure 49
I . Mount the engine in a test tank or move the boat to a body of water.
2. Remove the cowling and connect a tachometer to the powerhead.
3. Start the engine and allow it to reach operating temperature.
4. Check idle speed and compare it with the specified idle speed in the
'Tune-Up Specifications" chart.
5. If adjustment is necessary, rotate the idle adjustment screw on the
carburetor until the powerhead idles at the required rpm.
1 . Id le speed screw
Fig. 49 To raise or lower the idle, turn the throttle stop screw
DT4 and DT5Y
IGN ITION TIMING
t See Figure 50
The DT4 and DT5Y ignition system is a magneto CD! which provides high
spark performance regardless of engine rpm. The electronic advance system
provides optimum ignition timing for all conditions. Ignition timing is not
adjustable. Each coil is not provided with any base plate for installation, but
instead is constructed so that the coil itself can be mounted directly to the
boss projected from the cylinder or crankcase. If the coils are installed in the
correct position, the ignition timing will be within specification.
I . Mount the engine in a test tank or move the boat to a body of water.
2. Remove the cowling and connect a tachometer and a timing light to
the powerhead.
3. Start the engine and allow it to warm to operating temperature. Place
the engine in gear.
4. Aim the timing light at the timing window and the pointer on the recoil
starter should line up with the timing mark on the rotor.
Rotor assy
I g n i t i o n T i m i n g Match Mark
[7 l i nes sta mped a t the
pos i t ions fro m T ( T D C ) to 30°
BTDC at i nterva ls of 5° ]
Fig. 50 Ignition timing marks on the flywheei-DT4 and DT5Y
MAINTENANCE 3-1 9
5. Ignition timing is about: 7°BTDC at I 000 rpm and 24-25°BTDC at
5000 rpm. For more details, please refer to the Tune-Up Specifications chart.
6. Timing cannot be adjusted. If timing is incorrect, a fault has occurred
in the CDI system and a test of the CDI unit needs to be performed.
I DLE SPEED
t See Figure 51
I . Mount the engine in a test tank or move the boat to a body of water.
2. Remove the cowling and connect a tachometer to the powerhead.
3. Start the engine and allow it to warm to operating temperature.
4. Turn the air screw ( I ) in until it lightly seats and then back it out
gradually. The engine will pick up speed correspondingly and then cease to
rise. Set the air screw slightly before this point. See the "Idle Air Screw
Specifications" chart for the base setting.
5. Shift the clutch into the forward position.
6. Run the throttle stop screw (2) in and out until the correct engine
speed is reached. Idle speed specifications are :Ocated in the "Tune-Up
Specifications" chart.
1 . Air screw
2. Throttle stop screw
Fig. 51 Air screw and throttle stop screw-DT4 and DT5Y
DT6 and DT8
IGNITION T IMING
t See Figures 52, 53, 54, 55 and 56
The DT6 and DT8 models use the Suzuki PE! simultaneous ignition
system. The ignition timing is advanced in this system by moving the
magneto stator according to the carburetor throttle opening.
The Suzuki PEI system is maintenance free because of the absence of
breaker points. it produces a strong spark over a wide range of engine
speeds from idle to wide open throttle.
The CDI unit which is integral with the ignition coil is compact and easy to
handle.
I . Mount the engine in a test tank or the boat in a body of water.
2. Remove the cowling and connect a tachometer and timing light to the
powerhead.
• Magneto Stator Assembly
The slater base moves according to the throttle opening to obtain the
correct ignition timing. For this reason, brass is cast in the spigot joint of the
oil seal housing and the stator base. Parts of the stator base include a coil
which charges a capacitor of the CDI unit, a pulser coil which sends a signal
to the CDI unit at ignition timing, and a lighting coil which generates lighting
output of I 2V and BOW.
• Setting the static ignition timing
Bring the face of the retainer stopper in line with the alignment mark of
the magneto slater and fix the retainer stopper with bolts. When the end face
of the stopper retainer is aligned with the boss of the cylinder center, ignition
timing is -2°-t2°(no advance angle).
a. For the full-advance angle, adjust the length of the stator rod so that
the throttle arm contacts the inlet case-side stopper. Now the ignition timing
is 23-2?DBTDC (full advance angle).
3-20 MAI NTENAN C E
05003809
Fig. 52 Align the end of the retainer stopper (1 ) with the stator
alignment mark (2)
Advance angle is
0° ± 2" when the
No advance (TDC)
1 . Stator arm
2. Throttle arm
05003810
Fig. 53 Adjust the length of the stator rod so that the throttle arm
contacts the inlet case side stopper
Full advance 125° BTDC)
05003812 05003813 05003811
Fig. 54 Correct position of the retainer
stopper against the boss of the cylinder
center
Fig. 55 With the throttle fully closed, tim­
ing mark should be like this (no advance
TDC)-DT6 and DT8
Fig. 56 Fully open the throttle, timing
marks should line up this (full advance
25°BTDC) - DT6 and DT8
5. Checking the ignition timing (dynamic adjustment). To check ignition tim­
ing, warm up the engine for about 5 minutes. Then check if the cylinder center
l i ne is in l i ne with the mark engraved beside the letter 'T on the flywheel with
the throttle fully closed. If the marks in l i ne, the engine piston is at TDC. Next
fully open the throttle. If the cylinder center l i ne is within the range bounded by
the three mark lines engraved on the flywheel, the piston is with in 2°of 25°BTDC.
IDLE SPEED
t See Figures 57 and 58
1. Mount the engine i n a test tank or move the boat to a body of water.
05003814
Fig. 57 Adjust the pilot air screw the specified turns open
2. Remove the cowling and connect a tachometer to the powerhead.
3. Start the engine and allow it to warm to operating temperature.
4. Turn the air screw in until it l ightly seats and then back it out gradually.
The engine wi l l pick up speed correspondingly and then cease to rise. Set the
air screw sl ightly before this point. See the "Idle Air Screw Specifications" chart
for the base setting.
5. Sh ift the clutch into the forward position.
6. Run the throttle stop screw i n and out until the correct engine speed is
reached. Idle speed specifications are located in the "Tune-Up Specifications"
chart.
05003815
Fig. 58 With the engine in forward gear, adjust the throttle stop
screw to the correct position
DT9.9 and DT1 5
IGNITION TIMING
• See Figures 59, 60, 61 , 62 and 63
The DT9.9 and DT1 5 are equipped with a s ing le ignition coi l for both
cylinders and uses a mechanical advance system that changes the ignition
timing by interlocking the stator to the carburetor opening. The CDI un it and
the ign ition coi l are integrated to make the size compact and maintenance
easier.
• The stator is made up of the ignition coil and a 1 2v SOw battery charge
coil mounted on the aluminum base plate.
• The flywheel is constructed of cast iron and incorporates a tetra-pole. The
05003G16
Fig. 59 Flywheel ignition timing marks
MAINTENANC E 3-21
electric start model has a ring gear attached to the outer edge wh i le the manual
start model does not. The flywheel has 4 engraved l i nes marked in 2°increments
from 4°ATDC to 2°BTDC and 6 engraved l ines marked in 2 oincrements from
1 JOBTDC to 2JOBTDC. These marks are used in conjunction with a timing l ight
to inspect and adjust the ignit ion timing.
The static ignition timing adjustment is performed as fol lows:
• With the engine shut down, fu l ly close the throttle. Contact the projection
end surface of the magneto stator retainer to the inner side surface of the throttle
cam. Thus adjust the setting marks of both parts so that they align with each
other. Loosen the two cam set-screws and move the cam so that the stator-side
and cam-side setting marks al ign.
•On the DT9.9 make sure to lighten the cam stopper screw after adjust­
ing.
• The maximum retard timing is 0°-4°ATDC at 650 rpm. Maximum
advance timing is 1 6.5°-20.5°BTDC at 5000 rpm for the DT9.9 and
23°-2J0BTDC at 5000 rpm for the DT15.
Dynamic ignition timing adjustment:
• Start and warm up the engine for about 5 minutes.
• Shift the clutch to neutral and keep the eng ine speed to 650 rpm.
• Ignition timing is indicated by the timing arrow attached to the side of the
recoil starter pointing at any of the l i nes engraved on the outer surface of the
flywheel.
• Using a timing l ight, make sure the timing arrow remains within a range
of 0°-4°ATDC at 650 rpm. If not, the timing must be adjusted to al ign the tim­
ing marks.
IDLE SPEED
• See Figures 64 and 65
1. Mount the engine in a test tank or move the boat to a body of water.
2. Remove the cowling and connect a tachometer to the powerhead.
1 . Th rattle cam
05003G17 05003G18
05003G19
Fig. 60 Static adjustment alignment marks Fig. 61 Throttle cam adjustment Fig. 62 DT15 Maximum advance position
1 . Cam stopper screw
05003G20 05003G21
Fig. 63 Cam stopper screw on the DT9.9 Fig. 64 Adjust the pilot air screw to the specified turns out
3-22 MAI NTENAN C E
05003G22
Fig. 65 Adjust the engine speed by turning the throttle stop screw
3. Turn the pi lot air screw in until it l ightly seats and then back it out the
number of turns l isted in the "Idle Air Screw Specifications" chart
4. Start the engine and al low it to warm to operating temperature. Place the
engine in gear.
5. Set the throttle lever to the ful l closed position.
6. Adjust the engine speed to the specification l isted in the "Tune-Up Speci­
fications" chart by turning the throttle stop screw.
�Make sure that the choke valve on the carburetor is in the full open
position before adjusting the idle speed.
DT20, DT25 and DT30
IGNITION TIMING
This model uses the Suzuki IC (Integrated Circuit) ignition control to main­
tain precise spark timing for better power and acceleration.
A built in IC control un it mon itors the degree of throttle opening and the
engine rpm, it then determines the ideal spark timing. This not only improves
acceleration, but by maintaining optimum carburetion and ignition synchro­
nization the engine runs smoother and responds to throttle changes much
quicker.
Since the ignition timing is controlled according to the opening of the
throttle, it is not affected by any change in the engine speed.
For easier starting, every time the engine started, the ignition timing auto­
matically advances to 5°BTDC for 15 seconds, after which time the ignition tim­
ing will return to the idle speed circuit and what ever position the " Id le Speed
Adjustment Switch" is set at
�Due the higher rpm of this setting, do not shift gears until the rpm's
have returned to the idle setting.
The idle speed ignition t iming can be changed between 5 positions by means
of the "Idle Speed Adjustment Switch" when the carburetor throttle valves are in
the ful l closed position.
The ignition timing range of this switch is goATDC when it is in the slow
position and 1 °ATDC in the fast position. Each position of the switch repre­
sents a 50 rpm change. When the throttle valve is in the ful l closed position,
ignition timing is returned automatically to the timing of the "Idle Speed
Adjustment Switch" . This guarantees that the engine rpm will return to idle
automatically.
To further assure the exact ignition timing, a gear counter coi l measures fly­
wheel position and relays this information to the CDI unit
�The "Idle Speed Adjustment Switch" is the only means of adjusting
the engine trolling speed.
THROTTLE LINKAGE ADJUSTMENT
• See Figure 66
1. Loosen the throttle lever adjusting screws on the top and 3rd carburetors.
Then turn the plates counterclockwise to ensure fu l l they're at the fu l l closed
throttle position. Hold the plates and tighten the screws.
2. Adjust the lever l i nk rod to an in itial length of 3.0 in . (75.5 mm) between
the center holes in each connector.
3. At the fu l l closed throttle position, the throttle lever arm must be against
the stop boss on the block and a clearance of 0 .02-0.06 in. (0.5-1 .5 mm) must
exist at this point If the clearance is not correct, recheck the carburetor throttle
valves and make sure that they are in the ful l closed position and recheck the
throttle rod length. Readjust if necessary.
4. Check the synchronization of a l l three carburetors to make sure they fully
open and close.
�Always adjust the throttle l inkage after adjusting the oil pump link­
age.
05003G23
Fig. 66 Throttle linkage measurement positions
IDLE SPEED
1. Mount the engine in a test tank or move the boat to a body of water.
2. Remove the cowling and connect a tachometer to the powerhead.
3. Start the engine and a l low it to warm to operating temperature. Place the
engine in gear.
4. Check engine speed at idle. The powerhead should idle in at the rpm
specified in the Tune-up Specifications chart
5. Turn the p i lot screw in until it l ightly seats and then back it out the num­
ber of turns specified in the "Idle Air Screw Specifications" chart
6. Place the engine in gear and check engine tro l l ing speed in the same
manner.
7. Turn the idle speed adjusting knob to adjust the idle speed to the specifi­
cation l isted in the "Tune-Up Specifications chart.
�The engine trolling speed has been factory adjusted to the optimum
speed. Trolling speed varies depending on boat type, weather conditions,
propeller type and other variables. Adjustment can only be done with the
engine in the water so there is back pressure against the exhaust sys­
tem.
DT35 and DT40
IGNITION TIMING
• See Figures 67, 68 and 69
In these engines, a 2-cylinder simu ltaneous ignition CO l system has been
adopted. The component parts of the ignition system are a magneto and CO l
unit. The COl un it contains the ignition coi l . The ignition timing characteristics
are made up of the advance angle of the magneto itself and the advance angle
of stator sl iding. An electronic advance system employing IC has been adopted
in the advance angle of the magneto itself to assure highly precise ignition
characteristics. The COl unit also includes the over-rev l imiter and oil warn ing
circuit.
The total 27"ignition timing is the result of the combination of magneto and
COl unit that produces the ?"electrical advance angle shown in the i l l ustration
and the 20°advance angle when the magneto stator slides.
When the flywheel rotates, e lectromotive force is generated in the condenser
charge coil and causes the current output from the positive side to flow from
the condenser charge coil to the diode to the condenser to the ignition coi l
where it then charges the condenser charge co i l . Next, when the timing coi l
and the flywheel magneto pole piece position become opposed, output is gen­
erated in the timing coi l , resulting i n the current f low from the timing coi l to
the diode to the SCR gate to ground, causing the SCR to change over from
OFF to ON.
.--------@
CD--��......., IU��-
® @
1 . Condenser charge coil
2. Stator assy
3. Timing coil
4 . Lighting coil
05003G36
Fig. 67 Ignition system components-DT40
MAINTENANC E 3-23
A. Timing marks
05003G37
Fig. 68 Timing marks on the flywheel assembly
+ 20
+ 1 0
00
-1 0
Ql "ii -20 c
r-""I I
"' -30 I» u
c -40 "' >
"0 -50 <
I
-60
-70
I I I
I V
1 000 2000 3000 4000 5000 6000
--- Engine rpm
05003G38
Fig. 69 The total ignition timing is the result of the combination of
magneto and CDI unit that produces the electrical advance angle
shown
The e lectrical charge in the previously charged condenser flows from the
condenser to the SCR to ground then to the ignition coi l primary side and
causes high voltage to be induced in the ignition coil secondary side causing
the spark to jump across the spark plug gap. Since this is a simultaneous igni­
tion system, both cylinders fire at the same time irregardless of which cylinder
is firing.
This type of ignition system has flat wave characteristics up to 1 ,000 rpm.
When engine speed rises above 1 ,000 rpm, the output of the arithmetic circuit
built into the IC advances ahead of the output of the timing coil which starts the
angle advance.
Up to 2,500 rpm, the advance angle i ncreases in a designated ratio
corresponding to the engine rpm. When above this rpm, the angle advance
stops and exhibits a nearly flat wave characteristic. The advance angle of
the magneto itself is ?"but in actual ity, wh i l e mechanical ly s l id ing the mag­
neto stator 20°, a total of 27"(ATDC 2°- BTDC 25°) advance angle is real­
ized.
3-24 MAINTENANC E
Static Adjustment
MAXIMUM ADVANCE SIDE
• See accompanying i l lustration
To adjust the ign ition timing without starting the engine, proceed as fol lows
whi le referring to the accompanying i l lustration:
1 . Shift the clutch into forward gear.
2. Put the throttle in the wide lu l l open position.
3. Keep this condition to align the mark (A) on the magneto stator (1) and
the cylinder-to-crankcase fitting surface (C) with each other.
4. Keep this condition to loosen the screws (9) on the throttle cam (2)
toward the direction indicated by the arrow mark (S) until contacting the
crankcase side stopper (E), and fix the cam by tightening the screws (9) at this
position.
5. Stil l keep this position to loosen the screw (1 0) on the carburetor, open
the carburetor link toward the direction indicated by the arrow mark (T) fu l ly hit­
ting against the opponent, move the rotor (U) toward the direction indicated by
Static t iming adjustment reference points
the arrow mark (V) so as to contact the throttle cam (2) and tighten the screw
( 10) at this condition.
MAXIMUM RETARD SIDE
1 . Place shift lever into the Forward 1 st notch.
2 . A l ign the mark (B) on the magneto stator and the cyl inder-to­
crankcase fitting surface (C) with each other. Turn the adjust bolt (5) so that
the adjust bolt cap (4) contacts the crankcase-side stopper (D), and fix it by
the nut (6).
3. Move the throttle l imiter (1) toward the direction (W) unti l hitting against
the undercover-side stopper (F) and check to see whether the carburetor can be
ful ly opened at this condition.
4. 11 the carburetor cannot be fu l ly opened, adjust the rod (7) for the proper
length and fix it by the nut (8). The rod (7) should have a standard length of
4.25 in. (1 08 mm).
5. Adjust the throttle cable so that the stator can be fu l ly opened and c losed
(DT 40C/DT 40CE).
Dynamic adjustment
** CAUTION
Before this adjustment, start the engine and warm it up for about 5
m inutes. Before starting this adjustment, be sure to remove the
throttle rod ( 11 ) .
FULL ADVANCED IGNITION TIMING ADJUSTMENT
• See accompanying i l lustrations
1 . Sh ift the clutch to forward.
2. To check the fu l l-advanced ign ition timing, keep the engine running at
1 ,000 rpm and move the throttle limiter (1 ) to the fu l l advanced position (W).
** WARNING
This procedure is required to check the ignition timing whi le the
engine is running at 5 ,000 rpm, but this method is very dangerous
and here is an alternative method in which the ignition timing is
advanced by hand with the engine running less than 1 ,ODD rpm .
3 . Keep the throttle l imiter (1 ) i n this position.
4. Check that the timing plate points to 1 8.5°BTDC, using a timing light.
05003G41
Step 3
05003G42
Step 4
,.When this method is used as a substitute, the ignition timing should
be set at 1 8.SOBTDC at 1 ,ODD rpm, but in actual operation, the ignition
timing will be 18°8TDC at 5,000 rpm, showing a time lag of D.SO. The
actual ignition timing is 25°8TDC, this being the result of rot advance
by the magneto and 18°0f advance caused by sliding the stator.
5. If the ign ition timing is off 1 8.5°BTDC, loosen the two screws ( 1 ) and
move throttle cam (2) to right and left as shown in the i l l ustration to adjust.
After adjusting, tighten the screws (1 ) securely.
6. After adjustment, install the throttle rod to the original position.
MAI NTENANC E
, / / I I I
3-25
, " " ./' ) /
,•
05003G43
Step 5
FULL RETARDED IGNITION ADJUSTMENT
1 . Sh ift the c lutch to Neutral and keep the engine speed at 1 ,000 rpm.
2. Ignition timing is indicated by the timing arrow attached on the side of
the recoil starter pointing at any of the l i nes engraved on the outer surface of the
flywhee l .
3. Us ing a t iming l ight, make sure the timing arrow remains within a range
of 2°plus or minus 1 °ATDC at 1 ,000 rpm. If not, the ignition timing must be
readjusted.
4. To retard the t iming, loosen the lock nut and turn the adjusting screw
counterclockwise. To advance the timing, turn the adjusting screw clockwise.
5. After the timing has been adjusted correctly, tighten the lock nut.
I DLE SPEED
• See accompanying i l lustration
** CAUTION
.
Before this adjustment is made, be sure to check the ignition timing
and adjust it as needed. Start and thoroughly warm up the engine
for about 5-minutes.
1 . Using the access holes in the air s i lencer, insert a screwdriver to the car­
buretor, and turn in the p i lot air screw all the way in unti l it l ightly seats, and
then back it out the number of turns specified in the "Idle Air Screw Specifica­
tions" chart.
** CAUTION
Be extra cautious to not tighten the a i r screw too much . 1 t wi l l dam­
age the screw and seat.
2. Place the shift lever (or remote control) in the first notch of Forward gear.
3. Keeping the engine in this condition, turn the carburetor-side throttle
05003G44
Step 3
3-26 MAINTENAN C E
screw. This wi l l allow you to adjust the engine speed to the specification located
in the "Tune-Up Specifications" chart.
,..Make sure that the choke valve on the carburetor is in the full-open
position.
THROTTLE LINKAGE
• See Figure 70
The rod length can be determined by measuring the two throttle rods. The
lengths should measure as fol l ows:
• Dimension "A" 4.25 in . (1 08 mm)
• Dimension "B" 1 .77 in. (45 mm)
Measure the rods between the connectors.
1 . Turn the throttle grip (or remote control lever) to the ful l open position
and turn the shaft lever "C" to the fu l l open position until the stopper "D" con­
tacts the protrusion on the carburetor. The lock the lever in position with the
lock screw.
** CAUTION
After making the above adjustment, move the throttle grip to check
for smooth throttle operation .
05003G39
Fig. 70 Throttle l inkage adjustment dimensions-DT35 and DT40
DT55 and DT65
IGNITION TIMING
• See Figures 71 , 72 and 73
The DT55 and DT65 use the Suzuki IC (integrated circuit) ignition system.
Ignition timing adjustment is not necessary on models equipped with these
ignition systems with the exception of adjusting the throttle valve sensor. They
are equipped with the following features:
• Engine Start Advance Mechanism. This feature ensures easy engine start­
ing by automatically advancing the ignition advance to 1 0°BTDC for about 1 5
seconds, after which, the IC control circuit changes over to troll ing ignition tim­
ing "A"
• Tro l l ing Speed Adjusting Mechanism. The tro l l ing ignition timing can be
changed at 2° intervals from oo to 6°ATDC by means of an idle speed adjusting
switch. By changing over the tro l l ing ignition timing, the troll ing speed can be
adjusted.
• All models after 1 991 have had the Idle Speed Adjustment Switch
removed and instead an ignition timing resistor has been instal led. With this
modification, the in gear id le timing with the throttle ful ly returned is kept at a
constant 6°ATDC.
,.. The engine rpm at trolling speed has been factory set at approxi­
mately 700 rpm. The trolling speed varies depending on boat type,
weather conditions, propeller types and other variables. Adjust the
trolling speed with the idle speed adjusting switch to obtain the desired
engine speed.
• Advance Stop Mechanism. When closing the throttle valve fu l ly, an idle
switch " 1 " is "ON" in conjunction with the carburetor and regardless of the
engine rpm, the tro l l ing ignition timing can be obtained. Therefore, by returning
the throttle valve to its fu l ly closed position during high speed travel , the boat's
speed can be decreased suddenly.
• Acceleration Advance Mechanism. This device is avai lable to increase
engine rpm quickly during sudden acceleration. When an acceleration switch
"2" is "ON" in cooperation with the carburetor, the ignition timing of the basic
advance characteristic "2" is quickened to the ignition timing of the acceleration
advance characteristic "C"
• Throttle Valve Switch and Cam. As the throttle valve moves, a cam fitted
to the end of the throttle valve shaft moves accord ingly to put the roller of the
throttle valve switch in motion. By moving the rol ler, the switch is turned ON
and OFF sending a signal to the CDI unit where the ignition timing is changed.
When the throttle valve is fully closed, the idle switch "1" is "ON" and the accel­
eration switch is "OFF". Once the throttle valve is opened, the idle switch "1" is
"OFF" and the acceleration switch "2" is "ON"
On the DT55 and DT65, the working angles at which the idle switch and
acceleration switch turn "On" and "OFF" differ from each other. Therefore, two
d ifferent cams have been developed, one being for thew DT55 and the other for
the DT65. They can be told apart by the different markings on them. The numer­
als on the cams denote the angle until the switch is "OFF" "C" from the vertical
l i ne "A" and an angle until the acceleration switch is "ON" "D" from the vertical
l ine "A"
IDLE SPEED
1. On the carburetor, turn the p i lot air screw al l the way in until it l ightly
seats and then back it out the number of turns specified i n the "Idle Air Screw
Specifications" chart.
2. Place the remote control lever forward gear (idle).
3. Turn the idle speed adjusting switch, and adjust the idle speed to the
specification l isted in the "Tune-Up Specifications" chart.
,..Make sure the choke valve is in the fully open position.
I dle speed
adjusting switch
Fig . 71 Trol l ing speed a djusting mechanism
05003G25
CD "OFF" @ "ON"
Throttle valve full open
Fig. 72 Throttle valve switch and cam
DT55 DT65
Surface
f@f Back
05003G27
Fig. 73 Working angles of throttle valve switch
MAINTENANC E
Cam
Throttle valve
shaft Throttle valve close
Throttle valve open
THROTTLE LINKAGE
• See Figures 74 and 75
3-27
05003G26
Ful l-close adjustment of the throttle valve. DT55 (serial number
501001-502859) and DT65 (serial number 501001-502959)
1 . Remove the throttle lever rod (1) from the throttle control (2) lever.
2. Loosen the set screw (4) on the lever (3) of the #1 and #3 carburetors.
3. Tighten the set screw (4) with the throttle valves of the #1 and #3 carbu­
retors fu l ly closed.
4. Check operation by moving the lever (5) of the #2 carburetor to make
sure the individual throttle valves o! each carburetor operate together.
_.If they do not work together uniformly, make the above adjustments
again.
Full close adjustment of the throttle valve. DT55 (serial number
502860 to present) and DT65 502960 to present).
5. Remove the throttle lever rod (1 ) from the throttle control lever (2).
6. Loosen the set screw (4) of the lever (3) of #1 and #3 carburetors. In
th is case, the throttle valve is set to its lull-closed position by the action of a
return spring.
7. Move the lever (5) of the second carburetor, a few times (more than 30°)
as shown by the arrow (A) to e l im inate any play i n the throttle rod between the
carburetors. A l l the throttle valves should be closed evenly.
8. Apply a thread locker to the loosened set screw (4) and tighten.
9. Check operation by moving the lever (5). All throttle valve should move
at the same time.
Adjustment of the throttle lever rod
1 0. Adjust the dimension (B) of the throttle lever rod (1) to the following
length and attach the control lever:
• Standard dimension (B): DT55-4.5 in. ( 1 1 4 mm); DT65-4.3 in. (1 08
mm)
1 1 . Move the control lever in the direction of the arrow (C) and adjust the
length of the rod (1) with the connector (7) so that the control lever comes in
contact with the stopper (6) at a position where the throttle valve fu l ly opens or
a position of no 2°this side from the lu l l-open position.
3-28 MAI NTENAN C E
Engine No.
DT55 501 001 - 502859
DT65 501 00 1 - 502959
05003G28
Fig. 74 Full close adjustment of the throttle valve (DT55 serial number 501001-502859 and DT65 serial number 501001 -502959)
Engine No.
DT55 502860 -
DT65 502960 -
1 . Th rottle lever rod
2. Control lever
3. Lever, No. 1 /No. 3 carburetors
4. Set screw
5. Lever, No. 2 carburetor
6. Stopper
7. Connector
3 No. 1
No. 2
05003G29
Fig. 75 Full close adjustment of the throttle valve (DT55 serial number 520860 to present and DT65 serial number 502960 to present)
** CAUTION
If there is a gap between the control lever (2) and the stopper (6)
when the throttle valve has opened fully, the throttle rod, throttle
valve or carburetor(s) may be damaged and may not operate cor­
rectly at full throttle operation.
1 2. If a l l adjustments are correct, tighten the throttle rod lock nuts securely.
DT75 and DT85
IGN ITION TIMING
• See Figure 76
Starting in 1 988, the Suzuki dig ital iC ignition system was adopted. This sys­
tem el iminates a d i rect mechanical l inkage between the engine end the ignition
system. Instead, sensors relay information detai l i ng throttle position sensor, gear
counter (engine speed) and engine temperature to the ignition module which pro­
cesses this information and then determines the optimal ignition timing.
No adjustment is necessary on this system.
The DT75 and DT85 use the Suzuki IC ( integrated circuit) ignition system.
Ignition t iming adjustment is not necessary on models equipped with these
ignition systems with the exception of adjusting the throttle valve sensor. They
are equipped with the following features:
• Engine Start Advance Mechanism. This feature ensures easy engine start­
ing by automatically advancing the ignition advance to 5°BTDC for about 1 5
seconds, after which, the IC control circuit changes over to tro l l ing ignition tim­
ing "A"
• Tro l l ing Speed Adjusting Mechanism. The trol l i ng ign ition timing can be
changed from JDATDC i n the slow position to 1 °BTDC by means of an id le
speed adjusting switch. Each position on the switch represents approximately
50 rpm change. By changing over the tro l l ing ignition t iming, the tro l l ing speed
can be adjusted.
All models from1 991 have had the Idle Speed Adjustment Switch removed
and instead an ignition timing resistor has been installed. With this modifica­
tion, the in gear id le timing with the throttle ful ly returned is kept at a constant
2°-6°ATDC and the in-gear id le speed is now adjusted by the throttle stop
screw on the #3 carburetor.
�The engine rpm at trolling speed has been factory set at approximately
700 rpm. The trolling speed varies depending on boat type , weather con­
ditions, propeller types and other variables. Adjust the trolling speed
with the idle speed adjusting switch to obtain the desired engine speed.
• Advance Stop Mechanism. When closing the throttle valve ful ly, an id le
switch is "ON" in conjunction with the carburetor and regardless of the engine
05003824
Fig. 76 Idle speed adjusting switch
MAINTENAN C E 3-29
rpm, the tro l l ing ignition timing can b e obtained. Therefore, by returning the
throttle valve to its ful ly closed position during h igh speed travel, the boat's
speed can be decreased suddenly.
CARBURETOR LINKAGE ADJUSTMENT
• See Figure 77
Ful ly closed adjustment of the throttle valve.
1. Remove the throttle lever rod (1 ) from the throttle control lever.
2. Ensure that the throttle stop screw (on the #3 carburetor) if fully backed out.
3. Loosen the screws ( 4) of the adjustable levers on the #1 and #3 carbure­
tors. The return springs wi l l close the throttle valves ful ly.
4. Fl ick the lever (5) of the #2 carburetor 2 or 3 times, as shown by the
arrow (A), which wi l l ensure that all three throttle valves are closed evenly.
5. Tighten the lever screws (4) on the #1 and #3 carburetors and apply
thread lock compound.
6. Final ly, check the operation by flicking the lever (5), to see i f the three
carburetor throttle valves are balanced and synchronized with each other.
Adjustment of the throttle lever rod.
1 . Adjust the dimension (B) of the throttle lever (1) to the correct length. For the
DT75: 6.1 in. (155 mm) and the DT85: 5.7 in. (145 mm). Attach the control lever.
2. Move the control lever (2) i n the d i rection of the arrow (C) and adjust the
length of the rod (1) by screwing the connector (7) accord ingly. The cam on the
control lever should touch the stopper (6) when the throttle valves are ful ly
open, or within 1 o_2oof being ful ly open.
I ** CAUTION
I f there is a gap between the control lever (2) and stopper (6) at full
throttle, damage may result to the throttle rod, throttle valves and
carburetors.
1 . Th rottle lever rod
2. Control lever No. 1 3. Lever
4. Lever screws
5. Lever
6. Stopper
7. Connector
No. 2
05003G30
Fig. 77 Throttle rod adjustment dimensions
IDLE SPEED
• See Figure 78
Adjust the in-gear idle speed in the fol lowing way.
1 . Warm up the engine for approximately 5 minutes
3-30 MAINTENAN C E
Fig. 78 Idle adjustment screw
2. Turn the pilot air screws in fu l ly (clockwise) until l ightly seated, then back
them out (counterclockwise) the number of turns specified in the "Idle Air Screw
Specifications" chart.
3 . Engage forward gear
4. Set the pi lot air screws as specified, then maintain a stable id le by turn­
i ng the idle adjustment screw (A) c lockwise to i ncrease idle speed or counter­
clockwise to decrease idle speed. Idle speed specifications are located in the
"Tune-Up Specifications" chart.
,..If in-gear idle speed is not in the specified range, or if the engine will
not maintain idle rpm, it is possible that there is an abnormality in
either the fuel or ignition systems. If the fuel and ignition systems are
working correctly, it is possible that the throttle valve sensor may need
adjustment. For this adjustment refer to the applicable section in "Elec­
trical and Ignition".
DT90 and DT1 00
IGNITION TIMING
The OT90 and DT100 are al l equipped with the Micro Link Ignit ion system.
This system uses a microcomputer to maximize combustion control and thus
improve engine performance. The system uses various sensors and switches to
monitor engine rpm, throttle valve opening, shift lever position and operator
selected idle speed. The computer constantly evaluates this information and
provides the optimal ignition spark timing for the current engine runn ing condi­
tion.
No adjustment is necessary on these models. If there is a problem with igni­
tion t iming, it is most l ikely caused by a faulty COl module . Refer to the appro­
priate section in "Electrical and Ignition" for CO l troubleshooting.
CARBURETOR LINKAGE ADJUSTMENT
• See Figure 79
1. Check the length of the throttle l i nkage rod (1 ) to the carburetors.
2. Loosen the throttle lever adjusting screws (2) on the top carburetor
3. Lightly push the throttle lever (3) clockwise unti l the throttle valves are
completely closed. Then tighten the adjusting screws (2)
4. Actuate the throttle l inkage and check if both throttle valves are synchro­
nized in the completely closed position. If the throttle valves are not synchro­
nized, perform the adjustment again
IDLE SPEED
1 . Warm up the engine for approximately live minutes.
2. On the carburetor, turn the p i lot screw all the way in until it l ightly seats
and then back it out the number of turns specified in the "Idle Air Screw Specifi­
cations" chart.
,..Do not overtighten the pilot screw or you may damage the screw. Just
l ightly seat it and then turn it out.
�---CD
------®
1 . Top carburetor
2. 2nd carburetor
05003G32
Fig. 79 Throttle linkage synchronization
3. Place the remote control lever into forward gear, fi rst notch.
4. Turn the idle speed adjusting switch to position 5 (slow). This adjusts the
engine speed to a range of 600-650 rpm. The engine must maintain this speed
for 3 minutes.
5 . If the engine speed is less than 600 rpm or it wi l l not maintain tro l l ing
speed for three minutes:
• Adjust the top carburetor throttle stop screw to maintain the id le speed
specified in the "Tune-Up Specifications" chart.
• Recheck the throttle valve sensor resistance value and readjust if nec­
essary. See "Electrical and Ignition"
DT1 1 5 and DT1 40
IGNITION TIMING
The DT1 1 5 and OT140 models are equipped with the Suzuki digitai iC igni­
tion system. This system e l iminates a direct mechanical l inkage between the
engine end the ignition system. Instead, sensors relay information detai l i ng
throttle position sensor, gear counter (engine speed) and engine temperature to
the ignition module which processes this information and then determines the
optimal ignition t iming.
Ignit ion timing adjustment is not necessary on models equipped with these
ignition systems with the exception of adjusting the throttle valve sensor. They
are equipped with the following features:
• Engine Start Advance Mechanism. This feature ensures easy eng ine start­
ing by automatically advancing the ignition advance to ?"BTDC for about 1 5
seconds, alter wh ich, the time the ign ition timing wi l l return t o the idle speed
circuit and what ever position the "Idle Speed Adjustment Switch" is set at.
,..Due to the higher rpm created by the automatic starting device, do not
shift gears until the engine speed has returned to normal idle speed.
• Tro l l i ng Speed Adjusting Mechanism. The tro l l ing ignition timing can be
changed from ?"ATDC in the slow position to 1 °BTDC by means of an id le
speed adjusting switch. Each position on the switch represents approximately
50 rpm change. By changing over the tro l l ing ign ition timing, the tro l l ing speed
can be adjusted.
Within id le speed range, the t iming is not a!!ected by any change in engine
speed, up to 900 rpm. To further assure exact ignition t iming, a gear counter
coil electrically measures the flywheel position and sends this i nformation to the
COl module.
,..All models from 1991 have had the "Idle Speed Adjustment Switch"
removed and instead an ignition timing resistor has been installed. With
this modification, the in gear idle timing with the throttle fully returned
is kept at a constant s·ATDC and the in-gear idle speed is now adjusted
by the throttle stop screw on the #4 carburetor.
�The engine rpm at trolling speed has been factory set at approxi­
mately 700 rpm. The trolling speed varies depending on boat type,
weather conditions, propeller types and other variables. Adjust the
trolling speed with the idle speed adjusting switch to obtain the desired
engine speed.
• Advance Stop Mechanism. When closing the throttle valve ful ly, an idle
switch is "ON" in conjunction with the carburetor and regardless of the engine
rpm, the tro l l ing ignition t iming can be obtained. Therefore, by returning the
throttle valve to its fu l ly closed position during high speed travel, the boat's
speed can be decreased sudden ly.
CARBURETOR LINKAGE
• See Figures 80 and 81
1. Check the throttle l i nkage rod (1 ) to the carburetors.
2. Loosen the throttle lever adjusting screws (2) on the #1 , #2, #3 carbure­
tors.
3. Lightly push the throttle lever (3) clockwise unti l the throttle valves are
completely closed. Tighten the adjusting screws (2) after applying a thread lock­
ing agent.
4. Move the throttle l inkage back and forth and check if al l the throttle
valves are synchronized in the completely closed position.
5. Adjust the link rod (1) to an in itial length of 6.3 in. ( 160 mm) measured
between the centers of each connector; the connectors must be at the same
angle after adjusting.
6. Install the l ink rod (1 ) onto the anchor pins (3) on the carburetor lever (4)
and the throttle control lever (5).
7. Push the throttle control lever (5) counterclockwise until the throttle
valves are completely opened. Then, the clearance between the throttle control
lever (5) and the stopper (6) on the crankcase must be zero.
8. Readjust the connectors to achieve this clearance.
9. Check for freedom of movement in the l inkage.
16Dmm (6.3 in)
1 . Link rod
2. Connector
3. Anchor pins
4. Carburetor lever
5. Throttle control lever
6. Stopper
Fig. 81 Adjusting the l ink rod to its initial setting
MAI NTENANC E 3-31
1 . Th rottle l inkage rod
2. Adjusting screws
3. Throttle lever
05003G33
F ig . 80 Throttle l inkage rods-DT11 5 and DT140
05003G34
3-32 MAI NTENAN C E
IDLE SPEED
1. Warm up the engine for approximately five m inutes.
2. On the carburetor, turn the pi lot screw in all the way unti l it l ightly seats,
and then back it out the number of turns specified in the "Idle Air Screw Specifi­
cations" chart.
3. Place the remote control in forward gear, f irst notch.
4. Turn the idle adjusting switch to maintain the min imum idle speed speci­
fied in the "Tune-Up Specifications" chart.
,..All models from 1991 have had the "Idle Speed Adjustment Switch"
removed and instead an ignition timing resistor has been installed. With
this modification, the in gear idle timing with the throttle fully returned
is kept at a constant 6°ATDC and the in-gear idle speed is now adjusted
by the throttle stop screw on the #4 carburetor.
DT1 50, DT1 75, DT200
.
IGNITION TIMING
The V6 models are equipped with the Suzuki d ig itai iC ignition system. This
system el iminates a direct mechanical l i nkage between the engine end the igni­
tion system. I nstead, sensors relay information detai l ing throttle position sensor,
gear counter (engine speed) and engine temperature to the ignition module which
processes this information and then determines the optimal ignition timing.
Ignition timing adjustment is not necessary on models equipped with these
ignition systems with the exception of adjusting the throttle valve sensor. They
are equipped with the following features:
• Engine Start Advance Mechanism. This feature ensures easy engine start­
ing by automatically advancing the ignit ion advance to 5°BTDC for about 1 5
seconds, after which, the time the ign ition t iming wi l l return t o the id le speed
circuit and what ever position the "Idle Speed Adjustment Switch" is set at.
,..Due to the higher rpm created by the automatic starting device, do not
shift gears until the engine speed has returned to normal idle speed.
• Trol l ing Speed Adjusting Mechanism. The tro l l ing ign ition timing can be
changed from 6.5°ATDC in the slow position to 0.5°BTDC by means of an idle
speed adjusting switch. Each position on the switch represents approximately
50 rpm change. By changing over the tro l l ing ignit ion t iming, the tro l l ing speed
can be adjusted. Within id le speed range, the t iming is not affected by any
change in engine speed, up to 900 rpm. To further assure exact ign ition t iming,
a gear counter coi l electrically measures the flywheel position and sends this
information to the CDI module.
,..All models from 1991 have had the " Idle Speed Adjustment Switch"
removed and instead an ignition timing resistor has been installed. With
this modification, the in gear idle timing with the throttle fully returned
is kept at a constant 5°ATDC and the in-gear idle speed is now adjusted
by the throttle stop screw on the #3 carburetor.
,.. The engine rpm at trolling speed has been factory set at approxi­
mately 700 rpm. The trolling speed varies depending on boat type,
weather conditions, propeller types and other variables. Adjust the
trolling speed with the idle speed adjusting switch to obtain the desired
engine speed.
• Accelerator and Idle Return Switches. These switches are :nounted in a
single sealed unit on the port side of the #3 carburetor and are activated by
throttle position.
• Accelerator switch. This switch prevents the ign ition timing from lagging
behind on qu ick acceleration by automatically giving the i gnition 5 more
degrees of advance as soon as it is activated. This switch is activated at 1 0
degrees of throttle valve opening. When the engine i s accelerated slowly, the
switch is activated at approximately 1 , 800 rpm.
• Idle return switch. This switch is "ON" when the throttle valve position is
between 0°(fu l l c losed) and 2°open. When the switch is on, the basic advance
curve is cancelled and ignit ion t iming is returned automatically to the t iming of
the "Idle Speed Adjustment Switch". This guarantees that the engi ne speed wi l l
return to id le automatically. If th is switch does not function properly, the engine
rpm wi l l take longer to return to idle speed.
CARBURETOR LINKAGE
• See Figure 82
1. Check the throttle l i nkage rod "1" to the carburetors.
2. Loosen the throttle lever adjust ing screws "2" on the top and center car­
buretors.
3. Lightly push the throttle lever "3" c lockwise until the throttle valves are
completely closed. Then tighten the adjusting screws "2".
4. Move the throttle l inkage and check to make sure al l the throttle valves
are synchron ized and in the completely c losed position.
Top carburetor
Center carburetor
1 . Th rottle l inkage rod
2. Adjusting screws
3. Throttle lever
05003G35
Fig. 82 Throttle l inkage rod-DT150, DT175, DT200
IDLE SPEED
1. Warm up the engine for approximately five minutes.
2. On the carburetor, turn the p i l ot screw in all the way until it l ightly seats,
and then back it out the number of turns specified in the "Idle Air Screw Specifi­
cations" chart.
3. Place the remote control in forward gear, first notch.
4. Turn the id le adjusting switch to maintain the min imum idle speed speci­
fied in the "Tune-Up Specifications" chart.
,..All models from 1991 have had the "Idle Speed Adjustment Switch"
removed and instead an ignition timing resistor has been installed. With
this modification, the in gear idle timing with the throttle fully returned
is kept at a constant 5°ATDC and the in-gear idle speed is now adjusted
by the throttle stop screw on the #3 carburetor.
Model Year
DT 2 1 988-96
DT2.2 1 997
DT 4 1 988-98
DT5Y 1 998-02
DT 6 1 988-02
1 988-02
DT 8 1 988-91
1 992-97
DT 9.9 1 988-97
DT 1 5 1 988-97
DT 20 1 988
DT 25 (2-cyl)
DT 25 (3-cyl) 1 989
1 988-90
1 99 1 -00
DT 30 1 989
1 988-90
1 99 1 -97
DT 35 1 988-89
DT 40 1 988-91
1 992-98
DT 55 1 988-89
1 990-97
DT 65 1 988-89
1 990-97
DT75 1 988-90
1 99 1 -94
1 995-97
DT85 1 988-90
1 991
1 992
1 993-00
DT 90 1 989-97
DT1 00 1 989-91
1 992-00
DT 1 1 5 1 988
1 989
1 990-91
1 992-95
1 996-01
DT 1 40 1 988
1 989-91
1 992-01
DT 1 50 1 988
1 989-03
DT 1 75 1 988
1 989-92
DT 200 1 988-00
DT225 1 998-03
MAINTENANCE 3-33
Carburetor Idle Air Screw Specification
Type
S-type
L and UL type
MC
Except MC
MC
Except MC
Turns Out From
Lightly Seated
1 .25-1 .75
0 .375-0.875
1 -1 .50
1 .25
0.875-1 .375
1 -1 .50
1 .75-2.25
0 .50-1 .0
1 . 1 25-1 .625
1 .50-2
1 .75-2.25
1 .25-1 .75
1 .25-1 .75
1 .5-2.0
1 .0-1 .5
1 .25-1 .75
1 .5-2.0
1 .0-1 .5
1 .5-2.0
1 .5-2.0
0 .875-1 .375
1 .25-1 .75
1 .0-1 .5
1 .25-1 .75
1 .0-1 .5
1 .75-2.25
1 .5-2.0
1 .375-1 .875
1 .625-2 . 1 25
0.75-1 .25
0 .50-1 .0
1 .375-1 .875
1 .1 25-1 .625
1 . 1 25-1 .625
1 .375-1 .875
1 .25-1 .75
0.875
1 .0-1 .5
0 .625-1 . 1 25
0.75-1 .25
1 .0-1 .5
1 . 1 25-1 .625
0.625-1 . 1 25
1 -1 .50
1 .25-1 .75
1 .5-2.0
1 .25-1 .75
1 .25-1 .75
EFI
3-34 MAINTENANCE
Model
DT2 1 988-89
1 990
1991
1 992-96
DT2.2 1 997
DT4 1 988-89
1 990.98
DT5Y 1 998-02
DT6 1988-02
DT8 1 988-97
DT9.9 1 988-97
DT15 1 988
1 989
1 991-97
DT20 1 988
DT25 1 990
1991
1 992-00
DT30 1 989-90
1991-97
DT35 1 988-89
DT40 1 988-98
DT55 1 988-89
1 990
1 991-97
DT65 1 988-90
1 991-97
DT75 1 988-94
1 995-97
DT85 1 988-91
1 992-94
1 995-00
DT90 1 989-91
1 992-97
DT100 1 989-91
1 992-00
DT 1 1 5 1 988
1 989-90
1991-95
1 996
1 996-01 EFI
DT 140 1 988
1 989-90
1 991-95
1 996
1 996-01 EFI
DT 150 1 988
1 989-94
1 995-03 EFI
DT1 75 1 988
1 989-92
DT200 1 988
1 989-92
1 993-94 EFI
1 995-00 EFI
DT 225 1 990.03
Tuneup Specifications Chart
Spark Plug
NGK Champion
B4H L81 , L88A
B4H L81 , L88A
B5HS L81, L88A
B5HS L81, L88A
BR5HS L81, L88A
BP6HS RL12Y, RL87Y, L66Y
BP5HS L81, L88A
BPR7HS-10
BR6HS-10 RL12Y, RL87Y, L66Y
BPR6HS RL12Y, RL87Y, L66Y
B6HS L9J, QL7 J, RL7 J
B7HS L5, L7J
B7HS-1 0 N/A
BR7HS-10 N/A
BR7HS L5, L7J
BR7HS-1 0 N/A
BR7HS L5, L7J
BR7HS-1 0 N/A
BR7HS-10 N/A
BR7HS-10 N/A
BSHS L4J, RL4J, L78, RL78
B8HS L4J, RL4J, L78, RL79
B8HS-10 L4J, RL4J, L78, RL78
B8HS-10 L4J, RL4J, L78, RL78
B8HS-10 L4J, RL4J, L78, RL78
B8HS-10 L4J, RL4J, L78, RL78
B8HS-10 L4J, RL4J, L78, RL78
B8HS-1 0 L4J, RL4J, L78, RL78
BR8HS-10 N/A
BBHS L4J, RL4J, L78, RL78
B8HS-10 L4J, RL4J, L78, RL78
BR8HS-10 N/A
BR8HS-1 0 N/A
BR8HCS-1 0 N/A
BRSHS-1 0 N/A
BR8HCS-10 N/A
B8HS L4J, RL4J, L78, RL78
B8HS L4J, RL4J, L78, RL78
B8HS L4J, RL4J, L78, RL78
BR8HCS-10 NIA
BR8HS-10 L4J, RL4J, L78, RL78
B8HS L4J, RL4J, L78, RL78
BBHS L4J, RL4J, L78, RL78
B8HS L4J, RL4J, L78, RL78
BR8HCS-10 N/A
BR8HS-10 L4J, RL4J, L78, RL78
B8HS-10 L4J, RL4J, L78, RL78
BR8HS-1 0 N/A
BP8HS-10 N/A
B8HS-10 L4J, RL4J, L78, RL78
BR8HS-10 N/A
B8HS-10 L4J, RL4J, L78, RL78
BR8HS-1 0 N/A
BR8HS-10 N/A
BP8HS-10 N/A
BRBHS-10 N/A
Spark
Plug Gap
lnch(mm)
.024-.028 (.6-.7)
.024-.028 (.6-.7)
.024-.028 (.6-.7)
.024-.028 (.6-.7)
.024-.028 (.6-.7)
.024-.028 (.6-.7)
.024-.028 (.6-.7)
.035-.039 (.9-1 .0)
.035-.039 (.9-1.0)
.031-.035 (.08-.09)
.035-.039 (.9-1.0)
.035-.039 (.9-1 .0)
.035-.039 (.9-1 .0)
.035-.039 (.9-1.0)
.035-.039 (.9-1.0)
.035-.039 (.9-1 .0)
.035-.039 (.9-1.0)
.035-.039 (.9-1.0)
.035-.039 (.9-1 .0)
.035-.039 (.9-1.0)
.031-.035 (.08-.09)
.031-.035 (08-.09)
.035-.039 (.9-1 .0)
.035-.039 (.9-1.0)
.035-.039 (.9-1.0)
.031-.035 (.8-.9)
.031-.035 (.8-.9)
.031-.035 (.8-.9)
.035-.039 (.9-1.0)
.031-.035 (.8-.9)
.031-.035 (.8-.9)
. 035-.039 (. 9-1 . 0)
.035-.039 (.9-1.0)
.035-.039 (.9-1.0)
.035-.039 (.9-1 .0)
.035-.039 (.9-1.0)
.031-.035 (.8-.9)
.031- 035 (.8-.9)
.035-.039 (.9-1.0)
.035-.039 (.9-1.0)
.035-.039 (.9-1.0)
.031-.035 (8-.9)
.031-.035 (.8-.9)
.035-.039 (.9-1.0)
.035-.039 (.9-1 .0)
.035-.039 (.9-1.0)
.035-.039 (.9-1 .0)
.035-.039 (.9-1.0)
.035-.039 (9-1.0)
.035-.039 (.9-1.0)
.035-.039 (.9-1.0)
.035-.039 (.9-1.0)
.035-.039 (.9-1 .0)
.035-.039 (.9-1.0)
.035-.039 (.9-1.0)
.035-.039 (.9-1.0)
Ignition
Timing
0 8TDC
1 5 @ 4500
1 9 @ 4500
1 9 @ 4500
17 - 21 @ 4500
23 - 27 @ 5000
25 @ 5000
24 @ 5000
26@5000
23-27 @ 5000
23-27 @ 5000
23-27 @ 5000
23-27 @ 5000
27 @ 2000
28 @ 2000
25 @ 5000
25 @ 5000
23-27 @ 5000
23-27 @ 5000
25 @ 5000
23-27 @ 5000
23-27 @ 5000
23-27 @ 5000
23 @ 5000
1 7 @ 5000
15-1 9 @ 5000
25 @ 5000
23-27 @ WOT
1 6-20 @ WOT
1 8 @ WOT
1 8 @ WOT
1 6-20 @ WOT
1 8 @ WOT
23 @ 5000
21-25 @ WOT
23 @ 5000
21-25 @ WOT
23 @ 5000
20 @ 5000
22-26 @ WOT
1 8-22 @ WOT
26 @ 5870.6130
23 @ 5000
20 @ 5000
22-26 @ WOT
1 8-22 @ WOT
26 @ 5870.6130
22 @ 5000
20.24 @ 5000
24 @ WOT
22 @ 5000
20-24 @ 5000
22 @ 5000
20-24 @ 5000
24 @ WOT
24 Non-Adjustable
13-17 @ WOT
Idle Speed
RPM
(Neutral)
800.900
800.900
800.900
800-900
1 000.1 100
850.900
850.900
1 1 50.1250
600.650
600.650
600.650
600.650
600-650
650-700
600-650
650-700
600-650
600-650
650-700
650-700
650-700
650-700
650-700
650-700
750-800
650-700
650-700
600.700
700.800
600.700
600.700
700.800
650.700
650.700
650.700
650.700
600.700
600.700
600.700
650.750
600.700
600.700
600.700
600.700
650.750
600.700
600-700
600.700
750.850
600-700
600.700
600.700
600.700
650.750
750.850
600.700
WINTER STORAGE CHECKLIST
Taking extra time to store the boat properly at the end of each season wi l l
increase the chances of satisfactory service at the next season. Remember, star­
age is the greatest enemy of an outboard motor. The unit should be run on a
monthly basis. The boat steering and shifting mechanism should also be
worked through complete cycles several times each month. If a small amount of
time is spent in such maintenance, the reward wi l l be satisfactory performance,
increased longevity and greatly reduced maintenance expenses.
For many years there has been the widespread bel ief s imply shutting off
the fuel at the tank and then runn ing the powerhead unti l i t stops is the
proper procedure before storing the eng ine for any length of time. R ight?
WRONG!
First, it is not possible to remove all fuel in the carburetor by operat ing the
powerhead until it stops. Considerable fuel is trapped in the float chamber and
other passages and in the l ine leading to the carburetor. The only guaranteed
method of removing all fuel is to take the time to remove the carburetors, and
drain the fuel.
Proper storage involves adequate protection of the unit from physical dam­
age, rust, corrosion, and dirt. The following steps provide an adequate mainte­
nance program for storing the unit at the end of a season.
1 . Squirt a small quantity of engine o i l into each spark plug hole and crank
the engine over to distribute the o i l around the engine internals. Reinstall the
old spark plugs (you wi l l install new spark plugs in the spring).
SPRING COMMISSIONING CHECKLIST
• See Figures 83 thru 90
A spring tune-up is essential to getting the most out of your engine. If the
engine has been properly winterized, it is usually no problem to get it i n top
running condition again in the springtime. If the engine has just been put in the
garage and forgotten for the winter, then it is doubly important to do a complete
tune up before putting the engine back into service. If you have ever been
stranded out on the water because your engine has died, and you had to suffer
the embarrassment of having to be towed back to the marina, now is the time to
prevent that from occurring.
Fig. 83 Removing the fuel filter for inspection and possible replace­
ment
MAI NTENANC E 3-35
2 . Drain all fuel from the carburetor float bowls. On fuel injected models,
drain the fuel from the vapor separator.
3. Drain the fuel tank and the fuel l ines Store the fuel tank i n a cool dry
area with the vent OPEN to allow air to circulate through the tank. Do not store
the fuel tank on bare concrete. Place the tank to allow air to circulate around it.
4. Change the fuel fi lter.
5. Drain, and then f i l l the lower unit with new lower unit gear o i l .
6. Lubricate the throttle and shift l inkage and the steering pivot shaft.
7. C lean the outboard unit thoroughly. Coat the powerhead with a commer­
cial corrosion and rust preventative spray. Install the cowl ing , and then apply a
thin f i lm of fresh engine o i l to a l l painted surfaces.
8. Remove the propeller. Apply Perfect Seal® or a waterproof sealer to the
propeller shaft spl ines, and then install the propeller back in position.
9. Be sure al l drain holes in the gear housing are open and free of obstruc­
tions. Check to be sure the flush plug has been removed to al low all the water to
drain. Trapped water could freeze, expand, and cause expensive castings to
crack.
1 0. Always store the outboard unit off the boat with the lower unit below the
powerhead to prevent any water from being trapped inside.
1 1 . Be sure to consult your owners manual for any particular storage proce­
dures applicable to your specific model.
Satisfactory performance and maximum enjoyment can be realized if a l ittle
time is spent in preparing the outboard unit for service at the begi nn ing of the
season . Assuming the unit has been properly stored, a min imum amount of
work is required to prepare the unit for use. The following steps outl ine an ade­
quate and logical sequence of tasks to be performed before using the outboard
the first time in a new season.
1 . Lubricate the outboard according to the manufacturer's recommenda­
tions.
2. Perform a tune-up on the engine. This should include replacing the
spark plugs and making a thorough check of the ignition system. The ignit ion
Fig. 84 Make a pre-season check of the fuel line coupling at the fuel
joint to ensure a proper and clean connection
3-36 MAINTENANC E
Fig. 85 This popular and inexpensive flushing device should be
included in every boat owner's maintenance kit
system check should include the ignit ion coi ls, stator assembly, condition of the
wiring and the battery.
3. If a bui lt-in fuel tank is installed, take time to check the tank and a l l
fue l l ines, fittings, coupl i ngs, valves, inc luding the flexible tank f i l l and vent.
Turn on the fuel supply valve at the tank. If the fuel was not drained at the end
of the previous season, make a careful inspection for gum formation. If a six­
gal lon fuel tank is used, take the same action. When gaso l i ne is a l lowed to
stand for long periods of time, particularly in the presence of copper, gummy
deposits form. This gum can clog the fi lters, l i nes, and passageways in the
carburetor.
4. Replace the o i l in the lower un it.
5. Replace the fuel fi lter.
6. Replace the engine o i l and fi lter. Make sure to use only a quality four
stroke engine o i l and NEVER use two stroke oil i n a four stroke engine.
7. Close al l water drains. Check and replace any defective water hoses.
Check to be sure the connections do not leak. Replace any spring-type hose
clamps with band-type clamps, if they have lost their tension or if they have
distorted the water hose.
8. The eng ine can be run with the lower u nit in water to flush it. If this
is not practical , a flush attachment may be used. This un it is attached to
the water p ick-up in the lower un it. Attach a garden hose, turn on the
water, a l low the water to flow i nto the engine for awh i le, and then run the
engine.
** CAUTION
Water must circulate through the lower unit to the powerhead any­
time the powerhead is operating to prevent the engine from over­
heating and damage to the water pump in the lower unit. Just five
seconds without water wil l damage the water pump impeller.
9. Check the exhaust outlet for water discharge. Check for leaks. Check
operation of the thermostat.
04893P73
Fig. 86 Honda outboards come with a self contained flushing port on
the lower unit that uses a special flush kit adapter available from
your dealer
04703P36
Fig. 87 Electrical and fuel system components should be checked on
a regular basis
10 . Check the e lectrolyte level in the battery and the voltage for a fu l l
charge. C lean and i nspect the battery terminals and cable connections.
Take t ime to check the polarity, if a new battery is being instal led. Cover the
cable connections with grease or special protective compound as a preven­
t ion to corrosion format ion . Check a l l electrical wir ing and grounding c i r­
cuits.
Fig. 88 Checking the condition of the battery electrolyte using a
hydrometer
1 1 . Check all electrical parts on the engine and lower portions of the hu l l .
Rubber boots he lp keep electrical connections clean and reduce the poss ib i l ity
of arcing.
�Electric cranking motors and high tension wiring harnesses should be
of a marine type that cannot cause an explosive mixture to ignite.
1 2. If a water separating fi lter is installed between the fuel tank and the pow­
erhead fuel f i lter, replace the element at least once each season. This filter
removes water and fuel system contaminants such as dirt, rust, and other
solids, thus reducing potential problems.
1 3. As a last step in spring commissioning, perform a ful l engine tuneup.
** CAUTION
Before putting the boat in the water, take time to verify the drain
p lugs are instal led. Countless number of boating excursions have
had a very sad beginning because the boat was eased into the
water only to have the boat begin to fill with the water.
MAINTENANC E 3-37
04703P38
Fig. 89 A water separating fuel filter installed inside the boat on the
transom
04897P69
Fig. 90 The thermostat is usually located in an accessible place for
easy maintenance or replacement
General Engine Specifications
Model Engme Dtsplace Bore and Oil Infection fgnition startmg Cooling
Year (Horsepower) Type cu.in.Jcc) Stroke Syste111_ sy_stem System System
2003 DT150 V-6 (60+) 164.3 (2693) 3.31 x 3.19 Oil Injection Microlink Electric lmpeller Pumpffhennostat Controlled
DT225 V-6 (60+) 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric lmpeller Pumpffhennostat Controlled
2002 DT5Y 1-cyinder 6.7 (109) 2.2x 1.8 Pre-mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT6 lnline 2-cyt 10.1 (165) 1.97 x 1.65 Pre-mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT150 V-6 (60+) 164.3 (2693) 3.31 X 3.19 Oil Injection Micro link Electric lmpeller Pumpffhennostat Controlled
DT225 V-6 (60+) 164.3 (2693) 3.31 X 3.19 Oil Injection Micro link Electric lmpeller Pumpffhennostat Controlled
2001 DT5Y 1-cyinder 6.7 (109} 2.2x 1.8 Pre-mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT6 lnline 2-cyl 10.1 (165) 1.97 x 1 .65 Pre-mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT115 lnline 4-cyl 103.2 (1773} 3.31 X 3.15 Oil Injection Digitai i.C Electric lmpeller Pumpffhennostat Controlled
DT140 lnline 4 cyl 103.2 (1773} 3.31 X 3.15 Oil Injection Digitai i.C Electric lmpeller Pumpffhennostat Controlled
DT150 V-6 (60+) 164.3 (2693) 3.31 x 3.19 Oil Injection Microlink Electric lmpeller Pumpffhennostat Controlled
DT225 V-6 (60+) 164.3 (2693} 3.31 X 3.19 Oil Injection Microlink Electric lmpeller Pumpffhennostat Controlled
2000 DT5Y 1-cyinder 6.7 (109) 2.2 X 1.8 Pre-mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT6 lnline 2-cyl 10.1 (165} 1.97x 1.65 Pre-mix Suzuki P.E.I. Manual w/manual choke lmpeller Pump
DT25 lnline 3-cyt 33.1 (543} 2.44x 2.36 Oil Injection Digitaii.C Electric/Manual w/ Electric/man C lmpeller Pumpffhennostat Controlled
DT85 lnline 3-cyt 73 (1197} 3.31 X 2.83 Oil Injection Digitai i.C Electric w/ electric choke lmpeller Pumpffhennostat Controlled
DT100 V-4(70+) 86.6 (1419) 3.31 X 2.52 Oil Injection Microlink Electric lmpeller Pumpffhennostat Controlled
DT115 lnline 4-cyl 103.2 (1773) 3.31 X 3.15 Oil Injection Digitai i.C Electric lmpeller Pumpffhennostat Controlled
DT140 lnline 4 cyl 1 03.2 (1773) 3.31 X 3.15 Oil Injection Digitai i.C Electric lmpeller Pumpffhennostat Controlled
DT150 V-6 (60+) 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric lmpeller Pumpffhennostat Controlled
DT200 V-6 (60+} 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric lmpeller Pumpffhermostat Controlled
DT225 V-6 (60+) 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric lmpeller Pumpffhermostat Controlled
1999 DT4 1 - cylinder 5.5 (90} 1.97 x 1.81 Pre-mix Suzuki P.E.I. Manual w/ manual choke lmpeller pump
DT5Y 1 - cylinder 6.7 (109} 2.2x 1.8 Pre-mix Suzuki P.E.I. Manual w manual choke lmpeller pump
DT 6 lnline 2-cytinder 10.1 (165} 1 .97 x 1 .65 Pre-Mix Suzuki P.E.I. Manual w/manual choke lmpeller Pump
DT25 lnline 3-cylinder 33.1 (543} 2.44 X 2.36 Oil Injection Digitai i.C. Electric/Manualw/ electrichnanual choke lmpeller Pump /Thermostat Controlled
DT 85 lnline 3-cylinder 73(1197) 3.31 X 2.83 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT 1 00 V-4 (70•) 86.6 (1419} 3.31 X 2.52 Oil Injection Microlink Electric lmpeller Pump I Thermostat Controlled
DT 1 15 EFI lnline 4-cylinder 103.2 (1773} 3.31 X 3.15 Oil Injection Digitai i.C. Electric lmpeller Pump I Thermostat Controlled
DT 140 EFI lnline 4-cylinder 1 03.2 (1773} 3.31 X 3.15 Oil Injection Digitai i.C. Electric Imp oiler Pump I Thermostat Controlled
DT 150 EFI V-6 (60•) 164.3 (2693) 3.31 x 3.19 Oil Injection Microlink Electric Imp oiler Pump I Thermostat Controlled
DT200EFI V-6 (60•) 164.3 (2693} 3.31 x 3.19 Oil Injection Microlink Electric Imp oiler Pump I Thermostat Controlled
DT 225 EFI V-6 (60•) 1 64.3 (2693} 3.31 x 3.19 Oil Injection Micro Link Electric lmpeller Pump I Thermostat Controlled
1998 DT 4 1-cylinder 5.5 (90} 1.97x 1 .81 Pre�Mix Suzuki P.E.I. Manual w/manual choke lmpeller Pump
DT5Y 1 - cylinder 6.7 (109) 2.2x 1.8 Pre..mix Susuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 6 lnline 2-cylinder 10.1 (165) 1.97 x 1 .65 Pro-Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 25 lnline 3-cylinder 33.1 (543) 2.44x 2.36 Oil Injection Digitai i.C. Electric/Manual w/ electriclmanual choke lmpeller Pump
DT 40 lnline 2-cylinder 42.5 (696) 3.11 X 2:80 Oil Injection Suzuki P.E.I. Electric/Manual w/ electrichnanual choke lmpeller Pump I Thermostat Controlled
DT85 lnline 3-cylinder 73 (1197) 3.31 X 2.83 Oil Injection Digitai i.C. Electric lmpeller Pump I Thermostat Controlled
DT 100 V-4 (70•) 86.6 (1419) 3.31 X 2.52 Oil Injection Microlink Electric Imp oiler Pump I Thermostat Controlled
DT 115 EFI lnline 4-cylinder 103.2 (1773} 3.31 X 3.15 Oil Injection Digitai i.C. Electric lmpeller Pump I Thermostat Controlled
DT 140 EFI lnline 4-cylinder 1 03.2 (1773) 3.31 X 3.15 Oil Injection Digitai i.C. Electric lmpeller Pump /Thermostat Controlled
DT 150 EFI V-6 (60'} 164.3 (2693} 3.31 X 3.19 Oil Injection Microlink Electric Imp oiler Pump /Thermostat Controlled
DT200EFI V-6 (60•) 164.3 (2693} 3.31 X 3.19 Oil Injection Microlink Electric Imp oiler Pump /Thermostat Controlled
DT 225 EFI V-6 (60•) 1 64.3 (2693) 3.31 X 3.19 Oil Injection Micro link Electric Imp oiler Pump I Thermostat Controlled
1997 DT2.2 1-cylinder 3.4 (55) 1.61 X 1.50 100:1 Pre-Mix Suzuki P.E.I. Manual w/ manual choke Imp oiler Pump
DT 4 1-cylinder 5.5 (90) 1 .97 x 1.81 100:1 Pre-Mix Suzuki P.E.I. Manual w/ manual choke Imp oiler Pump
DT 6 lnline 2-cylinder 10.1 (165) 1 .97 X 1.65 100:1 Pre-Mix Suzuki P.E.I. Manual w/ manual choke Imp oiler Pump
DT 8 lnline 2-cylinder 12.8 (21 1 ) 2.13x 1.81 Oil Injection Suzuki P.E.I. Manual w/manual choke lmpeller Pump
DT 9.9 lnline 2-cylinder 12.8(211} 2.13x 1.81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 15 lnline 2-cylinder 17.3 (284) 2.32x 2.05 Oil �jection Digital I. C. Manual/Electric w/ electriclmanual choke lmpeller Pump
DT 25 lnline 3-cylinder 33.1 (543) 2.44x 2.36 Oil Injection Digitai i.C. Manual/Electric w/ electriclmanual choke lmpeller Pump
DT 30 lnline 3-cylinder 33.1 (543} 2.44x 2.36 Oil Injection Digitai i.C. Manual/Electric w/ electrichnanual choke lmpeller Pump
DT 40 __ lnline 2-cylinder _ 42.5 (696) 3.11 x 2.80 Oil Injection Suzuki P.E.I. Electric/Manual w/ manual/electric choke lmpeller Pump w I w (X)
s:::
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z -I m z
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General Engine Specifications
Model engine ___ ·mspJace------aore and 011 lnJectton lgmbon startmg Coohng
Year (Horsepower) Type cu.ln. (cc) Stroke System System System System
1997 DT55 lnline 3-cytinder 54.4 (891) 2.87 X 2.80 Oil injection Suzuki P.E.I. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT65 tnline 3-cylinder 54.4 (891) 2.87 X 2.80 Oil injection Digitat i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT 75 lnline 3-cylinder 73 (1197) 3.31 X 2.83 Oil injection Digital l.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT 85 lnline 3-cyiinder 73 (1197) 3.31 X 2.83 Oil injection Digitai i.C. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
DT90 V-4 (70') 86.6 (1419) 3.31 X 2.52 Oil injection Microlink Electric w/ Suzuki Start System Imp ell er Pump I Thermostat Controlled
DT 100 V-4 (70') 86.6 (1419) 3.31 X 2.52 Oil injection Microlink Electric w/ Suzuki Start System lmpeller Pump /Thermostat Controlled
DT 115 lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT 115 EFI lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT140EFI lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT 150EFI V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump /Thermostat Controlled
DT200EFI V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT225 EFI V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpellerPump /Thermostat Controlled
1996 DT 2 1-cylinder 3.05 (50) 1.61 x 1 .49 100:1 Pre·Mix Flywheel Magneto Manual w/ manual choke lmpeller Pump
DT 4 1-cylinder 5.5 (90) 1.97 x 1.81 100:1 Pre·Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 6 tntine 2-cylinder 10.1 (165) 1.97 x 1.65 100:1 Pre-Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 8 lnline 2-cylinder 12.8(211) 2.13x 1.81 Oil injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT9.9 lnline 2-cylinder 12.8(211) 2.13x 1.81 Oil injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 15 lnline 2-cylinder 17.3 (284) 2.32x 2.05 Oil injection Digitat i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
DT25 lnline 3-cylinder 33.1 (543) 2.44x 2.36 Oil injection Digital i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
DT30 lnline 3-cylinder 33.1 (543) 2.44 x 2.36 Oil Injection Digital i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
DT 40 lnline 2-cylinder 42:5 (696) 3.11 x 2.80 Oil injection Suzuki P.E.I. Electric/Manual w/ manual/electric choke lmpeller Pump
DT 55 lnline 3-cylinder 54.4(891) 2.87 X 2.80 Oil tnjection Suzuki P.E.I. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
DT65 lnline 3-cylinder 54.4(891) 2.87 X 2.80 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT 75 lnline 3-cylinder 73 (1197) 3.31 X 2.83 Oil injection Digital l.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT85 lnline 3-cylinder 73 (1197) 3.31 X 2.83 Oil injection Digital i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT90 V-4 (70') 86.6 (1419) 3.31 X 2.52 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
DT 100 V-4(70') 86.6 (1419) 3.31 X 2.52 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
DT 115 lnline 4-cylinder 108.2 (1773) 3.31 x 3.15 Oil injection Digitai i.C. Electric wlelectric choke lmpeller Pump I Thermostat Controlled
DT 115 EFI lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil injection Micro link Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
DT 140 lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil injection Microlink Electric w/ Suzuki start System lmpeller Pump I Thermostat Controlled
DT 140EFI lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil Injection Micro link Electric w/ Suzuki Start System lmpeller Pump /Thermostat Controlled
DT 150EFI V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT200EFI V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT225EFI V-6 (60') 1 64.3 (2693) 3.31 X 3.19 Oil injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
1995 DT 2 1-cylinder 3.05 (50) 1.61 X 1 .49 100:1 Pre-Mix Flywheel Magneto Manual wl manual choke lmpeller Pump
DT 4 1-cylinder 5.5 (90) 1.97x 1.81 100:1 Pro-Mix Suzuki P.E.I. Manual wl manual choke lmpeller Pump
DT 6 lnline 2-cylinder 10.1 (165) 1.97x 1.65 100:1 Pre·Mix Suzuki P.E.I. Manual wl manual choke lmpeller Pump
DT 8 lnline 2-cylinder 12.8 (211) 2.13 x 1.81 Oil injection Suzuki P.E.I. Manual wl manual choke lmpeller Pump
DT 9.9 lnline 2-cylinder 12.8(211) 2.13x 1.81 Oil Injection Suzuki P.E.I. Manual w/manual choke lmpeller Pump
DT 15 lnline 2-cylinder 17.3 (284) 2.32 x 2.05 Oil Injection Digitai i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
DT25 lnline 3-cylinder 33.1 (543) 2.44x 2.36 Oil injection Digitai i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
DT 30 lnline 3-cylinder 33.1 (543) 2.44x 2.36 Oil injection Digitai i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
DT40 lnline 2-cylinder 42.5 (696) 3.11 X 2.80 Oil injection Suzuki P.E.I. Electric/Manual wlmanual/electric choke lmpeller Pump
DT55 lnline 3-cylinder 54.4(891) 2.87 x 2.80 Oil injection Suzuki P.E.I. Electric w/ electric choke lmpellerPump /Thermostat Controlled
DT65 lnline 3-cylinder 54.4(891) 2.87x 2.80 Oil injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT75 lnline 3-cylinder 73 (1197) 3.31 X 2.83 Oil injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT85 lnline 3-cylinder 73 (1197) 3.31 X 2.83 Oil injection Digital i.C. Electric wl electric choke lmpeller Pump I Thermostat Controlled
DT90 V-4 (70') 86.6 (1419) 3.31 X 2.52 Oil injection Microlink Electric wl Suzuki Start System lmpeller Pump I Thermostat Controlled
DT 100 V-4 (70') 86.6 (1419) 3.31 X 2.52 Oil injection Micro link Electric w/ Suzuki Start System lmpeller Pump /Thermostat Controlled
DT 115 lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil injection Digital l.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT 140 lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil injection Microlink Electric w/ Suzuki Start System lmpellerPump /Thermostat Controlled
DT 150EFI V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT200 EFI V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT225EFI V-6 (60') 164.3 (2693) 3.31 X3.19 Oil injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
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General Engine Specifications
Moctel Engine ---DISPface Bore an Year {Horsepower) Type cu.in. (cc) Stroke System System System System
1994
1993
1992
- ··-----
DT 2
DT4
DT 6
DT 8
DT9.9
DT 15
DT25
DT30
DT40
DT55
DT 65
DT 75
DT85
DT 90
DT 100
DT 115
DT140
DT 150
DT 200 EFI
DT 225 EFI
DT2
DT 4
DT 6
DT 8
DT9.9
DT 15
DT25
DT30
DT40
DT55
DT65
DT75
DT85
DT90
DT 100
DT 115
DT 140
DT 1 50
DT200
DT 225 EFI
DT 2
DT4
DT 6
DT 8
DT9.9
DT 15
DT25
DT30
DT40
DT55
DT65
DT75
DT 85
DT90 _ __ -
1-cylinder 3.05 (50)
1-cylinder 5.5 (90)
lnline 2-cylinder 10.1 (165)
lnline 2-cylinder 12.8(211)
lnline 2-cylinder 12.8(21 1 )
lnline 2-cylinder 17.3 (284)
lnline 3-cylinder 33.1 (543)
lnline 3-cylinder 33.1 (543)
lnline 2-cylinder 42.5 (696)
lnline 3-cylinder 54.4 (891)
In line 3-cylinder 54.4 (891)
lnline 3-cylinder 73(1 197)
lnline 3-cylinder 73(1197)
V-4 (70°) 86.6 (1419)
V-4 (70°) 86.6 (1419)
lnline 4-cylinder 1 08.2 (1773)
lnline 4-cylinder 108.2 (1773)
V-6 (60°) 164.3 (2693)
V-6 (60°) 164.3 (2693)
V-6 (60°) 164.3 (2693)
1-cylinder 3.05 (50)
1-cylinder 5.5 (90)
In line 2-cylinder 10.1 (165)
lnline 2-cylinder 12.8 (211)
In line 2-cylinder 12.8(211)
lnline 2-cylinder 17.3 (284)
lnline 3-cylinder 33.1 (543)
In line 3-cylinder 33.1 (543)
tnline 2-cylinder 42.5 (696)
lnline 3-cylinder 54.4(891)
lnline 3-cylinder 54.4 (891)
lnline 3-cylinder 73 (1197)
lnline 3-cylinder 73 (1 197)
V-4 (70°) 86.6 (1419)
V-4 (70°) 86.6 (1419)
lnline 4-cylinder 1 08.2 (1773)
lnline 4-cylinder 108.2 (1773)
V-6 (60°) 164.3 (2693)
V-6 (60°) 164.3 (2693)
V-6 (60°) 164.3 (2693)
1-cylinder 3.05 (50)
1-cylinder 5.5 (90)
lnline 2-cylinder 10.1 (165)
lnline 2-cylinder 12.8 (211)
lnline 2-cylinder 12.8 (211)
lnline 2-cylinder 17.3 (284)
lnline 3-cylinder 33.1 (543)
lnline 3-cylinder 33.1 (543)
lnline 2-cylinder 42.5 (696)
lnline 3-cylinder 54.4(891)
lnline 3-cylinder 54.4(891)
lnline 3-cylinder 73(1197)
lnline 3-cylinder 73(1197)
V-4 (70") 86.6 (1419)
1.61 X 1 .49 100:1 Pre·Mix Flywheel· Magneto Manual w/ manual choke lmpeller Pump
1.97x 1.81 100:1 Pre-Mix Suzuki PEJ. Manual w/ manual choke lmpeller Pump
1.97x 1.65 100:1 Pre-Mix Suzuki P .E.I. Manual w/ manual choke lmpeller Pump
2.13x 1.81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
2.13 x 1.81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
2.32 X 2.05 Oil Injection Digitai i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
2.44x 2.36 Oil Injection Digitai i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
2.44x 2.36 Oil Injection Digitai i.C. Manual/Electric w/electriclmanual choke lmpeller Pump
3.11 X 2.80 Oil Injection Suzuki P.E.I. Electric/Manual w/ manual/electric choke lmpeller Pump
2.87 x 2.80 Oil Injection Suzuki P.E.I. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
2.87 X 2.80 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
3.31 X 2.83 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
3.31 X 2.83 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
3.31 X 2.52 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump /Thermostat Controlled
3.31 X 2.52 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump /Thermostat Controlled
3.31 X 3.15 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
3.31 X 3.15 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
3.31 X 3.19 Oil Injection Micro link Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
1.61 X 1.49 1 00:1 Pre-Mix Flywheel Magneto Manual w/ manual choke lmpeller Pump
1.97x 1.81 100:1 Pre-Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
1.97x 1.65 100:1 Pre·Mix Suzuki P.E.I. Manual wl manual choke lmpeller Pump
2.13x 1.81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
2.13x 1.81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
2.32 X 2.05 Oil Injection Digitai i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
2.44x 2.36 Oil Injection Digitai i.C. Manual/Electric w/ electric/manual choke knpeller Pump
2.44x 2.36 Oil Injection Digitai i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
3.11 X 2.80 Oil Injection Suzuki P.E.I. Electric/Manual w/ manual/electric choke lmpeller Pump
2.87 X 2.80 Oil Injection Suzuki P.E.I. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
2.87 X 2.80 Oil Injection Digitai i.C. Electric w/electric choke lmpeller Pump /Thermostat Controlled
3.31 X 2.83 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
3.31 x 2.83 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
3.31 X 2.52 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
3.31 X 2.52 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump /Thermostat Controlled
3.31 x 3.15 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
3.31 X 3.15 Oil Injection Micro link Electric w/ Suzuki Start System lmpeller Pump /Thermostat Controlled
3.31 .X3.19 Oil Injection Micro/ink Electric w/ Suzuki EFI lmpeller Pump /Thermostat Controlled
3.31 X 3.19 Oil Injection Micro link Electric w/ Suzuki EFI lmpeller Pump /Thermostat Controlled
3.31 X 3.19 Oil Injection Micro link Electric w/ Suzuki EFI lmpeller Pump /Thermostat Controlled
1.61 X 1.49 100:1 Pre-Mix Flywheel Magneto Manual w/ manu a! choke lmpeller Pump
1.97x 1.81 100:1 Pre-Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
1.97x 1.65 100:1 Pre·Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
2.1 3 x 1.81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
2.13x 1.81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
2.32 X 2.05 Oil Injection Digitai i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
2.44x 2.36 Oil Injection Digitai i.C. Manual/Electric w/ electriclmanual choke lmpeller Pump
2.44x 2.36 Oil Injection Digitai i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
3.11 x 2.80 Oil Injection Suzuki P.E.I. Electric/Manual w/ manual/electric choke lmpeller Pump
2.87 X 2.80 Oil Injection Suzuki P.E.I. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
2.87 X 2.80 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
3.31 X 2.83 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
3.31 X 2.83 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
3.31 X 2.52 Oil Injection Micro link Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
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General Engine Specifications
Model ----- Engine Displace Bore and---- -Oifli'ijeCUon lgnt ton Startmg Coohng
Year (Horsepower) Type cu.in. (cc) Stroke System System System System
1992 DT 100 V-4 (70°) 86.6 (1419) 3.31 X 2.52 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump /Thermostat Controlled
DT 115 lnline 4-cylinder 108.2 (1773) 3.31 x 3.15 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT 140 lnflne 4-cylinder 108.2 (1773) 3.31 X 3.15 o·1l lnjection Micro6nk Electric w/ Suzuki Steri System lmpeller Pump I Thermostat Controlled
DT 150 V-6 (60°) 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT 175 V-6 (60°) 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI hllpeller Pump I Thermostat Controlled
DT 225 EFI V-6 (60°) 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump /Thermostat Controlled
1991 DT2 1·cylinder 3.05 (50) 1 .61 X 1 .49 100:1 Pre-Mix Flywheel Magneto Manual w/ manual choke lmpeller Pump
DT4 1-cylinder 5.5 (90) 1.97 x 1.81 100:1 Pre-Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 6 lnline 2·cylinder 10.1 (165) 1 .97 X 1 .65 100:1 Pre-Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT8 lnline 2-cylinder 12.8 (211) 2.13x 1.81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT9.9 lnline 2-cylinder 12.8 (211) 2.13x 1.81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 15 lnline 2-cylinder 17.3 (284) 2.32x 2.05 Oil Injection Digitai i.C. Manual/Electric w/ electricknanual choke lmpeller Pump
DT25 lnline 3-cylinder 33.1 (543) 2.44x 2.36 Oil Injection Digitai i.C. Manual/Electric w/ electrichnanual choke lmpeller Pump
DT 30 lnline 3-cylinder 33.1 (543) 2.44x 2.36 Oil Injection Digitai i.C. Manual/Electric w/ electricknanual choke lmpeller Pump
DT 40 lnline 2-cylinder 42.5 (696) 3.11 x 2.80 Oil Injection Suzuki P.E.I. ElectricJManual w/ manuaUelectric choke lmpeller Pump
DT 55 lnline 3-cylinder 54.4(891) 2.87x 2.80 Oil Injection Suzuki P.E.I. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
DT 65 lnline 3-cylinder 54.4 (891) 2.87x 2.80 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT75 lnline 3-cylinder 73(1197) 3.31 X 2.83 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT 85 lnline 3-cylinder 73(1197) 3.31 X 2.83 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
DT 115 lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
DT 140 lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump /Thermostat Controlled
DT 150 V-6 (60") 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT 175 V-6 (60°) 1 64.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump /Thermostat Controlled
DT 200 V-6 (60°) 164.3 (2693) 3.31 X 3.19 Oil Injection Micro link Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT225EFI V-6 (60°) 164.3 (2693) 3.31 X 3.19 Oil Injection Micro link Electric wl Suzuki EFI lmpeller Pump /Thermostat Controlled
1 990 DT2 1-cylinder 3.05 (50) 1.61 X 1 .49 100:1 Pre-Mix Flywheel Magneto Manual w/ manual choke lmpeller Pump
DT 4 1-cylinder 5.5 (90) 1.97x 1.81 100:1 Pre-Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 6 lnline 2-cylinder 10.1 (165) 1.97 x 1 .65 100:1 Pre-Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT8 lnline 2�cylinder 12.8 (21 1) 2.13 x 1.81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT9.9 lnline 2-cylinder 12.8(211) 2.13x 1.81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 15 lnline 2-cylinder 17.3 (284) 2.32x 2.05 Oil Injection Digitai i.C. Manual/Electric w/ electrichnanual choke lmpeller Pump
DT25 lnline 3-cylinder 33.1 (543) 2.44x 2.36 Oil Injection o·1gital LC. Manual/Electric w/ electrichnanual choke lmpeller Pump
DT 30 lnline 3-cylinder 33.1 (543) 2.44x 2.36 Oil Injection Digitai i.C. Manual/Electric w/ electric/manual choke lmpeller Pump
DT 40 lnline 2-cylinder 42.5 (696) 3.1 1 x 2.80 Oil Injection Suzuki P.E.I. Electnc;IManual w/ manual/electric choke lmpeller Pump
DT 55 lnline 3-cylinder 54.4(891) 2.87x 2.80 Oil Injection Suzuki P.E.I. Electric w/ electric choke lmpeller Pump /Thermostat Con�olled
DT65 lnline 3-cylinder 54.4(891) 2.87 X 2.80 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
DT75 lnline 3-cylinder 73 (1197) 3.31 X 2.83 Oil Injection Digitai i.C. Electric w/ electric choke Imp ell er Pump I Thermostat Con�olled
DT 85 lnline 3-cylinder 73(1197) 3.31 X 2.83 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT 90 V-4 (70°) 86.6 (1419) 3.31 X 2.52 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
DT 100 V-4 (70°) 86.6 (1419) 3:31 X 2.52 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
DT115 lnline 4-cylinder 108.2 (1773) 3.31 x 3.15 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT 140 lnline 4-cylinder 108.2 (1773) 3.31 x3.15 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
DT150 V-6(60°) 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump /Thermostat Controlled
DT 175 V-6 (60°) 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT 200 V-6 (60°) 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT 225 V-6 (60°) 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
1989 DT 2 1-cylinder 3.05 (50) 1 .61 X 1 .49 100:1 Pre-Mix Flywheel Magneto Manual w/ manual choke lmpeller Pump
DT4 1-cylinder 5.5 (90) 1 .97x 1.81 100:1 Pro-Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 6 lnline 2-cylinder 10.1 (165) 1.97 x 1 .65 100:1 Pre-Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 8 lnline 2-cylinder 12.8(211) 2.13 x 1 .81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT9.9 lnline 2-cylinder 12.8 (21 1) 2.13x 1.81 Oil Injection Suzuki P.E.I. Manual w/ manual choke lmpeller Pump
DT 15 lnline 2-cylinder 17.3 (284) 2.32 X 2.05 Oil Injection Digitai i.C. Manual/Electric w/ electrichnanual choke lmpeller Pump
DT25 lnline 3-cylinder 33.1 (543) 2.44x 2.36 Oil Injection Digitai i.C. Manual/Electric w/ electrichnanual choke lmpeller Pump
DT 30 lnline 3-cylinder 33.1 (543) 2.44 x 2.36 Oil Injection Digitai i.C. Manual/Electric w/ electrichnanual choke lmpeller Pump
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General Engine Specifications
MoaeT Engine Displace Boreand- OIITr\jectton -lgmtlon startmg cooling
Year (Horsepower) Type cu.in. (cc) Stroke System System System System
1989 DT35 lnline 3-cylinder 42.5 (696) 2.44 x 2.36 Oil Injection Suzuki P.E.I. Manualtl:lectric w/ electric/manual choke lmpeller Pump I Thermostat Controlled
DT40 lnline 2-cylinder 42.5 (696) 3.1 1 x 2.80 Oil Injection Suzuki P.E.I. Electric/Manual w/ manual/electric choke lmpeller Pump
DT 55 lnline 3-cylinder 54.4 (891) 2.87x 2.80 Oil Injection Suzuki P.E.I. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT65 lnline 3-cylinder 54.4 (891) 2.87 x 2.80 Oil Injection Digitai i.C. Electric w/ electric choke Imp ell er Pump I Thermostat Controlled
DT 75 lnline 3-cylinder 73 (1197) 3.31 X 2.83 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump /Thermostat Controlled
DT 85 lnline 3-cylinder 73(1197) 3.31 X 2.83 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump / Thermostat Controlled
DT 90 V-4 (70') 86.6 (1419) 3.31 X 2.52 Oil Injection Micro link Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
DT 100 V-4 (70') 86.6 (1419) 3.31 X 2.52 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
DT 1 1 5 lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT 140 lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil Injection Microlink Electric w/ Suzuki Start System lmpeller Pump / Thermostat Controlled
DT 150 V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil Injection Microlink Electric w/ Suzuki EFI lmpeller Pump /Thermostat Controlled
DT 175 V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil Injection Micro link Electric w/ Suzuki EFI lmpeller Pump I Thermostat Controlled
DT 200 V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil Injection Micro link Electric wl Suzuki EFI lmpeller Pump I Thermostat Controlled
1988 DT 2 1-cylinder 3.1 (50) 1.61 X 1.5 100:1 Pre-Mix Suzuki P.E.I. Manual wl manual choke lmpeller Pump
DT 4 1-cylinder 5.5 (90) 1.97x 1 .81 100:1 Pre-Mix Suzuki P.E.I. Manual wl manual choke lmpeller Pump
DT 6 lnline 2-cylinder 10.1 (165) 1 .97x 1 .65 100:1 Pre-Mix Suzuki P.E.I. Manual wl manual choke lmpeller Pump
DT 8 lnline 2-cylinder 12.8 (21 1) 2.13x 1.81 Oil Injection Suzuki P.E.I. Manual wl manual choke lmpeller Pump
DT9.9 lnline 2-cylinder 12.8(211) 2.13x 1.81 Oil Injection Suzuki P.E.I. Manual wl manual choke lmpeller Pump
DT 15 lnline 2-cylinder 17.3 (284) 2.32 x 2.05 Oil Injection Digitai i.C. Manualtl:lectric wl electric/manual choke lmpeller Pump
DT 20 lnline 2-cylinder 27.1 (444) 2.64x 2.48 100:1 Pre-Mix Suzuki P.E.I. Manual w/ manual choke lmpeller Pump I Thermostat Controlled
DT 25 lnline 3-cylinder 33.1 (543) 2.44x 2.36 Oil Injection Suzuki P.E.I. ManuaiiEiectric wl electric/manual choke lmpeller Pump
DT30 lnline 3-cylinder 33.1 (543) 2.44 x 2.36 Oil Injection Digitai i.C. Manualtl:lectric wl electric/manual choke lmpeller Pump
DT 35 lnline 3-cylinder 42.5 (696) 2.44x 2.36 Oil Injection Suzuki P.E.I. ManuaiiEiectric wl electric/manual choke lmpeller Pump I Thermostat Controlled
DT 40 lnline 2-cylinder 42.5 (696) 3.11 X 2.80 Oil Injection Suzuki P.E.I. Electric/Manual wl manual/electric choke lmpeller Pump
DT 55 lnline 3-cylinder 54.4 (891) 2.87 X 2.80 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT 65 lnline 3-cylinder 54.4 (891) 2.87 x 2.80 Oil Injection Digitai i.C. Electric w/ electric choke lmpeller Pump I Thermostat Controlled
DT75 lnline 3-cylinder 73(1197) 3.31 X 2.83 Oil Injection Digitai i.C. Electric wl electric choke Imp ell er Pump I Thermostat Controlled
DT85 lnline 3-cylinder 73 (1197) 3.31 X 2.83 Oil Injection Digitai i.C. Electric wl electric choke lmpeller Pump I Thermostat Controlled
DT 1 1 5 lnline 4-cylinder 108.2 (1773) 3.31 x 3.15 Oil Injection Digitai i.C. Electric wl electric choke lmpeller Pump I Thermostat Controlled
DT 140 lnline 4-cylinder 108.2 (1773) 3.31 X 3.15 Oil Injection Dig�ai i.C. Electric wl electric choke lmpeller Pump /Thermostat Controlled
DT 1 50 V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil Injection Digitai i.C. Electric wl Suzuki Start System lmpeller Pump I Thermostat Controlled
DT 175 V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil Injection Digitai i.C. Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
DT 200 V-6 (60') 164.3 (2693) 3.31 X 3.19 Oil Injection Digitai i.C. Electric w/ Suzuki Start System lmpeller Pump I Thermostat Controlled
w I � I\,)
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Serial Number Identification
Parts Serial No. Sales Model Designation
novu""' . ...... "'"""""'l:t'"'u""'' ... ........ ... '"'"""'-'-�IIA�IVII .._l'loUIII '""
DT2 1988 VJ 8XXXXX J DT 2 SJ
1989 VK 9)()()()()( K DT 2 SK
1990 VL 011)()()( L DT 2LL
1991 VM 131XXX M DT 2SM
1992 VN 231)()()( N DT 2SN
1993 VP 351XXX p DT 2 SP
1994 VR 461XXX R DT 2SR
1995 vs 581XXX s DT 2 SS
1996 VT 651)()()( T DT 2 ST
1997 w 751)()()( V DT2.2SV
DT2.2 1997 sv lOOOOO< DT2.2SV
DT4 1988 VJ 8XXXXX J DT 4LJ
1989 VK 9)()()()()( K DT 4LK
1990 VL 011XXX L DT 4 LL
1991 VM 131XXX M DT 4LM
1992 VN 231 XXX N DT4LN
1993 VP 351)()()( p DT4LP
1994 VR 461)()()( R DT 4LR
1995 vs 581)()()( s DT4LS
1996 VT 651XXX T DT4LT
1997 w 751XXX V DT 4 LV
1998 1//W 861XXX w DT4LW
DT5Y 1998 vw lOOOOO< w DT5YW
1999- 2002 vx lOOOOO< X RT5YX
DT6 1988 VJ 8XXXXX J DT6SJ
1989 VK 9)()()()()( K DT 6SK
1990 VL 011)()()( L DT6SL
1991 VM 131XXX M DT 6 SM
1992 VN 231)()()( N DT 6 SN
1993 VP 351XYX p DT 6SP
1994 VR 461XXX R DT 6SR
1995 VS 581)()()( s DHSS
1996 VT 651)()()( T DT 6 ST
1997 w 751XXX V DT 6 SV
1998 1//W 851)()()( w DT 6 SW
1999 - 2002 XX 971)()()( X DT 6 SX
DT8 1988 VJ 8)()()()()( J DT 8 CSJ
1989 VK 9XXXX K DT 8 CLK
1990 VL 011XXX L DT 8 CLL
1991 VM 131)()()( M DT B CSM
1992 VN 231)()()( N DT8 MCSN
1993 VP 351XXX p DT8 MCSP
1994 VR 461XXX R DT8 MCSR
1995 vs 581)()()( s DT 8 MCSS
1996 VT 651XXX T DT 8 MCST
1997 w 751XXX V DT8 MCSV
DT9.9 1988 VJ 8XXXXX J DT9.9 CESJ
1989 VK 9)()()()()( K DT9.9 CELK
1990 VL 011)()()( L DT9.9 CESL
1991 VM 131XXX M DT 9.9CESM
1992 VN 231)()()( N DT9.9 CESN
1993 VP 351)()()( p DT9.9 CELP
1994 VR 461)()()( R DT9.9 CELR
1995 vs 581XXX s DT 9.9 CELS
1996 VT 651)()()( T DT9.9 CELT
1997 w 751)()()( V DT9.9 CELV
DT15 1988 VJ 8)()()()()( J DT 15 MLJ
1989 VK 9XXXX K DT 15 CESK
1990 VL 011)()()( L DT 15 CESL
1991 VM 131)()()( M DT 1 5 CESM
1992 VN 231XXX N DT 15 CESN
1993 VP 351XXX p DT15 MCLP
1994 VR 461)()()( R DT 15 CESR
1995 vs 581)()()( s DT 15 CESS
1996 VT 651)()()( T DT 15 MCLT
---- .. __ ___ 19_97 __ w 751XXX V DT 15 MCLV
Serial Number Identification
Parts Serial No. Sales
........ .... . .. ,.. _ ...... �11LUIVII _,., ... . . t''""' ---·� . ..... ...... .
DT20 1988 VJ 8XXXXX J
DT25 1990 VL 011XXX L
1991 VM 131XXX M
1992 VN 231XXX N
1993 VP 351XXX p
1994 VR 461XXX R
1995 vs 581XXX s
1996 VT 651XXX T
1997 w 751XXX V
1998 ww 861XXX w
1999 - 2000 XX 971XXX X
DT30 1988 VJ 8XXXXX J
1989 VK 9XXXXX K
1990 VL 011XXX L
1991 VM 131XXX M
1992 VN 231XXX N
1993 VP 351XXX p
1994 VR 461XXX R
1995 vs 581XXX s
1996 VT 651XXX T
1997 w 751XXX V
DT35 1966 VJ 8XXXXX J
1969 VK 9XXXXX K
DT40 1969 VK 9XXXXX K
1990 VL 011XXX L
1991 VM 131XXX M
1992 VN 231XXX N
1993 VP 351XXX p
1994 VR 461XXX R
1995 VS 561XXX s
1996 VT 651XXX T
1997 w 751XXX V
1998 ww 661XXX w
DT55 1966 VJ 6XXXXX J
1969 VK 9XXXXX K
1990 VL 011XXX L
1991 VM 131XXX M
1992 VN 231XXX N
1993 VP 351XXX p
1994 VR 461XXX R
1995 VS 561XXX s
1996 VT 651XXX T
1997 w 751XXX V
DT65 1986 VJ 6XXXXX J
1989 VK 9XXXXX K
1990 VL 011XXX L
1991 VM 131XXX M
1992 VN 231XXX N
1993 VP 351XXX p
1994 VR 461XXX R
1995 vs 581XXX s
1996 VT 651XXX T
1997 w 751XXX V
Model Designation
-""'"' ·-
DT 20 ESJ
DT25 CESL
DT25 CESM
DT 25 CESN
DT25 CELP
DT 25CUR
DT 25 CELS
DT 25 CEST
DT25CESV
DT25 CESW
DT25CESX
DT30 MCLJ
DT 30 CESK
DT 30 CESL
DT30 MCLM
DT 30 MCLN
DT 30 MCLP
DT30 MCLR
DT 30 MCLS
DT30 MCLT
DT30 CRSV
DT35 CRSJ
DT 35 CRSK
DT 40 CELK
DT 40 CELL
DT 40 CRSM
DT 40 CRSN
DT40 CRSP
DT 40 CRSR
DT 40 CRSS
DT 40 CRST
DT 40 CRSV
DT40CRSW
DT 55 TCLJ
DT 55 TCLK
DT 55 TCLL
DT 55 TCLM
DT 55 TCLN
DT 55 TCLP
DT 55 TCLR
DT 55 TCLS
DT55 TCLT
DT 55 TCLV
DT 65 CRLJ
DT 65 TCLK
DT 65 TCLL
DT65 TCLM
DT 65 TCLN
DT 65 TCLP
DT 65 TCLR
DT 65 TCLS
DT 65 TCLT
DT 65 TCLV
� )>
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() m
w I � w
···---· · --·
DT75 1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
DT85 1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999- 2000
DT90 1989
1990
1992
1993
1994
1995
1996
1997
DT100 1989
1990
1992
1993
1994
1995
1996
1997
1998 - 2000
DT115 1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000 - 2001
Serial Number Identification
Parts serial No.
---· ··--·-··
VJ
VK
VL
VM
VN
VP
VR
vs VT
w VJ
VK
VL
VM
VN
VP
VR
vs VT
w ww XX
VK
VL
VN
VP
VR
vs VT
w VK
VL
VN
VP
VR
vs VT
w ww VJ
VK
VL
VM
VN
VP
VR
vs VT
w ww XX
TC
-�·-· · · · -
8)()()()()(
9)()()()()(
011XXX
131)()()(
231 XXX
351)()()(
461)()()(
581XXX
651)()()(
751)()()(
8)()()()()(
9)()()()()(
011XXX
131 )()()(
231)()()(
351XXX
461XXX
581XXX
651)()()(
751XXX
861XXX
971)()()(
9)()()()()(
011XXX
231)()()(
351XXX
461XXX
581XXX
651XXX
751XXX
9)()()()()(
011XXX
23 1)()()(
351XXX
461)()()(
581XXX
651)()()(
751XXX
861)()()(
8)()()()()(
9)()()()()(
011XXX
131 XXX
231XXX
351XXX
461XXX
581XXX
651XXX
751XXX
861XXX
971XXX
XJOOOO(
Sales
---· ··-�· .... · ·
J
K
L
M
N
p R
s T
V
J
K
L
M
N
p R
s T
V
w X
K
L
N
p R
s T
V
K
L
N
p R
s T
V
w J
K
L
M
N
p R
s T
V
w X
y Model Designation
-n-••• •DT75 TCLJ
DT 75 TCLK
DT75 TCLL
DT75 TCLM
DT 75TCLN
DT75 TCLP
DT75 TCLR
DT75 TCLS
DT75 TCLT
DT 75TCLV
DT85 TCLJ
DT 85TCLK
DT 85TCLL
DT85TCLM
DT 85TCLN
DT85 TCLP
DT 85TCLR
DT 85 TCLS
DT 85TCLT
DT 85 TCLV
DT85 TCLW
DT 85TCLX
OT90TCLK
DT90TCLL
DT 90TCLN
DT90 TCLP
DT 90TCLR
DT 90TCLS
DT90 TCLT
DT90 TCLV
DT 100TCXK
DTIOOTCXL
DT100TCLN
DT 100 TCLP
DT100TCLR
DT 100 TCLS
DT 100 TCLT
DT 100TCLV
DT100 TCLW
DT 115 TCXJ
DT115 TCXK
DT 115TCXL
DT 115 TCXM .
DT 115 TCXN
DT 115 TCXP
DT 115 TCXR
DT 115 TCXS
DT 115TCXT
DT 115 TCXV
DT 115 STCLW
DT 115 STCLX
DT 115 STC ---
Serial Number Identification
Parts Serial No.
---� ---- . ---
DT14D 1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000 - 2001
DT150 1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999- 2003
DT175 1988
1989
1990
1991
1992
DT200 1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999- 2000
DT225 1990
1991
1992
1993
1994
1995
1996
1997
1998
1999- 2003
---· · ·-··-··
VJ
VK
VL
VM
VN
VP
VR
VS
VT
w ww XX
TC
VJ
VK
VL
VM
VN
VP
VR
vs VT
w ww XX
VJ
VK
VL
VM
VN
VJ
VK
VL
VM
VN
VP
VR
vs VT
w ww XX
VL
VM
VN
VP
VR
vs VT
w ww XX
-··-···.-·-
8)()()()()(
9)()()()()(
011)()()(
131)()()(
231)()()(
351XXX
461XXX
581)()()(
651)()()(
751XXX
861)()()(
971)()()(
)()()()()()(
8)()()()()(
9)()()()()(
011XXX
131XXX
231)()()(
351XXX
461XXX
581XXX
651XXX
751XXX
861XXX
971XXX
8)()()()()(
9)()()()()(
011XXX
131)()()(
231)()()(
8XXXXX
9)()()()()(
011)()()(
131)()()(
231XXX
351)()()(
461XXX
581XXX
651)()()(
751)()()(
861XXX
971XXX
011XXX
131XXX
231XXX
351XXX
461XXX
581XXX
651)()()(
751XXX
861)()()(
971XXX
Note: Last letter of model designation indicates model year. A!! other letters are identified as follows.
C = Oil Injection H = Ti!!er Control N = Sail
E = Electric Start L = 20• Shaft PU = Jet Propultion System
G = Counter Rotation M = Manual Start R = Remote Control
Sales
---·::r·-··-••
J
K
L
M
N
p R
s T
V
w X
y J
K
L
M
N
p R
s T
V
w X
J
K
L
M
N
J
K
L
M
N
p R
s T
V
w X
L
M
N
p R
s T
V
w X
S � 15" Shaft
SS= Super Six
T = Tiltand Trim
Model Designation
----- - -... --
DT 14D TCLJ
DT14DTCLK
DT 14D TCLL
DT 140TCLM
DT 14D TCLN
DT 14D TCLP
DT 14DTCLR
DT 14D TCLS
DT 14DTCLT
DT 14D TCLV
DT 14DTCLW
DT14DTCLX
DT 14DTC
DT 150 TCXJ
DT 150 TCXK
DT 150 TCXL
DT 150 TCXM
DT 150TCXN
DT150TCXP
DT 150 TCXR
DT150 TCXGS
DT 150 TCXGT
DT 150 TCXGV
DT 150TCXGW
DT 150 TCXX
DT 175 TCXJ
DT 175TCXK
DT 175 TCXL
DT 175 TCXM
DT175TCXN
DT 200TCXJ
DT 200TCXK
DT200TCXGL
DT200TCXGM
DT 200TCXN
DT 200TCXP
DT 200TCXR
DT 200TCXS
DT 200TCXT
DT200TCXV
DT200 TCXW
DT 200TCXX
DT 225TCXL
DT225 TCXM
DT225 TCXN
DT 225 TCXP
DT 225 TCXR
DT 225TCXS
DT 225TCXT
DT 225 TCXV
DT225TCXW
DT 225 TCXX
x � 25" Shaft
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MAINTENANCE 3-45
Maintenance Interval Chart 2 2 2 4 5Y 20 25 28 d E I M d I 5 6 8 9 9 1 5 ' . ' ' ' ' ' an an y 0 e ' ' ' . '
Component
Bolts and nuts
Spark plugs
Wire harness
Starter Motor Brush Length
Ignition timing
Carburetor
Gear oil
Pistons, cylinder and head
Propeller
Choke
Fuel tank
Fuel strainer
Fuel hoses
Water pump
Handle
Clutch lever
Starter rope
Tilt
Neutral start interlock switch
Zinc Anodes
A-AdjUSt
L-Lubricate
First
1 mth/1 0hrs
C-Ciean
R-Replace
T
I
C&A
R
I
I
I
L
Every Every
3mths/50hrs 6mths/1 00hrs
T
C&A
I
I
C&A
C&A
R
De-Carbon
I
I
I
I
I
L & A
L
I
A
I
I
!-Inspect and Clean, Adjust, Lubncate or Replace
T-Tighten
Maintenance Interval Chart DT35, DT40, DT55, DT65, DT75, DT85, DT90 and DT1 00
Component
Spark plugs
Wiring harness and connector
Starter motor brushes
Ignition timing
N.S.I. switch
Ignition switch
Battery
Vapor separator
Fuel filter
Fuel hose and clip
Oil pump
Oil hose and clip
Oil filter {oil flow sensor)
Gear oil
Oil check valve
Lubrication
Water hose
Water pump
Water pump impeller
Zinc anode
Remote control
Power trim and tilt
Propeller
Propeller nut
Bolts and nuts
Bolts {cyL head, exhaust cover etc.)
A-AdjUSt
L -Lubricate
First
1 mth/1 0hrs
C-C lean
R-Replace
I
I
I
I
I
I
R
I
I
I
T
T
T
Every Every
3mths/50hrs 6mths/1 00hrs
I
I
I
I
I
I
I
I
I
I
I
I
After oil flow caution system is activated
R
I
I
I
I
I
T
T
T
!-Inspect and Clean, Adjust, Lubncate or Replace
T-Tighten
Off
Season
T
C&A
C&A
C&A
R
I
I
I
I
L
L
I
Off
Season
I
I
I
I
I
I
I
I
I
I
I
R
I
I
I
I
R
I
I
I
I
T
T
T
3-46 MAINTENANCE
Maintenance Interval Chart DT25, DT30 and Late Model DTS, DT6, DT8, DT9.9, DT1 5
Component
Carburetor
Piston, cylinder and cylinder head
Spark plugs
Fuel line
Fuel filter
Oil pump
Oil filter
Oil line
Lubrication
Wire harness
Starter motor
Emergency switch
Ignition switch and choke solenoid
Battery
Propeller
Protection zinc and trim tab
Gear oil
Bolts and nuts
Water pump
Remote control
A-AdjUSt
L -Lubricate
First
1 mth/1 0hrs
C-Ciean
R-Replace
I
I
I
I
I
I
R
T
I
I
Every Every
3mths/50hrs 6mths/1 OOhrs
I
I
C&A
I
R
I
I
I
I
I
I
I
I
I
R
T
I
!-Inspect and Clean, Adjust, Lubncate or Replace
T-Tighten
Maintenance Interval Chart DT1 1 5, DT1 40, DT1 50, DT1 75, DT200 and DT225
Component
Spark plugs
Wiring harness and connector
Starter motor brushes
Ignition timing
N.S.I. switch
Ignition switch
Battery
Vapor separator
Fuel filter
Fuel hose and clip
Oil pump
Oil hose and clip
Oil filter (oil flow sensor)
Gear oil
Oil check valve
Lubrication
Water hose
Water pump
Water pump impeller
Zinc anode
Remote control
Power trim and tilt
Propeller
Propeller nut
Bolts and nuts
Bolts (cyl. head, exhaust cover etc.)
A-AdjUSt
L-Lubricate
First
1 mth/1 0hrs
C-C lean
R-Replace
I
I
I
I
I
I
R
I
I
I
T
T
T
Every Every
3mths/50hrs 6mths/1 00hrs
I
I
I
I
I
I
I
I
I
I
I
I
After oil flow caution system is activated
R
I
I
I
I
I
T
T
T
!-Inspect and Clean, Adjust, Lubricate or Replace
T-Tighten
Off
Season
I
I
C&A
I
I
I
I
I
I
I
I
I
I
I
R
T
I
I
Off
Season
I
I
I
I
I
I
I
I
I
I
I
R
I
I
I
I
R
I
I
I
I
T
T
T
FUEL AND COMBUSTION 4-2
FUEL 4-2
RECOMMENDATIONS 4-2
OCTANE RATING 4-2
VAPOR PRESSURE AND ADDITIVES 4-2
THE BOTTOM LINE WITH FUELS 4-2
H IGH ALTITUDE OPERATION 4-2
ALCOHOL-BLENDED FUELS 4-2
COMBUSTION 4-3
ABNORMAL COMBUSTION 4-3
FACTORS AFFECTING COMBUSTION 4-3
FUEL SYSTEM 4-3
CARBURETION 4-3
GENERAL INFORMATION 4-3
CARBURETOR CIRCUITS 4-4
BASIC FUNCTIONS 4-5
DUAL-THROAT CARBURETORS 4-6
REMOVING FUEL FROM THE SYSTEM 4-6
FUEL PUMP 4-6
TROUBLESHOOTING 4-7
FUEL SYSTEM 4-7
LOGICAL TROUBLESHOOTING 4-7
COMMON PROBLEMS 4-8
FUEL PUMP 4-8
FUEL LINE 4-9
COMMON PROBLEMS 4-1 0
COMBUSTION RELATED PISTON FAILURES
4-1 0
CARBURETOR SERVICE 4-11
DT2 AND DT2.2 4-1 1
REMOVAL & INSTALLATION 4-1 1
DISASSEMBLY 4-1 1
CLEANING & INSPECTION 4-1 2
ASSEMBLY 4-1 2
DT4 AND DT5Y 4-1 3
REMOVAL & INSTALLATION 4-1 3
DISASSEMBLY 4-1 3
CLEANING & INSPECTION 4-1 3
ASSEMBLY 4-1 4
DT6 AND 1 988 DT8 4-1 4
REMOVAL & INSTALLATION 4-1 4
DISASSEMBLY 4-1 4
CLEANING & INSPECTION 4-1 5
ASSEMBLY 4-1 5
DT9.9, DT1 5 AND 1 989-97 DT8 4-1 5
REMOVAL & INSTALLATION 4-1 5
DISASSEMBLY 4-1 6
CLEANING & INSPECTION 4-1 6
ASSEMBLY 4-1 7
DT20 TO DT85, DT1 1 5 AND DT140 4-1 7
REMOVAL & INSTALLATION 4-1 9
DISASSEMBLY 4-20
CLEANING & INSPECTION 4-21
ASSEMBLY 4-21
V4 & V6 POWERHEADS 4-22
REMOVAL & INSTALLATION 4-23
DISASSEMBLY 4-24
FUEL LEVEL TEST 4-24
CLEANING & INSPECTION 4-25
ASSEMBLY 4-25
REED VALVE SERVICE 4·25
DT2, DT2.2 4-25
REMOVAL & INSTALLATION 4-25
ALL OTHER MODELS 4-25
REMOVAL & INSTALLATION 4-26
INSPECTION & CLEANING 4-26
REED & REED STOP REPLACEMENT 4-26
FUEL PUMP SERVICE 4-27
DIAPHRAGM TYPE FUEL PUMPS 4-27
DESCRIPTION & OPERATION 4-27
REMOVAL & INSTALLATION 4-27
OVERHAUL 4-27
ELECTRONIC FUEL INJECTION 4-32
DESCRIPTION AND OPERATION 4-32
FUEL INJECTION BASICS 4-32
SUZUKI ELECTRONIC FUEL INJECTION 4-
32
CYLINDER WALL TEMPERATURE SENSOR 4-
36
DESCRIPTION & OPERATION 4-36
TESTING 4-38
REMOVAL & INSTALLATION 4-39
AIR TEMPERATURE SENSOR 4-39
DESCRIPTION & OPERATION 4-39
TESTING 4-39
REMOVAL & INSTALLATION 4-39
ATMOSPHERIC PRESSURE SENSOR 4-39
DESCRIPTION & OPERATION 4-39
TESTING 4-39
REMOVAL & INSTALLATION 4-39
THROTTLE VALVE SENSOR 4-40
DESCRIPTION AND OPERATION 4-40
TESTING 4-40
ADJUSTMENT 4-42
REMOVAL AND INSTALLATION 4-45
GEAR COUNTER COIL (ENGINE SPEED
SENSOR) 4-45
DESCRIPTION AND OPERATION 4-45
TESTING 4-45
PULSER COIL 4-45
DESCRIPTION AND OPERATION 4-45
TESTING 4-45
FUEL INJECTORS 4-45
DESCRIPTION AND OPERATION 4-45
TESTING 4-45
FUEL PRESSURE REGULATOR 4-46
TESTING 4-46
REMOVAL AND INSTALLATION 4-47
H IGH PRESSURE FUEL PUMP 4-47
TESTING 4-48
ADDITIONAL INPUTS 4-48
SELF DIAGNOSTIC SYSTEM 4-48
DESCRIPTION AND OPERATION 4-48
DIAGNOSIS PROCEDURE 4-49
FAIL SAFE EMERGENCY BACKUP 4-49
SPECIFICATIONS 12-5
CARBURETOR SPECIFICATIONS
(DT4 THRU DT85) 1 2-5
CARBURETOR SPECIFICATIONS
(DT90 THRU DT200) 1 2-6
4-2 FUEL SYSTEM
I FUEl AND COMBUSTION
Fuel
RECOMMENDATIONS
Reformulated gasol ine fuels are now found in many market areas. Current test­
ing indicates no particular problems with using this fuel. Shelf life is shorter and,
because of the oxygenates, a slight leaning out at idle may be experienced. This
sl ightly lean condition can be compensated for by adjusting idle mixture screws.
Fuel recommendations have become more complex as the chemistry of modern
gasoline changes. The major driving force behind the changes in gasoline chem­
istry is the search for additives to replace lead as an octane booster and lubricant.
These new additives are governed by the types of emissions they produce in the
combustion process. Also, the replacement additives do not always provide the
same level of combustion stabi l ity, making a fuel's octane rating less meaningful.
In the search for new fuel additives, automobiles are used as the test
medium. Not one h igh performance two cycle engine was tested in the process
of determining the chemistry of today's gasoline.
In the 1 960's and 1 970's, leaded fuel was common. The lead served two
functions. The lead served as an octane booster (combustion stabil izer) and, in
four cycle engines, served as a valve seat lubricant. For two cycle engines, the
primary benefit of lead was to serve as a combustion stabi l izer. Lead served very
well for this purpose, even in h igh heat appl ications.
Today, all lead has been removed from the gasol ine process. This means that
the benefit of lead as an octane booster has been e l im inated. Several substitute
octane boosters have been introduced in the place of lead. Whi le many are ade­
quate in an automobile, most do not perform nearly as wel l as lead did, even
though the octane rating of the fuel is the same.
OCTANE RATING
A fuel's octane rating is a measurement of how stable the fuel is when heat is
introduced. Octane rating is a major consideration when deciding whether a fuel
is suitable for a particular appl ication. For example, in an engine, we want the
fuel to ignite when the spark plug fires and not before, even under high pressure
and temperatures. Once the fuel is ign ited, it must burn slowly and smoothly,
even though heat and pressure are bui lding up wh i le the burn occurs. The
unburned fuel should be ign ited by the travel ing flame front, not by some other
source of ignition , such as carbon deposits or the heat from the expanding
gasses. A fuel's octane rating is known as a measurement of the fuel's anti­
knock properties (abil ity to burn without exploding).
Usual ly a fuel with a higher octane rating can be subjected to a more severe
combustion environment before spontaneous or abnormal combustion occurs.
To understand how two gasol ine samples can be different, even though they
have the same octane rating, we need to know how octane rating is determined.
The American Society of Testing and Materials (ASTM) has developed a uni­
versal method of determining the octane rating of a fuel sample. The octane rat­
ing you see on the pump at a gasol ine station is known as the pump octane
number. Look at the small print on the pump. The rating has a formula. The rat­
ing is determined by the R+M/2 method.
Therefore, the number you see on the pump is the average of two other
octane ratings.
The Research Octane Reading is a measure of a fuel's anti-knock properties
under a l ight load, or part throttle conditions. During this test, combustion heat
is easily dissipated.
The Motor Octane Rating is a measure of a fuel's anti-knock properties under
a heavy load, or ful l throttle conditions, when heat buildup is at maximum.
Because a two cycle engine has a power stroke every revolution, with heat
bui ldup every revolution, it tends to respond more to the motor octane rating of
the fuel than the research octane rating. Therefore, in an outboard motor, the
motor octane rating of the fuel is the best indication of how it wi l l perform, not
the research octane. Unfortunately, the user has no way of knowing for sure the
exact motor octane rating of the fue l .
VAPOR PRESSURE AND ADDITIVES
Two other factors besides octane rating affect how suitable the fuel is for a
particular appl ication.
Fuel vapor pressure is a measure of how easily a fuel sample evaporates.
Many additives used in gasol ine contain aromatics. Aromatics are l ight hydro­
carbons disti l led off the top of a crude o i l sample. They are effective at increas­
ing the research octane of a fuel sample, but can cause vapor lock on a very hot
day. If you have an inconsistent running engine and you suspect vapor lock, use
a piece of clear fuel l i ne to look for bubbles, indicating that the fuel is vaporiz­
ing.
One negative side effect of aromatics is that they create additional combus­
tion products such as carbon and varnish. If your engine requ i res h igh octane
fuel to prevent detonation, de-carbon the engine more frequently with an
internal engine cleaner to prevent r ing sticking due to excessive varnish
bui ldup.
Besides aromatics, two types of alcohol are used in fue l today as octane
boosters, ethanol and methanol. Again, alcohol tends to raise the research
octane of the fuel. This usually means they wi l l have l im ited benefit in an out­
board motor. Also, alcohol contains oxygen, which means that since it is replac­
ing gasol ine without oxygen content, alcohol fuel blends cause the fuel-air
mixture to be l eaner.
THE BOTTOM LINE WITH FUELS
If we could buy fuel of the correct octane rating, free of alcohol and aromat­
ics, this would be our first choice.
Suzuki continues to recommend un leaded fuel . This is almost a redundant
recommendation due to the near universal unavailab i l ity of any other type fuel.
According to the fuel recommendations that come with your outboard, there
is no engine in the product l i ne that requires more than 89 octane. Most Suzuki
engines need only 86 octane or less. An 89 octane rating generally means mid­
dle grade un leaded. Premium unleaded is more stable under severe conditions,
but also produces more combustion products. Therefore, when using premium
un leaded, more frequent de-carboning is necessary.
Regardless of the fuel octane rating you choose, try to stay with a name
brand fue l . You never know for sure what kinds of additives or how much is in
off brand fuel.
HIGH ALTITUDE OPERATION
At e levated altitudes there is less oxygen i n the atmosphere than at sea
level. Less oxygen means lower combustion efficiency and less power output.
Power output is reduced three percent for every thousand feet above sea level.
At ten thousand feet, power is reduced 30 percent from that avai lable at sea
level.
Re-jetting for high altitude does not restore this lost power. Re-jetting simply
corrects the air-fuel ratio for the reduced air density, and makes the most of the
remaining available power. If you re-jet an engine, you are locked into the
higher e levation. You cannot operate at sea level until you re-jet for sea level.
Understand that going below the elevation jetted for your motor wi l l damage the
engine. As a general rule, jet for the lowest e levation anticipated . Spark p lug
insulator tip co lor is the best gu ide for high altitude jetting.
If you are in an area of known poor fuel qual ity, you may want to use fuel
additives. Today's additives are mostly alcohol and aromatics, and their effec­
tiveness may be l imited. lt is difficult to find additives without ethanol ,
methanol, or aromatics. I f you use octane boosters frequent de-carboning may
be necessary. If possible, the best pol icy is to use name brand pump fuel with
no additional additives except Suzuki fuel conditioner and Ring-Free•.
ALCOHOL-BLENDED FUELS
The Environmental Protection Agency mandated a phase-out of the leaded
fuels. Lead was used to boost the octane of fuel. By January of 1 986, the maxi­
mum al lowable amount of lead was 0.1 gm/gal , down from 1 .1 gm/gal .
Gasoline suppliers, i n general, feel that the 0 . 1 gm/gal l imit is too low to
make lead of any real use to improve octane. Therefore, alternate octane
improvers are being used. There are multiple methods currently employed to
improve octane but the most inexpensive additive seems to be alcohol .
There are, however, some special considerations due to the effects o f alcohol
in fue l . You should know about them and what steps to take when using alco­
hol-blended fuels commonly called gasohol.
Alcohol in fuel is either methanol (wood alcohol) or ethanol (grain alcohol).
Either type can have serious effects when applied to outboard motor appl ica­
tions.
The leaching affect of alcohol will, i n time, cause fuel l ines and plastic com­
ponents to become brittle to the point of cracking. Unless replaced, these
cracked l i nes could leak fuel, increasing the potential for hazardous situations.
_..Suzuki fuel lines and plastic fuel system components have been spe­
cially formulated to resist alcohol leaching effects.
When gasohol becomes contaminated with water, the water combines with
the alcohol then settles to the bottom. This leaves the gasol ine and the o i l for
models using premix, on a top layer. With alcohol-blended fuels, the amount of
water necessary for this phase separation to occur is 0.5% by volume.
Al l fuels have chemical compounds added to reduce the tendency towards
phase separation . If phase separation occurs, however, there is a poss ib i l ity of a
lean o i l/fuel mixture with the potential for engine damage. With o i l-injected out­
boards (Precision Blend models), phase separation wi l l be less of a problem
because the oil is injected separately rather than being premixed.
Combustion
A two cycle engine has a power stroke every revolution of the crankshaft. A
four cycle engine has a power stroke every other revolution of the crankshaft.
Therefore, the two cycle engine has twice as many power strokes for any given
RPM. If the displacement of the two types of engines is identical, then the two
cycle engine has to dissipate twice as much heat as the four cycle engine. I n
such a h i gh heat environment, the fuel must be very stable to avoid detonation.
If any parameters affecting combustion change suddenly (the engine runs lean
for example), uncontrolled heat bui ldup occurs very rapidly in a two cycle
engine.
ABNORMAL COMBUSTION
There are two types of abnormal combustion:
• Pre- ign it ion-Occurs when the a i r-fuel mixture is i gn ited by some
other i ncandescent source other than the correctly timed spark from the
spark p lug .
• Detonation-Occurs when excessive heat and or pressure ign ites the
air/fuel mixture rather than the spark plug. The burn becomes explosive.
FUEL SYSTEM
Carburetion
GENERAL INFORMATION
The carburetor is merely a metering device for mixing fuel and air in the
proper proportions for efficient engine operation. At idle speed, an outboard
engine requi res a mixture of about 8 parts air to 1 part fuel. At h igh speed or
under heavy duty service, the m ixture may change to as much as 12 parts air to
1 part fuel.
Float Systems
• See Figure 1
A small chamber in the carburetor serves as a fuel reservoir. A float valve
admits fuel into the reservoi r to replace the fuel consumed by the engine. If the
carburetor has more than one reservoir, the fuel level in each reservoi r (cham­
ber) is controlled by identical float systems.
Fuel level in each chamber is extremely critical and must be maintained
accurately. Accuracy is obtained through proper adjustment of the floats. This
adjustment wi l l provide a balanced metering of fuel to each cylinder at al l
speeds.
Following the fuel through its course, from the fuel tank to the combustion
chamber of the cyl inder, will provide an appreciation of exactly what is taking
place. In order to start the engine, the fuel must be moved from the tank to the
carburetor by a squeeze bulb installed in the fuel l ine. This action is necessary
because the fuel pump does not have sufficient pressure to draw fuel from the
tank during cranking before the engine starts.
FUEL SYSTEM 4-3
FACTORS AFFECTING COMBUSTION
The combustion process is affected by several interrelated factors. This
means that when one factor is changed, the other factors also must be changed
to maintain the same controlled burn and level of combustion stabi l ity.
Compression
Determines the level of heat buildup in the cylinder when the air-fuel m ixture
is compressed. As compression increases, so does the potential for heat bui ldup.
Ignition Timing
Determines when the gasses wi l l start to expand in relation to the motion of
the piston. If the gasses begin to expand too soon, such as they would during
pre-ignition or in an overly advanced ignit ion t iming, the motion of the piston
opposes the expansion of the gasses, resu lting in extremely h igh combustion
chamber pressures and heat.
As ignition t iming is retarded, the burn occurs later in relation to piston posi­
tion. This means that the piston has less d istance to travel under power to the
bottom of the cyl inder, resulting in less usable power.
Fuel M ixture
Determines how efficient the burn will be. A rich mixture burns s lower than a
lean one. If the mixture is too lean, it can't become explosive. The slower the
burn, the cooler the combustion chamber, because pressure bui ldup is gradual.
Fuel Quality (Octane Rating)
Determines how much heat is necessary to ign ite the mixture. Once the burn
is in progress, heat is on the rise. The unburned poor quality fuel is ign ited al l
at once by the rising heat i nstead of burning gradually as a flame front of the
burn passing by. This action results in detonation (pinging).
Other Factors
In general, anything that can cause abnormal heat buildup can be enough to
push an engine over the edge to abnormal combustion, if any of the four basic fac­
tors previously discussed are already near the danger point, for example, excessive
carbon buildup raises the compression and retains heat as glowing embers.
The fuel for some small horsepower units is gravity fed from a tank mounted
at the rear of the powerhead. Even with the gravity feed method, a small fuel
pump may be an integral part of the carburetor. After the engine starts, the fuel
passes through the pump to the carburetor. All systems have some type of filter
installed somewhere in the l ine between the tank and the carburetor. Many units
have a fi lter as an integral part of the carburetor.
THROTTLE
VENTURI
IDLE AND
SLOW SPEED
ORIFICES INTAKE
H IGH SPEED N EEDLE
H IGH SPEED ORIFICE
04704G01
Fig. 1 Fuel flow through a venturi, showing principle and related
parts controlling i ntake and outflow
4-4 FUEL SYSTEM
At the carburetor, the fuel passes through the inlet passage t o the needle and
seat, and then into the float chamber (reservoir). A float in the chamber rides up and
down on the surface of the fuel. After fuel enters the chamber and the level rises to
a predetermined point, a tang on the float closes the inlet needle and the flow enter­
ing the chamber is cut off. When fuel leaves the chamber as the engine operates,
the fuel level drops and the float tang al lows the inlet needle to move off its seat and
fuel once again enters the chamber. In this manner, a constant reservoir of fuel is
maintained in the chamber to satisfy the demands of the engine at all speeds.
A fuel chamber vent hole is located near the top of the carburetor body to
permit atmospheric pressure to act against the fuel in each chamber. This pres­
sure assures an adequate fuel supply to the various operating systems of the
powerhead.
Air/Fuel Mixture
• See Figure 2
A suction effect is created each time the piston moves upward in the cylinder.
This suction draws air through the throat of the carburetor. A restriction in the
throat, called a venturi, controls air velocity and has the effect of reducing air
pressure at this point.
The difference in air pressures at the throat and i n the fuel chamber, causes
the fuel to be pushed out of metering jets extending down into the fuel chamber.
When the fuel leaves the jets, it mixes with the air passing through the venturi.
This fuel/air mixture should then be in the proper proportion for burning in the
cylinders for maximum engine performance.
In order to obtain the proper air/fuel mixture for all engine speeds, some mod­
els have high and low speed jets. These jets have adjustable needle valves which
are used to compensate for changing atmospheric conditions. In almost al l
cases, the high-speed circuit has fixed high-speed jets and are not adjustable.
A throttle valve controls the flow of air/fuel mixture drawn into the combus­
tion chambers. A cold powerhead requires a richer fuel mixture to start and dur­
ing the brief period it is warming to normal operating temperature. A choke
valve is placed ahead of the metering jets and venturi. As this valve begins to
close, the volume of air intake is reduced, thus enriching the mixture entering
the cylinders. When this choke valve is fully closed, a very rich fuel mixture is
drawn into the cylinders.
The throat of the carburetor is usually referred to as the barre l . Carburetors
with single, double, or four barrels have individual metering jets, needle valves,
throttle and choke plates for each barre l . Single and two barrel carburetors are
fed by a single float and chamber.
I NDUCED
LOW
� .... �. �-' �\� � ...__ . ' +--
ATMOSPHER I C A I R PRESSURE
04704G02
Fig. 2 Air flow principle of a modern carburetor
CARBURETOR C IRCUITS
The following section i l l ustrates the circuit functions and locations of a typi­
cal marine carburetor.
Starting Circuit
• See Figure 3
The choke plate is closed, creating a partial vacuum in the venturi. As the
piston rises, negative pressure in the crankcase draws the rich air-fuel mixture
from the float bowl into the venturi and on into the engine.

PILOT OUTLET
......._,
PILOT SCREW
:::::" = a:;� BY-PASS HOLES "'-. 1 � 1: ;,.·.::�- - THROTILE PLATE
PILOT AIR JET -.:::..'1:r',, i � � ': -'": � ? _ ff· · · . . · - : : ·...,. .' "'-= . . = . . ""'.= c=="=
MAIN AIRJET
. -:- _. . ':" ·-� . .::=> {/ g :::=>
PILOT JET
04704G20
Fig. 3 The starting circuit
Low Speed Circuit
• See Figure 4
Zero-one-eighth throttle, when the pressure in the crankcase is lowered, the
air-fuel mixture is discharged into the venturi through the pi lot outlet because
the throttle plate is closed. No other outlets are exposed to low venturi pressure.
The fuel is metered by the p i lot jet. The air is metered by the p i lot air jet. The
combined air-fuel mixture is regulated by the p i lot air screw.
Fig. 4 The low speed circuit
Mid-Range Circuit
• See Figure 5
04704G21
One-eighth-three-eighths throttle, as the throttle plate continues to open, the
air-fuel mixture is discharged into the venturi through the bypass holes. As the
throttle plate uncovers more bypass holes, i ncreased fuel flow results because
0 AIR
• nJEl.
COOD CO,DmO� UNSUTTABL[
u Fig. 5 The mid-range circuit
04704G22
of the low pressure in the venturi. Depending on the model, there could be two,
three or four bypass holes.
High Speed Circuit
• See Figure 6
Three-eighths-wide-open throttle, as the throttle p late moves toward wide
open, we have maximum air flow and very low pressure. The fuel is metered
through the main jet, and is drawn into the main discharge nozzle. Air is
metered by the main air jet and enters the discharge nozzle, where it combines
with fuel. The mixture atomizes, enters the venturi, and is drawn into the engine.
" L.J 41R
[J rt,;£1.
04704G23
Fig. 6 The high speed circuit
BASIC FUNCTIONS
• See Figures 7, 8 and 9
The carburetor systems on in l i ne engines require careful cleaning and
adjustment if problems occur. These carburetors are compl icated but not too
complex to understand. All carburetors operate on the same principles.
Traditional carburetor theory often involves a number of laws and principles.
To troubleshoot carburetors learn the basic principles, watch how the carburetor
comes apart, trace the c i rcuits, see what they do and make sure they are clean.
These are the basic steps for troubleshooting and successful repair.
The diagram i l l ustrates several carburetor basics. If you blow through the
straw an atomized mixture (air and fuel droplets) comes out. When you blow
through the straw a pressure drop is created i n the straw column i nserted in
the l iquid . I n a carburetor this is mostly air and a l ittle fuel . The actual ratio of
air to fuel differs with engine conditions but is usually from 15 parts air to one
part fuel at optimum cruise to as l itt le as 7 parts air to one part fuel at ful l
choke.
If the top of the container is covered and sealed around the straw what wi l l
happen? No flow. This is typical of a clogged carburetor bowl vent. If the base of
the straw is clogged or restricted what wi l l happen? No f low or low flow. This
ATOMIZED FUEL
..,__ �
( �R
( .-'
FUEL
'-� V I ......
CARBURETOR OPERATING PRINCIPLES
04704G18
Fig. 7 If you blow through the straw, an atomized mixture (air and
fuel droplets) comes out
FUEL SYSTEM 4-5
05004P78
Fig. 8 The V4 and V6 engines use a solenoid release valve and
large volume chamber for fuel delivery into the intake system
represents a clogged main jet. If the l iquid in the glass is lowered and you blow
through the straw with the same force what will happen? Not as much fuel wi l l
flow. A lean condition occurs. If the fuel level is raised and you blow again at
the same velocity what happens? The result is a richer mixture.
Suzuki carburetors control air flow semi-independently of RPM. This is done
with a throttle plate. The throttle p late works i n conjunction with other systems
or circuits to deliver correct mixtures within certain RPM bands. The idle circuit
pilot outlet controls from 0-Vs throttle. The series of small holes i n the carbure­
tor throat called transition holes control the Ys-% throttle range. At wide open
throttle the main jet handles most of the fuel metering chores, but the low and
mid-range circu its continue to supply part of the fuel.
Enrichment is necessary to start a cold engine. Fuel and air mix does not
want to vaporize in a cold engine. In order to get a little fuel to vaporize, a lot of
fuel is dumped into the engine. On many older in l i ne engines a choke p late is
used for cold starts. This plate restricts air entering the engine and i ncreases the
fuel to air ratio.
The V4 and V6 engines use a solenoid release valve and large volume
chamber for fuel del ivery into the i ntake system behind No. 2 and No.3 carbu­
retors (V6 models), and No.1 and No.2 (V4 models) to ensure easy starting
under all conditions. Fuel for this system is del ivered from the fuel pump (top
pump on the V6) di rectly to the fuel starter valve assembly where it is con­
trol led by a float and in let needle valve. When the ignition key, in the ON posi­
tion, is pushed in, the solenoid will open the solenoid release valve and fuel
will flow to the two starter jet ports at the end of the carburetor bore. Turning
the manual valve counterclockwise, to open, wi l l al low fuel to flow i n the event
of an e lectrical problem. The manual valve must remain closed during normal
engine operation.
05004G77
Fig. 9 Il lustration of the V4 and V6 solenoid release valve starting
system. The V4 engines have only one fuel pump
4-6 FUEL SYSTEM
DUAL-THROAT CARBURETORS
The carburetor systems on V4 and V6 engines require careful cleaning and
adjustment if problems occur. These carburetors are not difficult to understand.
Al l carburetors operate on the same principles. For best results, trace and ana­
lyze one circuit at a time.
Beginn ing in 1 996, al l Saltwater series 90 degree V engines have an addi­
tional jet in the carburetor. This pu l l over or enrichment jet improves mid-range
response whi le maintain i ng fuel economy. Additional enrichment is necessary to
start a cold engine. Fuel/air mixes to not want to vaporize in a cold engine. In
order to get a l ittle fuel to vaporize, a lot of fuel is dumped i nto the engine. On
most V4 and V6 engines, a choke plate is used for co ld starts. Th is plate
restricts air entering the engine and increases the fuel/air ratio.
The enrichment system on the 90-degree 225 hp engines is controlled by a
microprocessor. Temperature and throttle position are monitored and enrich­
ment is automatic. A pair of injectors with d ifferent d iameters are used to pro­
vide enrichment.
REMOVING FUEL FROM THE SYSTEM
• See Figures 1 0 and 1 1
For many years there has been the widespread bel ief that simply shutting off
the fuel at the tank and then running the engine until it stops is the proper pro­
cedure before storing the engine for any length of time. Right? Wrong!
lt is not possible to remove al l of the fuel in the carburetor by operating the
engine until it stops. Some fuel is trapped in the float chamber and other pas­
sages and in the l i ne leading to the carburetor. The only guaranteed method of
removing ALL of the fuel is to take the time to remove the carburetor, and drain
the fuel.
If the engine is operated with the fuel supply shut off unti l it stops, the fuel
and oil mixture inside the engine is removed, leaving bearings, pistons, rings,
and other parts with l ittle protective lubricant, during long periods of storage.
Proper procedure involves:
1 . Shutting off the fuel supply at the tank.
2. Disconnecting the fuel l i ne at the tank.
3. Operating the engine until it begins to run rough, then stopping the
engine, which wi l l leave some fuel/o i l mixture inside.
4. Removing and drain ing the carburetor.
By disconnecting the fuel supply, a l l small passages are c leared of fuel even
though some fuel is left in the carburetor. A l ight oil should be put in the com­
bustion chamber as instructed in the owner's manual. On some model carbure­
tors the h igh-speed jet p lug can be removed to drain the fuel from the
carburetor.
For short periods of storage, simply running the carburetor dry may help
p revent severe gum and varnish from forming in the carburetor. This is espe­
cially true during hot weather.
Fuel Pump
• See Figures 12 thru 1 8
A fuel pump is a basic mechanical device that uti l izes crankcase positive and
negative pressures to pump fuel from the fuel tank to the carburetors.
This device contains a flexible diaphragm and two check valves (flappers or
fingers) that control flow. As the piston goes up, crankcase pressure drops
(negative pressure) and the in let valve opens, pu l l ing fuel from the tank. As the
piston nears TDC, pressure in the pump area is neutral (atmospheric pressure).
At this po int both valves are closed. As the piston comes down, pressure goes
up (positive pressure) and the fuel is pushed toward the carburetor bowl by the
diaphragm through the now open outlet valve.
This is a reliable method to move fuel but can have several problems. Some­
times an engine backfire can rupture the diaphragm. The diaphragm and valves
are moving parts subject to wear. The flexib i l ity of the diaphragm material can
go away, reducing or stopping flow. Rust or d i rt can hang a valve open and
reduce or stop fuel flow.
t t � CRANKCASE PRESSURE
04704619
04704P11 04704P14
Fig. 10 Typical fuel line quick disconnect
fitting
Fig. 11 Fuel shutoff knob on a 4 hp out­
board
Fig. 12 A fuel pump is a basic mechanical
device that utilizes crankcase positive and
negative pressures to pump fuel
Fig. 13 The diaphragm is most subject to
wear in a fuel pump
05004P84
Fig. 14 Typical fuel pump mounting on the
engine crankcase
Fig. 15 Make sure to inspect the fuel
pump gasket . . .
05004P35
FUEL SYSTEM 4-7
05004P88
05004P87
Fig. 1 6 . . . or 0-ring for tears or damage
Fig. 17 When taking the pump apart, mark
the pump sections for correct reassembly
Fig. 18 Exploded view of a diaphragm fuel
pump-DT175
TROUBLESHOOTING
Fuel System
Troubleshooting fuel systems requires the same techniques used in other
areas. A thorough, systematic approach to troubleshooting wi l l pay big rewards.
Bui ld your troubleshooting checklist, with the most likely offenders at the top.
Use your experience to adjust your list for local conditions. Everyone has been
tempted to jump into the carburetor on a vague hunch. Pause a moment and
review the facts when this urge occurs.
In order to accurately troubleshoot a carburetor or fuel system problem, you
must first verify that the problem is fuel related. Many symptoms can have sev­
eral different possible causes. Be sure to el iminate mechanical and electrical
systems as the potential fault Carburetion is the number one cause of most
engine problems, but there are other possib i l ities.
One of the toughest tasks with a fuel system is the actual troubleshooting.
Several tools are at your disposal for making this process very simple. A timing
light works well for observing carburetor spray patterns. Look for the proper
amount of fuel and for proper atomization in the two fuel outlet areas (main noz­
zle and bypass holes). The strobe effect of the l ights helps you see in detail the
fuel being drawn through the throat of the carburetor. On multiple carburetor
engines, always attach the timing l ight to the cylinder you are observing so the
strobe doesn't change the appearance of the patterns. If you need to compare
two cylinders, change the timing l ight hookup each time you observe a different
cylinder.
Pressure testing fuel pump output can determine whether the fuel spray is
adequate and if the fuel pump diaphragms are functioning correctly. A pressure
gauge placed between the fuel pumps and the carburetors wi l l test the entire fuel
del ivery system. Normally a fuel system problem will show up at h igh speed
where the fuel demand is the greatest A common symptom of a fuel pump out­
put problem is surging at wide open throttle, but normal operation at slower
speeds. To check the fuel pump output, install the pressure gauge and acceler­
ate the engine to wide open throttle. Observe the pressure gauge need le. lt
should always swing up to some value between 5-6 psi and remain steady. This
reading would indicate a system that is functioning properly.
If the needle gradually swings down toward zero, fuel demand is greater than
the fuel system can supply. This reading isolates the problem to the fuel deliv­
ery system (fuel tank or l i ne). To confirm this, an auxil iary tank should be
CIRCUIT/POSIDON 0
IDLE
BYPASS
MID-RANGE
MAIN JET
CHOKE/ENRICHENER
1/8
installed and the engine re-tested. Be aware that a bad anti-siphon valve on a
bu ilt-in tank can create enough restriction to cause a lean condition and serious
engine damage.
If the needle movement becomes erratic, suspect a ruptured diaphragm in the
fuel pump.
A quick way to check for a ruptured fuel pump diaphragm is while the engine
is at idle speed, to squeeze the primer bu lb and hold steady f irm pressure on it
If the diaphragm is ruptured, this will cause a rough running condition because
of the extra fuel passing through the diaphragm into the crankcase. After per­
forming this test you should check the spark plugs for cylinders that the fuel
pump suppl ies. If the spark plugs are OK, but the fuel pumps are sti l l sus­
pected, you should remove the fuel pumps and completely disassemble them.
Rebui ld or replace the pumps as needed.
To check the boat's fuel system for a restriction, install a vacuum gauge in
the l i ne before the fuel pump. Run the engine under load at wide open throttle to
get a reading. Vacuum should read no more than 4.5 in . Hg (15 .2 kPa) for
engines up to and including 200 hp, and should not exceed 6.0 in. Hg (20.2
kPa) for engines greater than 200 hp .
To check for air entering the fuel system, install a clear fue l hose between the
fuel screen and fuel pump. If air is in the l i ne, check all fittings back to the
boat's fuel tank.
Spark plug tip appearance is a good indication of combustion efficiency. The
tip should be a l ight tan. A white insu lator or small beads on the insulator indi­
cate too much heat A dark or oi l fouled insulator indicates incomplete combus­
tion. To properly read spark p lug tip appearance, run the engine at the RPM you
are testing for about 15 second and then immediately turn the engine OFF with­
out changing the throttle position.
Reading spark plug tip appearance is also the proper way to test jet verifica­
tions in h igh altitude.
The following chart explains the relationship between throttle position and
carburetion circuits.
LOGICAL TROUBLESHOOTING
The fol lowing paragraphs provide an orderly sequence of tests to pinpoint
problems in the fuel system.
114 3/8 1/2 5/8 3/4 WOT I
..
04704C03
4-8 FUEL SYSTEM
1 . Gather as much i nformation as you can.
2. Dupl icate the condition. Take the boat out and verify the complaint
3. If the problem cannot be dupl icated, you cannot fix it This could be a
product operation problem.
4. Once the problem has been dupl icated, you can begin troubleshooting.
G ive the entire unit a careful visual inspection. You can tel l a lot about the
engine from the care and condition of the entire rig. What's the condition of the
propeller and the lower un it? Remove the hood and look for any visible signs of
failure. Are there any signs of head gasket leakage. Is the engine paint discol­
ored from high temperature or are there any holes or cracks in the engine
block? Perform a compression and leak down test. While cranking the engine
during the compression test, l isten for any abnormal sounds. If the engine
passes these simple tests we can assume that the mechanical condition of the
engine is good Al l other engine mechanical inspection would be too time con­
suming at this point.
5 . Your next step is to isolate the fuel system into two sub-systems. Sepa­
rate the fuel del ivery components from the carburetors. To do this, substitute the
boat's fuel supply with a known good supply. Use a 6 gal lon portable tank and
fuel l ine. Connect the portable fuel supply directly to the engine fuel pump,
bypassing the boat fuel delivery system. Now test the engine. If the problem is
no longer present, you know where to look. If the problem is sti l l present, fur­
ther troubleshooting is required.
6. When testing the engine, observe the throttle position when the problem
occurs. This wi l l help you p inpoint the circuit that is malfunctioning. Carburetor
troubleshooting and repair is very demanding. You must pay close attention to
the location, position and sometimes the numbering on each part removed. The
abi l ity to identify a circuit by the operating RPM it affects is important. Often
your best troubleshooting tool is a can of cleaner. This can be used to trace
those mystery c ircuits and find that last speck of d i rt. Be careful and wear safety
g lasses when using this method.
COMMON PROBLEMS
Fuel Del ivery
t See Figure 1 9
Many times fuel system troubles are caused by a plugged fuel f i lter, a defec­
tive fuel pump, or by a leak in the l ine from the fuel tank to the fuel pump. A
defective choke may also cause problems. would you bel ieve, a majority of
starting troubles which are traced to the fuel system are the result of an empty
fuel tank or aged sour fuel.
04704P09
Fig. 1 9 An excellent way of protecting fuel hoses against contami­
nation is an end cap filter
Sour Fuel
t See Figure 20
Under average conditions (temperate c l imates), fuel wi l l begin to break down
in about four months. A gummy substance forms in the bottom of the fuel tank
and in other areas. The filter screen between the tank and the carburetor and
small passages in the carburetor will become clogged. The gasol i ne wi l l begin
to give off an odor s imi lar to rotten eggs. Such a condition can cause the owner
much frustration, time in cleaning components, and the expense of replacement
or overhaul parts for the carburetor.
04701P24
Fig. 20 The use of an approved fuel additive, such as this Suzuki
Fuel Conditioner and Stabilizer, will prevent fuel from souring for up
to twelve months
Even with the h igh price of fuel, removing gasoline that has been standing
unused over a long period of time is sti l l the easiest and least expensive pre­
ventative maintenance possible. In most cases, this old gas can be used without
harmful effects in an automobi le using regular gasol ine.
The gasoline preservative additive Suzuki Fuel Conditioner and Stabi l izer for
2 cycle engines, will keep the fuel fresh for up to twelve months. If this particu­
lar product is not available in your area, other s imi lar additives are produced
under various trade names.
Choke Problems
When the engine is hot, the fuel system can cause starting problems. After a
hot engine is shut down, the temperature inside the fuel bowl may rise to 200
degrees F and cause the fuel to actually boi l . A l l carburetors are vented to allow
this pressure to escape to the atmosphere. However, some of the fuel may per­
colate over the h igh-speed nozzle.
If the choke should stick in the open position, the eng i ne wi l l be hard to
start. If the choke should stick in the closed position, the engine wi l l flood,
making it very difficult to start.
In order for this raw fuel to vaporize enough to burn, considerable air must
be added to lean out the mixture. Therefore, the only remedy is to remove the
spark plugs, ground the leads, crank the powerhead through about ten revolu­
tions, clean the plugs, reinstall the plugs, and start the engine.
If the needle valve and seat assembly is leaking, an excessive amount of fuel
may enter the reed housing in the following manner. After the powerhead is shut
down, !he pressure left in the fuel l i ne wi l l force fuel past the leaking needle
valve. This extra fuel wi l l raise the level in the fuel bowl and cause fuel to over­
flow into the reed housing.
A continuous overflow of fuel into the reed housing may be due to a sticking
i nlet needle or to a defective float, which would cause an extra h igh level of fuel
in the bowl and overflow i nto the reed housing.
Fuel Pump
t See Figure 21
Fuel pump testing is an excel lent way to p inpoint air leaks, restricted fuel
l i nes and fittings or other fuel supply related performance problems.
When a fuel starvation problem is suspected such as engine hesitation or
engine stopping, perform the following fuel system test:
1 . Connect the p iece of clear fuel hose to a side barb of the "T" fitting 0.
HOSE TO Al.TER --.u
CHECK VALVE �� �HORT CLEAR HOSE
.. HOSE TO GAUGE'� ff�n?SETOFUaPUMP
04704G27
Fig. 21 Connecting a fuel pressure gauge inline in preparation for a
fuel pump test
2. Connect one end of the long piece of fuel hose to the vacuum gauge and
the other end to the center barb of the "T" fitting.
�use a long enough piece of fuel hose so the vacuum gauge may be
read at the helm.
3. Remove the existing fuel hose from the fuel tank side of the fuel pump,
and connect the remain ing barb of the "T" fitting to the fuel hose.
4. Connect the short piece of clear fuel hose to the fuel check valve leading
from the fuel filter. If a check valve does not exist, connect the clear fuel hose
d i rectly to the fuel fi lter.
5. Check the vacuum gauge reading after running the engine long enough
to stabi l ize at ful l power.
�The vacuum is to not exceed 4.5 in. Hg (15.2 kPa) for up to 200 hp
engines. The vacuum is to not exceed 6.0 in. Hg (20.3 kPa) for engines
greater than 200 hp.
6. An anti-siphon valve (required if the fuel system drops below the top of
the fuel tank) wi l l cause a 1 .5 to 2.5 in . Hg (8.4 kPa) increase in vacuum.
7. If high vacuum is noted, move the T-fitt ing to the fuel fi lter outlet 0 and
retest.
8. Continue to the fuel filter in let and along the remain ing fuel system unti l
a large drop in vacuum locates the problem.
9. A good clean water separator fuel filter wi l l increase vacuum about 0.5
in . Hg (1 . 7 kPa).
1 0. Small internal passages inside a fuel selector valve, fuel tank pickup, or
fuel l ine fittings may cause excessive fuel restriction and high vacuum.
1 1 . Unstable and slowly rising vacuum readings, especially with a ful l tank
of fuel, usually ind icates a restricted vent l ine.
�Bubbles in the clear fuel line section indicate an air leak, making for
an inaccurate vacuum test. Check all fillings for lightened clamps and a
light fuel filter.
�vacuum gauges are not calibrated and some may read as much as 2
in. Hg (6.8 kPa) lower than the actual vacuum. 11 is recommended to
perform a fuel system test while no problems exist to determine vacuum
gauge accuracy.
Fuel line .
t See F igures 22, 23 and 24
On most installations, the fuel l ine is provided with quick-disconnect fittings
at the tank and at the engine. If there is reason to bel ieve the problem is at the
quick-disconnects, the hose ends should be replaced as an assembly. For a
small additional expense, the entire fuel l ine can be replaced and thus e l iminate
this entire area as a problem source for many future seasons.
The primer squeeze bu lb can be replaced in a short time. F irst, cut the hose
line as close to the old bulb as possible. Sl ide a small clamp over the end of the
fuel l ine from the tank. Next, install the small end of the check valve assembly
into this side of the fuel l ine. The check valve always goes towards the fuel tank.
Place a large clamp over the end of the check valve assembly. Use Primer Bulb
Adhesive when the connections are made. Tighten the clamps. Repeat the pro­
cedure with the other side of the bulb assembly and the l i ne leading to the
engine.
FUEL SYSTEM 4-9
04704P18
Fig. 22 To test the fuel pickup in the fuel tank, operate the squeeze
bulb and observe fuel flowing from the disconnected line at the fuel
pump. Discharge fuel into an approved container.
04704P21
Fig. 23 Many times restrictions such as foreign material may be
cleared from the fuel lines using compressed air. Ensure the open end
of the hose is pointing in a clear direction to avoid personal injury
4-1 0 FUEL SYSTEM
04704P23
Fig. 24 Major parts of a typical fuel line squeeze bulb. The bulb is
used to prime the fuel system until the powerhead is operating and
the pump can deliver the required amount of fuel to run the engine
COMMON PROBLEMS
Rough Engine Idle
If an engine does not id le smoothly, the most reasonable approach to the
problem is to perform a tune-up to el iminate such areas as:
• Defective points
• Faulty spark plugs
• Timing out of adjustment
Other problems that can prevent an engine from running smoothly include:
• An air leak in the intake manifold
• Uneven compression between the cylinders
• Sticky or broken reeds
Of course any problem in the carburetor affecting the air/fuel mixture wi l l
a lso prevent the engine from operating smoothly at id le speed. These problems
usually include:
• Too high a fuel level in the bowl
• A heavy float
• Leaking needle valve and seat
• Defective automatic choke
• Improper adjustments for idle mixture or idle speed
Excessive Fuel Consumption
Excessive fuel consumption can be the result of any one of four conditions,
or a combination of a l l .
• Inefficient engine operation.
• Faulty condition of the hu l l , including excessive marine growth.
• Poor boating h.abits ofthe operator.
• Leaking or out of tune carburetor.
If the fuel consumption suddenly increases over what could be considered
normal, then the cause can probably be attributed to the engine or boat and not
the operator.
Marine growth on the hu l l can have a very marked effect on boat perfor­
mance. This is why sail boats always try to have a haul-out as close to race time
as possible.
Whi le you are checking the bottom, take note of the propeller condition. A
bent blade or other damage wil l definitely cause poor boat performance.
If the hu l l and propeller are in good shape, then check the fuel system for
possible leaks. Check the l i ne between the fuel pump and the carburetor wh i le
the eng ine is running and the l ine between the fuel tank and the pump when the
engine is not running. A leak between the tank and the pump many times wi l l
not appear when the engine is operating, because the suction created by the
pump drawing fuel will not a l low the fuel to leak. Once the engine is turned off
and the suction no longer exists, fuel may begin to leak.
If a minor tune-up has been performed and the spark plugs, points, and tim­
ing are properly adjusted, then the problem most l i kely is in the carburetor and
an overhaul is in order.
Check the needle valve and seat for leaking. Use extra care when making any
adjustments affecting the fuel consumption, such as the float level or automatic
choke.
Engine Surge
If the engine operates as if the load on the boat is being constantly increased
and decreased, even though an attempt is being made to hold a constant engine
speed, the problem can most l ikely be attributed to the fuel pump, or a restric­
tion in the fuel l i ne between the tank and the carburetor.
Combustion Related Piston Fai lures
• See Figure 25
When an engine has a piston failure due to abnormal combustion, fixing
the mechanical portion of the engine is the easiest part. The hard part is
determin ing what caused the problem, i n order to prevent a repeat failure.
Think back to the four basic areas that affect combustion to find the cause of
the failure.
Since you probably removed the cylinder head. Inspect the failed piston, look
for excessive deposit bui ldup that could raise compression, or retain heat in the
combustion chamber. Statically check the wide open throttle timing. Be sure that
the timing is not over advanced. lt is a good idea to seal these adjustments with
paint to detect tampering.
Look for a fuel restriction that could cause the engine to run lean. Don't for­
get to check the fuel pump, fuel tank and l i nes, especially if a bui lt in tank is
used. Be sure to check the anti-siphon valve on built in tanks.
If everyth ing else looks good, the final possibi l ity is poor qual ity fue l .
Fig. 25 This burned p iston is typical of a combustion relate failure.
The combustion chamber temperature got so hot that it melted the
top of the piston (hole in the top of the piston)
CARBURETOR SERVICE
DT2 and DT2 .2
This carburetor i s a single-barrel , float feed type with a manual choke. Fuel to
the carburetor is gravity fed from a fuel tank mounted at the rear of the powerhead.
REMOVAL & INSTALLATION
• See accompanying i l lustrations
Good shop practice dictates a carburetor repair kit be purchased and new
parts be installed any time the carburetor is disassembled.
Make an attempt to keep the work area organized and to cover parts after they
have been cleaned. This practice will prevent foreign matter from entering pas­
sageways or adhering to critical parts.
1 . Remove the port and starboard engine covers.
05004G02
Step 1
2. With the fuel petcock lever in the OFF position (marked "S"), remove the
fuel hose from the carburetor fitting and plug the hose to prevent fuel from leaking.
3. Loosen the choke knob set screw and remove the knob from the control
panel.
05004G03
Step 3
4. Remove the screws holding the control panel to the carburetor and I ift
off the control panel and throttle l i nk knob.
5. Loosen the carburetor clamp and remove the carburetor from the engine
crankcase. Discard the 0-ring.
To install:
6. Install the throttle lever post in the throttle valve with the anchor in the
pocket at the bottom of the valve body.
7. Secure the carburetor in place by tightening the bolt and nut securely.
8. Install the control panel and the chock knob. Don't forget to tighten the
set screw.
Slowly tighten the idle speed screw until it barely seats, then back it out the
FUEL SYSTEM 4-1 1
05004G04
Step 5
same number of turns recorded during disassembly. If the number of turns was
not recorded, back the screw out 1 -% turns as a rough adjustment. Id le speed
should be as specified in the ''Tune-Up Specifications" chart.
9. Install the two halves of the cowling around the powerhead.
1 0. Secure the engine cover.
Mount the outboard unit in a test tank, or the boat in a body of water, or con­
nect a flush attachment and hose to the lower unit. Start the engine and check
the completed work. Al low the powerhead to warm to normal operating tempera­
ture. Adjust the idle speed to specification.
DISASSEMBLY
• See Figure 26
1 . With the carburetor on c lean working surface, remove the screws secur­
ing the fuel float bowl to the carburetor body. Discard the float bowl gasket.
CD Throttle lever ass'y
CV Carburetor top
® Pipe
@) Spring seat
@ Throttle rod
® Seat pin
([; Jet needle
® Throttle valve ® Stop screw i]J ''0" ring
® Filter
@ Needle valve ass'y
@ Needle nozzle
® Float
@ Floatarm
@ Float pin
@ Throttle link knob
@ Choke knob
@ Main jet
05004801
Fig. 26 Exploded view of carburetor with major parts identified­
DT2 and DT2.2 models
4-1 2 FUEL SYSTEM
2. Push the float p i n free using a fine pointed awl and remove the float p in
from the float arm and lift off the float and needle valve from the bowL
3. Remove the main nozzle and the main jet assembly.
4. Remove the needle seat and gasket using a wide bladed screwdriver. Dis­
card the gasket
5. Loosen the throttle stop screw and unscrew the carburetor top with the
throttle lever assembly as one unit
6. Disconnect the throttle plunger from the needle valve and remove the
valve, spring and retainer.
,.lt is not necessary to remove the E-clip from the jet needle, unless
replacement is required or if the powerhead is to be operated at a sig­
nificantly d ifferent elevation.
7. Turn in the throttle stop screw (counting the turns for reassembly) until it
lightly seats. Turn out the screw and remove it and the attached spring.
8. Remove the fuel inlet fitting and fuel fi lter.
CLEANING & INSPECTION
t See Figures 27 and 28
** CAUTION
Never dip rubber parts, plastic parts, diaphragms, or pump
plungers in carburetor cleaner. These parts should be cleaned only
i n solvent, and then blown dry with compressed air.
Place al l metal parts in a screen-type tray and d ip them in carburetor
cleaner until they appear completely clean, then blow them dry with com­
pressed air.
Blow out al l passages in the castings with compressed air. Check al l parts
and passages to be sure they are not clogged or contain any deposits. Never
use a piece of wire or any type of pointed instrument to clean dri l led passages
or calibrated holes in a carburetor.
Move the throttle shaft back and forth to check for wear. If the shaft appears
to be too loose, replace the complete throttle body because individual replace­
ment parts are not avai lable.
Inspect the main body, airhorn, and venturi c luster gasket surfaces for cracks
and burrs which might cause a leak. Check the float for deterioration. Check to
be sure the float spring has not been stretched. If any part of the float is dam­
aged, the unit must be replaced. Check the float arm needle contacting surface
and replace the float if this surface has a groove worn in it
04704P52
Fig. 27 Metal parts from our disassembled 2 hp carburetor in a bas­
ket ready to be immersed in carburetor cleaner
04704P30
Fig. 28 A carburetor repair kit, like this one for our disassembled
carburetor, are available at your local service dealer. They contain
the necessary components to perform a carburetor overhaul
Inspect the tapered section of the idle adjusting needles and replace any that
have developed a groove. As previously mentioned, most of the parts which
should be replaced during a carburetor overhau l are included in overhaul kits
available from your local marine dealer. One of these kits wi l l contain a matched
fuel in let needle and seat This combination should be replaced each time the
carburetor is disassembled as a precaution against leakage.
ASSEMBLY
t See accompanying i l lustrations
1. Install a new carburetor 0-ring into the carburetor body.
2. Apply an all-purpose lubricant to a new idle speed screw. Install the idle
speed screw and spring.
3. Install the main jet into the main nozzle and tighten it just snug with a
screwdriver.
4. Sl ide a new needle valve into the groove of the float arm.
5. Lower the float arm into position with the needle valve sl id ing into the
needle valve seat Now, push the float pin through the holes in the carburetor
body and hinge using a small awl or simi lar tooL
6. Hold the carburetor body in a perfect upright position. Check the float
h inge adjustment The vertical distance between the float chamber mating face
and the float should be 0.75-0.83 in. (1 9-21 mm).
05004G05
Step 6
7. Carefully, bend the hinge, if necessary, to achieve the required measurement
,.Make sure the gasket is removed when making the float height mea­
surement.
Step 7
8. Position a new float bowl gasket in place on the carburetor body.
Install the float into the float bowl. Place the float bowl in position on the
carburetor body, and then secure it with the two Phi/lips head screws.
9. If the E-clip on the jet needle is lowered, the carburetor will cause the
powerhead to operate rich. Raising the E-clip will cause the powerhead to
operate lean. Higher altitude raise E-clip to compensate for rarefied air.
Standard E-clip setting is in the 3rd notch. Begin to assemble the throttle
valve components by inserting the E-clip end of the jet needle into the
throttle valve (the end with the recess for the throttle cable end). Next, place
the needle retainer into the throttle valve over the E-clip and align the
retainer slot with the slot in the throttle valve.
1 0. Reassemble the throttle valve assembly. Align the jet needle retainer
should be positioned with the slot aligned.
Step 9
DT4 and DT5Y
• See Figure 29
Jet needle 1
2 �
3 ::::::; 4 / 5
I to leaner
- �
� to richer
This type of carburetor has been used is various configurations for many
years. Most of the changes are in jetting calibration and control linkages.
The needle valve seat is not replaceable. If it is damaged or worn, the
carburetor must be replaced as a complete unit.
REMOVAL & INSTALLATION
1. Remove the engine cover.
2. Pull the fuel hose off the carburetor. Plug the fuel hose to prevent
leakage.
3. Remove the choke knob from the control panel.
4. Loosen the two nuts and remove the carburetor from the engine.
To install:
5. Position a new float bowl gasket in place on the carburetor body.
Install the float into the float bowl. Place the float bowl in position on the
carburetor body, and then secure it with the two Phi/lips head screws.
6. Secure the carburetor in place by tightening the bolt and nut
securely.
7. I nstall the chock knob.
FUEL SYSTEM 4-1 3
1 . Carburetor assy 6. Knob, starter
2. Jet, pilot (45) 7. Jet, main
3. Screw, throttle stop 8. Float
4. Screw, pilot air 9. Bolt
5. Lever, choke 10. Adjuster
Fig. 29 Exploded view of the DT4 and DT5Y carburetor with major
parts identified
Slowly tighten the idle speed screw until it barely seats, then back it out
the same number of turns recorded during disassembly. If the number of
turns was not recorded, back the screw out 1 -3/4 turns as a rough
adjustment. Idle speed should be as specified in the "Tune-Up
Specifications" chart.
8. Secure the engine cover.
Mount the outboard unit in a test tank, or the boat in a body of water, or
connect a flush attachment and hose to the lower unit. Start the engine and
check the completed work. Allow the powerhead to warm to normal operating
temperature. Adjust the idle speed to specification.
DISASSEMBLY
1 . Remove the bolt and washer from the float bowl. Remove the float
bowl and 0-ring from the carburetor body. Discard the used 0-ring.
2. Remove the float hinge pin and remove the float and pin assembly
from the carburetor body.
3. Remove the inlet needle.
• Do not force removal of the inlet needle, on some models the inlet
needle is permanently installed in the valve seat.
4. Remove the main jet. Use jet removal tool or a wide blade
screwdriver.
5. Remove the pilot (idle) jet.
6. Remove the air jet.
7. Turn in the pilot (idle) screw, counting the turns in (for reassembly
later) until it lightly seats. Now, remove the pilot screw and spring.
CLEANING & INSPECTION
**CAUTION
Never dip rubber parts, plastic parts, diaphragms, or pump plungers in
carburetor cleaner. These parts should be cleaned only in solvent, and
then blown dry with compressed air.
Place all metal parts in a screen-type tray and dip them in carburetor
cleaner until they appear completely clean, then blow them dry with
compressed air.
Blow out all passages in the castings with compressed air. Check all parts
and passages to be sure they are not clogged or contain any deposits.
Never use a piece of wire or any type of pointed instrument to clean drilled
passages or calibrated holes in a carburetor.
4-1 4 FUEL SYSTEM
Move the throttle shaft back and forth to check for wear. I f the shaft appears
to be too loose, replace the complete throttle body because individual replace­
ment parts are not available.
Inspect the main body, air-horn, and venturi cluster gasket surfaces for
cracks and burrs which might cause a leak. Check the float for deterioration.
Check to be sure the float spring has not been stretched. If any part of the float
is damaged, the unit rnust be replaced. Check the float arm needle contacting
surface and replace the float if this surface has a groove worn i n it.
Inspect the tapered section of the idle adjusting needles and replace any that
have developed a groove. As previously mentioned, most of the parts which
should be replaced during a carburetor overhaul are included in overhaul kits
available from your local marine dealer. One of these kits wi l l contain a matched
fuel in let needle and seat. This combination should be replaced each time the
carburetor is disassembled as a precaution against leakage.
ASSEMBLY
1 . Install a new carburetor 0-ring into the carburetor body.
2. Apply an al l-purpose lubricant to a new idle speed screw. Install the idle
speed screw and spring.
�The standard setting is: 1-1% turns out.
3. Install the main jet into the main nozzle and tighten it just snug with a
screwdriver.
4. Sl ide a new needle valve into the groove of the float arm.
5. Lower the float arm into position with the needle valve sl id ing into the
needle valve seat. Now, push the float pin through the holes in the carburetor
body and h inge using a small awl or simi lar tool.
6 . Hold the carburetor body in a perfect upright position. Check the float
hinge adjustment. The vertical d istance between the float chamber mating face
and the float should be 0.47-0.55 in . (1 2-14mm). Carefully, bend the h inge, if
necessary, to achieve the required measurement.
�Make sure the gasket is removed when making the float height mea­
surement.
DT6 and 1 988 DT8
• See Figure 30
REMOVAL & INSTALLATION
1 . Remove the engine cover.
CD Pilot air screw
(i) Throttle stop screw
@ Needle ass'y
@) Mai'l jet
@ Air jet
® Pilot jet
(J) Float
@ Float pin
05004G09
Fig. 30 Exploded view of the DT6 and 1988 DT8 carburetor with
major parts identified
2. Pul l the fuel hose off the carburetor. Plug the fuel hose to prevent leakage.
3. Remove the choke knob from the control panel.
4. Loosen the two nuts and remove the carburetor from the engine.
To insta l l :
5. Secure the carburetor in place by tightening the bolt and nut securely.
6. Install the chock knob.
Slowly tighten the idle speed screw until it barely seats, then back it out the
same number of turns recorded during disassembly. If the number of turns was
not recorded, back the screw out 1 -% turns as a rough adjustment. Idle speed
should be as specified in the "Tune-Up Specifications" chart.
7. Secure the engine cover.
Mount the outboard unit in a test tank, or the boat in a body of water, or con­
nect a flush attachment and hose to the lower unit. Start the engine and check
the completed work. Allow the powerhead to warm to normal operating tempera­
ture. Adjust the idle speed to specification.
DISASSEMBLY
• See Figures 31 and 32
1 . Remove the bolt and washer from the float bowl. Remove the float bowl
and 0-ring from the carburetor body. D iscard the used 0-ring.
2. Remove the float h inge pin and remove the float and pin assembly from
the carburetor body.
3. Remove the inlet needle.
�Do not force removal of the inlet needle, on some models the inlet
needle is permanently installed in the valve seat.
4. Remove the main jet. Use jet removal tool or a wide blade screwdriver.
5. Remove the p i lot (idle) jet.
6. Remove the air jet.
7. Turn in the p i lot (idle) screw, counting the turns in (for reassembly later)
unti l it l ightly seats. Now, remove the p i lot screw and spring.
05004G10
Fig. 31 Typical locations for the pilot air screw .
05004G1 1
Fig. 32 . . . and the throttle stop screw
CLEAN ING & INSPECTION
• See Figures 33 and 34
Never dip rubber parts, plastic parts, diaphragms, or pump plungers in car­
buretor cleaner. These parts should be cleaned only in solvent, and then blown
dry with compressed air.
Place al l metal parts in a screen-type tray and dip them in carburetor c leaner
until they appear completely clean, then blow them dry with compressed air.
Blow out al l passages in the castings with compressed air. Check al l parts
and passages to be sure they are not clogged or contain any deposits. Never
use a piece of wire or any type of pointed instrument to clean dril led passages
or calibrated holes in a carburetor.
Move the throttle shaft back and forth to check for wear. If the shaft appears
to be too loose, replace the complete throttle body because individual replace­
ment parts are not available.
Inspect the main body, airhorn, and venturi cluster gasket surfaces for cracks
and burrs which might cause a leak. Check the float for deterioration. Check to
be sure the float spring has not been stretched. If any part of the float is dam­
aged, the unit must be replaced. Check the float arm needle contacting surface
and replace the float if this surface has a groove worn in it.
04704PBO
Fig. 33 Good shop practice dictates a carburetor rebuild kit be pur­
chased and new parts, especially gaskets and 0-rings be installed
any lime the carburetor is disassembled. This photo includes parts
in a repair kit for the 6 hp, 8 hp, 9.9 hp and 15 hp carburetor
04704PB9
Fig. 34 Remove all rubber and plastic parts before immersing metal
parts of the 6 hp, 8 hp, 9.9 hp and 15 hp carburetor in cleaning
solution
FUEL SYSTEM 4-1 5
Inspect the tapered section of the id le adjusting needles and replace any
that have developed a groove. As previously mentioned, most of the parts
wh ich should be replaced during a carburetor overhaul are inc luded in over­
hau l kits avai lable from your l ocal marine dealer. O ne of these kits wi l l con­
tain a matched fuel in let needle and seat. This combination should be
replaced each t ime the carburetor is d isassemb led as a precaution against
leakage.
ASSEMBLY
1 . Install a new carburetor 0-ring into the carburetor body.
2. Apply an al l-purpose l ubricant to a new idle speed screw. Install the idle
speed screw and spring.
�The standard setting is:
• DT6: 1-1 % turns out.
• DTB: %-1-1f4turns out.
3. Install the main jet into the main nozzle and tighten it just snug with a
screwdriver.
4. Sl ide a new needle valve into the groove of the float arm.
5. Lower the float arm into position with the needle valve sl iding into the
needle valve seat. Now, push the float pin through the holes in the carburetor
body and hinge using a small awl or simi lar tool.
6. Hold the carburetor body in a perfect upright position. Check the float
hinge adjustment. The vertical d istance between the float chamber mating face
and the float should be as fol lows:
• DT6 and DTB: 0.9-1 .0 in. (22-26mm). Careful ly, bend the h inge, if
necessary, to achieve the required measurement.
�Make sure the gasket is removed when making the float height mea'
surement.
7. Position a new float bowl gasket in place on the carburetor body. Install
the float into the float bowl. Place the float bowl in position on the carburetor
body, and then secure it with the two Phi l l ips head screws.
DT9.9, DT1 5 and 1 989-97 DT8
• See Figure 35
The fuel pump is constructed as an i ntegral component of the carburetor. The
pump is a diaphragm type, operating with the pressure pulses inside the engine
crankcase. These pressure pulses are characteristic of a two-stroke type engine.
The crankcase pressure becomes positive during the downward stroke of the
piston and negative during the upward stroke. In response to these pressure
pulses, the diaphragm wi l l flex cyclically to pump the fuel from the fuel tank to
the carburetor float bowls.
When the engine is started, positive and negative pressures are produced alter­
nately in the crankcase, passing into the pump body which is mounted on the car­
buretor itself and actuating the diaphragm in the pump housing. The diaphragm
pulsing action causes the fuel from the fuel filter to flow from the inlet into the
pump. Then, the fuel inside the fuel pump is sent from the discharge outlet to the
carburetor, which it passes through a valve hole and then into the float bowl.
If the engine speed is increased, the diaphragm cycles are increased propor­
tionally, supplying the correct amount of fuel needed for that particular engine
speed.
REMOVAL & INSTALLATION
1 . Remove the engine cover.
2. Pul l the fuel hose off the carburetor. Plug the fuel hose to prevent leakage.
3. Remove the choke knob from the control panel.
4. Loosen the two nuts and remove the carburetor from the engine.
To instal l :
5. Place a new carburetor mounting gasket on the powerhead studs. Install
the carburetor and secure it in place with the washers and nuts. Tighten the nuts
alternately and evenly.
6. Adjust the air screw setting. Basel ine setting is: 1 1f4-1%turns out.
7. Install the choke knob onto the control panel.
8. Connect the fuel l i ne onto the carburetor in let fitting.
9. Install the engine cover.
4-1 6 FUEL SYSTEM
1 1
1 . Carburetor assy
2. Jet, pilot
3. Screw, pi lot
4. Float
5. Needle
6. Screw, throttle stop
7. Bolt
lf--3
i I
8. Jet, main
9. Pump assy. set
10. Valve set
1 1 . Knob. choke lever
12 . Lever, choke
05004G12
Fig. 35 Exploded view of the DT9.9, DT15 and 1989-97 DTB carbure­
tor with major parts identified
DISASSEMBLY
• See accompanying i l lustrations
1 . Remove the fuel pump from the carburetor body by removing the screws.
2. Remove the bolt and washer from the float bowl. Remove the float bowl
and 0-ring from the carburetor body. D iscard the used 0-ring.
3. Remove the float h i nge pin and remove the float and pin assembly from
the carburetor body.
4. Remove the in let needle.
,.. The inlet needle valve seat is fixed to the carburetor body. If the seat
is damaged, the carburetor body must be replaced . .
05004G13
Step 1
5. Remove the main jet. Use jet removal tool or a wide blade screwdriver.
6. Remove the p i lot (idle) jet with the proper tool.
7. Turn in the p i lot (idle) screw, counting the turns in (for reassembly later)
unti l it l ightly seats. Now, remove the p i lot screw and spring.
8. Clean and inspect a l l the parts.
CLEANING & INSPECTION
• See Figures 36 and 37
** CAUTION
Never d ip rubber parts, plastic parts, diaphragms, or pump p lungers
in carburetor cleaner. These parts should be cleaned only in solvent,
and then blown dry with compressed air. Place all metal parts in a
screen-type tray and dip them in carburetor cleaner until they appear
completely clean, then blow them dry with compressed a ir.
Blow out al l passages in the castings with compressed air. Check all parts
and passages to be sure they are not clogged or contain any deposits. Never
use a piece of wire or any type of pointed instrument to clean dri l led passages
or calibrated holes in a carburetor.
Move the throttle shaft back and forth to check for wear. If the shaft appears
to be too loose, replace the complete throttle body because individual replace­
ment parts are not avai lable.
Inspect the main body, airhorn, and venturi cluster gasket surfaces for cracks
and burrs which might cause a leak. Check the float for deterioration. Check to
be sure the float spring has not been stretched. I f any part of the float is dam­
aged, the unit must be replaced. Check the float arm needle contacting surface
and replace the float if this surface has a groove worn in it.
Inspect al l 0-rings, seals and gaskets. Al l of these components become hard
with age and tend to become brittle and deteriorate. This affects their abi l ity to
seal properly, so its always a good idea to replace them anytime the carburetor
is apart for service.
Inspect the tapered section of the id le adjusting needles and replace any that
have developed a groove.
Inspect the fuel pump diaphragm for tears. Any damage to the diaphragm
means it must be replaced.
As previously mentioned, most of the parts which should be replaced during
a carburetor overhaul are included in overhaul kits available from your local
marine dealer. One of these kits will contain a matched fuel in let needle and
05004G14
Fig. 36 Blow out a l l passages with compressed air
05004G15
Fig . 37 Replace idle adjusting needles that have developed
grooves
seat. This combination shou ld be replaced each time the carburetor is disas­
sembled as a precaution against leakage.
ASSEMBLY
t See accompanying i l lustrations
A float level inspection and adjustment are very important parts of an engine
tune-up. The float level setting is correct when the "float height" is set to the
proper specification.
1. Install the float and hinge pin into the carburetor body.
2. Invert the carburetor body, making sure that the float hinge p in doesn't
fal l out.
3. Keeping the float arm free, measure the distance between the carburetor
body (with the gasket removed) to the bottom of the float. Correct float height is:
0.91-0 98 in. (23 0-25.0 mm).
4. Turn in the pilot (idle) screw, counting the turns in (for reassembly later)
unti l it l ightly seats.
5. Install the pilot (idle) jet with the proper tool.
6. Install the main jet. Use jet removal tool or a wide blade screwdriver.
7. Install the in let needle.
8. Install the float bowl and new 0-ring onto the carburetor body.
9. Install the fuel pump onto the carburetor body.
1 . Pilot jet
2. Nozzle
3. Main jet
4. Needle valve assy.
Fig. 38 Exploded view of the single carburetor with all major parts identified
FU EL SYSTEM 4-1 7
05004G16
Step 3
DT20 to DT85, DT1 1 5 and DT140
t See Figures 38, 39 and 40
Different variations of these carburetor models have been used on Suzuki
outboards, but they all operate in the same manner. The major differences in
5. Float
6. Pilot air screw
7. Float bowl
8. Float bowl gasket
05004P56
4-1 8 FUEL SYSTEM
CD Throttle control rod
® Pilot screw
@ Pilot jet
@ Needle valve @ High speed nozzle
@ Main jet
(]) Float
@ Drain screw
05004G18
Fig. 39 Exploded view of the three-cylinder carburetors including linkage rods
(DT115)
1 . Top carburetor 9. Adjuster
2. 2nd carburetor 10. Spring
3. 3rd carburetor 1 1 . Pilotjet
4. 4th carburetor 12. Main jet
5. Stud bolt 13. Nozzle
6. Washer 14. Valve seat gasket
7. Lock washer 15. Needle valve assy
8. Nut 16. Pin
Fig. 40 Exploded view of the four-cylinder carburetors including linkage rods
24 �
23
17. Float
18. Gasket
(DT140)
3 25 23 •c -• '}l:!c--- 26 2�fl ,. r; 11 l
e:i2 -.·f'l::::. • ' 6 1 , � 10 � t�n•oA-13 ' s�� 15� ll-12 16---""'®--1 7 �· Q_1;9 . !--20 __j
25. Fuel hose
26. Fuel hose clip
19 Lock washer
20. Bolt
21. Throttle lever
22. Connector
23. Plate
24. Circlip
05004G19
these carburetors are mostly confined to different calibrations and l inkage
setups. Removal procedures may vary sl ightly due to differences in l i nkage.
These differences wi l l be noted whenever they make a substantial change in a
procedure.
REMOVAL & INSTALLATION
t See accompanying i l lustrations
1 . Disconnect the negative battery cable.
2. Mark each individual carburetor on the float to aid in reinstal lation.
3. Disconnect any l i nkage rods and control cables.
4. Disconnect any fuel or oil injection hoses.
5. Remove the air silencer cover from the carburetor assembly
6. Remove the si lencer case from the carburetors.
05004P22
Step 1 1 Step 12
FUEL SYSTEM 4-1 9
7. After removing the carburetor nuts, lift the carburetors off the engine.
To instal l :
8. Identify each carburetor by the mark scribed on the float bowl during
removal. Place the carburetors in-line on the work bench.
9. Install the throttle and choke l inkage.
1 0. Place a new one piece gasket on the carburetor throats and al ign the
silencer case to the carburetor assemblies.
1 1 . Install the fuel hose from the fuel fi lter to the carburetors. Secure al l
connections with the clamps.
12. Install the si lencer cover over the silencer case.
13 . Install and tighten the screws securing the silencer cover in place.
14. Mount the outboard unit in a test tank, or put the boat in a body of
water, or connect a flush attachment and hose to the lower unit. Connect a
tachometer to the powerhead.
05004P12 05004P15
Step 13
4-20 FUEL SYSTEM
** CAUTION
Never operate the engine at h igh speed with a flush device
allached. The engine, operating at high speed with such a device
allached, would runaway from lack of a load on the propeller, caus­
ing extensive damage.
Start the engine and check the completed work.
** CAUTION
Water must circulate through the lower unit to the powerhead any­
time the powerhead is operating to prevent damage to the water
pump in the lower unit. Just five seconds without water will damage
the water pump impeller.
Allow the powerhead to warm to normal operating temperature. Adjust the
throttle stop screw until the powerhead idles at specification. Rotating the
throttle stop screw clockwise increases powerhead speed, and rotating the screw
counterclockwise decreases powerhead speed.
05004P47
Step 7
DISASSEMBLY
t See accompanying i l lustrations
The following procedures pick up the work after the carburetors have been
removed from the powerhead. The procedures for each of the carburetors is
identical. Any d ifferences in float height measurement, p i lot screw turns, jets, or
any other adjustments wi l l be c learly identified for the carburetor including loca­
tion and model .
1 . Remove the float bowl drain screw and spring and drain any remaining
fuel into a suitable container.
2. Remove the screws securing the float bowl to the mixing chamber.
3. Remove and discard the 0-ring or gasket from the float bowl.
4. Slide the float h inge pin to one side and remove the float and the p in
from the carburetor body.
5. Grasp the float and gently remove it from the carburetor body.
6. Gently remove the needle valve from the needle seat.
7. Inspect the needle valve tip for damage.
8. Remove the needle seat and gasket assembly. Inspect the gasket for
damage.
Step 8
05004P54
Step 15
9. Remove the p i lo t jet.
1 0. Remove the main jet.
1 1 . Inspect the main jet for damage or debris blocking the orifice. Look
closely and you can read the jet number stamped on the jet itself.
12 . Invert the mixing chamber and shake it, keeping a hand over the center
turret. The main nozzle should fall free from the turret. If the nozzle refuses to
fall out, gently reach in with a pick or similar instrument to raise the nozzle.
13. Obtain the correct size th in walled socket and remove the valve seat.
Remove and discard the 0-ring.
1 4. Remove the two Phi l l ips head screws securing the top cover to the top
of the mixing chamber. Lift off the cover.
1 5. Remove the pilot screw and spring from the carburetor. Count and record
the number of turns in to a l ightly seated position as a guide for instal lation. The
specific number of turns wi l l also be specified in the installation procedures.
CLEANING & INSPECTION
• See Figure 41
** CAUTION
Never dip rubber or plastic parts, in carburetor cleaner. These parts
should be cleaned only i n solvent, and then blown dry with com­
pressed air.
Place al l metal parts in a screen type tray and d ip them in carburetor cleaner
until they appear completely clean, then blow them dry with compressed ai r.
B low out all passages in the castings with compressed air. Check al l parts
and passages to be sure they are not clogged or contain any deposits. Never
use a piece of wire or any type of pointed instrument to clean dri l led passages
or calibrated holes in a carburetor.
Move the throttle and choke shafts back and forth to check for wear. If the
shaft appears to be too loose, replace the complete mixing chamber because
individual replacement parts are not available.
Inspect the mixing chamber, and fuel bowl gasket surfaces for cracks and
FUEL SYSTEM 4-21
04704PS1
Fig. 41 Inspect the taper on the end of the pilot screw for ridges or
signs of roughness. Good shop practice dictates a new pilot screw
be installed each time the carburetor is overhauled
burrs which might cause a leak. Check the float ior deterioration. Check to be
sure the needle valve spring has not been stretched. If any part of the float is
damaged, the float must be replaced. Check the needle valve rubber tip contact­
ing surface and replace the needle valve if this surface has a groove worn in it.
Inspect the tapered section of the p i lot screw and replace the screw if it has
developed a groove.
As previously mentioned, most of the parts which should be replaced during
a carburetor overhaul are included in an overhaul kit available from your local
marine dealer. One of these kits wi l l contain a matched fuel in let needle and
seat. This combination should be replaced each time the carburetor is disas­
sembled as a precaution against leakage.
ASSEMBLY
• See accompanying i l lustration
1 . Sl ide a new spring over the p i lot screw.
2. Install the pi lot screw into the carburetor. Tighten the p i lot screw until it
barely seats. From this position, back out the screw the specified number of
turns. Take notice, each year of manufacture has a different p i lot screw setting.
Furthermore, each carburetor has a different screw setting on certain models.
3. Slide a new 0-ring over the shaft of the valve seat. Install and tighten the
seat snugly, using a th in walled socket.
4. Insert the main nozzle into the aft hole on the center turret. Position the
series of holes in the nozzle to face port and starboard when instal led.
5. Install the main jet over the main nozzle. Tighten the jet until it seats
snugly.
6. Install the pilot jet into the forward hole on the center turret. Tighten the
jet unti l it seats snugly.
7. Check to be sure the wire c l ip is securely in position around the needle
valve. Slide the clip over the tang on the float, and check to see if the needle
valve can be moved freely.
8. Sl ide the h inge pin through the hole in the float.
9. Lower the float assembly over the center turret, guiding the needle valve
into the needle seat and positioning the end of the hinge p in under its retaining
screw. Tighten the screw securely.
4-22 FUEL SYSTEM
Step 10
1 0. Hold the mixing chamber in the inverted position, (as i t has been held
during the past few steps). Measure the distance between the carburetor
body and the bottom of the float on all models with the exception of the
1 989-00 DT25 and the 1 988-97 DT30. These models are measured from the
float bowl mating surface (gasket removed) to the bottom of the float. This
distance should be as specified in the carburetor float height chart.
**CAUTION
Carefully bend the adjustment arm or tang when adjustment is
necessary. DO NOT press down on the float. Downward pressure on
the float will press the inlet needle into the valve seat and damage the
needle tip.
CD Pi lot screw (l:: Needle valve assembly
@ Pilot jet (!:. F loat ([; High speed nozzle
® Jet holde r assembly (f; Main jet
V4 & V6 Powerheads
• See Figures 42 and 43
Suzuki V4 powerheads use two carburetors and V6 powerheads use three
carburetors. Complete, detailed, illustrated, procedures to remove, service, and
G) Pilot screw
® Needle valve assembly
@ Pilot jet
@ Float
@ High speed .nozzle
@ Jet holder assembly
(J) Main jet
Fig. 42 Exploded view of the V4 carburetor assembly with the
major components identified
Fig. 43 Exploded view of the V6 carburetor assembly with the major components identified
install the carburetors fol low. Removal procedures may vary sl ightly due to dif­
ferences in l inkage.
As explained in the description of the carburetors, the float arrange­
ment and adjustments differ due to a change in carburetor vendor. These
differences are noted whenever they make a substantial change in a proce­
dure.
REMOVAL & INSTALLATION
t See accompanying i l lustrations
1 . Disconnect the battery negative cable.
2. Remove the engine cover.
3. Remove the fuel in let hose from the fuel fi lter.
4. Disconnect the o i l level switch lead wires
5. Disconnect the oil hoses.
6 . Remove the o i l tank.
7. Disconnect the throttle lever rod from the carburetors.
8. Remove the bolts and then remove the si lencer cover.
9. Remove the throttle control lever and arm.
1 0. Snip the plastic hose retainers and gently pu l l off the fuel supply hoses
from the carburetors.
1 1 . After marking the position of the throttle sensor, remove the two secur­
ing screws and lift out the sensor from its plastic coupl ing. Sl ide the plastic
coupl ing from the throttle shaft.
05004P94
Step 8
FUEL SYSTEM 4-23
12 . Identify each carburetor by inscribing or painting a 1 , 2 and 3 ( i f applic­
able) on the float bowl cover to ensure each carburetor will be instal led back
into the same position from which it was removed.
1 3. Remove the mounting nuts, then remove the carburetors as an assem­
bly. Each carburetor has a separate gasket which may either come away with
the carburetor, or remain on the intake manifold. Remove and discard these
gaskets.
Place the carburetor assembly on the workbench and remove each piece of
l inkage one at a time. Arrange the l inkage on the workbench as it was instal led
on the carburetors, as an assist during assembling.
To instal l :
Install each marked carburetor ( in the same location as disassembly) and
gasket assembly on the engine and install the correct l inkages.
1 4. Install the throttle sensor on the throttle shaft.
1 5. Install the fuel supply hoses to the carburetors and install the plastic
hose retainers.
1 6. lnnsta l l the throttle control lever and arm.
1 7. Connect the oi l hoses.
1 8. Install the silencer cover and bolts.
1 9. Connect the throttle lever rod from the carburetors.
20. Connect the o i l level switch lead wires and install the o i l tank.
21 . Install the fuel in let hose from the fuel fi lter.
22. Install the engine cover.
23. Connect the battery negative cable.
05004P95
Step 13
4-24 FUEL SYSTEM
DISASSEMBLY
• See accompanying i l lustrations
1 . Remove the !!oat bowl attaching screws and remove the !!oat bowl
2. Always discard the old gasket.
3. Sl ide the !!oat hinge pin to one side and remove the pin assembly from
the carburetor body.
4. Remove the !!oat from the carburetor body.
5. Remove the inlet needle valve from the valve seat.
6. Remove the inlet needle valve seat using the appropriate tool.
7. Remove the pi lot (idle) jet from the carburetor body:
05004P4A
Step 5 Step 1 0
,..Before removing the pilot screw, turn i t all the way i n until i t l ightly
seats. Record the number of turns needed to turn in the screw for
reassembly.
8. Unscrew and remove the p i lot (idle) screw and spring assembly.
9. Remove both high speed nozzles.
1 0. Remove the main jet holder from each side o! the float bowl.
1 1 . Remove the main jet from each main jet holder with the appropriate tool.
1 2. Remove and always discard the 0-ring on each main jet holder.
13 . Clean and inspect a l l the internal parts in the carburetor.
FUEL LEVEL TEST
For this test, you wi l l need to acquire the following Suzuki special tools: Fuel
Level Gauge Adaptor (p/n 09913-1 871 1 ) and Fuel Level Gauge (p/n
09932-2821 1 )
1 . Remove the engine cover.
2. Connect a tachometer to the engine following the manufacturers instructions.
3. Remove the l eft-hand main jet holder from the carburetor float bowl.
4. Remove the main jet and 0-ring from the main jet holder.
5. Install the main jet into the special tool adaptor.
6. Install the fuel level gauge into the and install the entire assembly into
the carburetor !!oat bowl.
7. Start the engine and let it idle. If necessary, readjust the idle to the
speed specified i n the "Tune-Up Specifications" chart.
8. The height of the fuel in the gauge should be as fol lows: 0.83-0.91 in .
(21 .0-23.0 mm).
9. I! the fuel level is not to specification, adjust the fuel level by adjusting
the float level tab.
1 0. Remove the main jet and 0-ring from the adaptor.
1 1 . Reinstall the main jet and 0-ring onto the main jet holder and install
them into the carburetor float bowl.
1 2. Repeat this procedure with the other carburetors.
1 3. Remove the tachometer.
05004P98 05004P99
Step 1 1
CLEANING & INSPECTION
• See Figure 44
** CAUTION
Never dip rubber or plastic parts in carburetor cleaner. These parts
should be cleaned only i n solvent, and then blown dry with com­
pressed a i r.
Place al l metal parts in a screen type tray and dip them in carburetor cleaner
until they appear completely clean, then blow them dry with compressed air.
Blow out al l passages in the castings with compressed air. Check al l parts
and passages to be sure they are not clogged or contain any deposits. Never
use a piece of wire or any type of pointed instrument to c lean dri l led passages
or calibrated holes in a carburetor.
Move the throttle and choke shafts back and forth to check for wear. If the
shaft appears to be too loose, replace the complete mixing chamber because
individual replacement parts are not avai lable.
Inspect the mixing chamber, and fuel bowl gasket surfaces for cracks and
burrs which might cause a leak. Check the floats for deterioration. Check to be
sure the needle valve loop has not been stretched. If any part of the float is dam­
aged, the float must be replaced. Check the needle valve tip contacting surface
and replace the needle valve if this surface has a groove worn in it.
Inspect the tapered section of the p i lot screw and replace the screw if it has
developed a groove.
As previously mentioned, most of the parts which should be replaced during
05004G14
Fig. 44 Use compressed air to blow out all the carburetor passage­
ways
REED VALVE SERVICE
The reed valves operate in response to changes i n crankcase pressure.
Located between the i ntake manifold and the crankcase, the reed valves admit
the air-fuel mixture into the crankcase and during the scavenging stroke, act
as a one-way valve to prevent the mixture from flowing back into the intake
manifold. The travel of the reed itself is l imited by the reed stop. By this
action, the scavenging action is improved and the engine wi l l produce greater
power.
On a l l Suzuki models, except the DT2 and DT2.2, the reed valves are located
between the i ntake manifold and the crankcase. On the DT2 models the reed
valves are an integral part of the front crankcase half of the engine.
DT2 , DT2 .2
REMOVAL & INSTALLATION
On these models, the reed valves are located i n the front half of the
engine crankcase. In order to access the reed valves on this model , the
engine must be removed and the crankcase separated. See "Powerhead
Overhaul".
F U EL SYSTEM 4-25
a carburetor overhaul are included in an overhaul kit available from your local
marine dealer. One of these kits wi l l contain a matched fuel i n let needle and
seat. This combination should be replaced each time the carburetor is disas­
sembled as a precaution against leakage.
ASSEMBLY
• See accompanying i l lustration
1. Install the main jet in the main jet holder with a new 0-ring.
2. Install the main jet holders into the float bowl.
3. Install the high speed nozzles.
4. Install the p i lot screw and spring. Turn in the screw unti l it l ightly seats,
then back 1! out the correct number of turns.
5. Install the pilot (idle) jet.
6. Install the fuel i nlet needle valve and valve seat into the carburetor body.
7. Install the float.
8. Invert the carburetor and lower the float until the adjusting tab on the float
just touches the needle. Hold the float in the is position and measure the height
between the carburetor body (with gasket removed) and the bottom of the float.
9. If the float level is not within specification, adjust the level by bending the
adjusting tab as needed.
Step 8
All Other Models
• See Figures 45 and 46
CD Valve seat
� Reed valve stopper
@ Reed valve
Fig. 45 Typical in-line reed valve assembly
05004P9A
05004G23
4-26 FUEL SYSTEM
1 . Reed
2. Seat
Fig. 46 Typical V·block reed valve assembly
REMOVAL & INSTALLATION
• See accompanying i l lustrations
1 . Remove the carburetor assembly.
05004G27
2. Disconnect any hose attached to the intake manifold.
�on some models, the reed valve assembly is secured by separate fas­
teners. On models with this design, the intake manifold must first be
removed in order to remove the reed valve and gasket assembly.
3. Remove the intake manifold fasteners holding the intake manifold to the
crankcase cover.
4. Remove the intake manifolds.
5. Remove the gaskets and reed valve assemblies from the crankcase.
Make sure to discard all used gaskets.
6. Clean all the mounting surfaces of any sealant or gasket residue.
To instal l :
7. Make sure during installation that the reeds are instal led i n the correct
direction.
05004P26
Step 3 Step 4
05004G26
Step 7
8. Install new gaskets and tighten the reed valve assembly to the
crankcase.
9. Reconnect any hoses to the intake manifold.
1 0. Install the carburetor assembly.
I NSPECTION & CLEANING
• See Figures 47 and 48
1 . Check the reeds for s ign o f cracking, wear or any other damage. Replace
the reeds if any damage is found.
2. Check the reeds to see if they lie flat on the valve seat with no preload on
them.
3. To check the flatness of the reed, gently push each reed out from the seat.
Constant resistance should be felt whi le pushing the reed.
4. Check the clearance between the reed and the seat with a feeler gauge. If
the c learance is greater than 0.008 in . (0.20 mm), you wi l l need to replace the
reed set.
5. Measure the distance between the reed stop and the valve seat. If
the measurement is not with in specifications, check the valve seat for
warpage and replace it as required. If the seat is okay, replace the reed stop
assembly.
REED & REED STOP REPLACEMENT
• See Figure 49
1 . Remove the screws holding the reed stop and reeds to the valve seat.
2. Remove the reed stop and reeds.
3. Place the new reed on the valve seat and check the assembly for flatness.
4. Center the reed over the valve seat openings.
5. Before insta l l ing the reed stop screws, apply a thread locker.
6. Check the reed tension and range of motion.
05004P27
Step 5
® ®
CD
CD Valve seat
® Reed valve stopper
@ Reed valve
05004G24
Fig. 47 Typical reed valve measurement dimensions
05004P30
Fig. 48 Check the clearance between the reed and the seat with a
feeler gauge
FUEL PUMP SERVICE
Diaphragm Type Fuel Pumps
DESCRIPTION & OPERATION
The smaller capacity powerheads do not have a fuel pump of any type.
Fuel is provided to the carburetor by gravity flow from the fuel tank atop the
powerhead.
The rest of the carbureted models use a diaphragm-type fuel pump.
These pumps are operated by crankcase pressures. These pressure pulses
are created by the movement of the piston in the crankcase and are directed
to the pump by a passageway in the crankcase wall.
The piston moving upwards creates a low-pressure on the diaphragm in
the pump body. This low pressure opens a check valve in the pump body,
allowing fuel to be drawn from the fuel line to the pump. At the same time,
the low pressure in the crankcase draws the air-fuel mixture into the
crankcase from the intake manifold and carburetors.
Downward motion of the piston creates a high-pressure on the
diaphragm. This high-pressure closes the inlet check valve in the pump body
and open the outlet check valve, forcing the fuel in the fuel lines into the
carburetor float bowl and moving the fuel-air mixture in the crankcase into
the combustion chamber where ignition occurs.
This type of fuel pump is not powerful enough to draw fuel from the fuel
tank during cranking. In that case, it is necessary to introduce fuel into the
carburetor with the priming bulb mounted on the fuel line.
Suzuki uses both powerhead mounted, remote pumps and integral
carburetor/fuel pumps. Both designs are very simple and reliable. The most
common failure is to the diaphragm, and dirty fuel can block the check valve,
causing it to fail. Most fuel systems are equipped with a separate fuel filter
and some are equipped with a fuel/water separating filter assembly.
REMOVAL & INSTALLATION
Remote Mounted
1 . Loosen the hose clamps and slide the fuel lines off the pump body.
Plug the hoses to prevent fuel leaks.
2. Remove the screws holding the pump to the powerhead and pull the
fuel pump off the power head.
3. If so equipped, remove the fuel pump insulator from the powerhead.
4. Thoroughly clean the pump mounting surface of any gasket or sealer
residue. Do not scratch or gouge the sealing surface of the powerhead.
To install:
5. If needed, install the fuel pump insulator and new 0-ring.
6. Install the pump onto the powerhead with a new gasket and 0-ring in
the pump body.
Carburetor Mounted
1 . Remove the fuel hose at the pump inlet cover and plug the line.
FUEL SYSTEM 4-27
Fig. 49 Removing the reed valve stop
2. Remove the retaining screws that hold the pump to the carburetor.
3. Remove the pump as an assembly.
To install:
4. Reassemble the pump components in the reverse order of
disassembly, using new gaskets.
5. Mount the pump assembly back on the side of the carburetor. Do not
over-tighten the mounting screws.
6. Unplug and reinstall the fuel hoses.
OVERHAUL
Remote Mounted
• See Figures 50 thru 61
There are several variations in the pumps used on the different models.
All operate in the same manner, but there are differences in the internal
1 . Pump assy, fuel 7. Net, filter
2. Gasket 8. Gasket, filter
3. Diaphragm, fuel pump 9. Hose, vacuum ( L : 1 1 )
4. Membrane, fuel pump 10. Filter, fuel
5. Cock assy, fuel 1 1 . Plug, fuel connector
6. Cup, filter 1 2. 3 way, joint pipe
Fig. 50 Fuel pump assembly-DT4 and DT5Y
4-28 FUEL SYSTEM
1 Fuel pump assy.
2 : Diaphragm set
3 Valve set
er 4: Diaphragm stopp
5 O-ring
·ng
.
I mp o-n 6. Fue pu
p insulator 7. Fuel pum
8 Stud bolt
9 : Lock washer
1 0. Nut
1 1 . Hose
1 2 . Hose
1 3. Hose
==---
1 4 Clip
1 5
.
Fuel hose clamp
1 6 : Fuel filter assy.
1 7. Filter assy.
1 8 . Packing
1 9. O-ring
20. Strainer
2 1 . Cup
22. Filter bracket
23. Lock washer
24 Nut .
Lock washer 25.
26. Bolt
27. Fuel hose
osoo4G31
Fig. 52 Fuel pump and fu -DT20 and DT25 (2-el filter assembly
cyl inder)
G) Fuel fi lter
® Packing
@ 0 ring
@ Strainer
@ Cup
® Fuel pump assy
® Gasket
Fig. 53 Fuel pump and fu el filter assembly­DT25 and DT35 (3cylinde .. r,)�---fuel 1 . Pump assy
• set 2 Diaphragm
3. Gasket, fuel pump 4: Hose, fuel
5. Valve
05004G71
Fig. 54 Fuel pump and fu bly-DT40 el filter assem '-:=::...:.:..._ __ _
4
1 . Fuel pump ass'y
2. Diaphragm set
3. Fuel pump insulator
4. Fuel hose
5. Fuel hose
6. Fuel hose
7. Fuel filter ass'y
8. 0-ring
9. Strainer 10. Cup 1 1 . Packing
05004G33
Fig. 55 Fuel pump and fuel filter assembly-DT50
CD Fuel t i l ter assy.
® Fuel pump assy.
@ Fuel strainer
@ Cap
@ Fuel pump gasket
® Diaphragm set
Fig. 57 Fuel pump and fuel filter assembly-DT55 and DT65
FUEL SYSTEM 4-29
Match marks
05004G34
Fig. 56 Matchmark the pump assembly for installation reference
05004G35
4-30 FUEL SYSTEM
CD Fuel pump assy.
@ Diaphragm set
@ "0" ring
@ Insulator
® "0" ring
® Fuel filter assy.
(J) Fuel strainer
® Cap
Fig. 58 Fuel pump and filter assembly-DT75 and DT85
CD Fuel pump assy. @ Diaphragm set
@ "0" ring
@ Fuel fi lter assy.
@ Fuel strainer
@ Cap (j) Primer bulb
Fig. 59 Fuel pump and fuel filter assembly-DT90 and DT100
05004G36
05004G37
CD Fuel pump assy.
® Diaphragm set
@ "0" ring
@ Insulator
@ "0" ring
® Fuel filter assy. (]) Fuel strainer
@ Cap
Fig. 60 Fuel pump and fuel filter assembly-DT115 and DT140
CD F uel pump assy.
® D iaphragm set @ "0" ring
@ Fuel fi lter assy. @ F uel strainer
@ Cap
Fig. 61 Fuel pump and fuel filter assembly-DT150, DT175 and DT200
FUEL SYSTEM 4-31
05004G38
05004G39
4-32 FUEL SYSTEM
parts. Make sure to note the location of any of these parts during d isassem­
bly.
Mark the pump assembly prior to disassembly. This wi l l ensure that the
pump wi l l go back together in the order that it was taken apart.
Refer to the exploded view drawings in this section during overhaul.
Carburetor Mounted
• See Figures 62 and 63
Mark the pump assembly prior to disassembly. This wi l l ensure that the
pump wi l l go back together in the order that it was taken apart.
Refer to the exploded view drawing in this section during overhaul.
Separate the pump cover, diaphragm, valve assembly and pump body. Dis­
card the used gaskets.
05004G13
Fig . 62 Remove the fuel pump from the carburetor body- DT9.9
and DT15
ELECTRONIC FUEL INJECTION
Description and Operation
The fuel injection control system on the DT1 1 5, DT140, DT150, DT200 and
DT225 models, detects the current condition of the engine through various sen­
sors mounted on the engine. These sensors send information to the micro-com­
puter as electrical signals. Based on these e lectrical signals, the computer
determines the optimal amount of fuel needed for the engines current condition
and calculates the injection duration time. The fuel injectors receive this dura­
tion signal and inject the fuel into the intake manifo ld .
FUEL INJECTION BASICS
• See Figure 64
** CAUTION
Precautions must be taken not to cause damage to expensive elec­
tronic components during these service procedures.
Fuel injection is not a new invention. Even as early as the 1 950s, various
automobi le manufacturers experimented with mechanical-type injection sys­
tems. There was even a vacuum tube equipped control unit offered for one sys­
tem! This might have been the first "electronic fuel injection system." Early
problems with fuel injection revolved around the control components. The e lec­
tronics were not very smart or reliable. These systems have stead i ly improved
since. Today's fuel injection technology, responding to the need for better econ­
omy and emission control , has become amazingly reliable and efficient. Com­
puterized engine management, the brain of fuel injection, continues to get more
reliable and more precise.
Components needed for a basic computer-control led system are as fol lows:
• A computer-control led engine manager, which is the Electronic Control
Unit (or ECU), with a set of internal maps to follow.
1 1
1 . Carburetor assy
2. Jet, pilot
3. Screw, pilot
4. Float
5. Needle
7. Bolt
'if-3
i I
8. Jet, main
9. Pump assy, set
10. Valve set
1 1 . Knob, choke lever
6. Screw, throttle stop 12. Lever, choke
Fig. 63 DT9.9 and DT15 fuel pump assembly
05004G30
• A set of input devices to inform the ECU of engine performance parameters.
• A set of output devices. Each device is controlled by the ECU. These
devices modify fuel del ivery and timing. Changes to fuel and timing are based
on input information matched to the map programs.
This l ist gets a little more compl icated when you start to look at specific
components. Some fuel injection systems may have twenty or more input
devices. On many systems, output control can extend beyond fuel and timing.
The Suzuki Fuel Injection System provides more than just the basic functions,
but is stil l straight forward in its layout. There are twelve input devices and six
output controls. The diagram on the following page shows the input and output
devices with their functions.
There are several fuel injection del ivery methods. Throttle body injection is
relatively inexpensive and was used widely in early automotive systems This is
usually a low pressure system running at 15 PSI or less. Often an engine with a
single carburetor was selected for throttle body injection. The carburetor was
recast to hold a single injector. and the original manifold was retained. Throttle
body injection is not as precise or efficient as port injection.
Mu lti-port fuel injection is defined as one or more e lectrically activated sole­
noid injectors for each cylinder. Mu lti-port injection generally operates at higher
pressures than throttle body systems. The Suzuki system operates at 35.5 PSI.
Port i njectors can be triggered two ways. One system uses simultaneous
injection. All injectors are triggered at once. The fuel "hangs around" until the
pressure drop in the cylinder pul ls the fuel into the combustion chamber.
The second type is more precise and follows the firing order of the engine.
Each cylinder gets a squirt of fuel precisely when needed.
SUZUKI ELECTRONIC FUEL INJECTION
• See Figure 65
Suzuki uses the multi-point, sequential method of fuel injection. The whole
system can be divided into three areas: air i ntake system, fuel system and the
control system.
FUEL SYSTEM
04704G40
Fig. 64 Suzuki electronic fuel injection schematic
_L AIR INDUCTION SYSTEM
ELECTRONIC FUEL INJECTION . L FUEL SYSTEM ELECTRONIC CONTROL SYSTEM
r- 1=- -
- -:
fS�
a a
;
i ;
:
,r r s switch
r------. �J relay r
1. THROTTLE POSITION SENSOR
2. AIR TEMPERATURE SENSOR
3. AIR PRESSURE SENSOR
4. OXYGEN SENSOR
5. KNOCK SENSOR
6. WATER TEMPERATURE SENSOR
7. CRANK POSITION SENSOR
8. PULSER COIL
�----�. M . __[___. Starter motor Battery
Vapor separator
Fig. 65 Suzuki electronic fuel injection system components
FUEL SYSTEM
... Gasoline
· =::> Oil l � Pre-mixed fuel
-- - � l
-
4-33
4-34 FUEL SYSTEM
Air flows through the throttle body and surge tank t o the intake manifo ld ,
where the i ntake air is mixed with a combined fuel/oil m ixture that has been
delivered through the fuel injector. The throttle sensor assesses the throttle
opening angle and sends the corresponding signal to the control unit
Fuel is drawn through the primer bulb to the low pressure fuel pump. Upon
reaching the vapor separator, the gasol ine is mixed with o i l (supplied directly
from the o i l pump to the vapor separator) and the combined fuel/oil m ixture
goes through the high-pressure fuel pump and del ivery gallery. The pressure
regulator maintains the fuel pressure in the feed l i ne , from the high pressure
fuel pump to the fuel injector. This pressure, maintained at a constant level, is
higher than the manifold pressure (injector nozzle ambient pressure). When the
higher fuel pressure in the feed l i ne exceeds the pressure in the manifold by
more than approximately 36.6 psi (2.55 kg-cm), the valve in the pressure regu­
lator wi l l open, thereby returning fuel to the vapor separator through the fuel
return hose. The fuel/oil m ixture is injected into the intake manifold by the fuel
injector when the signal is supplied from the engine control unit (ECU).
The e lectronic fuel injection control system is primarily based on the signals
supplied from both the engine speed sensor (gear counter coi l ) and the throttle
valve sensor (TPS). To compensate for other conditions, a cylinder wall temper­
ature sensor, air temperature sensor and atmospheric pressure sensor are also
used. Based on these sensor signals, the engine control unit (ECU) determines
the injection time duration and sends the injection signal to the injector. The
ECU's sequential multi-point programming provides individual control of each
injector operating duration and timing.
An additional feature of the Suzuki system is return-to-port capabil ity or fail
safe mode. If there is a major sensor failure that prevents the ECU from pro­
cessing, the engine is run on a minimum performance map. If either the counter
coil or pulser coil fai l , the ECU will not provide an injection signal without a refFuel tank
erence signal from these coi ls. Under this condition, the engine can be cranked
but it wi l l not start without fuel injection.
The only input that will shut the engine down completely is battery voltage. If
the battery is disconnected or the battery voltage falls below 9 volts, the fuel
pump quits pumping so the engine stops.
The Suzuki fuel injection system is divided into three component groups.
These are:
• Electronic control system
• Fuel system
• Air i ntake system
The air induction and fuel systems are the del ivery agents for the fuel/ air
mixture. The fuel del ivery system is contro l led by the e lectronic control system.
The e lectron ic control system can be further subdivided into input sensors (the
informants), outputs (the workers that make adjustments to fuel and timing), and
the computer (the boss or decision maker).
Electronic Control System
t See Figure 66
The electronic control system has the largest number of individual compo­
nents. Each component is connected to the control unit The control unit func­
tions in several modes
FAIL SAFE MODE
When any of the sensors of the ECU fails, the self diagnostic system wi l l indi­
cate the failure location by means of the indicator lamp flashing out the code for
the fai lure. In the event of such a failure, another system, called the back-up sysElectronic
fuel injec­
tion control
unit
Ignition
control
unit
Throttle
sensor
Throttle
valve
05004G41
Fig. 66 Note how each component of the system is interconnected to other components
FUEL SYSTEM 4-35
tern, wi l l come into operation. This system provides alternative signals t o compen­
sate for the ECU or sensor failure so that the engine wi l l not stop running and
continue to operate. Because of this provision, an emergency, return-to-dock oper­
ation will be possible, but the engine will run in a much reduced state of tune.
mal duty (repeating the "ON" time rate within a cycle) and sends the signal to
the fuel pump.
INJECTION MODE
FUEL PUMP CONTROL
• See Figure 67
• See Figure 68
During starting conditions, fuel is sequentially injected into each cylinder
whi le cranking.
To supply the optimal amount of fuel, the ECM controls the duty cycle signal
for the fuel pump drive, which repeats the ON/OFF cycle at a specified rate
After the powerhead is started, fuel control falls under one of three modes.
1 . Warm-up mode. For the first 3 minutes upon start-up, the ECU controls
the fuel injection duration as the "Warm-up (Enrichment) mode". This mode is (1 ,000 times a second). Based on engine speed, the ECM determines the optiIgnition switch
"ON"
Ignition switch
"START"
(Cranking)
Engine start
(Operating)
Pulser coil
signal
Pulser coil
signal
Power from battery
Fuel pump
..,
I r - - .. L� �; r-----�---------------� :---� r•' ® 1- - - - - �1-------...J
I �--J
I
Power from
battery
charge coil
05004G48
Fig. 67 Schematic drawing of the fuel pump control system
F U EL INJECTION TIMING CHART
BTDCS0 BTDC s o BTDCS 0 BTDC S0
( # 1 CYL) ( # 3 CYL) ( # 1 CYL) ( # 3 CYL)
P I -� · 1 -, ,�--�u��--------------�u�----�. r--u ser co1 s1gna U u
Ignition signal
# 1 injection signal
# 3 CYL # 2 CYL # 4 CYL # 1 CYL # 3 CYL
_n n""'"" ___ .... n n""'"" __ ..,.,n�--__,n.____
lnject;on sta� l ln�ction end�,
� :•1
Duration of # 1
1
CYL I I ...._ '""' # 3 injection signal -----------_J�,-----;-t, �----+--------Duration of # 3 CYL I
# 2 i�ection �gnal ��������������������1���������­
Duration of # 2 CYL
I
# 4 injection signal ..HMt---�-J�t.. ____________ .JI������LDuration of # 4 CYL Duration of # 4 CYL
05004G49
Fig. 68 Fuel injection timing chart
4-36 FUEL SYSTEM
based o n the map control in relation t o engine speed, throttle valve opening
angle and cylinder wall temperature.
2. Normal operating mode. Three minutes after starting, the ECU changes to
the "Normal operating mode". This mode is based on the map control in rela­
tion to engine speed, throttle valve opening angle, cylinder wall temperature, air
temperature and atmospheric pressure.
3. Fail safe mode. Each sensor has an assigned default value programmed
into the ECU. In the event of a sensor failure, the monitor gauge wi l l flash a
code ind icating the failure and the engine wi l l continue to operate, but with
reduced performance. Injection duration during sensor failure automatical ly
defaults to the following control methods:
• Throttle valve sensor failure: Injection duration wi l l be automatically
set according to engine speed
• Cylinder wall temperature sensor failure: injection duration will be
automatically set if the sensor senses 30°C
• Air temperature sensor failure: Injection duration will be automatically
set if the sensor senses 20°C
• Atmospheric pressure sensor failure: Injection duration will be auto­
matical ly set if the sensor senses 763 mm Hg (1 01 .7 kPa)
If either the gear counter coi l or the pulser coil fails, the ECU wi l l not provide
and injection signal without a reference from these coils. Under this condition,
the engine can be cranked but it will not start due to no fuel being injected.
Fuel Delivery System
Fuel injectors requ i re clean, water-free, pressurized gasoline. Fuel is sup­
pl ied through the primer bu lb, fuel filter and low pressure fuel pump to the fuel
vapor separator. From the fuel vapor separator, the fuel goes through the high
pressure fuel pump and on to the fuel rai l . The pressure regulator maintains the
fuel pressure in the feed l i ne, from the high pressure fuel pump to the fuel injec­
tor. This pressure, maintained at a constant level, is higher than the barometric
pressure. When the higher fuel pressure in the feed l i ne exceeds the barometric
pressure by more than approximately 36.3 psi (255 kPa), the valve in the fuel
pressure regulator wi l l open, allowing fuel to return to the fuel vapor separator
through the fuel return hose. The fuel is injected into the intake manifold by the
fuel injector when the signal is supplied by the ECU. Oil mixing is accom­
pl ished with a standard oil pump. This pump injects oil into the vapor separator
tank.
FUEL SUPPLY AND VAPOR SEPARATOR TANK
t See Figures 69, 70 and 71
The vapor separator incorporates a float system which maintains a constant
fuel level inside the body of the unit. When the fuel level decreases, more fuel
will flow into the vapor separator from the low pressure fuel pump. The function
Fuel tank Primer bulb
of th is un it is to separate the vapor from the fuel del ivered by the low pressure
fuel pump, or fuel that has returned from the pressure regulator. This vapor is
"bled" to the throttle body through the hose on the top of the vapor separator.
OIL INJECTION
The separator also functions as the mixing chamber for oi l and fue l . O i l is
injected into the separator tank by the engine-driven oil pump. The amount of
oil del ivered to the separator tank is dependent upon engine RPM and throttle
opening. The supply side of the o i l injection system is simi lar to previous mod­
els.
Air Intake System
t See Figure 72
The throttle body assembly including the throttle valve sensor, is a precision­
made part which detects the throttle valve opening angle and supplies a signal
to the ECU. Therefore, when replacing any of the components within the throttle
body assembly, special care should be taken so as not to alter the precise c lear­
ances and operating efficiency of the throttle body.
The air which ahs passed through the throttle body, flows into the surge
tank/intake manifold and is then distributed to the reed valves. The throttle body
adjusts the air intake amount using the throttle valve which is connected to the
throttle lever and Throttle Position (TP) sensor. The TP sensor is installed on
the top of the throttle body and informs the ECM of the current throttle valve
opening angle and is used as a basic signal for the engine control system.
�Do not try to adjust or remove any of the component parts (sensor
base plate, throttle valve, throttle l inkage lever, etc.). The TP sensor
must be installed and adjusted by following the proper procedure.
Cyl inder Wal l Temperature Sensor
DESCRIPTION & OPERATION
The cylinder wall temperature sensor (a thermistor type) is located on the
cylinder bank port side. The thermistor's abil ity to change resistance with tem­
perature is used to measure engine temperature. Voltage flow through the sen­
sor, it is modified ( increased/decreased) by resistance, returns to the ECU as a
voltage signal measurement of the engine temperature. The ECU map then com­
pensates by effecting a temperature based change in fuel injection duration. For
example, a cold engine requires a richer fuel mixture for starting than a ful ly
warmed up engine. This temperature related resistance change also serves as
the signal for compensating ignition timing and overheat detection.
Fuel filter
High pressure
fuel pump
__., High pressure
- Low pressure
Fig. 69 Fuel flow
I ntake
manifold
05004G42
to Throttle body
lJ Fig. 70 One type of vapor separator . . .
� Fuel
... O i l
� Fuel/Oil mixture
� Vapor (Evaporation)
from Low pressure
fuel pump
from Fuel pressure
regulator (Return)
to High pressure
fuel pump
05004G43
CD Float
C2) Float arm
QJ Pin
@ Needle valve
@ Valve seat
@ Gasket
(]) Cover
@ Body
® Gasket
from Oil pump
� Fuel .. Oil .. Fuel/Oil mixture
� Vapor (Evaporation) '
to High pressure
fuel pump
Fig. 71 . . . and another style. They all work on the same principle
from Low pressure
fuel pump
05004G44
11
c m r(/)
-<
(/)
-I m s:
.1::;1.
I
(A) .......
4-38 FUEL SYSTEM
®
1 . Th rottle valve sensor
2. Th rottle valve
3. Th rottle body
4. Sensor base plate
I
I
I
I
I
I
I
.....,.
.....,. I
I
I
CD
1 . Reed valve assy.
2 . Surge tank
05004G47
Fig. 72 Throttle body, surge tank and reed valve assembly make up the air intake system
TESTING
t See Figures 73 and 74
•The sensor inspection must be performed with the battery connected.
If an out of range condition exists in the sensor signal sent back to the
ECU, the sell-diagnosis system will be indicated by the "CHECK
ENGINE" monitor gauge lamp flashing the code.
1. Connect the multi meter probes to each of the sensor leads.
2. Immerse the sensor's tip in water and gradually heat the water whi le mon­
itoring the changes in sensor resistance. Check if resistance matches specifica­
tions:
• 32°F (0°C): 5.3-6.6 kilo ohms
• 7JCF (25°C}: 1 .8-2.3 ki lo ohms
• 1 35°F (75°C): 0.33-0.45 kilo ohms
3. On the DT225, check for continu ity through the engine harness
between the ECU 2-pin connector Lg/W terminal and the sensor Lg/W lead as
shown.
4. Disconnect the harness to the ECU 2-pin connector and sensor Lg./W
lead.
5. Connect the tester as shown.
6. Check for an indication of continuity (0 Resistance)
Q
05004G54
Fig. 73 Immerse the sensor's tip in water and gradually heat the
water while monitoring the changes in sensor resistance
Lg/W
Cyl inder wal l
te� YC=r--J
Range : R x 1
Lg/W
Fig. 74 On the DT225, check for continuity through the engine
harness between the ECU 2-pin connector Lg/W terminal and the
sensor Lg/W lead as shown
REMOVAL & INSTALLATION
1. Disconnect the battery negative cable.
2. Remove the engine cover.
3. Locate the sensor on the engine and remove it using the appropriate
tools.
To instal l :
4. Replace the gasket or 0-ring as equipped.
5. Connect the sensor lead connector securely.
6. Install the sensor on the engine.
7. Replace the engine cover.
8. Connect the battery negative cable.
Air Temperature Sensor
DESCRIPTION & OPERATION
The air temperature sensor, also a thermistor, is located above the throttle
body. Voltage flow through the sensor, is modified (increased/decreased) by
resistance, returns to the ECU as a voltage signal measurement of the air
temperature flowing into the throttle body. As air intake temperature changes,
air density also changes, which affects the air/fuel mixture ratio. The ECU
map then compensates for these air density changes to the mixture by
adjusting the fuel injector duration time.
TESTING
1 . Connect the multi-meter probes to each of the sensor leads.
2. Immerse the sensor's tip in water and gradually heat the water while
monitoring the changes in sensor resistance. Check if resistance matches
specifications:
• 32°F (0°C): 5.3-6.6 kilo ohms
• 7rF (25°C): 1 .8-2.3 kilo ohms
• 1 35°F (75°C): 0.33-0.45 kilo ohms
REMOVAL & INSTALLATION
1 . Disconnect the battery negative cable.
2. Remove the engine cover.
3. Locate the sensor on the engine and remove it using the appropriate
tools.
FUEL SYSTEM 4-39
To install:
4. Replace the gasket or 0-ring as equipped.
5. Connect the sensor lead connector securely.
6. Install the sensor on the engine.
7. Replace the engine cover.
8. Connect the battery negative cable.
Atmospheric Pressure Sensor
DESCRIPTION & OPERATION
The atmospheric pressure sensor is located above the throttle body and
measures the ambient air pressure in which the engine is operating. As
pressure affects the sensors ability to conduct voltage, the sensor voltage
signal returning to the ECU is used as a measure of current air pressure. As
altitude changes, atmospheric pressure changes, this affects the air portion
of the fuel/air mixture. The ECU map then compensates for these changes
by effecting a pressure based change in fuel injection duration. For example,
an engine operating at sea level with more air pressure requires a richer fuel
mixture than an engine operating in lower air pressure at 5,000 feet altitude.
TESTING
DT11 5 and DT140
The following special tool is required to perform the sensor output test:
• 6-pin connector test cord (p/n 09930-89251 )
1 . With the multi-meter set o n DC volts, connect the tester positive (red)
to the gray lead on the test cord and the tester negative (black) to ground.
2. Turn the ignition on and check the voltage. Output should measure
approximately 3.64 volts at 1 4.6 psi ( 1 0 1 .3 kPa).
3. If the sensor does not meet this specification, replace the sensor.
• Make sure the wiring harness assembly between the ECU and
sensor has continuity.
DT150/DT200 (1 988-93)
1 . With the multi-meter set on DC volts, connect the negative (black) to
the sensor black wire and the tester positive (red) to the sensor white wire.
2. Turn the ignition on and check the voltage. Output should measure
approximately 3.64 volts at 1 4.6 psi ( 1 0 1 .3 kPa).
3. If the sensor does not meet this specification, replace the sensor.
DT1 50/DT200 (1 994 and later) and DT225
The following special tool is required to perform the sensor voltage test:
• 3-pin connector test cord (3-branch harness) (p/n 09930-89220)
1 . Turn the ignition switch off.
2. Connect the 3-pin connector test cord between the atmospheric
pressure sensor and the main wiring harness.
3. Connect the multi-meter as follows:
• Tester positive (+): atmospheric pressure sensor white lead
• Tester negative (-): atmospheric pressure sensor green lead
(black/white lead in wiring harness)
4. Turn the ignition on and check the voltage. Output should measure
approximately 3.8 volts at 1 4.6 psi ( 1 0 1 .3 kPa).
5. If the sensor does not meet this specification, replace the sensor.
REMOVAL & INSTALLATION
1. Remove the engine cover.
2. Locate the sensor and remove the wiring cover.
3. Disconnect the appropriate wiring harness connectors and install the
test cord assembly if needed.
To install:
4. Remove any test cords from the wiring harness and securely
reconnect the wiring harness connectors.
5. Use wire ties to bind the wiring harness in place.
6. Replace the wiring covers on the engine.
7. Replace the engine cover.
4-40 FUEL SYSTEM
Throttle Valve Sensor
DESCRIPTION & OPERATION
• See Figure 75
The throttle valve sensor (TVS) is located on the top of the throttle body and
is connected to the upper end of the throttle valve shaft. As the throttle valve
shaft turns, the sensor resistance changes. the resistance change of the voltage
returning to the ECU is a measure of the throttle valve opening angle. The
throttle valve opening angle signal serves as one of the signals for determin ing
ignition timing and fuel injection duration time (fuel injection amount) in the
ECU.
'------- ®
1 . Throttle valve sensor
2. Throttle valve
3. Throttle stop screw
05004G40
Fig. 75 Throttle valve sensor and throttle body
TESTING
,.. The throttle valve sensor (TVS) inspection/adjustment except for the
"TVS RESISTANCE CHECK" must be performed with the battery con­
nected. If an out-of-range condition exists in the TVS signal returned to
the ECU, the self-diagnosis system will be indicated by the monitor
gauge "CHECK ENGINE" lamp flash code. However, this system is
unable to detect an incorrect TVS adjustment.
Resistance Check
DT115 AND DT140
• See Figure 76
The following special tools must be obtained to perform the sensor check:
• 4-pin connector test cord (0993D-89240)
• Multimeter
1 . Connect the tester positive probe to the white lead of the test cord and
the negative lead to the yellow lead. Set the tester to the ohms k scale.
,..Do not connect the ECU side connector of the test cord.
Throttle valve
sensor (TVS)
Throttle body
r 05004G4A
Fig. 76 Connect the tester positive probe to the white lead of the
test cord and the negative lead to the yellow lead
2. Slowly move the throttle lever to the open position, then check to see if
the resistance changes l i nearly within the specifications according to the TVS
shaft turning angle:
• TVS resistance: 0-6 ki lo ohms (l inear change)
,.. The above resistance range specification is a minimum /maximum
reference only for an uninstalled TVS. When the TVS is installed on the
throttle body, the actual resistance may be shown as a narrower range
than the above specification. If the resistance changes suddenly at any
point, the TVS must be replaced.
DT150 AND DT200
• See Figure 77
The following special tool must be obtained to perform the sensor check:
• 1 2-pin connector test cord (09930-89940)
1 . Set the multi meter on the ohms scale.
2. Connect the negative tester lead to the light green/black test cord lead
and the positive tester lead to the orange/ye l low test cord lead.
,..Do not connect the ECM side connector of the test cord.
3. Slowly move the throttle lever to open, and check if resistance changes
l inearly within specification, accord ing to the TVS shaft turning angle:
• TVS resistance: 0-6 ki lo ohms (l inear change)
,.. The above resistance range specification is a minimum /maximum
reference only for an uninstalled TVS. When the TVS is installed on the
throttle body, the actual resistance may be shown as a narrower range
than the above specification. If the resistance changes suddenly at any
point, the TVS must be replaced.
Voltage Check
DT225 AND DT200
• See Figures 78 and 79
The following special tool must be obtained to perform the sensor check:
• 3-pin connector test cord (09930-89230)
1 . Set the multi meter on the DC voltage scale.
I
(2)
ECM
0
Yellow/Green
TP sensor .�
05004G3A
Fig. 77 Connect the negative tester lead to the light green/black test
cord lead and the positive tester lead to the orange/yellow test cord
lead
+
1 2V
I g.
control
u n i t
0
D igital
tester
-+- -
B
FU EL SYSTEM 4-41
�While performing these tests, the throttle valve must be in the fully
closed position. Make sure the throttle stop screw is not holding the
throttle valve open.
2. Install the test cord between the TVS and the harness connector. Using
the multi meter, perform the following procedures with the ignition switch in the
ON position and the throttle stop screw turned counter-clockwise unti l it no
longer touches the throttle lever.
3. Connect the negative tester lead to the black test cord lead and the posi­
tive tester lead to brown/yel low test cord lead. This voltage is referred to as V1
and must be between 3.64-4.39 volts.
�The V1 voltage is not adjustable and is supplied to the TVS through
the ICU (Ignition Control Unit). If the V1 voltage is not within the above
specifications, the ICU must be replaced. Under normal conditions the
diagnostic indicator lamp will show a TVS failure mode if the V1 voltage
is below specification.
4. Voltage V2 is a check voltage and is determined by multiplying the above
V1 voltage by 0.1 25. Example: 4.05 (V1 ) x 0.1 25 = 0.506 (V2).
R
05004G68
Fig. 78 Install the test cord between the TVS and the harness con­
nector
Mark ing
Throttle sensor
Screw ®
05004G69
Fig. 79 Connect the negative tester lead to the black test cord lead and the positive tester lead to brown/yellow test cord lead
4-42 FUEL SYSTEM
5. Connect the multi meter positive lead (red) t o the light green/red test cord
lead and the tester negative lead to the test cord black lead. This voltage is
referred to as V3. The difference of the voltage, V2 minus V3 must be within
+0.00--0.01 volts.
,..If the only difference between the V2 and V3 measurements is not
specified, it will be necessary to perform the following adjustment pro­
cedure.
ADJUSTMENT
,..Proper idling and acceleration are dependent on the correct V2 volt­
age. Because of the sensitivity of V2, even the slightest amount of
movement, fastening screws too tightly or securing screws unevenly
may alter this reading. Therefore, following installation or adjustment of
the TVS, recheck V2 to ensure accuracy.
OT115 ANO OT140
t See Figure 80
The following special tools must be obtained to perform the sensor check:
• 4-pin connector test cord (09930-89240)
1 . Loosen the locknut and unscrew the idle adjusting screw until it is fu l ly
backed out and not touching the throttle l ever.
,..Manually flock the throttle valve open and closed 2-3 limes by hand,
allowing the spring tension to snap the valve fully closed.
2. Set the multi meter on the DC volts setting and connect the 4-pin test
cord as fol lows: tester positive probe (red) to the test cord white lead and the
tester negative probe (black) to the test cord yellow lead.
3. Turn the ignition switch to the ON position, then check the voltage (V2) to
see if it matches that specified for the TVS power supply (V1 ) . Refer to the TVS
voltage specifications.
4. If the voltage (V2) not correct, loosen the TVS set screws and gently
VI V2 ± 0.01 Vt
(81-Yl (W-Yl ( W - Yl
4 . 7 5 0.70
4.76 0.70
4. 7 7 0.70
4.78 0 . 7 1
4 .79 0 . 7 1
4.80 0 . 7 1
4. 8 1 0 . 7 1
4 . 8 2 0 . 7 1
4 . 8 3 0 . 7 1 1 . 1 5
4 . 84 0. 7 1
4 . 8 5 0 . 7 2
4 . 86 0.72
4.87 0.72
4.88 0.72
4.89 0.72
4 . 90 0.72
4. 9 1 0.72
4.92 0. 73
4.93 0.73
4 . 94 0.73
4.95 0.73
4.96 0 . 73 1 . 1 9
4 . 9 7 0 . 7 3
4.98 0.74
4 .99 0 . 74
5.00 0.74
Fig. 80 TVS voltage specifications-DT115 AND DT140
rotate the TVS until the voltage indicated matches that specified in the chart.
Then retighten the set screws using a thread locking compound.
OT150 ANO OT200
The following special tools must be obtained to perform the sensor check:
• 1 2-pin connector test cord (09930-89940)
1 . Loosen the locknut and unscrew the idle adjusting screw until it is fu l ly
backed out and not touching the throttle lever.
,..Manually flock the throttle valve open and closed 2-3 limes by hand,
allowing the spring tension to snap the valve fully closed.
2. Set the multi meter on the DC volts setting and connect the 1 2-pin test
cord as fol lows: tester positive probe (red) to the test cord orange/yellow lead
and the tester negative probe (black) to the test cord light green/black lead.
3. Turn the ignition switch to the ON position , then check the voltage (V2) to
see if it matches that specified for the TVS power supply (V1 ).
4. If the voltage (V2) not correct, loosen the TVS set screws and gently
rotate the TVS until the voltage indicated matches that specified in the chart.
Then retighten the set screws using a thread locking compound.
OT200 ANO OT225
t See Figures 81 , 82, 83 and 84
The following special tools must be obtained to perform the sensor check:
• 3-pin connector test cord (09930-89230)
1 . Loosen the locknut and unscrew the id le adjusting screw until it is ful ly
backed out and not touching the throttle lever.
,..Manually flock the throttle valve open and closed 2-3 times by hand,
allowing the spring tension to snap the valve fully closed.
2. Set the multi meter on the DC volts setting and connect the 3-pin test
cord as fol lows: tester positive probe (red) to the test cord brown/yel low lead
and the tester negative probe (black) to the test cord black lead.
(Unit: volt)
VI V2 ± 0. 0 1 V t
(81 - Yl (W-Y} (W-Yl
5.01 0 .74
5.02 0 . 74
5 . 03 0 . 74
5 .04 0 . 74 1 . 1 9
5 . 0 5 0 . 7 5
5 . 06 0 . 7 5
5 . 0 7 0. 7 5
5.08 0 . 7 5
5.09 0 . 7 5
5. 1 0 0 . 7 5
5. 1 1 0 . 7 5
5. 1 2 0 . 7 6
5. 1 3 0 . 7 6
5. 1 4 0 . 76
5. 1 5 0 . 7 6
5. 1 6 0 . 7 6
5. 1 7 0 . 76 1 . 23
5. 1 8 0 . 7 6
5. 1 9 0 . 7 7
5 . 20 0 . 7 7
5 . 2 1 0. 77
5.22 0 . 7 7
5 . 23 0 . 7 7
5 . 24 0 . 7 7
5 . 2 5 0. 77
05004G78
FUEL SYSTEM 4-43
DT2 25TC L : V 3 + (V t x 0.02 1 ) = V4
Example: 0 . 506 (V 3 )
+ 0. 085 (4.05 x 0. 02 1 ) - - - - - - - ( from example above )
0.591 (V4 )
DT225TC U L : V 3 + ( V t x 0.0 1 0) = V4
E xample: 0.506 (V 3 )
+ 0.040 (4.05 x 0.0 1 0) - - - - - - - ( from example above )
0.546 (V4 )
Fig. 81 TVS adjustment formula-DT200 and DT225
TVS Voltage Chart
V I : TVS in put voltage
V2: TVS output voltage at F . C . T (VI x 0. 1 2 5 )
V max : T V S output voltage at 4 ° throttle valve a ng le (VI x 0. 1 583)
VI v2 V max VI v2 V max VI v2
3 . 64 0 . 4 5 5 0 . 5 7 6 3 . 9 0 0.488 0. 6 1 7 4 . 20 0 . 5 2 5
. 6 5 0 .456 0 . 578 . 9 1 0 .489 0 . 6 1 9 . 2 1 0 . 5 2 6
. 66 0 . 4 58 0 . 579 . 9 2 0.490 0 . 6 2 1 . 22 0 . 5 2 8
. 6 7 0 . 4 5 9 0 . 5 8 1 . 93 0 .49 1 0 . 6 2 2 . 2 3 0 . 5 2 9
. 68 0 .460 0. 583 . 94 0 .493 0 . 624 . 24 0 . 530
. 6 9 0 . 4 6 1 0 . 584 . 9 5 0.494 0 . 6 2 5 . 2 5 0 . 5 3 1
3 . 70 0 .463 0. 586 . 96 0 . 4 9 5 0 . 6 2 7 . 2 6 0 . 5 3 2
. 7 1 0 . 464 0 . 587 . 9 7 0.496 0. 6 28 . 2 7 0 . 5 34
. 7 2 0 . 4 6 5 0. 589 .98 0 .498 0 . 6 30 . 28 0 . 5 3 5
. 7 3 0 .466 0 . 590 . 99 0 .499 0 .632 . 29 0 . 536
. 7 4 0 . 468 0 . 5 9 2 4 . 00 0. 500 0.633 4 . 30 0. 538
. 7 5 0.469 0. 594 . 0 1 0 . 5 0 1 0 . 6 3 5 . 3 1 0 . 539
. 7 6 0 .470 0. 5 9 5 .02 0. 503 0 . 6 3 6 . 32 0 . 540
. 7 7 0 .47 1 0 . 597 . 03 0 . 504 0 . 638 . 3 3 0 . 54 1
. 7 8 0 .473 0 . 5 9 8 . 04 0. 505 0 . 640 . 34 0. 543
. 7 9 0 . 474 0. 600 .05 0 . 506 0 . 64 1 . 3 5 0 . 544
3 .80 0 . 4 7 5 0 . 6 0 2 . 0 6 0. 508 0. 643 . 3 6 0 . 54 5
. 8 1 0 .476 0 . 603 .07 0 . 509 0 . 644 .37 0 . 546
.82 0 . 478 0 .605 .08 0. 5 1 0 0. 646 . 3 8 0 . 548
. 8 3 0.479 0 . 606 .09 0. 5 1 1 0 . 647 . 3 9 0 . 549
. 84 0. 480 0. 608 4. 1 0 0. 5 1 3 0 . 649
. 85 0 . 4 8 1 0. 609 . 1 1 0 . 5 1 4 0 . 6 5 1
. 8 6 0.483 0. 6 1 1 . 1 2 0 . 5 1 5 0 . 6 5 2
. 8 7 0 . 484 0 . 6 1 3 . 1 3 0. 5 1 6 0 . 6 54
. 8 8 0 . 4 8 5 0. 6 1 4 . 1 4 0. 5 1 8 0 . 6 5 5
. 89 0.486 0 . 6 1 6 . 1 5 0 . 5 1 9 0 . 6 5 7
. 1 6 0 . 5 20 0 . 6 59
. 1 7 0. 5 2 1 0 . 660
. 1 8 0 . 5 2 2 0 . 6 6 2
. 1 9 0. 524 0 . 6 6 3
Fig. 8 2 TVS voltage specifications-1 988·93 DT150 and DT200
V max
0 . 6 6 5
0 . 6 6 6
0 . 668
0 .670
0 . 6 7 1
0 . 6 7 3
0 . 6 7 4
0 . 6 7 6
0 . 6 7 8
0 . 6 7 9
0 . 6 8 1
0 . 6 8 2
0. 684
0 . 6 8 5
0 . 6 8 7
0 . 6 8 9
0 . 690
0 . 6 9 2
0 . 6 9 3
0 . 6 9 5
4-44 FUEL SYSTE M
V1 V2 :t:0.01 Vt :t:0.01 V1
(Y/G - Lg/B) (ON - Lg/B) (ON - Lg/B) (Y/G - Lg/B)
4.80 0 .576 0 .806 5 .00
4.81 0.577 0.808 5.01
4.82 0.578 0.8 1 0 5 .02
4.83 0.580 0 .81 1 5 .03
4.84 0.581 0.8 1 3 5 . 04
4.85 0.582 0.8 1 5 5.05
4.86 0.583 0.8 1 6 5 .06
4.87 0584 0.8 1 8 5.07
4.88 0.586 0.820 5 . 08
4.89 0.587 0.822 5 .09
4.90 0.588 0.823 5. 1 0
4.91 0.589 0.825 5. 1 1
4.92 0.590 0.827 5 . 1 2
4.93 0.592 0.828 5. 1 3
4.94 0.593 0.830 5 . 1 4
4.95 0.594 0.832 5 . 1 5
4.96 0.595 0.833 5. 1 6
4.97 0.596 0.835 5 . 1 7
4.98 0.598 0.837 5 . 1 8
4.99 0.599 0.838 5. 1 9
Fig. 83 TVS voltage specifications-DT225, 1 994-99 DT200 and 1 994-03 DT150
+
1 2V
lg .
control
unit
Fig. 84 Multi meter terminal connections when adjusting the TVS -DT200 and DT225
(Unit: volt)
V2 :t0.01 Vt :t0.01
(ON - Lg/B} (ON - Lg/B)
0 .600 0 .840
0.601 0.842
0.602 0 .843
0.604 0.845
0.605 0.847
0.606 0.848
0.607 0.850
0.608 0.852
0.61 0 0.853
0.6 1 1 0.855
0.61 2 0.857
0.6 1 3 0.858
0.6 1 4 0.860
0.6 1 6 0.862
0.6 1 7 0.864
0.6 1 8 0.865
0.6 1 9 0.867
0.620 0.869
0.622 0.870
0.623 0.872
Throttle valve sensor {TVS)
Screw @
Throttle body
3. Turn the ignition switch to the ON position, then check the voltage (V2) to
see if it matches that specified for the TVS power supply (V1 ) Refer to the TVS
voltage specifications.
• Since V1 voltage is not adjustable, a read ing of 3.64-4.39 volts can be
considered correct If the voltage is not between these numbers, it may indi­
cate either a fault in the ICU or a short circuit of the TVS (although that is a
relatively uncommon occurrence). Both components therefore must be
replaced and checked sequential ly.
4. If the voltage (V2) not correct, loosen the TVS set screws and gently
rotate the TVS until the voltage indicated matches that specified in the chart
Then retighten the set screws using a thread locking compound.
5. With the test cord stil l attached, reattach the emergency switch lock plate
and start the engine, letting it warm up thoroughly.
6 . When the engine is at operating temperature, adjust the throttle stop
screw. Id le speed should be as specified in the "Tune-Up Specifications"
chart
7. Securely lock the throttle stop screw with the nut
The idle speed has been correctly adjusted, check the TVS output voltage.
The reading must be lower than an upper l imit referred to as V max. V max is
a designated value at throttle opening of 4° and when adjusting the in-gear
id le speed, the throttle opening should be 4°at most
,..Value V max corresponds directly to (and is listed alongside) inter­
related V1 and V2. Having checked V1 and V2 according to the TVS volt­
age chart. V max is the third relevant throttle valve factor. If V2 and V
max are accurate, and within specification respectively, and if in-gear
idle speed is as specified in the "Tune-Up Specifications" chart, the
TVS is adjusted correctly.
8. If the output voltage exceeding V max is required to obtain the specified
idle speed, then this abnormally wide throttle valve opening may ind icate
mechan ical, fuel del ivery or other electrical system problems. Such circum­
stances should be investigated immed iately.
,..li the above situation occurs when TVS input voltage (V1 ) and output
voltage at fully closed throttle (V2) are known to be correct, then the ICU
and TVS are operating correctly and should not be checked.
REMOVAL & INSTALLATION
1 . Remove the engine cover.
2. Disconnect the wiring to the TVS mounted on the throttle body.
3. Remove the TVS from the throttle body.
To install:
,..li the TVS has been moved even the slightest amount or taken off the
throttle body, you must perform the TVS adjustment procedure.
4. Install the TVS onto the throttle body.
5. Perform the TVS adjustment procedure covered in detai l above.
6. Make sure to use thread locking compound on the screws.
7. Connect the TVSwiring, making sure the connections are fastened
tightly.
8. Install the engine cover.
Gear Counter Coil (Engine Speed Sensor)
DESCRIPTION & OPERATION
The gear counter coil is located on top of the engine at the rear of the fly­
wheel. Voltage pulses induced in the coil by the passing flywheel ring gear teeth
are signals used by the ECU to determine engine speed. This signal also serves
as one of the basic signals used in determin ing ignition timing and fuel injector
duration time (amount of fuel injected) in the ECU.
TESTING
Gear counter coil testing is covered in detai l in "Ignition and Electrical".
FUEL SYSTEM 4-45
Pulser Coil
DESCRIPTION & OPERATION
The pu lser coil is located under the flywheel rotor. Voltage pulses induced in
the coil by the passing reluctor bar which is attached to the flywheel rotor are
signals used by the ECU to determine crankshaft angle This is the base infor­
mation from which the ECU computes the ignition spark signal in the correctly
sequenced firing order. Fuel injection timing is then set by this ignition signal.
TESTING
Pulser coil testing is covered in detai l in the in "Ignition and Electrical" .
Fuel Injectors ,
DESCRIPTION & OPERATION
• See Figure 85
The fuel injector is an e lectromagnet fuel injection valve operated by the
injection signal supplied by the fuel injection control unit The coil used in the
injector is a high pressure resistant type The fuel injection control unit deter­
mines the optimal fuel injection time duration on the basis of the signal input
from the various sensors mounted on the engine.
When the injection signal is sent to the fuel injector, it energizes the coil and
pulls up the needle valve, thereby opening the valve and injecting fuel . Because
fuel pressure (pressure d ifferential between fuel l i ne and manifold) is kept con­
stant, the amount of fuel injected is determined by the duration time of the open.
1 . Fuel
2. Coil
3. Plunger
@
®
4. Needle valve
05004G45
Fig. 85 Fuel injector components
TESTING
Operational Sound
DT115, DT140, DT150 AND DT200
,.. The fuel injector inspection must be performed with the battery termi­
nals connected.
1 . Using a mechanics stethoscope or a long bladed screwdriver, touch the
injector connector.
4-46 FUEL SYSTEM
2 . Crank the engine with the spark plugs removed and l isten for the sound
of the injector cl icking.
3. If there is no sound, then the injector is not operating and it wi l l need to
be replaced.
Obtain the following special tool:
• Injector test cord "A" (09930-99420)
�lt is not necessary to remove the injectors from the engine to perform
this test.
4. Disconnect the injector wire and connect the test cord.
5. Touch the stethoscope or screwdriver to the injector connector.
6. Momentarily touch the red wire of the test cord to the starter motor relay
left terminal (which is connected to the battery positive terminal) and l isten for
the sound of the injector c l icking.
7. If there is no sound, then the injector is not operating and it wi l l need to
be replaced.
OT225 (MULTIPLE INJECTORS)
1 . Obtain the following special tool to perform the test:
• 6-pin test harness (09930-89251 ) .
2. Disconnect the 6-pin ECU connector containing black/yellow leads and
install the test harness.
3. Turn ignition switch to the ON position and touch one b lack/yel low lead
to ground. Listen for the sound of the injector c l icking from 3 injectors each
time the black/yel low lead is touched to ground. This means the injector is
operating properly. Repeat the test for the other b lack/yellow lead.
�a injectors are controlled by each black/yellow ECU lead.
�Another way to tell if the injector is to place your finger on the injec­
tor itself and feel for the clicking motion inside the injector.
OT225 {INDIVIDUAL INJECTORS)
If injector operation is not heard or felt, you wi l l need to obtain the following
special tool to perform the check:
• 2-pin connector test cord (09930-89260)
1 . Disconnect the fuel injector's 2-pin connector and connect the 2-pin
connector test cord to the injector. Connect the black test lead first tot he bat­
tery negative terminal. Next, touch the positive test lead to the battery positive
terminal and then remove. Repeat this on and off contact action several times
and check for the sound of the injector operating If the c l icks are heard as this
on and off contact action is made, the injector is operating normally. If the
c l icks are not heard, there is a failure in the injector and it wi l l need to be
replaced.
** WARNING
Never allempt to disconnect or remove the fue l hose during this
test, or fuel under high pressure will spray out, causing an
extremely hazardous condition.
Power Supply
OT115, OT140, OT150 AND OT200 (NO LOAD)
1 . Obtain the following special tool:
• Injector test cord "B" (09930-99430)
2. Connect the test cord as shown in the i l l ustration to the injector wiring
harness.
3. Connect the test meter positive probe to the test cord red lead and the
negative lead to ground.
4. Turn the ignition to the ON position and check for voltage. The injector
voltage should read approximately .1 1 volts.
OT115, OT140, OT150 AND OT200TC (PEAK VOLT CHECK)
1 . Obtain the following special tools:
• Injector test cord "B" (09930-99430)
• Peak read ing voltage meter
2. Set the peak volt meter to NEG 50.
3. Connect the test cord positive probe (+) to the test cord black lead and
the negative test probe to the starter relay left terminal (connected to the battery
positive terminal ) .
4. Crank the engine with the spark plugs removed and check the indicated
voltage. The injector operating signal should indicate approximately 8-1 0 volts.
OT225 (NO LOAD)
Obtain the following special too l :
• 2-Pin connector test cord "B" (09930-89270)
1 . Turn the ignition switch to the OFF position.
2. With the injectors instal led on the engine, remove al l six of the 2-pin
connectors. Connect the 2-pin connector test cord between the injector being
checked and the wiring harness as i l lustrated.
�When inserting the 2-pin connector test cord connector, make sure the
same color lead are connected together.
3. Connect a peak voltage meter (set on Positive 50V) as fo l lows:
• Tester positive lead to the gray lead of the 2-pin connector test cord
• Tester negative lead to an engine ground
4. If the tester indication is approximately 12 volts with the ignition switch
in the ON position, the condition of the power system is normal. If the voltage is
not as specified, check the following:
• Loose or discolored connectors
• Open circu its of the gray lead
• Disconnected connector or lead, failure of the main relay etc.
5. Check the other five i njectors in the same manner.
OT225 (PEAK VOLT CHECK)
1 . Peform the first and second procedures of the previous power supply
check (no load).
2 . Connect the peak voltage meter (set on POSITIVE 50V) as fol lows:
• Tester positive lead to the black/yel low lead of the 2-pin test connector
cord.
• Tester negative lead to an engine ground.
3. If the tester indication is approximately 12 volts with the ignition switch
in the ON position, the operating condition is normal.
4. Check for voltage with the engine being cranked. If more than approxi­
mately 20 volts is indicated during engine cranking, the injector control signal
is normal. If the voltage being indicated is less than approximately 20 volts,
check for connector looseness or the disconnection of the black/yel low lead.
5. Check the other five injectors in the same manner. If less than 20 volts is
indicated at al l six injectors, perform an ECU power supply and ground checks.
Injector Resistance
1. Disconnect the injector connector.
2. Using a multi meter, measure the resistance between the injector termi­
nals. Resistance should measure approximately 12 .2-15.1 ohms at 68°(20°C).
3. If the measured resistance does not meet specifications, replace the
injector.
4. Reconnect the injector connector.
Fuel Pressure Regulator
• See Figure 86
The fuel pressure regulator is used in the system for the purpose of main­
taining the fuel pressure relative to the manifold at a constant level. The regu­
lator diaphragm chamber is connected with the surge tank to keep the
pressure balanced, wh i l e the fuel pressure is adjusted by the regulator to be
constantly h igher than the surge tank pressure by approximately 36.3 psi
(2.55 kg-cm), the diaphragm is pushed up , a l lowing fuel to flow through the
return p i pe to the vapor separator. When fuel returns to the vapor separator,
the excess fuel pressure is rel i eved, thus keeping the pressure adjusted to a
constant level.
TESTING
1 . Obtain the following special tools:
• Hand vacuum/air pump
• Air Pressure gauge Attachment (09940-44130)
2. Remove the fuel pressure regulator from the engine.
3. Connect the attachment, gauge and pump to the fuel pressure regulator
as shown in the i l lustration.
VALVE CLOSED
[below 2.55 kg/cm'
136.3 psi)!
VALVE OPENED
[over 2.55 kg/cm'
(36.3 psi)!
From
pipe
i} Return
IT o vapor separator)
05004G46
Fig. 86 Typical fuel pressure regulating valve with the valve open
and closed
1 . Pump housing
2. Internal ground
3. Magneto
4. Armature
5. Spacer
6. Cushion
7 . Rotor
8. Suction filter
Fig. 87 A typical in-line high pressure fuel pump
FUEL SYSTEM 4-47
4. Using the pump, pump a i r into the regulator until the a i r is released
through the outlet.
5. As air is released from the regulator, check the gauge to see if the pres­
sure meets specification:
• 34.1-38.4 psi (2.4-2.7 kg/cm2)
REMOVAL & INSTALLATION
1 . Remove the engine cover.
2. Turn the ignition switch to the OFF position and then disconnect the bat­
tery cables from the battery terminals.
3. Loosen the fasteners securing the oil tank to the engine and move the
oil tank to the outside.
4. Place a rag over the banjo bolt fitting on the fuel l i ne and then slowly
loosen the bolt relieving the fuel pressure in the fuel l i ne.
5. Wipe up any spi l led fuel immediately.
6. Pinch the fuel l i ne with your fingers to make sure a l l the pressure has
been relieved.
To install:
7. Reinstall al l the hoses on the regu lator.
8. Tighten the banjo bolt to 29 ft. lbs. (40 Nm)
9. Install the o i l tank back i n its place on the side of the engine and tighten
the fasteners.
1 0. Reconnect the battery cables to the battery terminals.
1 1 . Install the engine cover.
H igh Pressure Fuel Pump
• See Figure 87
This an "In-line" type pump which has al l the pump mechanisms located
within the fuel l i ne.
The pump unit consists of the housing, rotor and rol lers. As the rotor rotates,
the centrifugal force pushes the rol lers outward so that they revolve along the
inside housing wal l . During rotation, the space formed by these three parts:
9. Plate
1 0. Roller
1 1 . Relief valve
1 2. Motor housing
1 3. Bearing holder
1 4. Residual pressu re check valve
1 5. Nut
05004GSO
4-48 FUEL SYSTEM
rotor, rollers and housing wi l l alternate, first larger, then smaller. This space
variation is uti l ized for fuel suction and feed pressure.
Residual pressure check valve A check valve is provided to keep resid­
ual pressure in the fuel l ine after the engine has been shut off.
Relief valve A relief valve is provided to prevent overpressure in the high­
pressure side of the fuel l i ne.
Suction filter To prevent fuel tank or sediment from entering the high-pres­
sure fuel pump, there is a fine mesh suction filter at the pump in let.
TESTING
Fuel Pressure
1 . Obtain the following special tools:
• Fuel pressure gauge
• 3-way joint and hose
• Fuel pressure hose
2. After following the procedures for relieving the fuel pressure in the fuel
l i nes, connect the joint & hose and gauge as shown in the i l lustration.
3. Use a 50:1 fuel/o i l mixture for pressure testing.
4. Turn the ignition switch to the ON and OFF positions several times to
activate the high pressure fuel pump and fi l l the fuel hoses with fuel.
5. Inspect al l the fuel l i ne connections for leaks and correct any problems
before proceeding with the tests.
6. Check if the fuel pressure indicated on the gauge is within specification
at both idle speed and cranking speed.
,.. To prevent damage to the starter motor, do not crank the engine for
more than 20 seconds at a lime.
7. Fuel pressure should be approximately 36.3 psi (2.55 kg/cm2).
8. If the fuel pressure is not with in specification, recheck a l l the fuel l i ne
connections for leaks. If there are no leaks, replace the fuel pump assembly.
Residual Fuel Pressure
1 . After performing the fuel pressure check, shut off the engine and wait 5
minutes.
2. Check the fuel pressure indicated on the fuel gauge. Pressure should be
28.4 psi (2.0 kg/cm2) or more.
Power Supply
,.. The fuel pump inspection must be performed with the battery con­
nected to the terminals.
1 . Turn the ign ition switch to the ON position and l i sten for the sound
of the fuel pump operat ing. it should sound for approximately 2 seconds
on ly.
" T E M P" lamp
" REV L I M I T"
lamp
Fig. 88 Typical Suzuki monitor gauge
The following special tool must be obtained to perform the fuel pump power
supply check:
• 2-pin connector test cord (09930-89210)
2. Connect the multi meter positive probe to the pink test cord lead and the
multi meter negative probe to ground.
3. With the tester set on DC volts, fuel pump voltage should measure
approximately 12 volts (battery voltage).
To perform the fuel pump 2 second operating signal check, connect the mul­
ti meter positive probe to the pink test cord lead and the tester negative probe to
the black test cord lead.
4. Turn the ignition switch to the ON position and measure the voltage. Volt­
age should measure approximately 12 volts (battery voltage) for 2 seconds on ly.
,..Excepting the first 2 second after the ignition switch is turned ON, the
tester must indicate 0 voltage. If not, the pump has failed and needs to
be replaced.
5. To perform the fuel pump operating signal check, crank the engine with
the spark plugs removed and check the voltage.
6. The fuel pump operating signal should be approximately 9-1 0 volts dur­
ing cranking.
Additional Inputs
Additional inputs include:
• Neutral switch, which informs the ECU of the sh ifter position
• The key switch , which tells the computer when to begin the program
• The thermoswitich (overheat) for overheat information
• Oil level sensor information
• The sh if! cut switch
• The lanyard switch
• The gray over-rev loop lead
Although not strictly inputs, battery power and ground are essential for com­
puter operation. This computer also mon itors battery voltage. As battery voltage
drops, the injectors would open more slowly, decreasing fuel del ivery volume.
Therefore, when the computer detects low battery voltage, it makes adjustments
to injector "time on" to keep fuel del ivery volume correct.
Self Diagnostic System
DESCRIPTION & OPERATION
• See Figures 88, 89, 90, 91 and 92
The ECU is provided with a self diagnostic function . When a failure occurs in
the system and no input signal is sent from the sensors, the ECU stores this
information and activates the "Check Engine" LED on the monitor gauge. The
" CHECK E N G I N E " l amp
"O IL" l amp
" RE O O IL LEV E L " lamp
05004G76
location of the problem can be determined by the flashing l ight sequence of the
monitor LED as shown in the i l l ustration.
DIAGNOSIS PROCEDURE
1 . Turn on the ignit ion switch.
2. Check the "check engine" LED flashing sequence and count the number
of flashes. From the observed flashes, determine which one of the following
codes it corresponds to.
FUEL SYSTEM 4-49
FAIL SAFE EMERGENCY BACKUP
When any of the ECU system fails, the self-diagnostic system wi l l indicate
the failure location by means of the indicator lamp's flashing code. In the event
of such a failure condition, another system, called a back-up system , wi l l come
i nto operation. This system provides alternative signals to compensate for the
ECU or sensor failure so that the engine will not stop operating but wi l l be con­
tinuously operable. Because of this provision, emergency, return-to-port opera­
tion wi l l be possible, but in a much reduced performance mode.
Fai l u re location Code F lash i ng mode Check point Priority
Signal system
with i n u n i t
i tsel f
Throttl e sensor
signal system
Cy l inder wal l
temperature
sensor signal
system
Air temperature
sensor signal
system
Atmospheric
pressure sensor
signa l system
Constant
O N
2 - 1
1 - 4
2 - 3
3 - 4
Fig. 89 Sell-diagnostic system chart -DT225
PRIORITY FAILED ITEM
1 CKP sensor [NOTE 11
2 Engine speed sensor
3 T P sensor
2
4 Cylinder temp. sensor (STBD)
5 Cylinder temp. sensor (PORT)
6 I AT sensor
7 MA P sensor
8 Neutral switch
CODE
42
24
21
1 4
1 5
23
34
33
Fig. 90 Sell-diagnostic system chart -DT150 AND 1988-93 DT200
· Replace the u n it
· Wir ing harness
· Thrott l e sensor
· Wi ri ng harness
· Cy l i nder wal l
temperature
sensor
· Wi ri ng harness
· Ai r temperature
sensor
· Wi ri ng harness
· Atmospheric
pressure sensor
· Wi ri ng harness
1
2
3
4
5
05004G72
LAMP FLASHING PATTERN FAIL-SAFE SYSTEM ACTIVATING
on __lliUl_fLJ1_Jl
off
on __Illl__IUliUl_
off
on __IliLjl_
off
on __fL__flJlJ1Jl
off
on ___ll_IUlSUl_fl
off
on _Il_ILllflJ1_
off
on'�
off
on __fl_fUl_Jl_JlJ
off
NO (NOTE 2]
NO (NOTE 2]
YES
YES
YES
YES
YES
NO
05004G73
4-50 FUEL SYSTEM
F a i l u re location Code
Signal system
Constant
with in unit
itse lf
ON
Throttle sensor
2
signa l system
2 - 1
Cyl i nder wal l
temperatu re 1 - 4
sensor signal
system
A i r temperatu re
sensor signal 2 - 3
system
Atmospheric
pressu re sensor 3 - 4
signal system
Fig. 91 Self-diagnostic system chart-1994-99 DT2DD
Malfunction Range
* * More than
Battary 9.9 vdls (0T1 1 SSTC)i
10.2 vdls !DT140TC)
Throttle valve sensor
0.6 to
4. 7 volts
Cylinder wall 0. 1 to
temperature sensor 4. 7 volts
Air temperature 0.5 to
sensor 4. 7 volts
Atmospheric pressure 2.2 to
sensor 4.4 volts
Fig. 92 Self-diagnostic system chart-DT115 and DT140
F l ash i ng mode Check point
Code
CON.
2 - 1
1 - 4
2 - 3
3 - 4
· R ep lace the un it
· Wiring harness
· Th rottle sensor
· Wi ring harness
· Cy l inder wa l l
temperature
sensor
· Wi ring harness
· Air temperature
sensor
· Wiring harness
· Atmospheric
pressure sensor
· Wir ing harness
"CHECK ENGINE" lamp
flashing pattern
::�----��]
Constant "ON"
O N - - - -
-JUl�Xcl•
OFF - - - -
1 cycle
0�F - - - - - -truum 0 ----1 cycle
ON - - ---JiJLiirul
OFF·-- - - · ·
O N u m�
OFF·- ---
·�
-�
·�
- -
-�
Priority
2
3
4
5
05004G74
* Priority
1
2
3
4
5
05004G75
UNDERSTANDING AND
TROUBLESHOOTING ELECTRICAL
SYSTEMS 5·2
BASIC ELECTRICAL THEORY 5-2
HOW ELECTRICITY WORKS: THE
WATER ANALOGY 5-2
OHM'S LAW 5-2
ELECTRICAL COMPONENTS 5-2
POWER SOURCE 5-2
GROUND 5-3
PROTECTIVE DEVICES 5-3
SWITCHES & RELAYS 5-3
LOAD 5-3
WIRING & HARNESSES 5-4
CONNECTORS 5-4
TEST EQUIPMENT 5-4
JUMPER WIRES 5-4
TEST LIGHTS 5-5
MULTIMETERS 5-5
TROUBLESHOOTING THE ELECTRICAL
SYSTEM 5-6
TESTING 5-6
VOLTAGE 5-6
VOLTAGE DROP 5-6
RESISTANCE 5-6
OPEN CIRCUITS 5-7
SHORT CIRCUITS 5-7
WIRE AND CONNECTOR REPAIR 5-7
ELECTRICAL SYSTEM
PRECAUTIONS 5-7
BREAKER POINTS IGNITION
(MAGNETO IGNITION) 5-7
SYSTEM TESTING 5-8
BREAKER POINTS 5-8
POINT GAP ADJUSTMENT 5-8
TESTING 5-9
REMOVAL & INSTALLATION 5-9
CONDENSER 5-1 0
DESCRIPTION & OPERATION 5-1 0
TESTING 5-1 0
REMOVAL & INSTALLATION 5-1 0
IGN ITION COIL 5-1 0
DESCRIPTION & OPERATION 5-1 0
TESTING 5-1 1
REMOVAL & INSTALLATION 5-1 1
CAPACITOR DISCHARGE IGNITION
(CDI) SYSTEM 5·1 1
DESCRIPTION AND OPERATION 5-1 1
SINGLE-CYLINDER IGNITION 5-1 1
SUZUKI PE! IGN ITION 5-1 2
SYSTEM TESTING 5-1 4
PROCEDURE 5-14
PULSAR/CHARG ING/GEAR COUNTER
COILS 5-1 4
DESCRIPTION & OPERATION 5-1 4
TESTING 5-1 5
REMOVAL & INSTALLATION 5-20
IGNITION COILS 5-25
DESCRIPTION & OPERATION 5-25
TESTING 5-25
REMOVAL & INSTALLATION 5-26
CD! UN IT 5-28
DESCRIPTION & OPERATION 5-28
TESTING 5-28
REMOVAL & INSTALLATION 5-34
RECTIFIER 5-37
DESCRIPTION & OPERATION 5-37
TESTING 5-37
REMOVAL & INSTALLATION 5-38
REGULATOR 5-38
DESCRIPTION & OPERATION 5-38
TESTING 5-38
REMOVAL & INSTALLATION 5-38
ELECTRONIC IGNITION 5·38
DESCRIPTION AND OPERATION 5-38
WARNING SYSTEMS 5-38
OVER REVOLUTION 5-38
OIL LEVEL 5-38
OIL FLOW 5-38
OVERHEAT 5-38
BATTERY VOLTAGE 5-39
CHARGING CIRCUIT 5·39
DESCRIPTION AND OPERATION 5-39
SINGLE PHASE CHARGING
SYSTEM 5-39
THREE-PHASE CHARGING
SYSTEM 5-39
PRECAUTIONS 5-39
TROUBLESHOOTING THE CHARG ING
SYSTEM 5-40
OVERCHARGING 5-40
UNDERCHARG ING 5-40
ALTERNATOR (STATOR) 5-40
TESTING 5-40
BATTERY 5-41
MARINE BATTERIES 5-41
BATTERY CONSTRUCTION 5-41
BATTERY RATINGS 5-42
BATTERY LOCATION 5-42
BATTERY SERVICE 5-42
BATTERY TERMINALS 5-44
SAFETY PRECAUTIONS 5-44
BATTERY CHARGERS 5-44
BATTERY CABLES 5-45
BATTERY STORAGE 5-45
STARTING CIRCUIT 5-45
DESCRIPTION AND OPERATION 5-45
TROUBLESHOOTING THE STARTING
SYSTEM 5-46
STARTER MOTOR 5-46
DESCRIPTION & OPERATION 5-46
TESTING 5-48
REMOVAL & INSTALLATION 5-48
OVERHAUL 5-49
STARTER MOTOR RELAY SWITCH 5-50
DESCRIPTION & OPERATION 5-50
TESTING 5-51
REMOVAL & INSTALLATION 5-51
IGNITION AND ELECTRICAL WIRING
DIAGRAMS 5·52
5-2 I G N IT ION AN D ELECTRI CAL SYSTEMS
UNDERSTANDING AND TROUBLESHOOTING ELECTRICAL SYSTEMS
Basic Electrical Theory
• See Figure 1
For any 1 2 volt, negative ground, e lectrical system to operate, the electricity
must travel in a complete circuit. This simply means that current (power) from
the positive terminal (+) of the battery must eventually return to the negative ter­
minal (-) of the battery. Along the way, this current wi l l travel through wires,
fuses, switches and components. If, for any reason, the flow of current through
the circuit is interrupted, the component fed by that circuit wi l l cease to function
properly.
Perhaps the easiest way to visualize a circuit is to think of connecting a light
bulb (with two wires attached to it) to the battery-one wire attached to the neg­
ative (-) terminal of the battery and the other wire to the positive (+) terminal.
With the two wires touching the battery terminals, the circuit would be complete
and the light bulb would i l luminate. Electricity would follow a path from the bat­
tery to the bu lb and back to the battery. it's easy to see that with longer wires on
our l ight bulb, it could be mounted anywhere. Further, one wire could be fitted
with a switch so that the l ight cou ld be turned on and off.
The normal marine circuit differs from this simple example in two ways.
Fi rst, i nstead of having a return wire from each bu lb to the battery, the current
travels through a single ground wire which handles all the grounds for a spe­
cific circuit. Secondly, most marine circu its contain multiple components which
receive power from a single circuit. This lessens the amount of wire needed to
power components.
RETURN
CONDUCTOR
GROUND
PROTECTION
DEVICE
(FUSE)
RETURN
CONDUCTOR
GROUND
TCCS2004
Fig. 1 This example il lustrates a simple circuit. When the switch is
closed, power from the positive (+) battery terminal flows through
the fuse and the switch, and then to the light bulb. The light illumi·
nates and the circuit is completed through the ground wire back to
the negative (-) battery terminal .
HOW ELECTRICITY WORKS: THE WATER ANALOGY
Electricity is the flow of e lectrons-the sub-atomic particles that constitute
the outer shel l of an atom. Electrons spin in an orbit around the center core of
an atom. The center core is comprised of protons (positive charge) and neu­
trons (neutral charge). Electrons have a negative charge and balance out the
positive charge of the protons. When an outside force causes the number of
electrons to unbalance the charge of the protons, the electrons will split off the
atom and look for another atom to balance out. If this imbalance is kept up,
e lectrons wi l l continue to move and an electrical flow wi l l exist.
Many people have been taught e lectrical theory using an analogy with water.
In a comparison with water flowing through a pipe, the e lectrons would be the
water and the wire is the pipe.
The flow of e lectricity can be measured much l ike the flow of water through a
pipe. The unit of measurement used is amperes, frequently abbreviated as amps
(a). You can compare amperage to the volume of water flowing through a pipe.
When connected to a circuit, an ammeter wi l l measure the actual amount of cur­
rent flowing through the circuit. When relatively few electrons flow through a
circuit, the amperage is low. When many electrons flow, the amperage is high.
Water pressure is measured i n units such as pounds per square inch (psi);
The electrical pressure is measured in un its called volts (v). When a voltmeter is
connected to a circuit, it is measuring the e lectrical pressure.
The actual flow of electricity depends not only on voltage and amperage, but
also on the resistance of the circuit. The higher the resistance, the higher the
force necessary to push the current through the circuit. The standard unit for
measuring resistance is an ohm (Q). Resistance in a circuit varies depending
on the amount and type of components used in the circuit. The main factors
which determine resistance are:
• Material-some materials have more resistance than others. Those with
high resistance are said to be insulators. Rubber materials (or rubber-like plas­
tics) are some of the most common insulators used, as they have a very high
resistance to e lectricity. Very low resistance materials are said to be conductors.
Copper wire is among the best conductors. Si lver is actually a superior conduc­
tor to copper and is used in some relay contacts, but its h igh cost prohibits its
use as common wiring. Most marine wiring is made of copper.
• Size-the larger the wire size being used, the less resistance the wire wil l
have. This is why components which use large amounts of e lectricity usually
have large wires supplying current to them.
• Length-for a given thickness of wire, the longer the wire, the greater the
resistance. The shorter the wire, the less the resistance. When determining the
proper wire for a circuit, both size and length must be considered to design a
circuit that can handle the current needs of the component.
• Temperature-with many materials, the higher the temperature, the greater
the resistance (positive temperature coefficient). Some materials exhibit the
opposite trait of lower resistance with higher temperatures (negative temperature
coefficient). These principles are used in many of the sensors on the engine.
OHM'S LAW
There is a direct relationship between current, voltage and resistance. The
relationship between current, voltage and resistance can be summed up by a
statement known as Ohm's law.
• Voltage (E) is equal to amperage (I) times resistance (R): E=l x R
• Other forms of the formula are R=E/1 and I=E/R
In each of these formulas, E is the voltage in volts, I is the current in amps
and R is the resistance in ohms. The basic point to remember is that as the
resistance of a circuit goes up, the amount of current that flows in the circuit
wi l l go down, if voltage remains the same.
The amount of work that the electricity can perform is expressed as power.
The unit of power is the watt (w). The relationship between power, voltage and
current is expressed as:
• Power (W) is equal to amperage (I) times voltage (E): W=l x E
This is only true for direct current (DC) circuits; The alternating current for­
mula is a tad different, but since the e lectrical circuits in most vessels are DC
type, we need not get into AC circuit theory.
Electrical Components
POWER SOURCE
Power is supplied to the vessel by two devices: The battery and the alterna­
tor. The battery supplies electrical power during starting or during periods when
the current demand of the vessel's electrical system exceeds the output capacity
of the alternator. The alternator supplies e lectrical current when the engine is
running. The alternator does not just supply the current needs of the vessel, but
it recharges the battery.
The Battery
In most modern vessels, the battery is a lead/acid electrochemical device
consisting of six 2 volt subsections (cells) connected in series, so that the un it
is capable of producing approximately 1 2 volts of electrical pressure. Each sub­
section consists of a series of positive and negative plates held a short d istance
apart in a solution of sulfuric acid and water.
The two types of p lates are of dissimilar metals. This sets up a chemical
reaction, and it is this reaction which produces current flow from the battery
when its positive and negative terminals are connected to an e lectrical load. The
power removed from the battery is replaced by the alternator, restoring the bat­
tery to its original chemical state.
I G N IT ION AND ELECTRI CAL SYSTEMS 5-3
Charging System
When the imbedded magnets in the flywheel rotate past the charging coi ls or
A!C lighting coi l(s), it creates alternating current. This current is sent to the rec­
tifier or combination rectifier/voltage regulator, where it is then converted to D/C
and then supplied to the battery or electrical accessories through a fused l ink.
A malfunction i n the battery charging system will result i n the battery being
undercharged.
GROUND
Two types of grounds are used in marine electric circuits. Di rect ground
components are grounded to the electrically conductive metal through their
mounting points. Al l other components use some sort of ground wire which
leads back to the battery. The e lectrical current runs through the ground wire
and returns to the battery through the ground (-) cable; if you look, you'l l see
that the battery ground cable connects between the battery and a heavy gauge
ground wire.
,..lt should be noted that a good percentage of electrical problems can
be traced to bad grounds.
PROTECTIVE DEVICES
• See Figure 2
it is possible for large surges of current to pass through the e lectrical system
of your vessel . If this surge of current were to reach the load in the circuit, the
surge could burn it out or severely damage it. it can also overload the wiring,
causing the harness to get hot and melt the insulation. To prevent this, fuses,
circuit breakers and/or fusible l inks are connected into the supply wires of the
electrical system. These items are nothing more than a bui lt-in weak spot in the
system. When an abnormal amount of current flows through the system, these
protective devices work as fol l ows to protect the circuit:
• Fuse-when an excessive electrical current passes through a fuse, the
fuse "blows" (the conductor melts) and opens the circuit, preventing the pas­
sage of current.
• C ircuit Breaker-a circuit breaker is basically a self-repairing fuse. it wi l l
open the circuit in the same fashion as a fuse, but when the surge subsides, the
circuit breaker can be reset and does not need replacement.
• Fusible Link-a fusible l ink (fuse l ink or main l ink) is a short length of
special, high temperature insulated wire that acts as a fuse. When an excessive
electrical current passes through a fusible l i nk, the thin gauge wire inside the
l ink melts, creating an intentional open to protect the circuit. To repair the cir­
cuit, the l ink must be replaced. Some newer type fusible l inks are housed in
plug-in modules, which are simply replaced l ike a fuse, while older type fusible
l inks must be cut and spliced if they melt. Since this l i nk is very early in the
05005P64
Fig. 2 Fuses protect the vessel's electrical system from abnormally
high amounts of current flow
electrical path, it's the first place to look if noth ing on the vessel works, yet the
battery seems to be charged and is properly connected.
** CAUTION
Always replace fuses, circuit breakers and fusible l inks with identi­
cal ly rated components. Under no circumstances should a compo­
nent of higher or lower amperage rating be substituted .
SWITCHES & RELAYS
• See F igure 3
Switches are used in electrical circu its to control the passage of current. The
most common use is to open and close circu its between the battery and the var­
ious electric devices in the system. Switches are rated according to the amount
of amperage they can handle. If a sufficient amperage rated switch is not used in
a circuit, the switch could overload and cause damage.
Some e lectrical components which require a large amount of current to oper­
ate use a special switch called a relay. Since these c i rcuits carry a large amount
of current, the thickness of the wire in the circuit is also greater. If this large wire
were connected from the load to the control switch, the switch would have to
carry the high amperage load and the space needed for wiring in the vessel
would be twice as big to accommodate the increased size of the wiring harness.
To prevent these problems, a relay is used.
Relays are composed of a coil and a set of contacts. When the coil has a cur­
rent passed though it, a magnetic field is formed and this field causes the con­
tacts to move together, completing the circuit. Most relays are normally open,
preventing current from passing through the circuit, but they can take any elec­
trical form depending on the job they are intended to do. Relays can be consid­
ered "remote control switches." They allow a smaller current to operate devices
that require higher amperages. When a small current operates the coi l , a larger
current is al lowed to pass by the contacts. Some common circuits which may
use relays are horns, l ights, starter, electric fuel pumps and other high draw cir­
cuits.
SWITCH B+ ,---}----!-----.,
I ss 3ol I
I � I
RELAY ! +-- - - - !
COIL
I I -
�- i 1 J 86 87 1
L--J.---J------J
GROUND CONPONENT
RELAY
SWITCH
TCCA5G02
Fig. 3 Relays are composed of a coil and a switch. These two com­
ponents are l inked together so that when one operates, the other
operates at the same lime. The large wires in the circuit are con­
nected from the battery to one side of the relay switch (B+) and from
the opposite side of the relay switch to the load (component).
Smaller wires are connected from the relay coil to the control switch
for the circuit and from the opposite side of the relay coil to ground
LOAD
Every electrical circuit must include a "load" (someth ing to use the electricity
coming from the source). Without this load, the battery would attempt to deliver
its entire power supply from one pole to another. This is called a "short circuit".
Al l this electricity would take a short cut to ground and cause a great amount of
damage to other components in the circuit by developing a tremendous amount
of heat. This condition could develop sufficient heat to melt the insulation on a l l
the surrounding wires and reduce a multiple wire cable to a lump of plastic and
copper.
5-4 IG N ITION AND ELECTRI CAL SYSTEMS
WIRING & HARNESSES
The average vessel contains mi les of wiring, with hundreds of individual
connections. To protect the many wires from damage and to keep them from
becoming a confusing tang le, they are organized into bundles, enclosed in plas­
tic or taped together and called wiring harnesses. Different harnesses serve dif­
ferent parts of the vessel . Individual wires are color coded to help trace them
through a harness where sections are hidden from view.
Marine wiring or circuit conductors can be either single strand wire, multi­
strand wire or printed circu itry. Single strand wire has a solid metal core and is
usually used inside such components as alternators, motors, relays and other
devices. Multi-strand wire has a core made of many small strands of wire
twisted together into a single conductor. Most of the wiring in a marine e lectri­
cal system is made up of mu lti-strand wire, either as a single conductor or
grouped together in a harness. All wiring is color coded on the insulator, either
as a sol id color or as a colored wire with an identification stripe. A printed cir­
cuit is a th in film of copper or other conductor that is printed on an insu lator
backing. Occasional ly, a printed circuit is sandwiched between two sheets of
plastic for more protection and flexibil ity. A complete printed circuit, consisting
of conductors, insu lating material and connectors is called a printed circuit
board. Printed circu itry is used in place of individual wires or harnesses in
places where space is l imited, such as behind instrument panels.
Since marine electrical systems are very sensitive to changes in resistance,
the selectiOn of properly sized wires is critical when systems are repaired. A
loose or corroded connection or a replacement wire that is too small for the cir­
cuit will add extra resistance and an additional voltage drop to the circuit.
The wire gauge number is an expression of the cross-section area of the
conductor. Vessels from countries that use the metric system will typically
describe the wire size as its cross-sectional area in square mi l l imeters. In this
method, the larger the wire, the greater the number. Another common system for
expressing wire size is the American Wire Gauge (AWG) system. As gauge num­
ber mcreases, area decreases and the wire becomes smaller. An 18 gauge wire
1s smaller than a 4 gauge wire. A wire with a higher gauge number wi l l carry
less current than a wire with a lower gauge number. Gauge wire size refers to
the size of the strands of the conductor, not the size of the complete wire with
insu lator. lt is possible, therefore, to have two wires of the same gauge with dif­
ferent diameters because one may have thicker insu lation than the other.
I! is essential to understand how a circuit works before trying to figure out
why it doesn't. An electrical schematic shows the electrical current paths when a
circuit is operating properly. Schematics break the entire electrical system down
into individual circuits. In a schematic, usually no attempt is made to represent
wmng and components as they physically appear on the vessel; switches and
other components are shown as simply as possible . Face views of harness con­
nectors show the cavity or terminal locations in al l multi-pin connectors to help
locate test points.
CONNECTORS
• See Figures 4, 5 and 6
Three types of connectors are commonly used in marine applications­
weatherproof, molded and hard shel l .
• Weatherproof-these connectors are most commonly used where the
connector is exposed to the e lements. Terminals are protected against moisture
and dirt by sealing rings which provide a weather tight seal. All repairs require
the use of a special terminal and the tool requ i red to service it. Un l i ke standard
blade type terminals, these weatherproof terminals cannot be straightened once
they are bent. Make certain that the connectors are properly seated and al l of the
seal ing rings are in place when connecting leads.
• Molded-these connectors require complete replacement of the connector if
found to be defective. This means splicing a new connector assembly into the har­
ness. Al l splices should be soldered to insure proper contact. Use care when prob­
ing the connections or replacing terminals in them, as it is possible to create a
short circuit between opposite terminals. If this happens to the wrong terminal pair,
it is possible to damage certain components. Always use jumper wires between
connectors for circuit checking and NEVER probe through weatherproof seals.
• Hard Shell-unlike molded connectors, the terminal contacts in hard­
shel l connectors can be replaced. Replacement usually involves the use of a
special terminal removal tool that depresses the locking tangs (barbs) on the
connector terminal and a l lows the connector to be removed from the rear of the
shel l . The connector shell should be replaced if it shows any evidence of burn­
ing, melting, cracks, or breaks. Replace individual terminals that are burnt, cor­
roded, distorted or loose.
Test Equipment
Pinpointing the exact cause of troub le in an electrical circuit is most times
accomplished by the use of special test equipment. The following sections
describe different types of commonly used test equipment and briefly explain
how to use them in diagnosis. In addition to the information covered below the
tool manufacturer's instruction manual (provided with most tools) should b�
read and clearly understood before attempting any test procedures.
JUMPER WIRES
• See Figure 7
** CAUTION
Never use jumper wires made from a thinner gauge wire than the
circuit being tested. If the jumper wire is of too small a gauge, it
may overheat and possibly melt . Never use jumpers to bypass high
resistance loads in a circuit. Bypassing resistances, in effect, cre­
ates a short circuit. This may, in turn, cause damage and lire.
Jumper wires should only be used to bypass lengths of wire or to
simulate switches.
Jumper wires are simple, yet extremely valuable, pieces of test equipment.
They are basically test wires which are used to bypass sections of a circuit.
Although jumper wires can be purchased, they are usually fabricated from
lengths of standard marine wire and whatever type of connector (all igator c l ip ,
spade connector or p in connector) that is required for the particular app l ication
being tested. In cramped, hard-to-reach areas, it is advisable to have insulated
boots over the jumper wire terminals in order to prevent accidental grounding. I!
is also advisable to include a standard marine fuse in any jumper wire. This is
commonly referred to as a "fused jumper". By inserting an in-line fuse holder
TCCA6P03
Fig. 4 Hard shell (left) and weatherproof
(right) connectors have replaceable termi­
nals
TCCA6P04
Fig. 5 Weatherproof connectors are most
commonly used in the engine compart­
ment or where the connector is exposed to
the elements
04975P62
Fig. 6 The seals on weatherproof connec­
tors must be kept in good condition to pre­
vent the terminals from corroding
I G N IT IO N AND ELECTRICAL SYSTEMS 5-5
05005P75
Fig. 7 Jumper wires are simple, yet extremely valuable, pieces of
test equipment
between a set of test leads, a fused jumper wire can be used for bypassing open
circuits. Use a 5 amp fuse to provide protection against voltage spikes.
Jumper wires are used primarily to locate open e lectrical circu its, on either
the ground (-) side of the circuit or on the power (+) side. If an electrical com­
ponent fails to operate, connect the jumper wire between the component and a
good ground. If the component operates only with the jumper i nstal led, the
ground circuit is open. If the ground circuit is good, but the component does
not operate, the circuit between the power feed and component may be open. By
moving the jumper wire successively back from the component toward the
power source, you can isolate the area of the circuit where the open is located.
When the component stops functioning, or the power is cut off, the open is in
the segment of wire between the jumper and the point previously tested.
You can sometimes connect the jumper wire directly from the battery to the
"hot" terminal of the component, but first make sure the component uses 1 2
volts in operation. Some e lectrical components, such as fuel injectors o r sen­
sors, are designed to operate on about 4 to 5 volts, and running 12 volts
directly to these components wi 11 cause damage .
TEST LIGHTS
t See Figure 8
The test l ight is used to check circuits and components whi le e lectrical cur­
rent is flowing through them. it is used for voltage and ground tests. To use a
05005P70
Fig. 8 A 12 volt test light is used to detect the presence of voltage in
a circuit
12 volt test l ight, connect the ground c l ip to a good ground and probe wherever
necessary with the pick. The test l ight wi l l i l luminate when voltage is detected.
This does not necessarily mean that 1 2 volts (or any particular amount of volt­
age) is present; it only means that some voltage is present. it is advisable before
using the test light to touch its ground c l i p and probe across the battery posts
or terminals to make sure the light is operating properly.
** WARNING
Do not use a test light to probe e lectronic ignition, spark plug or
co i l wires. Never use a pick-type test light to probe wiring on elec­
tronically controlled systems unless specifically instructed to do so.
Any wire insulation that is pierced by the test light probe should be
taped and sealed with silicone alter testing.
Like the jumper wire, the 12 volt test l ight is used to isolate opens in circuits.
But, whereas the jumper wire is used to bypass the open to operate the load, the
1 2 volt test light is used to locate the presence of voltage in a circuit. If the test
l ight i l luminates, there is power up to that point in the circuit; if the test l ight
does not i l luminate, there is an open circuit (no power). Move the test l ight in
successive steps back toward the power source unt i l the l ight in the handle i l lu­
minates. The open is between the probe and a point which was previously
probed.
The self-powered test l ight is similar in design to the 12 volt test l ight, but
contains a 1 .5 volt penlight battery in the handle. it is most often used in place
of a multi meter to check for open or short circuits when power is isolated from
the circuit (continuity test).
The battery in a self-powered test l ight does not provide much current. A
weak battery may not provide enough power to i l luminate the test l ight even
when a complete circuit is made (especially if there is h igh resistance in the cir­
cuit). Always make sure that the test battery is strong. To check the battery,
briefly touch the ground c l ip to the probe; if the l ight glows brightly, the battery
is strong enough for testing.
,.A self-powered test light should not be used on any electronically
controlled system or component. The small amount of electricity trans­
mitted by the test light is enough to damage many electronic marine
components.
MULTIMETERS
t See Figure 9
Multi meters are an extremely useful tool for troubleshooting electrical prob­
lems. They can be purchased in either analog or digital form and have a price
range to suit any budget. A multi meter is a voltmeter, ammeter and ohmmeter
(along with other features) combined into one instrument. it is often used when
testing solid state c i rcuits because of its high input impedance (usually 1 0
Fig. 9 Multimeters are essential for diagnosing faulty wires,
switches and other electrical components
005005P54
5-6 I G N ITION AND ELECTRI CAL SYSTEMS
megohms or more). A brief description of the multi meter main test functions
fol lows:
• Voltmeter-the voltmeter is used to measure voltage at any point in a cir­
cuit, or to measure the voltage drop across any part of a circuit. Voltmeters usu­
ally have various scales and a selector switch to allow the reading of different
voltage ranges. The voltmeter has a positive and a negative lead. To avoid dam­
age to the meter, always connect the negative lead to the negative (-) side of the
circuit (to ground or nearest the ground side of the circuit) and connect the pos­
itive lead to the positive (+) side of the circuit (to the power source or the near­
est power source). Note that the negative voltmeter lead wi l l always be black and
that the positive voltmeter wi l l always be some calor other than black (usually
red).
• Ohmmeter-the ohmmeter is designed to read resistance (measured in
ohms) in a circuit or component. Most ohmmeters wi l l have a selector switch
which permits the measurement of different ranges of resistance (usually the
selector switch al lows the multipl ication of the meter reading by 1 0, 1 00, 1 ,000
and 1 0,000). Some ohmmeters are "auto-ranging" which means the meter itself
wi l l determine which scale to use. Since the meters are powered by an internal
battery, the ohmmeter can be used like a self-powered test light. When the ohm­
meter is connected, current from the ohmmeter flows through the circuit or
component being tested. Since the ohmmeter's internal resistance and voltage
are known values, the amount of current flow through the meter depends on the
resistance of the circuit or component being tested. The ohmmeter can also be
used to perform a continuity test for suspected open circu its. In using the meter
for making continuity checks, do not be concerned with the actual resistance
readings. Zero resistance, or any ohm reading, indicates continu ity in the cir­
cuit. Infinite resistance indicates an opening in the circuit. A high resistance
reading where there shou ld be none indicates a problem in the circuit. Checks
for short circuits are made in the same manner as checks for open circu its,
except that the circuit must be isolated from both power and normal ground.
Infinite resistance indicates no continu ity, whi le zero resistance ind icates a dead
short.
** WARNING
Never use an ohmmeter to check the resistance of a component or
wire while there is voltage appl ied to the circuit.
• Ammeter-an ammeter measures the amount of current flowing through a
circuit in un its called amperes or amps. At normal operating voltage, most cir­
cuits have a characteristic amount of amperes, called "current draw" which can
be measured using an ammeter. By referring to a specified current draw rating,
then measuring the amperes and comparing the two values, one can determine
what is happening within the circuit to aid in diagnosis. An open circuit, for
example, wi l l not al low any current to flow, so the ammeter reading will be zero.
A damaged component or circuit wi l l have an i ncreased current draw, so the
reading will be high. The ammeter is always connected in series with the circuit
being tested. Al l of the current that normally flows through the circuit must also
flow through the ammeter; if there is any other path for the current to fol low, the
ammeter reading will not be accurate. The ammeter itself has very l ittle resis­
tance to current flow and, therefore, wi l l not affect the circuit, but it wi l l measure
current draw only when the circuit is closed and e lectricity is flowing. Excessive
current draw can blow fuses and drain the battery, whi le a reduced current draw
can cause motors to run slowly, l ights to dim and other components to not
operate properly.
Troubleshooting the Electrical System
When diagnosing a specific problem, organized troubleshooting is a must.
The complexity of a modern marine vessel demands that you approach any
problem in a logical, organized manner. There are certain troubleshooting tech­
niques, however, which are standard:
• Establish when the problem occurs. Does the problem appear only
under certain conditions? Were there any noises, odors or other unusual symp­
toms? Iso late the problem area. To do this, make some simple tests and obser­
vations, then el iminate the systems that are working properly. Check for obvious
problems, such as broken wires and loose or dirty connections. Always check
the obvious before assuming something complicated is the cause.
• Test for problems systematically to determine the cause once
the problem area is isolated. Are a l l the components functioning properly?
Is there power going to e lectrical switches and motors. Performing careful, systematic checks wi l l often turn up most causes on the first inspection, without
wasting time checking components that have little or no relationship to the
problem.
• Test all repairs after the work is done to make sure that the
problem is fixed. Some causes can be traced to more than one component,
so a careful verification of repair work is important in order to pick up additional
malfunctions that may cause a problem to reappear or a different problem to
arise. A blown fuse, for example, is a simple problem that may require more
than another fuse to repair. If you don't look for a problem that caused a fuse to
blow, a shorted wire (for example) may go undetected.
Experience has i l lustrated that most problems tend to be the result of a fairly
simple and obvious cause, such as loose or corroded connectors, bad grounds
or damaged wire insu lation which causes a short. This makes careful visual
inspection of components during testing essential to qu ick and accurate trou­
bleshooting.
Testing
VOLTAGE
This test determines voltage available from the battery and should be the first
step in any e lectrical troubleshooting procedure after visual inspection. Many
electrical problems, especially on electronically controlled systems, can be
caused by a low state of charge in the battery. Excessive corrosion at the battery
cable terminals can cause poor contact that wi l l prevent proper charging and ful l
battery current flow.
1 . Set the voltmeter selector switch to the 20V position.
2. Connect the multi meter negative lead to the battery's negative (-) post or
terminal and the positive lead to the battery's positive (+) post or terminal.
3. Turn the ignition switch ON to provide a load.
4. A well charged battery should register over 12 volts. If the meter reads
below 1 1 .5 volts, the battery power may be insufficient to operate the electrical
system properly.
VOLTAGE DROP
When current flows through a load, the voltage beyond the load drops. This
voltage drop is due to the resistance created by the load and also by small resis­
tances created by corrosion at the connectors and damaged insulation on the
wires. The maximum al lowable voltage drop under load is critical, especially if
there is more than one load in the circuit, since all voltage drops are cumu lative.
1 . Set the voltmeter selector switch to the 20 volt position.
2. Connect the multi meter negative lead to a good ground.
3. Operate the circuit and check the voltage prior to the first component (load).
4. There should be little or no voltage drop in the circuit prior to the first
component. If a voltage drop exists, the wire or connectors in the circuit are
suspect.
5. While operating the first component in the circuit, probe the ground side
of the component with the positive meter lead and observe the voltage readings.
A small voltage drop should be noticed. This voltage drop is caused by the
resistance of the component.
6. Repeat the test for each component (load) down the circuit.
7. If a large voltage drop is noticed, the preceding component, wire or con­
nector is suspect.
RESISTANCE
** WARNING
Never use an ohmmeter with power appl ied to the circuit. The ohm­
meter is designed to operate on its own power supply. The normal
12 volt electrical system voltage could damage the meter!
1. Isolate the circuit from the vessel's power source.
2. Ensure that the ignition key is OFF when disconnecting any components
or the battery.
3. Where necessary, also isolate at least one side of the circuit to be checked,
in order to avoid reading paral lel resistances. Paral le l circuit resistances wi l l
always give a lower reading than the actual resistance of either of the branches.
I G N IT ION AND ELECTRICAL SYSTEMS 5-7
4. Connect the meter leads to both sides of the circuit (wire or component)
and read the actual measured ohms on the meter scale. Make sure the selector
switch is set to the proper ohm scale for the circuit being tested, to avoid mis­
reading the ohmmeter test value.
OPEN CIRCU ITS
• See Figure 1 0
This test al ready assumes the existence of an open i n the circuit and it is
used to help locate the open portion.
1. Isolate the circuit from power and ground.
2. Connect the self-powered test l ight or ohmmeter ground c l ip to the
ground side of the circuit and probe sections of the circuit sequentially.
3. If the l ight is out or there is infinite resistance, the open is between the
probe and the circuit ground.
4. If the light is on or the meter shows continuity, the open is between the
probe and the end of the circuit toward the power source.
TCCA6P10
Fig. 10 The infinite reading on this mullimeter (1 . ) indicates that
the circuit is open
SHORT CIRCUITS
,..Never use a self-powered test light to perform checks for opens or
shorts when power is applied to the circuit under test. The test light can
be damaged by outside power.
1 . Isolate the circuit fmm power and ground.
2. Connect the self-powered test l ight or ohmmeter ground clip to a good
ground and probe any easy-to-reach point in the circuit.
BREAKER POINTS IGNITION (MAGN ETO IGNITION)
• See Figures 1 1 , 12 and 13
,..All Suzuki outboard engines use a pointless electronic ignition system
with the exception of the pre-1990 DT2 engines which use a breaker
point type magneto.
This ignition system uses a mechanically switched, collapsing field to induce
spark at the plug. A magnet moving by a coi l produces current in the primary
coil winding. The current in the primary winding creates a magnetic field. When
the points are closed the current goes to ground. As the breaker points open the
primary magnetic field col lapses across the secondary field. This induces
(transforms) a high voltage potential in the secondary coil winding. This high
voltage current travels to the spark plug and jumps the gap.
The breaker point ignition system contains a condenser that works like a
sponge in the circuit. Current that is flowing through the primary circuit tries to
keep going. When the breaker point switch opens the current wi l l arc over the
3. If the light comes on or there is continuity, there is a short somewhere in
the circuit.
4. To isolate the short, probe a test point at either end of the isolated circuit
(the l ight should be on or the meter should indicate continuity).
5. Leave the test l ight probe engaged and sequentia l ly open connectors
or switches, remove parts, etc. unt i l the l ight goes out or continu ity is bro­
ken.
6. When the l ight goes out, the short is between the last two circuit compo­
nents which were opened.
Wire and Connector Repair
Almost anyone can replace damaged wires, as long as the proper tools and
parts are available. Wire and terminals are available to fit almost any need. Even
the specialized weatherproof, molded and hard shel l connectors are now avai l­
able from aftermarket suppl iers.
Be sure the ends of all the wires are fitted with the proper terminal hardware
and connectors. Wrapping a wire around a stud is never a permanent solution
and wi l l only cause trouble later. Replace wires one at a time to avoid confusion.
Always route wires in the same manner of the manufacturer.
When replacing connections, make absolutely certain that the connectors are
certified for marine use. Automotive wire connectors may not meet Un ited States
Coast Guard (USCG) specifications.
,..If connector repair is necessary, only attempt it if you have the proper
tools. Weatherproof and hard shell connectors require special tools to
release the pins inside the connector. Attempting to repair these con­
nectors with conventional hand tools will damage them.
Electrica l System Precautions
• Wear safety g lasses when working on or near the battery.
• Don't wear a watch with a metal band when servicing the battery or starter.
Serious burns can result if the band completes the circuit between the positive
battery terminal and ground.
• Be absolutely sure of the polarity of a booster battery before making
connections. Connect the cables positive-to-positive, and negative-to-nega­
tive. Connect positive cables first, and then make the last connection to
ground on the body of the booster vessel so that arcing cannot ign ite hydro­
gen gas that may have accumulated near the battery. Even momentary connec­
tion of a booster battery with the polarity reversed will damage alternator
d iodes.
• Disconnect both vessel battery cables before attempting to charge a bat­
tery.
• Never ground the alternator or generator output or battery terminal. Be
cautious when using metal tools around a battery to avoid creating a short cir­
cuit between the terminals.
• When instal l ing a battery, make sure that the positive and negative cables
are not reversed.
• Always disconnect the battery (negative cable fi rst) when charging.
• Never smoke or expose an open flame around the battery . Hydrogen gas
accumu lates near the battery and is highly explosive.
widening gap. The condenser is wired in paral le l with the points. The condenser
absorbs some of the current flow as the points open. This reduces arc over and
extends the life of the points.
The breaker point ignition consists of the rotor assembly, contact point
assembly, ignition coil, condenser spark plug, spark plug cap and the engine
stop switch.
As the pole pieces of the magnet pass over the heels of the coi l , a magnetic field
is built up about the coi l , causing a current to flow through the primary winding.
At the proper time, the breaker points are separated by action of a cam
designed into the collar of the crankshaft and the primary circuit is broken.
When the circuit is broken, the flow of primary current stops and causes the
magnetic field about the coil to break down instantly. At this precise moment, an
e lectrical current of extremely high voltage is induced in the fine secondary
windings of the coi l . This high voltage is conducted to the spark plug where it
jumps the gap between the points of the plug to ignite the compressed charge
of air-fuel mixture in the cylinder.
5-8 I G N ITION AND ELECTRI CAL SYSTEMS
CD Key
® Rotor assembly
® Spark plug cap
® Spark plug
® Contact point assembly
® Ignition coil
(J) Condenser
® Engine stop switch
05005G01
Fig. 1 1 Breaker points installation-DT2
r®r® © l .
® : Engine stop switch
@ : Contact point
© : Condenser @ : Ignition coil
® : Spark plug
Fig. 12 Breaker points ignition wiring-DT2
05005G03
®
1
05005G02
Bad
Good
The breaker points must be aligned accurately to provide the best contact
surface. This is the only way to assure maximum contact area between the point
surfaces; accurate setting of the point gap; proper synchronization; and satisfac­
tory point life. If the points are not aligned properly, the result wi l l be premature
wear or pitting. This type of damage may change the cam angle, although the
actual distance wi l l remain the same.
Magnetos instal led on outboard engines wi l l usually operate over extremely
long periods of time without requiring adjustment or repair. However, if ignition
system problems are encountered, and the usual corrective actions such as
replacement of spark plugs does not correct the problem, the magneto output
should be checked to determine if the un it is functioning properly.
System Testing
Perform a spark test i f you suspect the ignition system o f not working properly.
** WARNING
When checking the spark, make sure there is no fuel on either the
engine or the spark p lug. Also keep your hands away from h igh volt­
age electrical components.
1. Remove the spark plug and ground the plug electrode to the engine.
2. Pull the recoil starter and check for spark at the plug.
If there is a good spark at the plug, the ignit ion system should be performing
properly. If there is no spark, precede to the next step in Troubleshooting the
ignition system problem.
Breaker Points
POINT GAP ADJUSTMENT
• See Figures 14 and 1 5
�Before checking the ignition timing, b e sure that the contact point
faces are in good condition. Smoothen and make parallel the two faces
by grinding with an oil stone as much as necessary and then clean the
points by wiping them with cloth dampened with a suitable solvent.
Then apply a small amount of grease to the breaker shaft.
1 . Remove the engine cover to access the engine.
2. Remove the hand rewind starter assembly.
�There are slots in the flywheel rotor in which to insert the feeler
gauge and measure the points gap without removing the flywheel itself.
3. Rotate the stator base unti l it is at the wide open throttle position.
4. Turn the crankshaft using a wrench on the flywheel nut clockwiseuntil
the breaker point rubbing block touches the high point on the cam. At this point
the points will be wide open.
5. Measure the point gap with a feeler gauge. There should be a slight drag on
the feeler gauge if the gap is correct. The point gap should measure: 0.012-0.016
in. (0.3-0.4 mm). If the gap is out of specification, adjustment will be necessary.
Bad
05005G04 05005G08
Fig. 13 Adjusting the breaker points igni­
tion on the DT2 model
Fig. 14 Examples of good and bad point
faces
Fig. 1 5 Measure the point gap with a
feeler gauge
I GN IT ION AND ELECTRICAL SYSTEMS 5-9
TESTING
• See accompanying i l lustrations
1 . Remove the flywheel.
2. Remove the spark plug.
3. With the contact points set right, now check the ignition timing by using
the timing gauge (09931-001 1 2) . Remove the spark plug and install this gauge
in the spark plug hole as i l lustrated. Bring the piston up to TDC and set the
indicating hand of the gauge to read zero mi l l imeters.
4. Obtain a timing digital multi meter, also know as a buzz box: (0990G-27003).
5. Disconnect the breaker point leads from the stator base.
6. Connect the positive (red) digital multi meter lead to the black lead of the
contact breaker and the negative digital mu ltimeter lead to an engine ground.
7. Gently turn the flywheel clockwise (with the digital multi meter switch
turned ON) until the digital multimeter starts buzzing.
05005G07
Step 3
05005G09
Step 4
REMOVAL & INSTALLATION
• See accompanying i l lustrations
1. Remove the engine cover.
2. Remove the fuel tank assembly.
3. Remove the recoil starter assembly.
4. Remove the starter cup and magneto insulator.
5. With a flywheel holder or a commonly available strap wrench, hold the
flywheel and loosen the retain ing nut.
6. With the flywheel rotor remover (09930-3071 3) remove the fly­
wheel . Make sure to keep track of the flywheel key when removing the fly­
whee l .
7. Disconnect the p lug cap and the two lead wires (that are coming from
the stator) and remove the stator.
8. A typical points set with major components identified.
9 . Point faces must be in good condition and aligned correctly.
05005G05
Step 5
05005G06
Step 6
04706G05
Step 8
05004G04
Step 9
5-1 0 I G N IT ION AND ELECTRI CAL SYSTEMS
1 0. Remove the stator base screw which holds the breaker point assembly to
the base.
1 1 . Disconnect the coil and condenser leads at the breaker point. Now
remove the breaker point assembly.
12 . Remove the condenser from the stator base by removing the screw.
To install:
13. Install the replacement breaker point set on the stator base. Make sure
the pivot point on the bottom of the point set engages the hole in the stator
base. Now, insta l l , but don't tighten the retaining screw.
1 4. Install the condenser on the stator base and now tighten the retain ing
screw securely.
15. Reconnect the stator leads. Inspect the connectors and clean off any cor­
rosion before connecting.
1 6. Check the lubrication felt for dryness. If it dry, add a coup le of drops of
30w engine o i l .
1 7. Reconnect the spark plug lead.
�Before installing the flywheel, thoroughly inspect the crankshaft and
flywheel tapers. These surfaces must be absolutely clean and free of
oil, grease and dirt. Use solvent and a l int free cloth to clean the sur­
faces and then blow dry with compressed air.
1 8. Install the flywheel key, starter cup and flywheel and flywheel bolt.
Tighten the bolt to 30-36 ft. lbs. (40-50 Nm.)
1 9. Install the fuel and engine cover.
Condenser
DESCRIPTION & OPERATION
t See Figure 1 6
I n simple terms, a condenser i s composed of two sheets of tin o r aluminum
foil laid one on top of the other, but separated by a sheet of insu lating material
such as waxed paper, etc. The sheets are rolled into a cylinder to conserve
space and then inserted into a metal case for protection and to permit easy
assembling.
The purpose of the condenser is to prevent excessive arcing across the
points and to extend their useful l ife. When the f low of primary current is
brought to a sudden stop by the opening of the points, the magnetic field i n the
primary windings co l lapses instantly, and is not a l lowed to fade away, which
would happen if the points were al lowed to arc.
The condenser stores the electricity that would have arced across the points
and discharges that electricity when the points close again . This discharge is i n
the opposite direction to the original f low, and tends to smooth out the current.
The more quickly the primary field col lapses, the higher the voltage produced in
the secondary windings and del ivered to the spark plugs. In this way, the con­
denser ( in the primary circuit), affects the voltage ( in the secondary circuit) at
the spark plugs.
Modern condensers seldom cause problems, therefore, it is not necessary to
install a new one each time the points are replaced. However, if the points show
evidence of arcing, the condenser may be at fault and should be replaced. A
ALTERNATE LAYERS OF
INSULATION - WAXED PAPER
ALTERNATE LAYERS OF
� "'""FOIL (Tin or Aluminum) FOIL
INSULATION
04706P13
Fig. 16 This sketch i l lustrates how waxed paper, aluminum foil and
insulation are rolled in the manufacture of a typical condenser
faulty condenser may not be detected without the use of special test equipment.
Testing wi l l reveal any defects in the condenser, but will not predict the useful
life left in the unit.
The modest cost of a new condenser justifies its purchase and installation to
e l iminate this item as a source of trouble.
TESTING
1 . Remove the flywheel .
2 . Disconnect the condenser lead from the breaker points assembly.
3. Connect on test lead to the condenser lead. Connect the other test lead to
the stator base.
4. Set the digital multimeter controls according to the manufacturers
instructions. Check the condenser for resistance, leakage and capacity.
5. Compare the results in the previous step with the ignition digital multi­
meter. Replace the condenser if it does not pass any one of the three tests.
REMOVAL & INSTALLATION
1 . Remove the engine cover.
2. Remove the fuel tank assembly.
3. Remove the recoil starter assembly.
4. Remove the starter cup and magneto insulator.
5. With a flywheel holder or a commonly available strap wrench, hold the
flywheel and loosen the retaining nut.
6. With the flywheel rotor remover (09930-30713) remove the flywheel.
Make sure to keep track of the flywheel key when removing the flywheel.
7. Disconnect the plug cap and the two lead wires (that are coming from
the stator) and remove the stator.
8. Remove the stator base screw which holds the breaker point assembly to
the base.
9. Disconnect the coi l and condenser leads at the breaker point. Now
remove the breaker point assembly.
1 0. Remove the condenser from the stator base by removing the screw.
To insta l l :
1 1 . Install the replacement breaker point set on the stator base. Make sure
the pivot point on the bottom of the point set engages the hole in the stator
base. Now, instal l , but don't tighten the retaining screw.
12 . Install the condenser on the stator base and now tighten the retain ing
screw securely.
1 3. Reconnect the stator leads. Inspect the connectors and clean off any cor­
rosion before connecting.
14. Check the l ubrication felt for dryness. If it dry, add a couple of drops of
30w engine o i l .
1 5. Reconnect the spark plug lead.
�Before installing the flywheel, thoroughly inspect the crankshaft and
flywheel tapers. These surfaces must be absolutely clean and free of
oil, grease and dirt. Use solvent and a lint free cloth to clean the sur­
faces and then blow dry with compressed air.
1 6. Install the flywheel key, starter cup and flywheel and flywheel bolt.
Tighten the bolt to 30-36 ft. lbs. (40-50 Nm.)
1 7. Install the fuel and engine cover.
Ignition Coi l
DESCR IPTION & OPERATION
The coil is the heart of the ignition system. Essentially, it is nothing more
than a transformer which takes the relatively low voltage (1 2 volts) available
from the primary coi l and increases it to a point where it wi l l fire the spark plug
as much as 20,000 volts.
Once the voltage is discharged from the ign ition coi l the secondary circuit
begins and on ly stretches from the ign it ion coi l to the spark p lugs via
extremely large h igh tension leads. At the spark p lug end, the voltage arcs in
the form of a spark, across from the center e lectrode to the outer e lectrode,
and then to ground via the spark p lug threads. This completes the ign ition
circuit.
I G N IT IO N AND ELECTR I CAL SYSTEMS 5-1 1
TESTING
1 . Remove the flywheel.
2. For coil primary resistance:
a. Disconnect the black primary ignition coil lead at the connector.
b. Disconnect the secondary coi l lead (spark plug wire) at the spark plug.
c. Make sure the ohmmeter is on the low-ohm scale. Connect the meter
between the primary coi l lead and an engine ground.
d. Check the resistance reading in the "Ignition Coil Resistance" chart.
3. For coil secondary resistance:
a. Make sure the ohmmeter is on the high-ohms scale.
b. Connect the meter between the secondary coil lead and an engine
ground.
c. Check the resistance read ing i n the "Ignition Coil Resistance" chart.
4. Replace the ignition coil if the either the primary or secondary resistance
does not meet specifications.
REMOVAL & INSTALLATION
1. Remove the engine cover.
2. Remove the fuel tank assembly.
3. Remove the recoil starter assembly.
4. Remove the starter cup and magneto insulator.
5. With a flywheel holder or a commonly available strap wrench, hold the
flywheel and loosen the retaining nut.
6. With the flywheel rotor remover (09930-30713) remove the
flywheel . Make sure to keep track of the flywheel key when removing the fly­
wheel.
7. Disconnect the plug cap and the two lead wires (that are coming from
the stator) and remove the stator.
CAPACITOR DISCHARGE IGNITION (COl) SYSTEM
Description and Operation
SINGLE-CYLINDER IGNITION
• See Figure 1 7
I n its simplest form, a CDI ignition i s composed of the following e lements:
• Magneto
• Pulser coi l
• Charge, or source coi l
• Igniter (COl) box
• Ignition coil
• Spark plug
Other components such as main switches, stop switches, or computer sys­
tems may be included, though, these items are not necessary for basic CD I
operation.
To understand basic COl operation, it is important to understand the basic
CD
1 . Blue/Red 3. Plug cap
2. Tester 4. Core
05005G10
Fig. 17 DT2 I DT2.2 COl igniter unit
8. Remove the stator base screw which holds the breaker point assembly to
the base.
9. Disconnect the coi l and condenser leads at the breaker point. Now
remove the breaker point assembly.
1 0. Remove the condenser from the stator base by removing the screw.
To install:
1 1 . I nstall the replacement breaker point set on the stator base. Make sure
the pivot point on the bottom of the point set engages the hole in the stator
base. Now, insta l l , but don't tighten the retaining screw.
12 . Install the condenser on the stator base and now tighten the retain ing
screw securely.
13 . Reconnect the stator leads. Inspect the connectors and clean off any cor­
rosion before connecting.
14. Check the lubrication felt for dryness. If it dry, add a couple of drops of
30w engine o i l .
15 . Reconnect the spark plug lead.
_.Before installing the flywheel, thoroughly inspect the crankshaft and
flywheel tapers. These surfaces must be absolutely clean and free of
oil, grease and d i rt. Use solvent and a l int free cloth to clean the sur­
faces and then blow dry with compressed air.
1 6. Install the flywheel key, starter cup and flywheel and flywheel bolt.
Tighten the bolt to 30-36 ft. lbs. (40-50 Nm.)
1 7. Install the fuel and engine cover.
1 8. Remove the spark p lug caps
1 9. With an ohmmeter, measure the resistance between the spark plug
wires. Resistance should measure 6.4K-9.6K ohms.
20. Measure the resistance between the primary terminal and the coil
mounting lug (!or ground).
21 . Resistance should measure 0.46-0.66 ohms.
theory of induction. Induction theory states that if we move a magnet (magnetic
field) past a coil of wire( or the coi l by the magnet), AC current will be generated
in the coi l .
The amount of current produced depends on several factors:
• How last the magnet moves past the coi l
• The size of the magnet( strength)
• How close the magnet is to the coi l
• Number of turns of wire and the size of the windings
When the flywheel rotates, the electrical power generated at the exciter coi l is
rectified by the diode and charged into the ignition condenser. The thyristor is
off at this time.
When the magnet on the crankshaft passes the pulser coil, the electric pulser
coi l signal is emitted by the magnetic force. This signal passes the gate circuit,
turns on the thyristor, and discharges the e lectric charge from the condenser.
When the discharged current flows through the ignition coil primary circuit,
high voltage is generated in the secondary circuit and the spark plug sparks.
The spark advance is handled by e lectronic advance spark system, which
advances the ignition timing when the gate circuit turns on the thyristor accord­
ing to the engine speed to obtain high speed power.
The current produced in the charge coil goes to the CDI box. On the way in, it
is converted to DC current by a diode. This DC current is stored in the capacitor
located inside the box. As the charge coil produces current, the capacitor stores it.
At a specific time in the magneto's revolution, the magnets go past the pulser
coil . The pulser coi l is smaller than the charge coi l so it has less current output.
The current from the pulser also goes into the COl box. This current signals the
CDI box when to lire the capacitor (the pulser may be called a trigger coil for
obvious reasons). The current from the capacitor flows out to the ignition coil
and spark plug. The pulser acts much l i ke the points in older ignitions systems.
When the pulser signal reaches the COl box, a l l the e lectricity stored in the
capacitor is released at once. This current flows through the ignition coi l 's pri­
mary windings.
The ignition coi l is a step-up transformer. lt turns the relatively low voltage
entering the primary windings into high voltage at the secondary windings. This
occurs due to a phenomena known as induction.
The high voltage generated i n the secondary windings leaves the ignition coil
and goes to the spark plug. The spark in turn ign ites the air-fuel charge in the
combustion chamber.
5-1 2 IGN ITION AN D ELECTRICAL SYSTEMS
Once the complete cycle has occurred, the spinning magneto immediately
starts the process over again.
Main switches, engine stop switches, and the like are usually connected
on the wire in between the CDI box and the ignition coil. When the main
switch or stop switch is turned to the OFF position, the switch is closed. This
closed switch short-circuits the charge coil current to ground rather than
sending it through the CDI box. With no charge coil current through the CDI
box, there is no spark and the engine stops or, i f the engine is not running,
no spark is produced.
SUZUKI PEI IGNITION
The Suzuki PEI (Pointless Electronic Ignition) is a magneto CDI type
system.
DT4 and DT5Y
• See Figure 1 8
The DT4 and DT5Y models have an ignition which uses 1 ignition coil, a
single primary coil, one pulser coil, an optional lighting coil. The CDI unit
itself electronically advances the ignition timing when firing the spark plugs.
The secondary ignition coils and CDI unit are separate components.
DT6
The DT6 models use a single condenser charge coil, lighting coil and
single pulser coil which in turn supply current to a combined CDI unit and
single secondary coil with two spark plug wires. The stator base moves
according to the throttle opening to obtain the proper ignition timing. For this
reason , metal (brass) is cast in the spigot joint of the oil seal housing and
stator base.
Parts of the stator base include a coil which charges a capacitor of the
CDI unit, a pulser coil which sends a signal to the CDI unit at ignition timing,
and a lighting coil which generates a lighting output of 1 2V and SOW.
DT9.9 and DT15
The DT9.9 and DT1 5 are equipped with a single ignition coil for two
cylinders in their ignition systems. On these models the CDI unit
electronically advances the ignition timing when the spark plugs are firing.
The CDI unit and secondary ignition coils are separate components.
DT25 and DT30
The DT25 and DT30 use the I. C. ignition system. A built in I. C. control unit
monitors the degree of throttle opening and the engine rpm, then determines
ideal spark timing. This not only improves acceleration, but by maintaining
optimum carburetion and ignition synchronization, the engines run smoother
and respond quicker to changes in throttle operation.
The ignition system is comprised of three pulser coils, a battery charge
coil, condenser charging coil and a gear counter coil. These coils are
connected to the CDI unit and along with the throttle position sensor and
engine temperature sensor determines the ignition sequence.
• In the 91 and later models, a single sensor called a cooling water &
engine temperature sensor was used. This sensor served two purposes:
one is to detect the engine temperature with which to select either of the
two different starting ignition timing duration's at 5°BTDC (3 seconds for
a warm engine and 15 seconds for a cold engine) so as to improve engine
Emergency switch
(Option )
Lighting coi l
(Option )
R
1
Bl Stop switch
1 2V 30W
w B (Di rectly powered
by l ighting coi l )
B ,-l!l,.----,-'"-! E; Et
Battery
(Option)
1 2V
Fig. 18 The DT4 and DT5Y models have an ignition which uses 1 ignition coil, a single primary coil, one pulser coil, an optional lighting coil
I G N ITIO N AND ELECTRI CAL SYSTEMS 5-1 3
1 . Stator assy
2. Coil, lighting
3. Coi l, ignition primar
1. CDI unit
2. Cap, spark plug
3. Spark plug
4. Switch assy, stop
05005G13
Fig. 19 The DT9.9 and DT15 are equipped with a single ignition coil for two cylinders in their ignition systems
starting. The sensor's other function is to determine if the cooling water
level reaches the powerhead. From the 92-on models, this sensor has
been eliminated. To replace this sensor, two separate sensors, the
engine starting ignition timing sensor and overheat sensor, have been
installed.
DT35 and DT40
• See Figure 20
The OT35 and OT 40 models use a 2-cyl inder, simu ltaneous ignition COl sys­
tem. The system is made up of the magneto, COl unit. A condenser charge coi l ,
CD CDI unit holder
terminal fix bolt
® Magneto lead wire
@ CDI unit
@ CDI unit band
CD
@ Oil warning lamp
assy
® CDI unit holder
(]) High tension cord
05005G58
Fig. 20 The DT35 and DT40 models use a 2-cylinder, simultaneous
ignition COl system
timing coi l and a l ighting coil are mounted on the stator. The ign ition coi l is
contained in the COl un it. The ignition timing characteristics are the result of the
advance angle of the s l id ing stator. An e lectronic advance system employing the
I . C. ign ition has been adopted in the advance angl e of the magneto to assure
highly precise timing characteristics. The COl unit includes the over-rev limiter
and oi l warning circuit.
DT55, DT65, DT75 and DT85
The ignition systems on these models are equipped with the Oigitai iC Igni­
tion system. This ignition system automatically alters the ign ition timing elec­
tronically based on throttle valve position and engine speed. This system is
comprised of 3 pulser coils, battery charging coil, condenser charge coil. There
is also a gear counter coi l to control ignition timing at all rpm and an ignition
timing sensor that provides an automatic 5°BTDC advance for engine starting
(1 5 seconds when cold, 3 seconds when warm) and a throttle valve position
sensor.
DT90, DT100
These models are equipped with the Micro-Link ignition system. Th is system
incorporates a microcomputer to improve engine performance by maximizing
combustion control . This system uses information from sensors and switches
located a various positions on the engine to monitor throttle valve opening,
engine rpm, shift lever position and operator selected idle speed. The micro­
computer constantly evaluates this information and instantly provides the opti­
mal spark timing for the current engine running conditions.
The Micro-Link system also mon itors the caution system sensors for oil
level, o i l f low, water flow and engine over-rev. If any of these sensors indicate a
malfunction, the microcomputer wi l l activate a warn ing buzzer and/or monitor
gauge indicator lamp and then operate the engine under reduced power.
The magneto consists of the following components. Each coil functions as
fol lows:
• The condenser charging coi l charges the condenser for the spark primary
power source in the CO l unit.
• The pulser coils, being positioned at intervals of 70°and 1 1 0°, input a
reference pulse, for the corresponding cylinder, causing the condenser to be
discharged into the microcomputer inside the COl unit.
• The counter coil causes a reference pulse to decide the ignition timing to
be input into the microcomputer.
• The battery charging coi ls, No.1 and No.2, perform power generating nec­
essary to charge the battery.
In addition, the microcomputer gets it's 1 2 volt operating power from the bat­
tery.
Carbu reted DT1 1 5 and DT140
The ignition systems on these models is the Suzuki Oig itai iC Ignition sys­
tem. This ignition system automatically alters the ign ition timing e lectronically
5-1 4 IG N IT ION AND ELECTRI CAL SYSTEMS
based o n throttle valve position and engine speed. This system i s comprised of
4-pulser coils, battery charging coi l , condenser charge coi l . There is also a gear
counter coil to control ignition timing at all rpm, an ignition timing sensor that
provides an automatic JCBTDC advance for engine starting. lt wi l l remain at
JCBTDC for 1 2-15 seconds, at which time the ignition timing wi l l return to the
idle speed circuit and whatever position the "Idle Speed Adjustment Switch" is
set at.
** CAUTION
Due to the higher idle speed created by this automatic starting
device, DO NOT shift the engine until the engine rpm has returned
to idle speed.
Fuel Injected DT1 1 5 and DT140
The fuel injected models use the Suzuki Micro-Link ignition system. This
system uses sensors to monitor specific engine operating conditions and sup­
p l ies signals to an Engine Control Un it (ECU) for ignition and warning opera­
tion. The primary ignition sensors are the throttle valve sensor (TVS) for
determin ing throttle valve opening angle and the engine speed sensor (gear
count coi l) that determines engine speed.
Based on these signals, the ECU determines the ignition timing necessary for
the engine's current requirements and del ivers voltage to the ignition coils thus
producing ignition spark.
Two compensation sensors, cylinder wall temperature and air temperature,
supply signals used by the ECU to compensate ignition timing based on tem­
perature related conditions. A pulser coil supplies crankshaft angle signals
which the ECU uses when determin ing a trigger signal for the ignition.
DURING START
At engine start, the ignition timing is set at 5°BTDC Sequential operation
whi le cranking (below 440 rpm).
AFTER START
After engine start, keeping the throttle lever at the idle position wi l l allow the
ECU "Warm-up mode" map to control the ignition timing in relation to cylinder
wall temperature. In this mode, ignition timing stays advanced above normal
until the cylinder wall temperature reaches 1 1 3° (45°C) the timer, which was set
according to cylinder wall temperature, expires.
NORMAL OPERATING MODE
When the "Warm-up mode" ends, the ECU changes to the "Normal operating
mode". This mode is based on the map control in relation to engine speed,
throttle valve opening angle, cylinder wall temperature and air temperature.
FAIL SAFE MODE
Each sensor has an assigned default value programmed into the ECU. In the
event of a sensor failure, the monitor gauge flash code will indicate the failure
and the engine will continue to operate, but with much reduced performance,
ignition timing during a sensor failure wi l l automatically default to the following
method of control :
• Throttle valve sensor failure: Ignition timing w i l l be automatically set
according to the engine speed.
• Cylinder wall temperature sensor failure: Ign ition timing will be automati­
cally set as if the sensor senses 86°F (30°C).
• Air temperature sensor failure: Ignition timing wi l l be automatically set as
if the sensor senses 68°F (20°C).
• If either gear counter coil or pulser coil fails, the ECU will not provide and
injection signal without a reference from these coils. Under this condition, the
engine can be cranked, but it will not start due to no fuel injection pressure.
DT150, DT175, DT200 and DT225
These models are equipped with the Micro-Link ignition system. This system
incorporates a microcomputer to improve engine performance by maximizing
combustion control . This system uses information from sensors and switches
located a various positions on the engine to monitor throttle valve opening,
engine rpm, shift lever position and operator selected idle speed. The micro­
computer constantly evaluates this information and instantly provides the opti­
mal spark timing for the current engine running conditions.
The Micro-Link system also monitors the caution system sensors for o i l
level, o i l flow, water flow and eng ine over-rev. If any of these sensors indicate a
malfunction, the microcomputer wi l l activate a warning buzzer and/or monitor
gauge indicator lamp and then operate the engine under reduced power.
The magneto consists of the following components. Each coi l functions as
fol lows:
• The condenser charging coil charges the condenser for the spark primary
power source in the CDI unit.
• The pulser coi ls, positioned 1 20°apart. When the pulser coi l voltage
enters the delay circuit, the CDI unit begins to count the voltage signals from
the gear counter coil and wi l l release the signal from the delay circuit when the
flywheel indicates the proper piston position accord ing to the id le speed adjust­
ment switch setting.
• The counter coil causes a reference pulse to decide the ignit ion timing to
be input into the microcomputer.
• The battery charging coi ls, No.1 and No.2, perform power generating nec­
essary to charge the battery.
In addition, the microcomputer gets it's 1 2 volt operating power from the bat­
tery.
System Testing
PROCEDURE
Perform a visual inspection of the wir ing connections and grounds. Deter­
mine if the problem affects all or just certain cylinders and perform a spark
check using a spark gap tool ("spark tester") and then check ignition timing with
a timing light.
If the problem affects al l the cylinders, check the capacitor charge coi l out­
put, engine stop switch, CO l unit output and pulse coi l output.
If the problem affects individual cylinders only, check the components whose
failure would affect that particular cylinder such as the pulse coi l and ignition
coil performance.
If the problem is timing related, check the mechanical part of the system,
such as the pulse coi l or CDI box itself and then check the e lectron ic timing
advance components of the system, the throttle position sensor (if applicable),
the pulse coil(s) and the CDI module.
CDI troubleshooting can be performed with a peak reading voltmeter. This
wi l l check the CDI voltage to the ignition coils.
• If CDI voltage is good, isolate individual ignition coils or spark plugs and
check output voltage.
• If the COl voltage is bad, check all COl input voltages.
• Check the pulse coi l output to the CDI unit.
• Check the capacitor charge coi l output to the CDI unit.
• Check the pulser coil output to the COl unit.
If al l the input voltages are normal, the problem has now been isolated to the
CDI unit itself. If any input voltage is abnormal, check the appropriate coil for
winding resistance and insulation breakdown. If the problem is timing related,
check all the timing inputs to the CDI unit, such as the throttle position sensor.
If the timing inputs are good, the problem is isolated to the CDI un it.
Pulsar/Charging/Gear Counter Coils
DESCRIPTION & OPERATION
The second circuit used in CDI systems is the pu lsar circuit. The pulsar cir­
cuit has its own flywheel magnet, a pulsar coi l , a diode, and a thyristor. A
thyristor is a sol id state e lectron ic switching device which permits voltage to
flow only after it is triggered by another voltage source.
At the point in time when the ignition timing marks al ign, an alternating cur­
rent is induced in the pulsar coi l , in the same manner as previously described
for the charge coi l . This current is then passed to a second diode located in the
CDI unit where it becomes DC current and flows on to the thyristor. This voltage
triggers the thyristor to permit the voltage stored in the capacitor to be dis­
charged. The capacitor voltage passes through the thyristor and on to the pri­
mary windings of the ign ition coi l .
In this manner, a spark a t the p l ug may be accurately timed by the timing
marks on the flywheel relative to the magnets in the flywheel and to provide as
many as 1 00 sparks per second for a powerhead operating at 6000 rpm.
A system of battery charging is standard on all electric start model engines.
IGN ITION AN D ELECTRICAL SYSTEMS 5-1 5
The battery charging system is made up of charge coil(s) or an A/C
lighting coil on some models. The permanent magnets located on the
flywheel edge, a rectifier (voltage regulator/rectifier on some models), a
battery and the associated wiring and fuses.
Rotation of the flywheel magnets past the charge coil or A!C lighting coils
will create alternating current. This current is then sent to the rectifier or
voltage regulator/rectifier, where it is then converted to direct current and
then supplied to the battery or electrical accessories through a fuse.
The capacitor charge coil supplies electricity to the CDI unit. As the
flywheel rotates past the capacitor charge coil, alternating current is
produced. This voltage is supplied to the CDI unit and passes through a
diode where it is rectified to direct current. This D/C voltage is then stored in
the capacitor.
The gear counter coil (if equipped) is the same construction and operation
as the pulser coil, but it uses each ring gear tooth as a pulsar bar to
generate a signal voltage to send to the CDI unit.
TESTING
DT4, DTSV, DT6 and DT8
t See accompanying illustrations
1 . Remove the engine cover.
2. Disconnect the wires at the connectors between the stator plate and
the CDI unit.
3. To test the pulser coil, connect the digital multi-meter between the
white/red and black wires. Resistance should read 1 5.0-45.0 ohms for the
DT 4 and DT5Y and 70-100 ohms for the DT6 and DT8.
1 . Condenser charging coil
2. Pulser coil #1
3. Battery charging coil
4. Pulser coil #2
Step 3
Step 4
4. To test the lighting coil, connect the digital multimeter between the
yellow and red wires. Resistance should read between 0. 1 -0.2 ohms for the
DT4 and DT5Y and 0.37-0.45 ohms for the DT6 and DT8.
5. If the resistance reading is not within specification, replace the faulty
coil.
DT9.9 and DT15
t See accompanying illustrations
1 . The two pulser coils are located at 1 80°angles to each other and the
condenser and battery charge coils are also located opposite of each other
under the flywheel.
2. Remove the engine cover.
3. On models equipped with electric starters, disconnect the negative
battery cable.
4. Disconnect the connector and black ground wire.
5. On the No. 1 pulser coil, connect the digital multi meter between the
black/red wire terminal in the connector and the black ground wire. And the
No.2 coil between the white/green wire terminal in the connector and the
black ground wire. Resistance should be 260-380 ohms.
6. On the condenser charge coil, measure the resistance between the
black/red and green wires. Resistance should be between 1 70-250 ohms.
7. If the resistance reading is not within specification, replace the faulty
coil.
8 . On the battery charge coil, measure the resistance between the
yellow/red and yellow wires, red and yellow wires (DT1 5MC) or the red and
yellow wires (DT15CE). Resistance should measure between 0.2 and 0.5
ohms.
9. If the resistance reading is not within specification, replace the faulty
coil.
White/Green
• Black/Red
Step 5
CD

1 . Green 2 . Black red ®
Step 6
1 . Red/yel low 2. Red 3. Yel l ow
Step 8
5-1 6 I G N IT ION AND ELECTRICAL SYSTEMS
DT25 and DT30
• See accompanying illustrations
1 . The three pulser coils are located at 1 20°angles to each other underneath
the flywheel along with the condenser charge coi l , battery charge coi l and the
gear counting coi l .
2. Remove the engine cover.
3. On models equipped with electric starters, disconnect the negative battery
cable.
4. Disconnect the 6-pin connector and set the dig ital multi meter on the
ohms scale.
5. For the No.1 pulser coi l , connect the dig ital multimeter between the
Step 1
Red/Black ( No. 1 )
Step 5
Wh ite/Black ( No. 2)
Red/Wh ite ( No. 3)
Green
Green
Idle speed
adjustment
switch
1 . Throttle valve sensor
2. Gear counter coil
3. Pulser coil #2
4. Battery charging coil
05005G16
B lack/Red
05005G39
Step 6
red/black wire terminal and ground. For the No.2 pulser coi l , connect the digital
multi meter between the white/black wire terminal and ground and for the No.3
pulser coil, connect the digital multi meter between the red/white wire terminal
and ground. Resistance should measure 1 70-250 ohms on the multimeter.
6. For the condenser charge coi l , measure the resistance between the
black/green and green wires. Resistance should measure between 1 70-250 ohms.
7. For the battery charge coil, measure the resistance between the
yel low/red and yellow wires and red and yellow wires {DT30MC) and the red
and yel l ow wires {DT30CR). Resistance should measure between 0.2-0.6 ohms.
8. For the gear counter coil, measure the resistance between the orange/green
and black wires. Resistance should measure between 1 60-240 ohms.
9. Replace the faulty coil if the resistance read ing is not within specification.
5. Pulser coil #3
6. Condensor charging coil
7. Pulser coil #1
05005G57
Red
Yel low
Yel low/Red
05005G40
Step 7
Orange/Green
@ I �-..L....-...,....z::s-.L.�----0
05005G41
Step 8
I G N IT ION AN D ELECTR I CAL SYSTEMS 5-1 7
DT35 and DT40
1 . The pulser (timing coi l) and l ighting (battery) charge coi l and condenser
charge coil are al l located underneath the flywheel on the stator base.
2. Remove the engine cover.
3. On models equipped with e lectric starters, d isconnect the negative battery
cable.
4. For the pulser coi l , measure the resistance between the white/red wire
lead and the black ground. Resistance should read 1 75-210 ohms.
5. For the battery charge coil, measure the resistance between the red and
yel l ow wires. Resistance shou ld measure between 0.20-21 0 ohms.
6. For the condenser charge coi l , measure the resistance between the green
and black wires. Resistance should measure between 230-280 ohms.
7. Replace the faulty coil if the resistance reading is not within specification.
DT55 and DT65
• See accompanying i l lustrations
1. The three pulser coi ls , condenser charge coi l and battery charge coi l are
all located underneath the flywheel
2. Remove the engine cover.
3. On models equipped with electric starters, disconnect the negative bat­
tery cable.
4. Disconnect each coil at the bul let connector.
5. For the pulser coi ls , connect the d igital multi meter to the pulser leads as
fol lows:
• No.1 : Connect the tester between the red/black wire and the black
ground wire
• No.2: Connect the tester between the white/black wire and black
ground wire
05005P24
Step 1
-- � 8
No. 1 . . . R/8
Stay No. 2 . . . W/8
No. 3 . . . R/W
05005G18
Step 5
• No.3: Connect the tester between the red/white wire and the black
ground wire
6. Resistance should read between 1 70-250 ohms.
7. Connect the tester between each pulser coil colored wire lead and the
metal mounting stay. There should be no continu ity on the meter.
8. On the condenser charge coi l , measure the resistance between the
green and b lack/red wires. The resistance should read between 1 90-270
ohms.
9. On the battery charge coi l , measure the resistance between the red and
yellow wires. Resistance should read 0.2-0.6 ohms.
10. On the gear counter coil, measure the resistance between the
orange/green and black/green wires. Resistance should measure between
1 70-250 ohms.
1 1 . If the resistance read ing is not within specification , replace the faulty
coil
05005G44
Step 8
05005G45
Step 9
1 . Orange/Green
2. Black/Green
05005G46
Step 1 0
5-1 8 I G N IT ION AND ELECTRICAL SYSTEMS
DT75 and DT85
• See accompanying i l lustrations
1 . The three pulser coi ls are located at 1 20°angles to each other underneath the flywheel.
2. Remove the engine cover.
3. Disconnect the negative battery cable.
4. Disconnect the pulser coil wires which are located i nside the electrical
junction box.
5. Connect the d ig ital multi meter to the pulser coil leads as fol lows:
• No.1 : Connect the tester red lead between the red/black wire and the
black ground wire
• No.2: Connect the tester red between the white/black wire and black
ground wire
RiB
1 1
W/B
R/W
Step 5

Step 7
Step 8
Step 9
Tester
05005G19
1 . Orange/Green
2. Black/Green
05005G47
Tester
05005G48
Tester
05005G49
• No.3: Connect the tester red between the red/white wire and the black
ground wire
6. Resistance for the pulser coils should read between 1 60-240 ohms.
7. On the gear counting coi l , measure the resistance between the
orange/green and black/green wires. The resistance should read between
1 60-240 ohms.
8. On the condenser charging coi l , measure the resistance between the
green and black (red tube) wires. Resistance should read 1 70-250 ohms.
9. On the battery chargi ng coi l , measure the resistance between the red
and yellow wires. Resistance should read 0.2-0.6 ohms.
1 0. If the resistance reading is not within specification, replace the faulty
coi l .
DT9D and DT1 DD
• See accompanying i l lustrations
1. The four pulser coils, battery charging coi l , condenser charging coil and
gear counting coil are al l located underneath the flywheel , mounted on the stator
base.
2. Remove the engine cover.
3. Disconnect the negative battery cable.
4. Disconnect the pulser coil wires which are located inside the electrical
junction box.
5. Connect the d igital multi meter to the pulser coil leads as fol lows:
• No. 1 : Connect the tester red lead between the red/green wire and
ground
• No.2: Connect the tester red lead between the wh ite/black wire and
ground
Step 5
Black/Red
Red/White G reen
Red/Green
'
BlaJ�e�l liowj Red
� �: , , ' ' , , /' /
' · · /�� t:t·
CD Condenser charging coil
® Pulser coil No. 1
@ Pulser coil No. 2
@ Pulser coil No. 3 @ Pulser coil No. 4
® Battery charging coil No. 1
(J) Battery charging coil No. 2
@ Counting coil
05005G21
Step 7
� � ·
1 . Orange/Green
2. Black/Green
m Step 8
Step 9
I GN IT ION AND ELECTRI CAL SYSTEMS 5-1 9
Black/Red
Red/White Green
Red/Green
CD Condenser charging coil ® Pulser coil No. 1
@ Pulser coil No. 2 @ Pulser coil No. 3 ® Pulser coil No. 4 @ Battery charging coil No. 1 (j) Battery charging coil No. 2
@ Counting coil
05005850
05005852
05005851
• No.3: Connect the tester red lead between the red/white wire and
ground
• No.4: Connect the tester red lead between the white/green wire and
ground
6. Resistance should read between 1 60-230 ohms.
7. On the condenser charging coi l , measure the resistance between the
black/red and green wires. Resistance should read 1 80-270 ohms.
8. On the gear counting coi l , measure the resistance between the
orange/green and black/green wires. Resistance should measure between
1 60-230 ohms.
9. On the battery charging coi l , measure the resistance on both coi ls
between the red and yel low wires. Resistance should measure between 0.4-0.06
ohms.
1 0. I f the resistance readi ng is not within specification, replace the faulty
coi l .
DT1 1 5 and DT140
• See accompanying i l lustrations
1 . The four pulser coi ls, battery charging coi l , condenser charging coil and
gear counting coil are located, underneath the flywheel, mounted on the stator
base,.
2. Remove the engine cover.
3. Disconnect the negative battery cable.
4. Disconnect the pulser coil wires which are located inside the e lectrical
junction box.
5. Connect the d igital multi meter to the pulser coi l leads as fol l ows:
• No.1 : Connect the tester red lead between the red/green wire and the
black ground wire
• No.2: Connect the tester red lead between the wh ite/black wire and
black ground wire
• No.3: Connect the tester red lead between the red/white wire and the
black ground wire
• No.4: Connect the tester red lead between the white/green wire and the
black ground wire. Resistance should read between 1 70-250 ohms.
1 . Condenser charging coi l #2 5. Battery charging coil #2
2. Battery charging coil #1 6. Condenser charging coil #1
3. Pulser coil #3 7. Pulser coil #4
4. Pulser coil #2 8. Pulser coil #1
05005820
Step 5
5-20 IGN ITION AND ELECTRI CAL SYSTEMS
Orange/Green
m Step S
6. On the battery charging coils, measure the resistance on No. 1
between the yellow/red and yellow/red wires and on No.2 between the red
and yellow wires. Resistance should measure between 0 . 1-0.3 ohms.
7. On the condenser charging coils, measure the resistance on No.1
between the black/red and green wires and on No.2 between black/red and
brown wires. Resistance should measure between 1 70-250 ohms.
8. On the gear counting coil, measure the resistance between the
orange/green and black wires. The resistance should measure between
1 70-250 ohms.
. 9. If the resistance reading is not within specification, replace the faulty
cor I .
DT150, DT175, DT200 and DT225
• See accompanying illustrations
1 . The three pulser coils, condenser coil and battery charging coil are
all mounted on the stator base underneath the flywheel assembly.
2. Remove the engine cover
3. Disconnect the negative battery cable
4. Disconnect the pulser coil wires which are located inside the
electrical junction box.
Step 5
(j) Condenser charging coil
® Pulser coil No. 1
® Pulser coil No. 2
@ Pulser coil No. 3
Pulser coi l
---+--!-.- 8 mm (0.3 1 5 i n )
Step 1 0
5 . Connect the digital multi-meter to the pulser coil leads as follows:
o No.1 : Connect the tester red lead between the red/black wire and the
black to ground
o No.2: Connect the tester red lead between the white/black wire and the
black to ground
o No.3: Connect the tester red lead between the red/white wire and the
black to ground. Resistance should read between 1 60-240 ohms.
6. On the gear counter coil, measure the resistance between the coil
wires. Resistance should read 1 60-240 ohms (220-340 ohms for the "W"
models '98 1 50 , 175, 200).
7. On the condenser charge coil, measure the resistance between the
charge coil wires for the low speed (325-575 ohms) and high speed (50-1 00
ohms).
8. On the battery charge coil, measure the resistance between each of
the coil wires. Resistance should read between 0 . 1-0.4 ohms.
.
9 . If the resistance reading is not within specification, replace the faulty
COil.
1 0. If the coil is .:emoved or disturbed, it must be reassembled using the
pulser corl locatrng Jig (09931-887 1 1 ) to be sure that the coil-to-flywheel
pulser bar arr gap of 0.32 in. (8 mm) is maintained.
REMOVAL & INSTALLATION
DT4, DT5Y, DTG and DT8
• See accompanying illustrations">
1 . Remove the engine cover from the engine.
2 . Remove the built-in fuel tank (if equipped).
3. After removing the bolts, remove the recoil starter assembly.
4. Remove the starter cup. If the screws are hard to loosen use an
impact drive to remove them.
'
5. Use the flywheel holder (09930-40 1 1 3) to remove the flywheel nut.
Step 5
I G N IT ION AND ELECTRICAL SYSTEMS 5-21
05005G29
Step 6
05005G30
Step 1 0
6 . Use the flywheel holder and flywheel rotor remover (09930-30713) to
remove the flywheel.
7. Make sure to remove the flywheel key from the crankshaft.
8 . Disconnect the stator wire leads.
9. Remove the screws and remove the ignition coi l and pulser coi l .
To install:
1 0. Install the pulser coi l and ignition coi l onto the engine.
1 1 . Reconnect a l l the wires in their proper order.
12 . Install the flywheel key into the keyway on the crankshaft. Make sure the
key is seated correctly into the keyway.
13 . Install the flywheel onto the crankshaft.
14 . Using the flywheel holder, i nstal l the flywheel nut and tighten to 32.5 ft.
lbs. (45 Nm).
1 5. Install the starter cup onfo the flywheel and tighten the screws.
1 6. Install the recoi l starter.
1 7. Install the fuel tank.
1 8. Install the engine cover.
DT9.9 and DT15
t See accompanying i l lustrations
1. Remove the engine cover from the engine.
2. Remove the two nuts and disconnect the battery(s) cables and the neu­
tral switch wire (if equipped).
3. Remove the recoil starter assembly (if equipped).
4. Disconnect the wire lead extending from the stator assembly to the rectifier assembly.
5. Remove the two bolts and remove the starter motor from the engine.
6. Using the flywheel holder (09930-4931 0), remove the flywheel nut.
7. Using the flywheel holder and the flywheel remover plate
(09930-30713), remove the flywheel .
8. If any d i fficu lty is experienced in removing the flywheel, tap the head
of the bolt with a hammer. This wi l l usually he lp in the removal operat ion.
9. Remove the key from the crankshaft keyway.
05005G31
Step 3
05005G32
Step 6
05005G33
Step 7
05005G34
Step 8
5-22 I G N IT ION AND ELECTRICAL SYSTEMS
1 0. After the flywheel i s removed, remove the stator base retain ing screws
and l ift of the stator assembly.
1 1 . Remove the coi ls from the from the stator base.
To instal l :
12 . Install the co i ls onto the stator plate.
13. Install the stator base on the engine.
�Make sure that the stator's alignment mark is in line with the stop­
per's alignment mark.
14 . Install the key securely into the crankshaft keyway.
15 . Install the flywheel onto the crankshaft.
1 6. Using the flywheel holder, t ighten the flywheel nut to 58-65 ft. lbs.
(80-90 Nm)
1 7. Install the starter motor back onto the engine and securely tighten the
bolts (if equipped).
1 8. Reconnect the starter/battery cables and reconnect the neutral safety
switch lead wire.
1 9. Install the recoil starter assembly (if equipped)
20. Connect the stator wires making sure all connections are free from cor­
rosion and are securely fastened.
21 . Install the engine cover.
DT25 and DT30
• See accompanying i l lustrations
1 . Disconnect the negative battery cable lead to prevent accidental engine
start.
2. Remove the engine cover.
3. D isconnect the wire leads in the e lectrical junction box, lead ing from the
stator assembly.
4. Remove the recoi l starter assembly.
5. Using a screwdriver to hold the flywhee l , remove the starter pul ley bolts
and l ift of the starter pu l ley.
6. Using a flywheel holder (09930-48720), remove the flywheel nut.
7. Using a flywheel holder and a flywheel remover (09930-3941 1 ) , remove
the flywheel from the engine.
8 . Remove the four screws and l ift of the stator assembly and wiring har­
ness.
9. Remove the coils from the stator base.
To install:
1 0. Install the coils onto the stator base and use a small amount of thread
locking agent on the screw threads .
. 1 1 . Install the stator base onto the engine and using a thread locking agent,
lighten the screws securely.
12. Throughly clean the mating surface of the flywheel and crankshaft taper
with cleaning solvent. Install the key onto the crankshaft securely.
1 3. Using the flywheel holder, t ighten the flywheel nut to 94-108 ft. lbs.
(1 30-150 Nm).
1 4. Measure the air gap between the coil and flywheel with a feeler gauge.
C learance should be 0.03 in. (0.75 mm). Adjust the coil as necessary to obtain
the correct air gap c learance.
15 . Connect the stator wire leads to their proper connections.
Step 14
0.75 m m (0.03 in )
05005G35
1 6. Install the starter pu l ley onto the flywheel.
1 7. Install the recoi l starter assembly.
18 . Connect the battery negative battery cable.
1 9. Install the engine cover.
DT35 and DT40
1 . Disconnect the negative battery cable lead to prevent accidental engine
start.
2. Remove the engine cover.
3. Disconnect the wire leads in the e lectrical junction box and COl/control
un it holder, lead ing from the stator assembly.
4. Remove the recoi l starter assembly.
5. Using a flywheel holder (09930-39520), remove the flywheel nut.
6. Using a flywheel holder and a flywheel remover (09930-3941 0), remove
the flywheel and key.
7. Remove the stator screws and l ift off the stator assembly. If necessary,
use a impact driver to loosen the screws.
8. Remove the coi ls from the stator base.
To install:
9. Install the coi l onto the stator base and secure the screws with a small
amount of thread locking compound.
10. Install the stator assembly onto the engine and secure the screws with a
small amount of thread locking compound.
1 1 . Throughly clean the mating surface of the flywheel and crankshaft taper
with cleaning solvent. Install the key onto the crankshaft securely.
12 . Install the flywheel onto thew crankshaft.
13 . Using the flywheel holder, tighten the flywheel nut to 1 44.7-151 .9 ft.
lbs. (200-210 Nm).
1 4. Connect the stator wire leads to their proper connections.
15. Install the starter pul ley onto the flywheel.
1 6. Install the recoil starter assembly.
1 7. Connect the battery negative battery cable.
1 8. Install the engine cover.
DT55, DT65, DT75 and DT85
• See accompanying i l lustrations
1. The magneto assembly inc ludes three pulser coi ls, condensing charge
coi l , battery charg ing coi l .
2. Remove the engine cover.
3. Remove the e lectrical junction box cover and disconnect the stator leads.
4. Remove the flywheel cover.
5. Using a flywheel holder (09930-39520) and flywheel & propeller shaft
housing remover (09930-39410), remove the flywheel nut.
6. Using the special tools, remove the flywheel from the crankshaft.
05005P29
Step 6
Step 1 1
I G N IT ION AND ELECTRICAL SYSTEMS 5-23
05005P35
Pulser coil air gap adjustment
[Suzuki special tool : 0993 1 -894 1 01
[Air gap]: 0. 75 mm (0.03 in)
0. 75 mm (0.03 in)
05005G24
Step 1 6
7 . Make sure to remove the flywheel key before removing the magneto case
to prevent tearing the seaL
8. Remove the magneto case from the engine.
9. Remove the coil(s) from the magneto case
To install:
1 0. Install the coi l (s) in the magneto case and secure the screws with a
small amount of thread locking compound.
1 1 . Inspect the magneto case seal for damage or tears.
1 2. Install the magneto case on the engine and tighten the bolts using
thread locking compound.
1 3. Throughly c lean the mating surface of the flywheel and crankshaft taper
with cleaning solvent Install the key onto the crankshaft securely.
14. Install the flywheel onto the crankshaft
1 5. Using the special tools, tighten the flywheel nut to 1 44.5-152 ft lbs.
(200-210 Nm).
1 6. If the pulser coil i s removed or d isturbed, it must be reassembled using
the pulser coi l locating j ig (09931-8941 0) to be sure that the coi l-to-flywheel
pulser bar air gap of 0.03 in. (0.75 mm) is maintained.
1 7. Connect the stator wire leads to their proper connections.
1 8. Connect the battery negative battery cable.
1 9. Install the engine cover.
DT90, DT100, DT1 1 5 and DT140
• See accompanying i l lustrations
1 . Remove the engine cover.
2. Remove the e lectrical junction box cover and disconnect the stator
leads.
3. Remove the flywheel cover.
4. Using a flywheel ho lder (09930-48720), remove the flywheel
nut
5. Using a flywheel holder, flywheel remover (09930-3941 1 ) and flywheel
bolts (09930-39420), remove the flywheeL
6. Remove the flywheel from the crankshaft
7. Remove the stator assembly and gear counter co i l from the
engine.
8. Remove the coi ls from the stator assembly and wiring harness.
To instal l :
9 . Install the co i ls onto the stator assembly and secure the screws with
thread locking compound.
1 0. Install the stator assembly onto the engine and secure the bolts with
thread locking compound.
1 1 . Throughly clean the mating surface of the flywheel and crankshaft taper
with cleaning solvent Install the key onto the crankshaft securely.
1 2. Install the flywheel onto the crankshaft
13 . Using the flywheel holder, tighten the flywheel nut to 1 81-188 ft. lbs.
(250-260 Nm).
5-24 I G N ITION AND ELECTRI CAL SYSTEMS
(j)
®
� 0.75 mm
1 . Magneto lead wire protector tube 10. Spacer 19 . Clamp
2. Pulser coil no. 2 1 1 . Cushion 20. Ring gear
3. Condenser charging coil 12. Stalor 2 1 . Magneto key
4. Stator 13. Battery charging coil no. 1 22. Washer
5. Battery charging coil no. 2 14. Pulser coil no. 1 23. Flywheel nul
6. Pulser coil no. 3 15. White tape at clamp position 24. Rotor
7. Pulser coil no. 4 16. Clamp 25. Pulser coil
8. Stator bolt 17. Rectifier lead wire (to fuse) 26. Pulser coil locating jig
9. Washer 18 . Counting coil
05005G22
Step 14
1 . Counter coil 6. Condenser charging coil #1 1 1 . Pufser
2. Battery charging coil #1 7. Pulser coil #4 1 2. Pulser coil
3. Pulser coil #3 8. Condenser charging coil #2 13. No air gap
4. Battery charging coil #2 9. Pulser coil #1 14. Pulser coil locating jig
5. Purser col! #2 10. Rotor
05005G23
Step 1 5
1 4 . I f the pu lser coi l i s removed o r disturbed, i t must b e re­
assembled using the pu lser coi l locating j ig (09931-8871 0) to be sure
that the coi l-to-flywheel pu lser bar air gap of 0 .03 in. (0.75 mm) is main­
tained.
15. Make sure to use the proper jig, as the one for the DT1 1 5/140
(09931-89421 ) is different from other models
1 6. Connect the stator wire leads to their proper connections.
1 7. Connect the battery negative battery cable.
1 8. Install the engine cover.
I G N ITI ON AND ELECTRI CAL SYSTEMS 5-25
DT150, DT175, DT200 and DT225
• See accompanying i l lustrations
1. Remove the engine cover.
2. Remove the electrical junction box cover and disconnect the stator
leads.
3. Remove the flywheel cover.
4. Using a flywheel holder (09930-48720), remove the flywheel
nut.
5 . Using a flywheel holder, flywheel remover (09930-3941 1 ) and flywheel
bolts (09930-39420), remove the flywheel.
6. Remove the flywheel from the crankshaft.
7. Remove the coi ls from the stator assembly and wiring harness.
To install:
8. Install the coils onto the stator assembly and secure the screws with
thread locking compound.
9. Fit the pulser coi l locating j ig onto the crankshaft as i l lustrated.
1 0. Locate the pulser coi l 0.32 in . (8 mm) from the end of the pulser coi l
locating j ig using vernier calipers. With the pulser coi l held in this position,
secure the attach ing screws using a small amount of thread locking compound.
Install the other two pulser coi ls in this manner.
1 1 . Throughly clean the mating surface of the flywheel and crankshaft taper
with cleaning solvent. Install the key onto the crankshaft securely.
1 2. Install the flywheel onto the crankshaft.
1 3. Using the flywheel holder, tighten the flywheel nut to 181-1 88 ft. lbs.
(250-260 Nm).
14 . Connect the stator wire leads to their proper connections.
1 5. Connect the battery negative battery cable.
16. Install the engine cover.
Pulser coi l
Step 9
Ignition Coils
DESCRIPTION & OPERATION
• See Figures 21 and 22
.j I• 8 m m (0.31 5 i n )
05005G26
The coi l is the heart of the ignit ion system. Essential ly, it is noth ing more
than a transformer which takes the relatively low voltage (1 2 volts) available
from the primary coi l and increases it to a point where it wil l fire the spark plug
as much as 20,000 volts.
Once the voltage is d ischarged from the ign ition coi l the secondary circuit
begins and only stretches from the ignition coil to the spark plugs via extremely
large high tension leads. At the spark plug end, the voltage arcs in the form of a
spark, across from the center electrode to the outer electrode, and then to
ground via the spark p lug threads. This completes the ignition circuit.
TESTING
• See Figure 23
1. Although the best test for an ignition coil is on a dynamic ignition coil
d i gital multi meter, resistance checks can also be done.
2 . There are two circuits in an ign ition coi l , the primary winding circuit and
the secondary winding circuit. Both need to be checked.
Fig. 21 The coil is the heart of the ignition system
05005P46
Fig. 22 Once the voltage is discharged from the ignition coil the
secondary circuit begins and only stretches from the ignition coil to
the spark plugs via extremely large high tension leads
05005P48
Fig. 23 The digital multimeter connection procedure for a continuity
check will depend on how the coil is constructed
5-26 IGN ITION AND ELECTR ICAL SYSTEMS
3 . The digital multi-meter connection procedure for a continuity check
will depend on how the coil is constructed. Generally, the primary circuit is
the small gauge wire or wires, while the secondary circuit contains the high
tension or plug lead.
4. Some ignition coils have the primary and/or secondary circuits
grounded on one end. On these type coils, only the continuity check is done.
On ignition coils that are not grounded on one end, the short-to-ground test
must also be done. Regardless of the coil type, compare the resistance with
that found in supplemental "Ignition Coil Spec" chart.
• When checking the secondary side, make sure to read the
procedure for your particular engine. Some models require the spark
plug caps be removed and others require them to remain on. In some
cases the cap is bad, not the coil. Bad resistor caps can be the cause
of high-speed misfire. Unscrew the cap and check the resistance (5
kilo-ohms).
5. The other method used to test ignition coils is with a Dynamic Ignition
Coil Digital multi-meter. Since the output side of the ignition coil has very
high voltage, a regular voltmeter can not be used. While resistance reading
can be valuable, the best tool for checking dynamic coil performance is a
dynamic ignition coil digital multi-meter.
6. Connect the coil to the digital multi-meter according to the
manufacturer's instructions.
7. Set the spark gap according to the specifications.
8. Operate the coil for about 5 minutes.
9. If the spark jumps the gap with the correct spark calor, the coil is
probably good.
REMOVAL & INSTALLATION
DT4 and DTSY
1 . Remove engine cover.
2. Disconnect the ignition coil leads and spark plug wires.
3. Remove the retaining bolts and remove the ignition coil.
To install :
4. The ignition coil core should always be sanded with emery cloth
before installing on the engine. Also sand the area on the cylinder block. This
ensures a good ground.
5. Install the retaining bolts and tighten snugly.
6. Connect the ignition coil lead wires. Make sure the connections are
tight and corrosion free.
7. Install the spark plug wires on the spark plugs.
8. Install the engine cover.
DT6 and DT8
• See accompanying illustrations
1 . Remove the engine cover.
2. Disconnect the spark Qlug wires.
Step 4
3. Disconnect the CD! uniVignition coil leads.
4. Loosen the bolts and remove the CD! unit/ignition coil.
• The ignition coil and CDI unit are integrated into one assembly.
To install:
5. I nstall the CD! uniVignition coil onto the engine.
6. Connect the CD! uniVignition coil leads. Make sure all connections
are tight and free of corrosion.
7. Install the spark plug wires.
8. Install the engine cover.
DT9.9 and DT15
• See accompanying illustrations
1 . Remove the engine cover.
2. Disconnect the spark plug wires.
3. Disconnect the two pole connector and the lead wire extending from
the CD! uniVignition coil and remove from the engine.
• The ignition coil and CDI unit are integrated into one assembly.
To install:
4. Install the CD! uniVignition coil on the engine and connect the two­
pole connector.
5. Connect the CD! uniVignition coil lead wire. Make sure all
connections are tight and free of corrosion.
6. Connect the spark plug wires.
7. Install the engine cover.
Step 3
DT25 and DT30
1 . Disconnect the battery negative cable.
2. Remove the engine cover.
3. Disconnect the spark plug wires.
4. Open the electrical parts holder and disconnect the ignition coil leads
at the CD! unit.
5. Remove the ignition coil retaining bolts and remove the coils from the
engine.
To install:
6. Install the ignition coil on the engine and tighten the retaining bolts.
7. Connect the ignition coil leads at the CD! unit. Make sure all
connections are tight and free of corrosion.
8. Replace the electrical parts holder cover. Make sure the cover is on
properly and no wires or sealing ring is being pinched by the cover.
9. Connect the spark plug wires.
1 0. Install the engine cover.
DT35 and DT40
1 . Remove the engine cover.
2. Disconnect the spark plug wires.
I G N ITIO N AND ELECTRICAL SYSTEMS 5-27
3. Disconnect the CO l unit/ignition coil leads.
.,.. The ignition coil and CDI unit are integrated into one assembly.
4. Remove the elastic band and lift the CDI unit/ignition coil from the elec­
tric parts holder.
To instal l :
5. Set the CDI unit/ignition co i l assembly into the e lectric parts holder and
secure it with the elastic band.
6. Connect the COl unit/ignition coil leads. Make sure al l connections are
tight and free of corrosion.
7. Connect the spark plug wires.
8. Install the engine cover.
DT55 and DT65
• See accompanying il lustrations
1 . Remove the engine cover.
2. Disconnect the spark plug wires.
3. Open the e lectric parts holder and disconnect the ignition coil leads from
the COl un it.
4. Unbolt the ignition coils and remove them from the electric parts holder.
®
1 . Magneto ground lead wire
2. Low oil warning unit
3. COl unit ground lead wire
4. Fuse case assy. (battery)
5. Fuse case ass. (rectifier)
6. Rectifier assy.
7. COl unit
8. Wiring harness ground lead wire
9. Ignition coil no. 3
10 . Ignition coil no. 2
1 1 . Ignition coi l no. 1
12 . Ignition coil ground lead wire
05005G59
Step 3
To install:
5. Install the ignition coi ls in the electric parts holder. Make sure the retain­
ing bolts are secure.
6. Connect the ignition coil leads to the CDI unit. Make sure all the connections are tight and free of corrosion.
7. Install the cover on the e lectric parts holder.
8. Install the spark p lug wires.
9. Install the engine cover.
DT75 and DT85
• See accompanying i l lustrations
1 . Remove the engine cover.
2. Disconnect the spark plug wires.
3. Open the electric parts holder and disconnect the ign ition coil leads from
the CDI un it .
4. Unbolt the ignition co i ls and remove them from the e lectric parts holder.
To install:
5 . Install the ignition coils in the e lectric parts holder. Make sure the retain­
ing bolts are secure.
6. Connect the ignition coil leads to the CDI unit. Make sure all the connections are tight and free of corrosion.
7. Install the cover on the electric parts holder.
8. Install the spark plug wires.
9. Install the engine cover.
05005G60
Step 3
DT90 and DT100
1 . Remove the eng ine cover.
2. Disconnect the spark plug wires.
3 . Open the e lectric parts holder on the front of the engine and disconnect
the ignition coil leads from the CDI un it.
4. Unbolt the ignition coi ls and remove them from the e lectric parts holder.
To install:
5. Install the ignition coi ls i n the e lectric parts holder. Make sure the retain­
ing bolts are secure.
6. Connect the ignition coil leads to the CDI unit. Make sure al l the connections are tight and free of corrosion .
7. Install the cover on the e lectric parts holder.
8. Install the spark p lug wires.
9. Install the engine cover.
DT1 15 and DT140
1 . Remove the engine cover.
2. Disconnect the spark plug wires.
3. Open the electric parts holder on the side of the engine and disconnect
the ignition coil leads from the wiring harness leading to the COl unit.
5-28 IGN ITION AND ELECTRICAL SYSTEMS
4. Unbolt the ignition coils and remove them from the electric parts
holder.
To install:
5. Install the ignition coils in the electric parts holder. Make sure all
ground connections are in place and the retaining bolts are tight.
6. Connect the ignition coil leads to the CDI unit. Make sure all the
connections are tight and free of corrosion.
7. Install the cover on the electric parts holder.
8. Install the spark plug wires.
9. Install the engine cover.
DT150, DT175, DT200 and DT 225
1 . Remove the engine cover.
2. Disconnect the spark plug wires.
3. Open the electric parts holder on the front of the engine and
disconnect the ignition coil leads from the wiring harness leading to the CDI
unit.
4. Unbolt the ignition coils and remove them from the electric parts
holder.
To install :
5. Install the ignition coils in the electric parts holder. Make sure all
ground connections are in place and the retaining bolts are tight.
6. Connect the ignition coil leads to the CDI unit. Make sure all the
connections are tight and free of corrosion.
7. Install the cover on the electric parts holder.
8. Install the spark plug wires.
9. Install the engine cover.
CDI Unit
DESCRIPTION & OPERATION
I n its simplest form, a CDI ignition is composed of the following elements:
• Magneto
• Pulser coil
• Charge, or source coil
• Igniter (COl) box
• Ignition coil
• Spark plug
Other components such as main switches, stop switches, or computer
systems may be included, though, these items are not necessary for basic
COl operation.
To understand basic CDI operation, it is important to understand the basic
theory of induction. Induction theory states that if we move a magnet
(magnetic field) past a coil of wire (or the coil by the magnet), AC current will
be generated in the coil.
The amount of current produced depends on several factors:
• How fast the magnet moves past the coil
• The size of the magnet (strength)
• How close the magnet is to the coil
• Number of turns of wire and the size of the windings
The current produced in the charge coil goes to the CDI box. On the way
in, it is converted to DC current by a diode. This DC current is stored in the
capacitor located inside the box. As the charge coil produces current, the
capacitor stores it.
At a specific time in the magneto's revolution, the magnets go past the
pulser coil. The pulser coil is smaller than the charge coil so it has less
current output. The current from the pulser also goes into the CDI box. This
current signals the CDI box when to fire the capacitor (the pulser may be
called a trigger coil for obvious reasons). The current from the capacitor
flows out to the ignition coil and spark plug. The pulser acts much like the
points in older ignitions systems.
When the pulser signal reaches the CDI box, all the electricity stored in
the capacitor is released at once. This current flows through the ignition coil's
primary windings.
The ignition coil is a step-up transformer. it turns the relatively low voltage
entering the primary windings into high voltage at the secondary windings.
This occurs due to a phenomena known as induction.
The high voltage generated in the secondary windings leaves the ignition
coil and goes to the spark plug. The spark in turn ignites the air-fuel charge
in the combustion chamber.
Once the complete cycle has occurred, the spinning magneto immediately
starts the process over again.
Main switches, engine stop switches, and the like are usually connected
on the wire in between the CDI box and the ignition coil. When the main
switch or stop switch is turned to the OFF position, the switch is
closed. This closed switch short-circuits the charge coil current to ground
rather than sending it through the CDI box. With no charge coil current
through the CDI box, there is no spark and the engine stops or, if the engine
is not running, no spark is produced .
TESTING
The unit may remain installed on the powerhead, or it may be removed for
testing. In either case, the testing procedures are identical.
Measure the continuity between the CDI unit terminals. If the any of the
readings are not within specifications, the CDI unit must be replaced.
DT2 and DT2.2
• See accompanying illustrations
The DT2 model uses a combined COl unit/ignition coil.
1 . Using a multi-meter, measure the resistance in the primary
(core-blue/red wire: 0.8-1 .2 ohms) and the secondary (core-plug cap: 7-1 0
kilo-ohms)
®
1 . Tester
2 . Plug cap
Step 1
DT4 and DTSY
• See accompanying illustrations
1 . Obtain a Suzuki CDI tester (09930-9981 0) and test cord
(09930-401 1 3) .
2. Before using the tester, be sure to select the proper voltage range on the
6
5
1 . Power light
2. Fuse (2 amp.)
3. AC source
4. Test !ead connector
5. Test button 6. C D ! indicator light
7. COl test cord
Step 1
I G N IT ION AND ELECTRICAL SYSTEMS 5-29
05005G64
Step 3
voltage selector (1 OOv, 1 1 7v, 220v and 240v). If the selector socket is not set at
the proper voltage range, remove the fuse and pu l l out the voltage selector and
re i nsert into the unit so that the proper voltage scale is visible in the cutaway.
3. Disconnect the COl unit leads and install the test leads in their place.
4. Connect the COl unit to test lead to the tester.
5. Plug the tester into a power outlet.
6. Push the "Test" button.
• Both the power l ight and the COl indicator l ight should come on. This
indicates that the COl unit is functioning correctly.
• If the power light is ON and the COl indicator l ight is OFF, the COl unit
is not functioning correctly and needs to be replaced.
• If both l ights are OFF, check the fuse (replace if b lown) and the A/C
power source.
DT6 and DTB
• See accompanying i l lustrations
1 . Obtain a Suzuki CO l tester (09930-99830) and test cord (09930-89812).
2. Make sure the correct voltage range is chosen on the tester "1 ".
05005G65
Step 5
3. Connect the CDI test cord to the tester.
4. Connect the A/C cord to a power outlet.
5 . Connect the COl tester, CO l test cord and COl unit as i l lustrated.
�when checking the ignition coil assembly with a plug cap left
detached, insert the spark plug wire d irectly into the tester without
using the attachment "A".
** WARNING
Failure to connect this ground lead "2" wire may cause an e lectric
shock upon touching the tester.
Turn the main switch "3" of the tester to the ON position. Turning the switch
"4" to the "COl TEST" side, check if a spark occurs across the needles in the
indicator window "5" . If the spark occurs, it means that the COl un it is function­
ing normally. If there is no spark indicated, the COl unit is not operating nor­
mally and wi l l need to be replaced.
DT9.9, DT15, DT25 and DT30
• See Figure 24
1 . Obtain a COl tester (09930-99830) and COl test cord
(DT9.9/1 5:09930-8891 0; DT25/30: 09930-89630).
• ON: Meter reading should be 1 OOk ohms or less
• OFF: Meter read ing should be more than 1 00k ohms
• CON: The meter pointer swings sl ightly and immediately return to the
original position. Watch the meter careful ly. If you have failed to see the pointer
moving, wait for about 10 minutes and repeat the test.
e lead of tester
Green Black Blue/ H t H 2 Red
� Green �� ON O F F O F F O F F
� I CON "� O F F O F F O F F 0 B lack I '"" "0
I� "' Bl ue/ .!!! ON ON O F F O F F 83 R ed
H t O F F O F F O F F � 2soon
H2 O F F O F F O F F 2soon �
05005G66
Fig. 24 Use the CDI unit test chart to determine the condition of the
CDI unit
CHECK BY INDICATOR LAMP
• See Figure 25
1. Before using the tester first be sure to select the proper voltage range on
the voltage selector "1 " . (1 OOV, 1 1 7V, 220V and 240V)
2. Connect the COl test cord to the tester.
3. Connect the A/C power cord to a power outlet.
4. Connect the COl test cord to the COl unit lead wire as fol lows: (check
each cylinder individual ly) .
• OT9.9/1 5: No.1 cylinder: orange, Connectors, black; No.2 cylmder:
gray, Connectors, black
• OT25/30: No1 cylinder: orange, connectors; No.2 cylinder: blue, con­
nectors; No.3 cylinder: gray, connectors
5. Turn the main switch "2" of the tester to the ON position.
6. Turn the test switch "3" to the "LAMP TEST" side. Make sure the COl
indicator lamp "4" comes ON .
7 . Turning the switch "3" to the "CO l TEST" side, check i f the lamp "4"
comes on. If the lamp is ON, the COl un it is good. If the lamp is OFF, the COl
un i t is bad and needs to be replaced.
5-30 I G N IT ION AND ELECTRI CAL SYSTEMS
CD! UNIT
05005G67
Fig. 25 Connect the CDI test cord to the CDI unit as i l lustrated
CHECKING BY SPARK
t See Figure 26
1. Before using the tester first be sure to select the proper voltage range on
the voltage selector "1 " . (1 OOV, 1 1 7V, 220V and 240V)
2. Connect the CDI test cord to the tester.
3. Connect the A/C power cord to a power outlet.
4. Connect the connectors "2" of the CDI test cord to the CDI unit lead
wires as i l lustrated.
5. Inserting attachment "A" into the tester, connect each ignition coil assem­
bly as i l l ustrated.
�When checking the ignition coil assembly with a plug cap left
detached, insert the spark plug wire of the ignition coil assembly
directly into the tester without using the attachment "A".
6. Connect the black lead wire "3" of the ignit ion coi l assembly to the
ground lead wire "4" of the tester to the black lead wire "5" of the CDI unit.
** WARNING
Failure to connect this ground lead "4" wire may cause an electric
shock upon touching the tester.
7. Connect the lead wire "6" of the ignition coil assembly to the same col or
lead wire of the CDI unit.
• DT9.9/1 5:No.1 orange; No.2 gray
• DT25/30: No.1 orange; No.2 blue; No.3 gray
8. Turning the main switch "7" of the tester to the ON position. Turning the
switch "8" to the "CD I TEST" position, check if a spark occurs across the needles in
the indicator window "9" . If the spark occurs, the CDI unit is functioning correctly. If
there is no spark, the CDI unit is not functioning and wi l l need to be replaced.
05005G68
Fig. 26 Connect the CDi test cord to the CDI unit as il lustrated
DT35 and DT40
USING THE SUZUKI POCKET TESTER
t See Figure 27
1 . Use the CDI unit test chart to determine the condition of the CDI unit.
• ON: Meter reading should be 1 OOk ohms or less.
• OFF: Meter read ing should be more than 1 00k ohms.
• CON: Meter swings once and returns immediately.
- lead of tester
� Green White/ Black Blue/ Blue Pink red red
Green � ON ON OFF OFF ON
� White/
ON b ON OFF OFF ON t; red .'!!
0 Black ON ON � OFF OFF ON '0 "' � Blue/ � + red ON ON ON OFF ON
Blue ON ON ON OFF �� ON
Pink ON ON ON OFF OFF I�
05005G69
Fig. 27 Use the CDI unit ies! chart to determine the condition of the
CDI unit
I G N ITIO N AND ELECTRI CAL SYSTEMS 5-31
,..Set the meter to the R x 1 00 range. After checking CON, allow some
time before checking the reading.
USING THE SUZUKI CO/ TESTER (09930-99810)
• See Figure 28
1. Before using the tester, make sure to set the tester to the proper voltage
range (1 OOV, 1 1 7V, 220V and 240V). If the selector is not set at the proper volt­
age range, remove the fuse and pul l out the voltage selector and re insert into
unit so that the proper voltage scale is visible in the cutaway.
2. Connect the CDI unit to the test cord and the test cord to the CDI tester.
3. Connect the A/C cord to a power source.
4. Push the "TEST' button .
• Both the power l ight and CDI indicator l ight should come on . This
indicates that the CDI unit is functioning properly.
• If the power l ight is ON and the CDI ind icator l ight is OFF, the CDI unit
is not working properly and need to be replaced.
• If both the l ights on the CDI tester are out, check to see if the tester
unit fuse is blown, and if so find the cause and then replace the fuse. Also
check the A!C power source going to the tester.
Q) Power l ight
@ Fuse (2 amp.)
@ AC source
@) Test lead connector
® Test button
® COl i ndicator l ight
®
05005G70
Fig. 28 Make sure to check that it set to the proper voltage range on
the voltage selector
DT55 and DT65
• See Figure 29
1 . Obtain a CDI tester (09930-99830) and test cord (09930-89480)
CHECK BY INDICATOR LAMP
1 . Before using the tester, make sure the tester is set on the proper voltage
range (1 OOV, 1 1 7V, 220V AND 240V).
2. Connect the COl test cord tot he tester.
3. Connect the A/C power cord to an e lectrical outlet.
4. Turn ON the main switch "2" on the tester.
5. Turn the test switch "3" to the "LAMP TEST' position. Make sure the COl
indicator lamp "4" comes on then.
6. Turn the switch "3" to the "COl TEST' position, then check if the lamp
"4" comes on.
• ON: the COl unit is functioning properly
• OFF: the COl unit is not functioning properly and will need to be
replaced.
CO l unit
05005G71
Fig. 29 Connect the CDi test cord to the CDI unit lead wires as i l lus­
trated
CHECKING BY SPARK
• See Figure 30
1. Before using the tester, make sure the tester is set on the proper voltage
range (1 OOV, 1 1 7V, 220V and 240V).
2. Connect the COl test cord tot he tester.
3. Connect the A/C power cord to an e lectrical outlet.
4. Connect the CDI test cord to the COl unit lead wires as i l lustrated.
5. Connect the ground lead wire "2" of the tester to the black lead wire "3"
of the CDI unit.
** CAUTION
Failure to connect this ground lead wire "2" may cause an electric
shock upon touching the tester.
6. Inserting attachment "A" into the checker, connect each ignition coi l
assembly as i l lustrated in the i l l ustration.
,..When checking the ignition coil assembly with a plug cap left
detached, insert the spark plug wire directly into the checker without
using the attachment "A".
7. Turning ON the main power switch of the tester. If a spark occurs
5-32 I G N ITION AN D ELECTR ICAL SYSTEMS
CO l u n i t
05005G72
Fig. 30 Connect the CD! test cord to the CDI unit lead wires as il lus­
trated
across the needles in the ind icator window "5" the CO l un i t is operating nor­
mal ly.
8. If there is no spark in the window, the COl un it is not operating properly
and wi l l need to be replaced.
DT75 and DT85
• See Figure 31
Testing the COl unit with the COl tester.
l Obtain a COl tester (09930-99830) and test cord (09930-89521 ) .
2. Before using the tester, make sure the tester is set on the proper voltage
range (1 OOV, 1 1 7V, 220V or 240V).
3. Connect the COl test cord to the tester.
4. Connect the A/C power cord to an electrical outlet
** WARNING
Make sure the tester main switch "2" is OFF before connecting the
power supply or test leads.
5. Connect the COl test cord to the COl unit lead wires as i l lustrated (check
each cylinder separately).
COl UNIT
05005G73
Fig. 31 Connect the CD! test cord to the CDI unit lead wires as illus­
trated
** WARNING
Fai lure to connect the ground wires may cause an electric shock
upon touching the tester.
,..When checking the ignition coil with the spark plug cap removed,
insert the high tension cord of the ignition coil directly into the checker
without using the attachment "A".
6. Individually connect the cylinder c ircuits to be checked.
7. Turn the tester main switch "2" ON.
8. Turn the tester switch "3" to the "COl TEST" position. Check for spark in
the "spark i ndicator" window. A continuous spark wi l l mean that the circuit
being tested is performing normal ly.
9. If there is no spark indicated, check the tester fuse and the power supply.
If these are operational, then there is a failure in the COl unit and it wi l l need to
be replaced.
DT90 and DT100
Test the COl peak voltage output using a Stevens C0-77 peak voltage tester.
1 . Remove a l l spark plugs to e l im inate variables at cranking speed.
2. Use a 1 2-volt, 70AH ful ly charged battery.
I G N IT ION AND ELECTRICAL SYSTEMS 5-33
3 . Crank the engine using the electric starter for no more than 20 seconds
at a time.
4. CDI peak voltage should measure 1 02 volts or over at 300 rpm, and 121
volts at 500 rpm.
DT1 1 5 and DT140
The CDI unit can be checked using either a Stevens CD-77 peak voltage
tester or a Suzuki CDI tester (09930-99830) and CDI test cord (09930-99410).
CHECK BY INDICATOR LAMP
• See Figure 32
1. Before using the CDI tester, make sure the tester is set at the proper voltage for your location .
2. Connect the CDI test cord to the tester.
3. Plug the tester into a power outlet.
4. Connect the CDI test cord to the CDI unit lead wires as i l lustrated.
5. Turn ON the main power switch "2".
6. Turn the test switch "2" of the tester to the "LAMP TEST" position. Make
sure the CDI indicator lamp "4" comes ON then.
7. Turn the switch "3" to the "CD I TEST" position, now check to see if the
lamp "4" comes ON.
8. If the lamp is on, the CDI un i t is functioning correctly. If the lamp does
not come on, check the tester fuse and power supply. If both are working, then
the CDI unit is not working and wi l l need to be replaced.
05005G75
Fig. 32 Connect the COl test cord to the COl unit lead wires as illus­
trated
CHECK BY SPARK
• See Figure 33
1. Connect the CDI unit lead, CDI test cord and ignition coil lead as i l lustrated.
2. Connect the ground lead wire "2" of the tester to the black lead wire "3"
of the CDI unit.
** CAUTION
Failure to connect this ground lead "2" wire may cause an electric
shock upon touching the tester.
3. Inserting the attachment "A" into the tester, connect each ignition coil
assembly as i l lustrated in the i l lustration.
...when checking the ignition coil assembly with a plug cap left
detached, insert the high tension cord of the ignition coil assembly
directly into the tester without using the attachment "A".
4. Turn the main power switch "4" of the checker to the ON position and
check for a spark between the needles in the spark indicator window "5".
5. If a spark occurs, the CDI unit is functioning properly. If there is no
spark, the unit is not working and wi l l need to be replaced.
To check voltage on the EFI equipped models, check the ECU using a
Stevens Model CD-77 peak voltage tester and test cord.
6. Remove all the spark plugs to e l iminate variables at cranking speed.
7. Install the 6-pin connector between the CD-77and the ECU.
05005G76
Fig. 33 Connect the COl test cord to the CDI unit lead wires as illus­
trated
5-34 IGN ITION AND ELECTRICAL SYSTEMS
8 . Connect each of the ECU leads to the positive tester probe and
ground the negative test probe.
9. Crank the engine using the electric starter. DO NOT crank the engine
for more than 20 seconds at a time.
1 0. Peak voltage measured at the CD-77 should be 1 04 volts or over.
Make each measurement at least three times and if the voltage is too low,
the ECU will need to be replaced.
DT150, DT175, DT200 and DT225
Check the ECU/CDI using a Stevens Model CD-77 peak voltage tester.
1 . Remove all the spark plugs to eliminate variables at cranking speed.
2. Connect each of the ECU leads to the positive tester probe and
ground the negative test probe.
3. Crank the engine using the electric starter. DO NOT crank the engine
for more than 20 seconds at a time.
4. Peak voltage measured at the CD-77 should be 1 20 volts or over.
Make each measurement at least three times and if the voltage is too low,
the ECU will need to be replaced.
REMOVAL & INSTALLATION
DT2 and DT2.2
• See Figure 34
1 . Remove the engine cover.
2. With the fuel petcock in the closed position (marked "S") , remove the
fuel hose from the petcock.
3. Unbolt the fuel tank and remove it from the engine.
4. Disconnect the spark plug wire.
5. Disconnect the CDI unit lead.
6. Unbolt the CDI unit and remove.
COl unit
Fig. 34 Unbolt the CDI unit and remove
To install:
7. When installing the COl/ignition coil unit, measure the clearance
between the flywheel magneto and the ignition unit.
• Clearance should measure 0.0 1 6 in. (0.4 mm) .
DT4 and DTSY
1 . Remove the engine cover.
2. Disconnect the spark plug lead.
3. Disconnect the CD I leads and remove the retaining bolt.
4. Remove the CDI unit.
To install:
5. Install the CDI unit. Make sure that the ground wire is connected and
the retaining bolt is tightened.
6. Connect the CDI unit leads making sure they are tight and corrosion
free.
7. Connect the spark plug wire.
8. Install the engine cover.
DT6 and DT8
The CDI unit and ignition coil are integrated into one unit. Removal and
installation are covered in the ignition coil section.
DT9.9 and DT15
The CDI unit and ignition coil are integrated into one unit. Removal and
installation are covered in the ignition coil section.
DT25 and DT30
The removal and installation of the CDI unit is covered in the ignition coil
section.
I G N IT ION AND ELECTRI CAL SYSTEMS 5-35
DT35 and DT40
1 . The CDI unit and ignition coi ls are integrated into one unit. The removal
and installation of the CDI unit is covered in the ign ition coi l section.
DT55 and DT65
• See accompanying i l lustrations
1. Remove the engine cover.
2. Disconnect the spark plug wires.
3. Open the e lectric parts holder.
4. Disconnect the CDI unit leads.
5. Remove the elastic bands and remove the CDI un it from the e lectric
parts holder.
To instal l :
6. Install the CDI un i t in the e lectric parts holder. Make sure the elastic
bands are secure.
7. Connect the CDI unit leads. Make sure all the connections are tight and
free of corrosion.
8. Install the cover on the e lectric parts holder.
9. Install the spark p lug wires.
1 0. Install the engine cover.
05005P07
Step 3
05005P17
Step 4
05005P37
Step 5
DT75 and DT85
1 . Remove the engine cover.
2. Disconnect the spark plug wires.
3. Open the electric parts holder and disconnect the CDI unit from the igni­
tion coi l leads.
4. Release the elastic bands or unscrew the bolts holding the CD I unit in
place and remove the CDI unit from the e lectrical parts holder
To instal l :
5 . Install the ignition coi ls i n the e lectric parts holder. Make sure the retain­
ing bolts are secure.
6. Connect all the wire leads to the CD I unit. Make sure all the connections
are tight and free of corrosion.
7. Install the cover on the electric parts holder.
8. Install the spark plug wires.
9. Install the engine cover.
DT90 and DT100
• See Figure 35
1 . Disconnect the negative battery cable.
2. Remove the engine cover.
5-36 I G N IT ION AND ELECTRICAL SYSTEMS
Ground terminal nut
Rectifier/Regulator nut
Parts holder
Rectifier/Regulator
Rectifier/Regulator bolt
Cooling water sensor ( L)
Clamp
Water sensor lead wire
Engine temp. lead wire
Oil warning
Reset switch lead wire
Clip
High-tension lead
clamp Wiring harness
Fig. 35 Open the electrical parts holder on the front of the engine
3. Open the electrical parts holder on the front of the engine. The COl unit
is mounted behind the ignition coi ls.
4. Loosen the ignit ion coi l mounting bolts and move them out of the way.
5. Disconnect the COl wire leads.
6. Unbolt the COl unit and remove it from the e lectric parts holder.
To insta l l :
7 . Install the COl un i t into the electrical parts holder. Make sure al l connec­
tions are tight and free of corrosion. Also make sure al l ground connections are
made tight
8. Install the ign ition coi ls-.
9. Replace the electric parts holder cover.
1 0. Install the engine cover.
1 1 . Connect the negative battery cable.
DT1 1 5 and DT140
• See Figures 36 and 37
1 . Disconnect the negative battery cable.
2 . Remove the engine cover.
3. Open the electrical parts holder on the side of the engine to access the
COl unit
4. The same procedure is used to access the ECU on the fuel injected
models.
5. Disconnect the ECU/CDI wire leads and grounds.
6. Loosen the retaining screws and remove the unit from the e lectrical
parts holder.
To insta l l :
7. Install the ECU/CDI in the e lectrical parts holder. Make sure al l ground
points are tight, clean and free of corrosion. This is especially important on the
EFI equipped engines.
8. Reconnect the ECU/CDI Ieads. Again, make sure al l connections are
tight and free of corrosion.
Bolt
COl/Rectifier ground
lead wire
Cooling water sensor ( R )
Cooling water sensor
lead clamp
CD! unit nut
Spark plug cap
Clamp
High-tension lead clamp
Securely clamp the connector so it does
not interfere with cover sealing.
05005G76
05005G74
Fig. 36 Open the electrical parts holder on the side of the engine to
access the CDI unit
I G N IT ION AND ELECTRI CAL SYSTEMS 5-37
9 . Use wire ties t o bind together the wiring harnesses.
1 0. Install the electrical parts holder cover.
1 1 . Install the engine cover.
12 . Connect the battery negative cable.
DT150, DT175, DT200 and DT225
1 . Disconnect the negative battery cable.
2. Remove the engine cover.
3. The CDI unit is mounted behind the ign it ion coi ls on the front of the
engine.
4. Disconnect the ignition coi l leads and remove the entire ign it ion coil
assembly as a unit.
5. Disconnect the leads and remove the CDI un it from the back of the igni­
tion coi l assembly.
To instal l :
6. Install the CDI unit onto the back of the ign it ion coi l assembly.
7. Install the ignition coi l assembly onto the engine and connect the CDI
unit and ignition coi l wire leads.
8. Install the ignition cover.
9. Install the engine cover.
1 0. Attach the negative battery cable.
Rectifier
DESCRIPTION & OPERATION
The rectifier consists of a series of diodes or one-way electrical valves. lt rec­
tifies or corrects the alternating current (AC) produced within the windings to
charge the di rect current (DC) battery.
TESTING
1. The unit may remain installed on the powerhead, or it may be removed
for test ing. In either case, the testing procedures are identical.
2. Disconnect the red, white, yel l ow and black rectifier leads.
This ground point is most important for ECU system.
After wiping off any dirt using a cloth dipped with thin­
ner, tighten bolt, two ground wires of ECU and ignition
NOTE:
coil wire together.
Tighten bolt and
ground wires together.
NOTE:
Position white tape
on harness as shown.
Fig. 37 The same procedure is used to access the ECU on the fuel injected models
Fix wires with tube.
Route wires outside this
cable
Tighten bolt and
ground wire together.
holder
05005G77
5-38 I G N ITION AND ELECTRICAL SYSTEMS
3 . Connect a test l ight between the yellow and white leads and then reverse
the test l ight leads. The light should l ight up when tested in one di rection and
not the other.
4. Test the red and white, black and red, and yellow and black rectifier leads.
5. 11 the test light does not light as described in any one ol the diode di rec­
tions, the rectifier must be replaced.
REMOVAL & INSTALLATION
1 . Disconnect the negative battery cable.
2. Disconnect the rectifier or voltage regulator/rectifier connectors.
3. Remove the fastener attaching the unit to the engine or electrical compo­
nent and remove the unit.
4. 11 so equipped, remove the ground lead and disconnect it !ram the pow­
erhead.
To install:
5. Install the rectifier or voltage regulator/rectifier onto the powerhead or
electrical component.
6. Connect al l leads and make sure al l connections are tight and tree ol cor­
rosion.
7. Connect the negative battery cable.
Regulator
DESCRIPTION & OPERATION
The voltage regulator controls the alternators field voltage by grounding one
end ol the lield windings very rapidly. The frequency varies according to current
demand the more the field is grounded, the more voltage and current the alterElECTRONIC IGNITION
Description And Operation
The luel injected engines use an electronic ignit ion system which, when
combined with the luel injection system, becomes an integrated electronic
engine management system that improves luel consumption, performance and
exhaust emissions.
The ignition timing control system controls the ignition timing by first deter­
mining the basic ignition timing based on an engine speed signal sent by the
pulser coil and the intake manifold vacuum signal sent by the MAP sensor.
The ignition timing control system, with inputs !ram the Throttle Position
Sensor (TPS), the Engine Temperature Compensation Sensor (ECT), and the
Suction Air Temperature Sensor (IAT), compensates the base timing !or opti­
mum ignition timing.
Warning Systems
OVER REVOLUTION
• See Figure 38
Once engine speed reaches 6,1 00 rpm and remains over 5,900 rpm !or 1 0seconds, engine speed wi l l automatically be reduced to 3,000 rpm. Whi le the
G) 1 . "Check engine" lamp
2. "O i l " lamp
3. "Red o i l level" lamp
-...p-H--® 4. "Rev l imit" lamp
5. "Temp" lamp
®
05005G79
Fig. 38 Typical Suzuki monitor gauge with warning lamps
nator produces Voltage is maintained at about 1 3.5-15 volts. During high
engine speeds and low current demands, the regulator wi l l adjust the voltage ol
the alternator lield to lower the alternator output voltage. Conversely, when the
engine is id l ing and the current demands may be high, the regulator wi l l
increase lield voltage, increasing the output o l the alternator.
TESTING
1 . Make sure that the battery is fully charged.
2. Remove the engine cover.
3. Connect a tachometer accord ing to the manufacturers instructions.
4. Start the engine and let it warm up to normal operating temperature.
5. Connect a voltmeter across the battery terminals.
6. Slowly increase engine speed to approximately 5,000 rpm. Note the volt­
meter read ing, il it is not 1 4-15 volts, the voltage regulator must be replaced.
REMOVAL & INSTALLATION
1 . Disconnect the negative battery cable.
2. Disconnect the voltage regulator connections.
3. Remove fasteners holding the voltage regulator to the powerhead or electrical component and remove the regulator.
4. 11 equipped, remove the ground wire and fastener.
To instal l :
5. Install the regulator onto the powerhead or electrical component and
tighten the lastener(s).
6. 11 equipped, reattach the ground wire and fastener.
7. Connect the regulator leads, making sure that they are a l l tight and tree ol
corrosion.
8. Connect the negative battery cable
caution system is activated, the "REV LIMIT" lamp will l ight up when the engine
speed is above 2750 rpm. The system can be reset by reducing engine speed
below 2,500 rpm !or one-second.
OIL LEVEL
11 the oil level switch is turned on !or 1 0-seconds, engine speed will auto­
matically be reduced to 3,000 rpm. While the caution system is activated, the
buzzer wi l l sound and the red "OIL LEVEL" lamp will l i ght up. The "REV LIMIT"
lamp wi l l also light when the engine speed is above 2,750 rpm. This system can
be reset to normal operation when the oi l level switch is turned oil (oil tank is
refi l led) and engine speed is reduced below 2,500 rpm.
Only engine speed l imit control ol this caution system can be cancelled !or
emergency use by pushing the reset switch. This status can be reset by stop­
ping the engine or by resetting the system to normal operation as described
above.
OIL FLOW
11 the o i l llow sensor is kept on !or 2-seconds, engine speed wi l l automati­
cally be reduced to 3,000 rpm. While the caution system is activated, the buzzer
wi l l sound and the "OIL" lamp wi l l l ight up. The "REV LIMIT" lamp wi l l also
light up when the engine speed is above 2,750 rpm.
The system can be reset to normal operation when the o i l llow sensor is
turned oil and engine speed is reduced below 2,500 rpm.
OVERHEAT
Engine speed is reduced to 2,000 rpm when the engine temperature reaches
1 49°F (65°C) or the engine temperature rising rate exceeds the level preset in
the system. While the caution system is activated, the buzzer wi l l sound and the
"TEMP" lamp wi l l l i ght up. The "REV LIMIT" lamp wi l l also light up when the
engine speed is above 1 ,750 rpm.
The system can be reset when the engine temperature drops lower than
140°F (60°C) and engine speed is reduced below 1 ,500 rpm.
I G N ITIO N AND ELECTRI CAL SYSTEMS 5-39
BATTERY VOLTAGE
Engine speed i s reduced to either 2,000 or 3,000 rpm when the system
detects low battery voltage which is preset by engine speed. (Example: 8 volts
@ 2,500 rpm, 9.8 volts @ 5,500 rpm).
CHARGING CIRCUIT
Description and Operation
The voltage regulator controls the alternator's field voltage by grounding one
end of the field windings very rapidly. The frequency varies according to current
demand. The more the field is grounded, the more voltage and current the alter­
nator produces. Voltage is maintained at about 1 3.5-15 volts. During h igh
engine speeds and low current demands, the regulator wi l l adjust the voltage of
the alternator field to lower the alternator output voltage.
SINGLE PHASE CHARGING SYSTEM
The sing le-phase charging system found on in l ine engines provides basic
battery maintenance. Single-phase, fu l l wave systems l ike these are found on a
variety of products. Many outboard engines, water vehicles, motorcycles, golf
cars and snowmobiles use simi lar systems.
This charging system produces e lectricity by moving a magnet past a fixed
coi l . Alternating current is produced by this method. Since a battery cannot be
charged by AC (alternating current), the AC current produced by the lighting
coil is rectified or changed into DC (direct current) to charge the battery.
To control the charging rate an additional device called a regulator is used.
When the battery voltage reaches approximately 1 4.6 volts the regulator sends
the excess current to ground. This prevents the battery from overcharging and
boi l ing away the e lectrolyte.
The charging system consists of the following components:
• A flywheel containing magnets
• The lighting coil or alternator coil
• The battery, fuse assembly and wiring
• A regulator/rectifier
The lighting coil is usually a bright exposed copper wire with a lacquer-type
coating. Lighting coils are built in with the ignition charge coils on some models.
If the charge coil or lighting coil fails the whole stator assembly must be replaced.
The flywheel contains the magnets. The number of magnets determines the
number of poles. Each magnet has two poles, so a 4-pole system has two mag­
nets. You need to know the number of poles in order to set the tachometer cor­
rectly.
Servicing charging systems is not difficult if you follow a few basic rules.
Always start by verifying the problem. If the complaint is that the battery wi l l not
stay charged do not automatically assume that the charging system is at fault.
Something as simple as an accessory that draws current with the key off wi l l
convince anyone they have a bad charging system. Another culpr it is the battery.
Remember to clean and service your battery regularly. Battery abuse is the num­
ber one charging system problem.
The regulator/rectifier is the brains of the charging system. This assembly
controls current flow in the charging system. If battery voltage is below 1 4.6
volts the regu lator sends the available current from the rectifier to the battery. If
the battery is fully charged (about 1 5 volts) the regulator d iverts most of the
current from the rectifier back to the lighting coil through ground.
Do not expect the regulator/rectifier to send current to a fu l ly charged battery.
You may find that you must pul l down the battery voltage below 1 2.5 volts to
test charging system output. Running the power trim and tilt wi l l reduce the bat­
tery voltage. Even a pair of 12 volt sealed beam lamps hooked to the battery wi l l
reduce the battery voltage quickly.
In the charging system the regu lator/rectifier is the most complex item to
troubleshoot. You can avoid Troubleshooting the regulator/rectifier by checking
around it. Check the battery and charge or replace it as needed. Check the AC
voltage output of the lighting coil. If AC voltage is low check the charge coil for
proper resistance and insulation to ground. If these check OK measure the
resistance of the Black wire from the rectifier/regulator to ground and for proper
voltage output on the Red lead coming from the rectifier/regulator going to the
battery. If all the above check within specification replace the rectifier/regulator
and verify the repair by performing a charge rate test. This same check around
method is used on other components l i ke the COl unit.
Wh i le the caution system is activated , the buzzer will sound and the "CHECK
ENGINE" lamp will l ight The "REV LIMIT" lamp wi l l also l ight up when the
engine speed is above either 1 , 750 or 2,750 rpm. The system can be reset by
not using any electrical equipment which consumes high electric energy such
as the power ti lt and trim system, hydraul ic jack plate, etc. and engine speed is
reduced to idle for one second.
THREE-PHASE CHARGING SYSTEM
Three-phase systems have two more coils in the stator and one more wire
than single-phase charg ing systems. They create higher amperage output than
single-phase in nearly the same space.
•If you do not have a solid grasp of single-phase charging systems,
please read the description and operation for single-phase systems
before continuing.
AC current is generated identical ly i n both three-phase and sing le-phase
systems. These charg ing systems produce AC (alternating current) by moving
magnets past a fixed set of coils. Since a battery cannot be charged by AC, the
AC produced by the l ighting coils is rectified or changed into DC (direct cur­
rent). The rate at which the battery receives this rectified current is controlled by
the regulator.
The two additional l ighting coi ls found in a three-phase charging system add
complexity to circuit tracing and troubleshooting. Some systems also incorpo­
rate a battery isolator. These additional components can make these systems
intimidating.
When attempting to troubleshoot these systems, apply a divide and conquer
method to demystify this system. Once you have separated the components and
circu itry into digestible b locks the system will be much easier to understand.
The charging system consists of the following components:
• A flywheel contain ing magnets
• The stator assembly, consisting of three ind ividual l ighting coi ls tied
together in a "Y" configuration
• The battery, fuse assembl ies and wiring
• A battery isolator and wiring, if so equipped
Servicing this system requires a consistent approach using a reliable check­
list. If you are not systematic you may forget to check a critical component.
PRECAUTIONS
To prevent damage to the on-board computer, alternator and regulator, the
following precautionary measures must be taken when working with the electrical system:
·
• Wear safety glasses when working on or near the battery.
• Don't wear a watch with a metal band when servicing the battery. Serious
burns can result if the band completes the circuit between the positive battery
terminal and ground.
• Be absolutely sure of the polarity of a booster battery before making con­
nections. Connect the cables positive-to-positive, and negative-to-negative.
Connect positive cables first, and then make the last connection to ground on
the body of the booster vehicle so that arcing cannot ignite hydrogen gas that
may have accumulated near the battery. Even momentary connection of a
booster battery with the polarity reversed wi l l damage alternator diodes.
• Never ground the alternator or generator output or battery terminal. Be
cautious when using metal tools around a battery to avoid creating a short c ir­
cuit between the terminals.
• Never ground the field circuit between the alternator and regulator.
• Never run an alternator or generator without load unless the field circuit is
disconnected.
• Never attempt to polarize an alternator.
• When insta l l ing a battery, make sure that the positive and negative cables
are not reversed.
• When jump-starting the boat, be sure that l i ke terminals are connected.
This also applies to using a battery charger. Reversed polarity wi l l burn out the
alternator and regulator in a matter of seconds.
• Never operate the alternator with the battery disconnected or on an other­
wise uncontrolled open circuit.
• Do not short across or ground any alternator or regulator terminals.
• Do not try to polarize the alternator.
5-40 I G N IT ION AN D ELECTRI CAL SYSTEMS
• Do not apply fu l l battery voltage to the field (brown) connector.
• Always disconnect the battery ground cable before disconnecting the
alternator lead.
• Always disconnect the battery (negative cable fi rst) when charging it.
• Never subject the alternator to excessive heat or dampness. If you are
steam cleaning the engine, cover the alternator.
• Never use arc-welding equipment on the car with the alternator connected.
Troubleshooting the Charging System
The charg ing system should be inspected if:
• A Diagnostic Trouble Code (DTC) is set relating to the charg ing system
• The charging system warning l ight is i l luminated
• The voltmeter on the instrument panel indicates improper charging (either
high or low) voltage
• The battery is overcharged (electrolyte level is low and/or boi l ing out)
• The battery is undercharged (insufficient power to crank the starter)
The starting point for a l l charging system problems begins with the inspec­
tion of the battery, related wiring and the alternator drive belt (if equipped). The
battery must be in good condition and fully charged before system testing. If a
Diagnostic Trouble Code (DTC) is set, diagnose and repair the cause of the
trouble code first.
If equipped, the charg ing system warn ing l ight wi l l i l luminate if the charging
voltage is either too high or too low. The warni ng l ight should l ight when the
key is turned to the ON position as a bu lb check. When voltage is produced due
to the engine starting, the l ight should go out. A good sign of voltage that is too
high are l ights that burn out and/or burn very brightly. Over-charg ing can also
cause damage to the battery and electronic c ircuits.
A thorough, systematic approach to troubleshooting will pay big rewards.
Bu i ld your troubleshooting check l ist with the most l ikely offenders at the top.
Do not be tempted to throw parts at a problem without systematically Trou­
b leshooting the system fi rst.
Do a visual check of the battery, wiring and fuses. Are there any new addi­
tions to the wiring? An excellent clue might be, "Everything was working OK
unti l ! added that l ive well pump." With a comment l i ke this you would know
where to check first.
The regulator/rectifier assembly is the brains of the charging system. The
regulator controls current flow in the charging system. If battery voltage is
below about 1 4.6 volts the regulator sends the available current to the battery. If
the battery is fu l ly charged (about 1 4.5 to 15 volts) the regulator d iverts the cur­
rent/amps to ground.
Do not expect the regulator to send current to a fu l ly charged battery. Check
the battery for a possible draw with the key off. This draw may be the cumulative
effect of several radio and/or clock memories. If these accessories are wired to
the cranking battery then a complaint of charg ing system fai lure may really be
excessive draw. Draw over about 25 mi l l iamps should arouse your suspicions.
The fuel management gauge memory and speedometer clock draw about 1 0
m i l l iamps each. Remember that a m i l l iamp i s 1ftooo of an amp. Check battery
condition thoroughly because it is the #1 culprit in charg ing system failures.
Do not forget to check thro·ugh the fuses. it can be embarrassing to overlook
a blown fuse.
You must pu l l the battery voltage down below 1 2.5 volts to test charging
system output. Running the power trim and tilt wi l l reduce the battery voltage. A
load bank or even a pair of 1 2-volt sealed-beam headlamps hooked to the bat­
tery can also be used to reduce the battery voltage.
Once the battery's good condition is verified and it has been reduced to
below 1 2.5 volts you can test further.
Install an ammeter to check actual amperage output. Several tool manufactur­
ers produce a shunt adapter that wi l l attach to your mu lti-meter and allow you to
read the amp output. Verify that the system is delivering sufficient amperage.
Too much amperage and a battery that goes dry very quickly indicates that the
rectifier/regulator should be replaced.
If the system does not put out enough amperage, then test the l ighting coi l .
Isolate the co i l and test for correct resistance and short to ground.
During these test procedures the regulator/rectifier has not been bench
checked. Usually it is advisable to avoid troubleshooting the regulator/rectifier
d i rectly. The procedures l isted so far have focused on checking around the recti­
fier/regu lator. If you verify that all other systems stator are good then what is left
in the system to cause the verified problem? The process of e l im ination has
declared the rectifier/regulator bad.
This check around method is also useful on other components that can not
be checked d i rectly or involve time-consuming test procedures. This is the
same method suggested for checking the capacitor discharge ignition box.
OVERCHARGING
There is really only one cause for th is type of failure, the regulator is not
working. it isn't contro l l ing charging output to the battery. Since there is no
repair of this part, replace it .
UNDERCHARGING
If there is an undercharge condition after running the DC amperage check at
the fuse assembly, then disconnect the stator coup l i ng from the harness and
perform AC voltage checks between the three stator leads. Check between two
stator leads at a time. There are three volt checks done to cover al l possible
combinations.
At idle, there is typically 14+ volts on each test. it can be higher if the idle is
higher. Al l three readings should be equal, within a volt or two. Stator shorts to
ground can be checked by doing a voltage test between one stator lead and
ground, engine runn ing. There should be roughly half the normal stator voltage
check reading.
If the readings are al l within specification, the stator is working correctly. I f
any or al l readings are below normal, turn the engine OFF and check the stator
windings using an ohmmeter. An isolated continuity check and a short to ground
check should be done. If the stator is bad, replace it since it can't be repaired.
�The charging system is an integral part of the ignition system. For
information on service procedures, please refer to the "Ignition" section
of this manual.
Alternator (Stator)
TESTING
�Before testing, make sure all connections and mounting bolts are
clean and tight. Many charging system problems are related to loose
and corroded terminals or bad grounds. Don't overlook the engine
ground connection to the body, or the tension of the alternator drive
belt.
Voltage Drop Test
1 . Make sure the battery is in good condition and ful ly charged.
2 . Perform a voltage drop test of the positive side of the circuit as fol l ows:
a. Start the engine and allow it to reach normal operating temperature.
b. Turn the headlamps, heater b lower motor and interior l ights on.
c . Br ing the engine to about 2,500 rpm and hold it there.
d . Connect the negative (-) voltmeter lead d i rectly to the battery positive
(+) terminal.
e . Touch the positive voltmeter lead d i rectly to the alternator B+ output
stud, not the nut. The meter should read no higher than about 0.5 volts. If it
does, then there is higher than normal resistance between the positive side of
the battery and the B+ output at the alternator.
f. Move the positive (+) meter lead to the nut and compare the voltage
reading with the previous measurement. If the voltage reading drops sub­
stantial ly, then there is resistance between the stud and the nut.
�The theory is to keep moving closer to the battery termina I one con­
nection at a time in order to find the area of high resistance (bad con­
nection).
3. Perform a voltage drop test of the negative side of the circuit as fol lows:
a. Start the engine and allow it to reach normal operating temperature.
b. Turn the headlamps, heater blower motor and i nterior l ights on.
c. Bring the engine to about 2,500 rpm and hold it there.
d . Connect the negative (-) voltmeter lead directly to the negative battery
terminal.
e. Touch the positive (+) voltmeter lead directly to the alternator case or
ground connection. The meter should read no h igher than about 0.3 volts. If
it does, then there is higher than normal resistance between the battery
ground terminal and the alternator ground.
I G N IT IO N AND ELECTRI CAL SYSTEMS 5-41
f . Move the positive (+) meter lead to the alternator mounting bracket, if
the voltage reading drops substantially then you know that there is a bad
electrical connection between the alternator and the mounting bracket.
,.. The theory is to keep moving closer to the battery terminal one con­
nection at a time in order to find the area of high resistance (bad con­
nection).
Current Output Test
• See Figure 39
1 . Perform a current output test as fol lows:
,.. The current output test requires the use of a volt/amp digital multi me­
ter with battery load control and an inductive amperage pick-up. Follow
the manufacturer's instructions on the use of the equipment.
a. Start the engine and allow it to reach normal operating temperature.
b. Turn off all electrical accessories.
c. Connect the digital multi meter to the battery terminals and cable
according to the instructions.
d. Bring the engine to about 2,500 rpm and hold it there.
e. Apply a load to the charging system with the rheostat on the digital
multi meter. Do not let the voltage drop below 1 2 volts.
f. The alternator should deliver to within 1 0% of the rated output. If the
amperage is not within 1 0% and all other components test good, replace the
alternator.
FULL FIELD
TESTER
LEAD (BLUI
VOLTMETER
NEGATIVE
LEAD (BLKI
NEGATIVE TESTER
CABLE (BLKI
POSITIVE TESTER
CABLE (REDI
B TERMINAL WIRE
8852BG09
Fig. 39 VAT-40 charging system digital multimeter. Many similar
digital multimeters are available that perform equally as well
Battery
The battery is one of the most important parts of the electrical system. In
addition to providing electrical power to start the engine, it a lso provides power
for operation of the running l ights, radio, and electrical accessories.
Because of its job and the consequences (fai l ure to perform in an emer­
gency), the best advice is to purchase a well-known brand, with an extended
warranty period, from a reputable dealer.
The usual warranty covers a pro-rated replacement pol icy, which means the
purchaser would be entitled to a consideration for the time left on the warranty
period if the battery should prove defective before its time.
Do not consider a battery of less than 70- amp/hour or 1 00-minute reserve
capacity. If in doubt as to how large the boat requ i res, make a l iberal estimate
and then purchase the one with the next higher amp rating. Outboards equipped
with an on board computer, should be equipped with a battery of at least 1 00 to
1 05 amp/hour capacity.
MARINE BATTERIES
• See Figure 40
Because marine batteries are required to perform under much more rigorous
conditions than automotive batteries, they are constructed d ifferently than those
used in automobiles or trucks. Therefore, a marine battery should always be the
No. 1 unit for the boat and other types of batteries used only i n an emergency.
Marine batteries have a much heavier exterior case to withstand the violent
pounding and shocks imposed on it as the boat moves through rough water and
in extremely tight turns. The plates are thicker and each plate is securely anchored
within the battery case to ensure extended life. The caps are spi l l proof to prevent
acid from spi l l ing into the bilges when the boat heels to one side in a tight turn, or
is moving through rough water. Because of these features, the marine battery wi l l
recover from a low charge condition and give satisfactory service over a much
longer period of time than any type intended for automotive use.
** WARNING
Never use a Maintenance-free battery with an outboard engine that
is not voltage regulated . The charging system will continues to
charge as long as the engine is running and it is possible that the
electrolyte could boil out if periodic checks of the cel l electrolyte
level are not done.
04709P01
Fig. 40 A fully charged battery, filled to the proper level with elec·
trolyte, is the heart of the ignition and electrical systems. Engine
cranking and efficient performance of electrical items depend on a
full rated battery
BATTERY CONSTRUCTION
• See Figure 41
A battery consists of a number of positive and negative p lates immersed in a
solution of d i luted sulfuric acid. The plates contain dissimilar active materials
and are kept apart by separators. The p lates are grouped into elements. Plate
5-42 I G N IT ION AND ELECTR I CAL SYSTEMS
CRACKED
CELL COVER ELECTROLYTE
04709G01
Fig. 41 A visual inspection of the battery should be made each lime
the boat is used. Such a quick check may reveal a potential problem
in its early stages. A dead battery in a busy waterway or far from
assistance could have serious consequences
straps on top of each element connect all of the positive plates and all of the
negative plates into groups.
The battery is divided into cells holding a number of the e lements apart from
the others. The entire arrangement is contained within a hard plastic case. The
top is a one-piece cover and contains the fi l ler caps for each cel l . The terminal
posts protrude through the top where the battery connections for the boat are
made. Each of the cells is connected to its neighbor in a positive-to-negative
manner with a heavy strap called the cel l connector.
BATTERY RATINGS
• See Figure 42
Three different methods are used to measure and indicate battery e lectrical
capacity:
• Amp/hour rating
• Cold cranking performance
• Reserve capacity
The amp/hour rating of a battery refers to the battery's abil ity to provide a set
amount of amps for a given amount of time under test conditions at a constant
temperature. Therefore, if the battery is capable of supplying 4 amps of current
for 20 consecutive hours, the battery is rated as an 80 amp/hour battery. The
amp/hour rating is useful for some service operations, such as slow charg ing or
battery testing.
POWER (WATTS) AVAILABLE 1 00% e
63% e
ENERGIZERS
RATED AT ooFe·'"" 61% - ---- oo •

• 45% e -20°�
POWER (WATTS) REQUIRED 1 00%
165%
-250%-� ��8
04709G02
Fig. 42 Comparison of battery efficiency and engine demands at var­
ious temperatures
Cold cranking performance is measured by cool ing a fu l ly charged battery to
ooF (-1JCC) and then testing it for 30 seconds to determine the maximum cur­
rent flow. In this manner the cold cranking amp rating is the number of amps
available to be drawn from the battery before the voltage drops below 7.2 volts.
The i l lustration depicts the amount of power in watts avai lable from a battery
at different temperatures and the amount of power in watts required of the
engine at the same temperature. I! becomes quite obvious-the colder the cli­
mate, the more necessary for the battery to be fully charged.
Reserve capacity of a battery is considered the length of time, in minutes, at
80°F (2JCC), a 25 amp current can be maintained before the voltage drops
below 1 0.5 volts. This test is intended to provide an approximation of how long
the engine, including electrical accessories, could operate satisfactorily if the
stator assembly or l ighting coil did not produce sufficient current. A typical rat­
ing is 1 00 minutes.
If possible, the new battery shou ld have a power rating equal to or higher
than the unit it is replacing.
BATTERY LOCATION
Every battery installed in a boat must be secured in a wel l protected, venti­
lated area. If the battery area lacks adequate ventilation, hydrogen gas, which is
given off during charg ing, is very explosive. This is especially true if the gas is
concentrated and confined.
BATTERY SERVICE
• See Figures 43, 44 and 45
Batteries require periodic servicing and a definite maintenance program wi l l
ensure extended life. If the battery should test satisfactorily but sti l l fails to per­
form properly, one of four problems could be the cause.
1 . An accessory might have accidentally been left on overnight or for a long
period during the day. Such an oversight would result i n a discharged battery.
2. Using more e lectrical power than the stator assembly or lighting coi l can
replace would result in an undercharged condition.
3. A defect i n the charging system. A faulty stator assembly or lighting coi l ,
defective rectifier, o r h igh resistance somewhere in t he system could cause the
battery to become undercharged.
4. Failure to maintain the battery in good order. This might include a low
level of e lectrolyte in the cells, loose or dirty cable connections at the battery
terminals or possibly an excessively dirty battery top.
04709P02
Fig. 43 Explosive hydrogen gas is normally released from the cells
under a wide range of circumstances. This battery exploded when
the gas ignited from someone smoking in the area when the caps
were removed. Such an explosion could also be caused by a spark
from the battery terminals
I G N ITIO N AND ELECTRICAL SYSTEMS 5-43
04709P04
Fig. 44 A two part battery cable cleaning tool will do an excellent
job of cleaning the inside of the cable connectors
04709P05
Fig. 45 The second part of the battery cable cleaning tool contains a
brush for cleaning the battery terminals
Electrolyte level
• See Figures 46 and 47
The most common procedure for checking the electrolyte level in a battery is
to remove the cel l caps and visually observe the level in the cells. The bottom of
each cel l has a split vent which wi l l cause the surface of the e lectrolyte to
appear distorted when it makes contact. When the distortion first appears at the
bottom of the split vent, the e lectrolyte level is correct.
04709G03
Fig. 46 A check of the electrolyte in the battery should be on the
maintenance schedule for any boat
04709P03
Fig. 47 Testing the electrolyte's specific gravity using a temperature
corrected hydrometer
During hot weather and periods of heavy use, the e lectrolyte level should be
checked more often than during normal operation. Add disti l led water to bring
the level of e lectrolyte in each cell to the proper level. Take care not to overfil l ,
because adding an excessive amount o f water wi l l cause loss o f electrolyte and
5-44 I G N IT ION AND ELECTRICAL SYSTEMS
any loss wi l l result i n poor performance, short battery l ife, and wi l l contribute
qu ickly to corrosion.
�Never add electrolyte from another battery. Use only distilled water.
Battery Testing
A hydrometer is a device to measure the percentage of sulfuric ac id in the
battery electrolyte in terms of specific gravity. When the condition of the battery
drops from ful ly charged to discharged, the acid leaves the solution and enters
the plates, causing the specific gravity of the e lectrolyte to drop.
lt may not be common knowledge, but hydrometer floats are calibrated for
use at 80oF (27°C). If the hydrometer is used at any other temperature, hotter or
colder, a correction factor must be applied.
�Remember, a liquid will expand if it is heated and will contract if
cooled. Such expansion and contraction will cause a definite change in
the specific gravity of the liquid, in this case the electrolyte.
A qual ity hydrometer wi l l have a thermometer/temperature correction table in
the lower portion, as i l lustrated in the accompanying i l lustration. By knowing
the air temperature around the battery and from the table, a correction factor
may be applied to the specific gravity read ing of the hydrometer float. In this
manner, an accurate determination may be made as to the condition of the bat­
tery.
When using a hydrometer, pay careful attention to the following points:
1 . Never attempt to take a read ing immediately after adding water to the
battery. Allow at least % hour of charging at a high rate to thoroughly mix the
e lectrolyte with the new water. This time will also allow for the necessary gases
to be created.
2. Always be sure the hydrometer is clean inside and out as a precaution
against contaminating the e lectrolyte.
3. If a thermometer is an integral part of the hydrometer, draw l iqu id into it
several times to ensure the correct temperature before taking a reading.
4. Be sure to hold the hydrometer vertically and suck up l iqu id only unti l
the float is free and floating.
5. Always hold the hydrometer at eye level and take the read ing at the sur­
face of the l iqu id with the float free and floating.
6. D isregard the slight curvature appearing where the l iqu id rises against
the float stem. This phenomenon is due to surface tension.
7. Do not drop any of the battery fluid on the boat or on your clothing,
because it is extremely caustic. Use water and baking soda to neutralize any bat­
tery l iqu id that does accidental ly drop.
8 . After drawing e lectrolyte from the battery cell unti l the float is barely
free, note the level of the l iquid i nside the hydrometer. If the level is within the
Green band range for all cells, the condition of the battery is satisfactory. If the
level is within the white band for all cells, the battery is in fair condition.
9. If the level is within the Green or white band for al l cel ls except one,
which registers in the red, the cel l i s shorted internally. No amount of charging
wi l l bring the battery back to satisfactory condition.
1 0. If the level in a l l cel ls is about the same, even if it falls in the Red band,
the battery may be recharged and returned to service. If the level fails to rise
above the Red band after charg ing, the only solution is to replace the battery.
Battery Cleaning
Dirt and corrosion should be cleaned from the battery as soon as it is dis­
covered. Any accumulation of acid f i lm or d i rt wi l l permit current to flow
between the terminals. Such a current flow wil l drain the battery over a period of
time.
Clean the exterior of the battery with a solution of d i l uted ammonia or a paste
made from baking soda to neutralize any acid which may be present. Flush the
cleaning solution off with c lean water.
�Take care to prevent any of the neutralizing solution from entering the
cells, by keeping the caps tight.
A poor contact at the terminals will add resistance to the charging circuit.
This resistance will cause the voltage regulator to register a fully charged bat­
tery, and thus cut down on the stator assembly or l ighting coi l output adding to
the low battery charge problem.
Scrape the battery posts c lean with a suitable tool or with a stiff wire brush.
C lean the inside of the cable clamps to be sure they do not cause any resistance
in the circuit.
BATTERY TERMINALS
At least once a season, the battery terminals and cable clamps should be
cleaned. Loosen the clamps and remove the cables, negative cable first. O n bat­
teries with top mounted posts, the use of a pu l ler specially made for this pur­
pose is recommended. These are inexpensive and available in most parts stores.
C lean the cable clamps and the battery terminal with a wire brush, unti l al l
corrosion, grease, etc. , i s removed and the metal is sh iny. lt is especially impor­
tant to c lean the inside of the clamp thoroughly (a wire brush is useful here),
since a small deposit of foreign material or oxidation there will prevent a sound
electrical connection and inh ibit either starting or charging. lt is also a good
idea to apply some die lectric grease to the terminal, as this will aid in the pre­
vention of corrosion.
After the clamps and terminals are clean, reinstall the cables, negative cable
last, do not hammer the clamps onto battery posts. Tighten the clamps securely,
but do not distort them. Give the clamps and terminals a thin external coating of
grease after installation, to retard corrosion.
Check the cables at the same time that the terminals are cleaned. If the i nsu­
lation is cracked or broken, or if its end is frayed, that cable should be replaced
with a new one of the same length and gauge.
SAFETY PRECAUTIONS
Always follow these safety precautions when charg ing or handling a battery:
• Wear eye protection when working around batteries. Batteries contain cor­
rosive acid and produce explosive gas a byproduct of their operation. Acid on
the skin should be neutralized with a solution of baking soda and water made
into a paste. In case acid contacts the eyes, flush with c lear water and seek
medical attention immediately.
• Avoid flarne or sparks that could ign ite the hydrogen gas produced by the
battery and cause an explosion. Connection and disconnection of cables to bat­
tery terminals is one of the most common causes of sparks.
• Always turn a battery charger OFF, before connecting or disconnecting
the leads. When connecting the leads, connect the positive lead first, then the
negative lead, to avoid sparks.
• When lifting a battery, use a battery carrier or l ift at opposite corners of
the base.
• Ensure there is good ventilation in a room where the battery is being
charged.
• Do not attempt to charge or load-test a maintenance-free battery when the
charge indicator dot is i ndicating i nsufficient e lectrolyte.
• Disconnect the negative battery cable if the battery is to remain in the boat
during the charging process.
• Be sure the ignition switch is OFFbefore connecting or turning the
charger ON. Sudden power surges can destroy electronic components.
• Use proper adapters to connect charger leads to batteries with non-con­
ventional terminals.
BATTERY CHARGERS
Before using any battery charger, consult the manufacturer's instructions for
its use. Battery chargers are e lectrical devices that change Alternating Current
(AC) to a lower voltage of D irect Current (DC) that can be used to charge a
marine battery. There are two types of battery chargers-manual and autornatic.
A manual battery charger must be physically disconnected when the battery
has come to a fu l l charge. If not, the battery can be overcharged, and possibly
fail . Excess charging current at the end of the charg ing cycle will heat the e lec­
trolyte, resulting in loss of water and active material, substantial ly reducing bat­
tery l ife.
�As a rule, on manual chargers, when the ammeter on the charger reg­
isters half the rated amperage of the charger, the battery is fully
charged. This can vary, and it is recommended to use a hydrometer to
accurately measure state of charge.
Automatic battery chargers have an important advantage-they can be left
connected (for instance, overnight) without the possib i l ity of overcharging the
battery. Autornatic chargers are equipped with a sensing device to al low the bat­
tery charge to taper off to near zero as the battery becomes ful ly charged. When
charging a low or completely discharged battery, the meter wi l l read close to ful l
rated output. I f only partial ly discharged, the i n itial reading may b e less than fu l l
I G N IT ION AND ELECTRICAL SYSTEMS 5-45
rated output, as the charger responds to the condition of the battery. As the bat­
tery continues to charge, the sensing device monitors the state of charge and
reduces the charging rate. As the rate of charge tapers to zero amps, the charger
wi l l continue to supply a few mi l l iamps of current-just enough to maintain a
charged condition.
BATTERY CABLES
Battery cables don't go bad very often, but l ike anything else, they can wear
out. If the cables on your boat are cracked, frayed or broken, they should be
replaced.
When working on any electrical component, it is always a good idea to dis­
connect the negative (-) battery cable. This wi l l prevent potential damage to
many sensitive e lectrical components
Always replace the battery cables with one of the same length, or you wi l l
i ncrease resistance and possibly cause hard starting. Smear the battery posts
with a l ight f i lm of die lectric grease, or a battery terminal protectant spray once
you've installed the new cables. If you replace the cables one at a time, you
won't mix them u p.
�Any time you disconnect the battery cables, it is recommended that
you disconnect the negative (·) battery cable first. This will prevent you
from accidentally grounding the positive (+) terminal when disconnect­
ing it, thereby preventing damage to the electrical system.
STARTING CIRCUIT
Description and Operation
• See Figure 48
I n the early days, al l outboard engines were started by simply pu l l ing on a
rope wound around the flywheel . As time passed and owners were reluctant to
use muscle power, it was necessary to replace the rope starter with some form
of power cranking system. Today, many small engines are sti l l started by pul l ing
on a rope, but others have a powered starter motor installed.
The system util ized to replace the rope method was an electric starter motor
coupled with a mechanical gear mesh between the starter motor and the power­
head flywheel, s imi lar to the method used to crank an automobi le engine.
As the name impl ies, the sole purpose of the starter motor circuit is to con­
trol operation of the starter motor to crank the powerhead unti l the engine is
operating. The circuit includes a relay or magnetic switch to connect or d iscon­
nect the motor from the battery. The operator controls the switch with a key
switch.
Before you disconnect the cable(s), f irst turn the ignition to the OFFposition.
This will prevent a draw on the battery which could cause arcing. When the bat­
tery cable(s) are reconnected (negative cable last), be sure to check al l electrical
accessories are all working correctly.
BATTERY STORAGE
If the boat is to be laid up for the winter or for more than a few weeks, special
attention must be given to the battery to prevent complete discharge or possible
damage to the terminals and wiring. Before putting the boat in storage, disconnect
and remove the batteries. C lean them thoroughly of any dirt or corrosion, and then
charge them to full specific gravity reading. After they are fully charged, store them in
a clean cool dry place where they wi l l not be damaged or knocked over, preferably
on a couple b locks of wood. Storing the battery up oft the deck, wil l permit air to
circulate freely around and under the battery and wil l help to prevent condensation.
Never store the battery with anyth ing on top of it or cover the battery in such
a manner as to prevent air from circulating around the f i l ler caps. A l l batteries,
both new and old, wi l l d ischarge during periods of storage, more so if they are
hot than if they remain coo l . Therefore, the e lectrolyte level and the specific
gravity should be checked at regular intervals. A drop in the specific gravity
readi ng is cause to charge them back to a ful l reading.
In cold c l imates, care should be exercised in selecting the battery storage area.
A ful ly-charged battery wi l l freeze at about 60 degrees below zero. A d ischarged
battery, almost dead, wi l l have ice forming at about 19 degrees above zero.
A neutral safety switch is installed into the circuit to permit operation of the
starter motor only if the shift control lever is in neutral. This switch is a safety
device to prevent accidental engine start when the engine is i n gear.
The starter motor is a series wound e lectric motor which draws a heavy cur­
rent from the battery. it is designed to be used only for short periods of time to
crank the engine for starting. To prevent overheating the motor, cranking should
not be continued for more than 30-seconds without a l lowing the motor to cool
for at least three minutes. Actually, this t ime can be spent in making pre l im inary
checks to determine why the engine fails to start.
Power is transmitted from the starter motor to the powerhead flywheel
through a Bendix drive. This drive has a p inion gear mounted on screw threads.
When the motor is operated, the pin ion gear moves upward and meshes with
the teeth on the flywheel ring gear.
When the powerhead starts, the pin ion gear is driven faster than the shaft,
and as a result, it screws out of mesh with the flywheel. A rubber cushion is
bui lt into the Bendix drive to absorb the shock when the pin ion meshes with the
flywheel ring gear. The parts of the drive must be properly assembled for effiFLYWHEEL
8852BG5B
Fig. 48 A typical starting system converts electrical energy into mechanical energy to turn the engine. The components are: Battery, to provide
electricity to operate the starter; Ignition switch, to control the energizing of the starter relay or relay; Starter relay or relay, to make and break the
circuit between the battery and starter; Starter, to convert electrical energy into mechanical energy to rotate the engine; Starter drive gear, to
transmit the starter rotation to the engine flywheel
5-46 I G N IT ION AND ELECTRICAL SYSTEMS
cient operation. If the drive is removed for cleaning, take care to assemble the
parts as i l lustrated in the accompanying i l l ustrations in this section. If the screw
shaft assembly is reversed, it wi l l strike the splines and the rubber cushion wi l l
not absorb the shock.
The sound of the motor during cranking is a good indication of whether the
starter motor is operating properly or not. Naturally, temperature conditions wi l l
allect the speed at which the starter motor is able to crank the engine. The speed
of cranking a cold engine will be much slower than when cranking a warm
engine. An experienced operator wi l l learn to recognize the favorable sounds of
the powerhead cranking under various conditions.
Troubleshooting the Starting System
If the starter motor spins, but fails to crank the engine, the cause is usually a
corroded or gummy Bendix drive. The drive should be removed, cleaned, and
given an inspection.
1 . Before wasting too much time troubleshooting the starter motor circuit,
the following checks should be made. Many times, the problem will be cor­
rected.
• Battery fu l ly charged.
• Shift control lever in neutral.
• Main 20-amp fuse I ocated at the base of the fuse cover is good (not
blown).
• All e lectrical connections clean and tight.
• Wiring in good condition, insu lation not worn or frayed.
2. Starter motor cranks slowly or not at a l l .
• Faulty wir ing connection
• Short-circuited lead wire
• Shift control not engaging neutral (not activating neutral start
switch)
• Defective neutral start switch
• Starter motor not properly grounded
• Faulty contact point inside ignition switch
• Bad connections on negative battery cable to ground (at battery side
and engine side)
• Bad connections on positive battery cable to magnetic switch terminal
• Open circuit in the coil of the magnetic switch (relay)
• Bad or run-down battery
• Excessively worn down starting motor brushes
• Burnt commutator in starting motor
• Brush spring tension slack
• Short circuit in starter motor armature
3. Starter motor keeps running.
• Melted contact p late inside the magnetic switch
• Poor ignition switch return action
4. Starter motor picks up speed, put p in ion wi l l not mesh with ring
gear.
• Worn down teeth on clutch p inion
• Worn down teeth on-flywheel ring gear
5. Two more areas may cause the powerhead to crank slowly even though
the starter motor circuit is in excellent condition
• A tight or frozen powerhead
• Water in the lower un it.
Starter Motor
DESCRIPTION & OPERATION
• See Figures 49, 50, 51 and 52
As the name impl ies, the sole purpose of the cranking motor circuit is to
control operation of the cranking motor to crank the powerhead unti l the engine
is operating. The circuit includes a relay or magnetic switch to connect or dis­
connect the motor from the battery. The operator controls the switch with a key
switch.
A neutral safety switch is installed into the circuit to permit operation of the
cranking motor only if the shift control lever is in neutral. This switch is a safety
device to prevent accidental engine start when the engine is in gear.
The cranking motor is a series wound e lectric motor which draws a heavy
current from the battery. I! is designed to be used only for short periods of time
to crank the engine for starting. To prevent overheating the motor, cranking
should not be continued for more than 3D-seconds without allowing the motor
to cool for at least three minutes. Actually, this time can be spent in making pre­
l iminary checks to determine why the engine fails to start.
Power is transmitted from the cranking motor to the powerhead flywheel
through a Bendix drive. This drive has a pinion gear mounted on screw threads.
05005P04
Fig. 49 Typical location of the starter motor (OT55)
1
1 . Motor assy, starting
2. Relay, starter
3. Bracket, starter
05005G96
Fig. 50 Typical starter motor and relay assembly
CD Bracket
I G N IT ION AND ELECTR I CAL SYSTEMS 5-47
® Brush holder cover assy. ® Field coil case G) Brush (-) @ Brush (+) @ Brush holder assy. (j) Arm a tu re ® Pinion stopper set ® Pinion assy.
Fig. 51 Typical 3-brush starter motor assembly
CD Bracket
® Pinion stopper set
® Pinion assy.
@ Armature
@ Brush (+)
® Brush (-)
Fig. 52 Typical 2-brush starter motor assembly
CD
05005G97
05005G98
5-48 I G N IT ION AND ELECTR ICAL SYSTEMS
When the motor is operated, the pin ion gear moves upward and meshes with
the teeth on the flywheel ring gear.
When the powerhead starts, the pin ion gear is driven faster than the shaft,
and as a result, it screws out of mesh with the flywheel. A rubber cushion is
bui lt into the Bendix drive to absorb the shock when the p in ion meshes with the
flywheel ring gear. The parts of the drive must be properly assembled for effi­
cient operation. If the drive is removed for cleaning, take care to assemble the
parts as i l l ustrated in the accompanying i l lustrations in this section. If the screw
shaft assembly is reversed, it wi l l strike the spl ines and the rubber cushion wi l l
not absorb the shock.
The sound of the motor during cranking is a good indication of whether the
cranking motor is operating properly or not. Naturally, temperature conditions
will affect the speed at which the cranking motor is able to crank the engine. The
speed of cranking a cold engine will be much slower than when cranking a
warm engine. An experienced operator wi l l learn to recognize the favorable
sounds of the powerhead cranking under various conditions.
TESTING
• See accompanying il lustrations
1 . Using a multimeter, see if there is any continuity between the commutator
and armature core. The tester wi l l ind icate infin ite resistance if the insulation is
in good condition.
2. Using the tester, check for continu ity between each pair adjacent commu­
tator segment. If discontinu ity is noted at any part of the commutator, replace
the whole sub-assembly of the armature.
3. If the surface of the commutator is gummy or otherwise d i rty, wipe it off
with a cloth d ipped in kerosene. If the surface is coarse or in burnt, smooth it
with sandpaper. If the surface is grooved deeply, it may be necessary to
remove the grooved marks by turn ing the commutator in a lathe; such turn ing
is often successful in recond it ioning the commutator i f the extra stock neces­
sary for removal by cutting is avai lable without reducing its diameter to the
l im it.
05005G89
Step 1
Step 2
05005G91
Step 3
05005G92
Step 4
05005G93
Step 5
4. Using a multi meter, check to be sure that the positive brush holder is
insu lated from the negative brush holder. The tester should ind icate an absence
of any continuity between any two brush holders of opposite polarity. If continu­
ity is indicated, replace the brush holder.
5. Check the length of each brush. If the brushes are worn down to the ser­
vice l im it, replace them.
REMOVAL & INSTALLATION
• See accompanying i l lustrations
1 . Disconnect the negative battery cable.
2. Remove the engine cover.
3. Disconnect the starter relay electrical relay lead at the bul let connector.
Remove the ground wire.
I G N IT ION AND ELECTRICAL SYSTEMS 5-49
05005P06
Step 7
4. Disconnect the battery and starter cables.
5 . If equipped, remove the starter motor clamp.
6. Remove the mounting bolts holding the starter motor to the mounting
bracket.
7. Remove the starter motor.
To i nstal l :
8. Install the starter motor onto the mounting bracket. Do not forget to
install the clamp if so equipped.
9. Install the mounting bolts and tighten snugly.
1 0. Connect the starter motor cables. Make sure al l connections are tight
and free of any corrosion.
1 1 . Install the engine cover.
12 . Connect the negative battery cable
OVERHAUL
• See accompanying i l lustrations
The fol lowing is a typical starter motor overhaul procedure. Some models
may vary sl ightly.
1 . Remove the terminal nut and remove the motor cable.
2. Remove the two bolts from the bottom of the motor.
3. Separate the brush holder cover assembly and the two brush springs.
4. Separate the armature from the field coil case.
05005G80
Step 1
05005G81
Step 2
05005G82
Step 3
05005G83
Step 4
5-50
Step 5
Step 6
Step 7
Step 8
I G N IT ION AND ELECTRI CAL SYSTEMS
05005G84
05005G85
05005G86
05005G87
05005G88
Step 9
5. Remove the screw and nut to remove the brushes.
6. Push down on the pin ion stopper "A", remove the stopper ring "B" and
take oil the p in ion.
To assemble:
Assembly is the reverse of disassembly, but the following steps need to be
addressed during assembly.
7. Apply water resistant grease to the metal seals and brush holder cover.
8. When setting a brush to each brush holder, be sure to place a brush
spring in position before i nstall ing the brush.
9. When instal l ing the front cover and the holder cover in the field coil case,
al ign the mark "A" on the field coi l case with the mark "B" in both covers. When
instal l ing the holder cover, take care not to break the brush.
Starter Motor Relay Switch
DESCRI PTION & OPERATION
• See Figure 52
The job o f t he starter motor relay is to complete the circuit between the bat­
tery and starter motor. lt does this by closing the starter circuit electromagneti­
cally, when activated by the key switch. This is a completely sealed switch ,
which meets SAE standards for marine appl ications. DO NOT substitute an auto­
motive-type relay for this appl ication. lt is not sealed and gasol ine fumes can be
ignited upon starting the powerhead. The relay consists of a coil winding,
p lunger, return spring, contact disc, and lour externally mounted terminals. The
relay is installed in series with the positive battery cables mounted to the two
larger terminals. The smaller terminals connect to the neutral switch and
ground.
To activate the relay, the sh ift lever is placed in neutral, closing the neutral
switch. Electricity coming through the ignition switch goes into the relay coi l
winding which creates a magnetic f ie ld . The electricity then goes on to ground
in the powerhead. The magnetic field surrounds the p lunger in the relay, which
draws the disc contact into the two larger terminals. Upon contact of the termiI G N IT ION AND ELECTRI CAL SYSTEMS 5-51
05005P01
Fig. 53 Typical starter motor relay switch location
nals, the heavy amperage circuit to the starter motor is closed and activates the
starter motor. When the key switch is released, the magnetic field is no longer
supported and the magnetic field col lapses. The return spring working on the
plunger opens the disc contact, opening the circuit to the starter.
When the armature plate is out of position or the shift lever is moved into
forward or reverse gear, the neutral switch is placed in the open position and the
starter control circuit cannot be activated. This prevents the powerhead from
starting wh i le in gear.
TESTING
• See accompanying i l lustrations
The relay is usually trouble free. If there are suspected problems with the
relay, first test the battery. Then look up the starter circuit in the wiring diagram
05005G94
Step 1
05005G95
Step 2
for that particular model powerhead. Note that there are two circu its: the heavy
amperage starter motor circuit, and the control circuit from the key switch and
neutral switch. When the key is turned, l isten for a c l ick from the relay. If a
c l ick is heard, the control circuit is operating normally. Then test for voltage at
the starter motor. If there is voltage at the starter motor, a reading of below 9
volts with no starter action indicates a bad starter or resistance in the circuit. A
read ing at or near battery voltage indicates that the starter has an open circuit
inside.
If no c l ick is heard at the relay, use a jumper wire to jump between the
battery terminal of the relay and the "S" terminaL If it now works, the prob­
lem is i n the control circuit. Using a mu lti meter, test for voltage at the
neutral switch at the control (at both terminals). If there is no voltage, test at
the key switch , with the key switch in the start posit ion. Depending upon the
specific mode l , there may be a fuse between the battery and the ign ition
switch.
1 . To test the relay continu ity, use a multi meter to check whether conti­
nu ity exists between the two terminals of the relay with the battery con­
nected.
2. And when the battery is disconnected.
REMOVAL & INSTALLATION
1 . Disconnect the negative battery cable.
2 . Remove the engine cover.
3. Disconnect the starter relay electrical lead at the bul let connector.
Remove the ground wire.
4. Disconnect the battery and starter cables.
5. Remove the starter relay.
To install:
6. Install the starter relay.
7. Connect the battery and starter cables.
8. Connect the starter relay electrical lead at the bul let connector. Install the
ground wire.
9. Install the engine cover.
1 0. Connect the negative battery cable.
1 1 . Check the starting system for proper operation.
5-52 IGN ITION AND ELECTRICAL SYSTEMS
IGNITION AND ELECTRICAL WIRING DIAGRAMS
The following diagrams represent the most popular models with the most
popular optional equipment
1 988-96 DT2 and 1 997 DT2.2 Wiring Diagram
BI/R � BI/R
STOP SWITCH
WI R E COLOR
B . . . . . . . Black
B I/R . . . . . Blue with Red tracer MAGNETO
1988-98 DT4 and 1999 and later DTSY Wiring Diagram
I .__._.­I I I I I I r - - - - J •
o I 1 I : : : v l R
r-----------., rrl-,1 r�ii1
• I �LJ 'i)i,'t : Voltage I ty R ; : R t L-----�-----�� l regulator : f f : : I ,.-, :
'------�- - - --' : . .. !.1 1 8 I B I --- · I : :;., : • .. '-.: I ,' l ' ' - t' � ! "i
SI
_ _ _ _ _ ,
W/R
8
I �
( I I I I �
( I I ' I
Emergency Stop Switch
CAP ON -+ RUN
CAP OFF -+ STOP
R
' ... ·t· ,'
Rectifier • ..,,, Y-tube Receptacle
Engine Stop Switch
ON -+ STOP
OFF -+ RUN
B/R
C D I UNIT
W/R
8
8
l w / r···· I •• W r•••• " W • • .If. W .r••"t W
Or L.-- -!:;:T---1--"J-.;·-..* ---t��- - - - -t - ,.. - - -- - -f-rc:::: :c==�1- - ---------.., ....... 1 1 • : I -•· Battery r·····-y-t:i:�-----t�----·abt'_:_:� [:J-:Ja··---� -��- 1 2V
- - - - - - Optional
-�- R ·tube Plug L . • • . • J
Ignition Coil
IGN ITION AN D ELECTRICAL SYSTEMS 5-53
1990-98 DT4 and 1999-02 DTSY Wiring Diagram
MAGNETO
' ' l : ' '
BI/R
COl
UNIT
f- 0---cs:l--0 lit
I G NI TION
11 COI L
= --r r·---J i W/R ---1
I :
Y R B B ----1
: ' �---�---� � � � l � I I B1. j_ Y·TUBE • = -� ! l\' EM� AGENCY STOP SWITCH
1 2V 30W
l CAP ON -+ RUN W ? CAP OFF -+ STOP
L---1 : R-TUBE �::� RECEPTACL�
a.:-- -"
r-- -- ---1 f'ffiq PLUG ! ! L/.•f !.�'. l -r-�lo. ' I : : , L.- w --.,.J I ' ' L---------8 _ _ _ _ _ J
· · · · · · · OPTIONAL
MAGNETO
'
BI/R
i .-----" I v '---- WJ1D --"1.:J;t--+--- W/R ---1 �--8 --�J--+----B----� � � I
r---------... rt1 r-h I �.a...t d;!
lvOLTAGE : : l !
l R EGULATORr----t-- R - -�-�
I I : R I I Y r-� i L----�----� B � : B ' "' ' * , ,, , 11-, � - '* >: R ECTIF I ER
, , ,# Y·TUBE "(
EMERGENCY STOP SWITCH
CAP ON -+ RUN
CAP O F F -+ STOP
r--{>:3w.a:;�_::lw �:1----!l ! ., ___ ,. - - - - - - - OPTIONAL
i r..Ci:J---- Y --,
I t- : V IfA-TUBE � ;------: I I . • f ! L_ ______ B --- - - - -f·'fC21 fd-1--- B _j -t;- BATTE R Y l 1 t I : I -,-- 1 2V '--------- ·W - - -----.,-.E-:!1 �=::r·--W·--------�
R ECEPTACLE ;LUG
COl
UNIT
I
B
.,!..
- 0-c3J- O� ON
IGNITII
1 1 COI L
= -}
5-54 I G N IT ION AND ELECTRICAL SYSTEMS
IGNITION COIL
CD
1
OIL LEVEL SWITCH
REST O . ZL-ON
OIL LEVEL SWITCH
REST O . ZL-ON
1 988 DT8 Wiring Diagram
CONDENSER
CHARGING COIL
W/G � W/GI
G � G
B/R � B/R
B ---c3l-- B
RIB � R/B-
B
PULSER COIL I 1
BATTERY
CHARGING COIL
R -a :---:�:
y �--- y
MAGNETO
Y-TUBE FUSE ZOA r-------------!
W ---l--Sl-�---�--- w _ _ _ ! BATTERY -::�· --
: 1ZV35AH -:;�
B ---l--Sl- B l--- B - - - - - - - - - - - - - - - - -!
-- R-TUBE _ _ _ ;
RECEPTACLE PLUG
STOP SWITCH
PUSH-? STOP
0 EMERGENCY STOP SWITCH
CAP ON-?RUN
CAP OFF-7STOP
1 989-9 1 DT8 Wiring Diagram
CON>ENSER
CHARGING COIL PULSER COIL I 1
- - - · ' ' '
05005W04
WIG ---IL:}-- WIG ......... ,
i"'"'"'"'"'"'"'"'"'"'"'"'"'l
r.J VOLTAGE :........ B
---'.• :1 __ RE __ GULA _____T_OR ____ :
G ---IL:}-- G
81R ---IL:}-- 81R
8 --c:3J- 8
RIY --f:B::: � ----------.,..
-a ;�--- 8 ---(":;lt.;.� .. ,. .......................... . R .......... ,'" i :f: 1' RECTIFIER ;
Rl8 ---IL:}-- R/8 l � y -a--- y __________ _! � "" MAGNETO !
OIL LEVEL
II'I>ICATOR
8
8
PULSER COIL fZ 1____
_
_ ! f ................................................................................ r=-��---- W /R ---� .. -... ]--- W /R ............................... !
I I
: ! ·--- w -c-�--;- '[r- . _.r:-.=-�1, -- : 1 ZV35AH -:;�· ..........
! :::
8 ---L:--� _
__
j--- 8 -----------------!
STOP SWITCH
PUSH-? STOP
RECEPTACLE PLUG
0 EMERGENCY STOP SWITCH
CAP ON-?RUN
CAP OFF-?STOP
' ' ' !::
05005W4A
IGN ITION AN D ELECTRICAL SYSTEMS 5-55
1 988-02 DT6 and 1 982-97 DT8 Wiring Diagram
Pulser coi l
Lighting coi l
Receptacle ....-;:��ok-----W/R-C3:r-W/R
..-+-...._---- B/R---{3J--B/R
.---\----- B --tE}- B OPTION r - - - - - - --,
I
I
I
I
I
I
I
I I I I I I I I L - - - - - - --J
® c::J-R/Y
r-9--t:> @CJ-R B.J �
w� ©c:r-v
Yel low tube .- - - - --- --,
,------{> ® l I I I I I I I I
Emergency switch
BI/R �- 81/R BI/R
Engine stop switch
CDI
U N IT
L- - - - - - - -- - - -- - ------ - - - - -- -- - - - - - - - - 1 Yellow tube 1
w�w§w�w- l
Spark plug
R v s-W-el j_ 1 . r � U"·t : I
� - -
CHOKE
START
ON
OFF
�- -- - ----- ----- --- ----- - - -- - - - - - - - - - - - - - - - - - - - - - - - -J
.. "
OPTION
1 988-97 DT9.9 and DT15 Wiring Diagram
EMERGENCY STOP SWITCH
CAP ON - RUN
CAP OFF - STOP
�" --------------+" ·==rr�· w
: - - tUSE 20A ' BQ " " a> REMOTE CONTROL BOX l'JO> "' 0"' � J-j
�:��:�swiTcH
�v� coT::

ELAv
u BATTER� * 1
ACHO HOUR VOLT
-
12V 3SAH
L.y M- STARTING MOTOR E_T�R METER M�r:E_R _____ _ OPT.
5-56 I G N ITION AND ELECTRI CAL SYSTEMS
IGNITION COIL
IGNITION COil
1 989-97 DT 1 5C (Manual Start) Wiring Diagram
CONDENSER CHARGING COIL -��----�---� MAGNETO
COl UNIT
PULSER COIL #2
r--- - - - - - - -.
I o l BATTERY -f.­
l 1 2V 35AH -;:-
• I ' r--- w----------' ! . .�----8 -------------- -------'
RECEPTACLE PLUG
fO"ii:f'r-b STOP SWITCH ,r--8--------------� PUSH - STOP
OIL LEVEL SWITCH
REST 0.2 - ON
.,r-- 8
r-8
1 989-97 DT 1 5C (Electric Start) Wiring Diagram
CONDENSER CHARGING COIL ----- -- -- --- --,
MAGNETO
EMERGENCY
STOP SWITCH
CAP ON - RUN
CAP OFF - STOP
OIL LEVEL INDICATOR
OSOOSW07
PLUG
; - - - - - - w - - -(�-,/��; 1
BATTERY ( 1 :t' V I -_1.- l �-1 :
·r r- B --{_,-,,,�:J:i L _ _ _ .J
I G N IT ION AND ELECTRI CAL SYSTEMS
1 988 DT20 and DT25 (Manual Start) Wiring Diagram
PLUG SQCI
r- - - ,
I L.:l't- - - - - y - - -I ' I
I c.:::al- - - - Y/A t __ j
• In case of battery charging k1t bemg mounted
- - - - ------ optional
1 98 8 DT20 and DT25 (Electric Start) Wiring Diagram
IGNIT ION SWITCH
5-57
05005W11
OFF F�b i i . � "=: . . : ,•;t§l ··;·:: ;:'"" � E G l i L A TOR�
- - - -
8 - I
I t. _ _ _ _ __ J j n r uB£ "'" 'F: . . i ·· ·r··)1 1C":1 Bl · r r.___l· --o . . . . . . . . . . .
••• _ _ _ _ _ _:] L-������������������������ Bo �------�
--- - -- - - .optional
BATTERY
(12V. 35A.HI
A
$ 8
r---�--�-� YIG-------�
Bl!R
STARTER MOTOR
G TUBE
EMERGENCY STOP SWt·KH
PULl - ON !STOP I
05005W10
5-58 I G N IT IO N AND ELECTRI CAL SYSTEMS
- - - - - - - - Option
'-- -
- - - - - - - - Option
1 989 DT25C and DT30C Wiring Diagram
... ,,_ � 14:TER LIGHT �WITCH (�-.�� } _:_:::�---!.:��: __ �:.;· :��;!-;:.�, -·,·_,r,. -:: :b"9ifJ<>----�-:-r,:.:·� i.j___L ... ···t:::E+ .... • _.a Lcv- •··E23-
.:.:'::I .. ;!·j 1 i
"--- ---·-----, : [·�·��:�: -------------------- - ---- i .
· .. ____ ...- ::::::.::::::::::::::::=:::t l i A
I !){};�·�--: : : '· ___
.
,:. _ ,:','·
..
--·--·�

,-·---;,_�.,,-_;;:�_
-_:_)JI"'"'" �� ¥ .:�:�-:�-:-::�-�� t · �· ...
1 990 DT25C and DT30C Wiring Diagram
- - 1 !--------1
aATTIIIY
12V 11AH
NI.UfAAL IWITC:H
N - ON F.R-Off
IT ll
05005W12
05005W13
- - - - - - - Opt io n
L__ ­
'-- --
_ _ _ _ _ _ _ Optional parts
IGN ITION AND ELECTR ICAL SYSTEMS 5-59
1991 DT25C and DT30C Wiring Diagram
COOllNGWATIII&
Oil W .. IINING afJllU
5-60 I G N ITION AND ELECTRI CAL SYSTEMS
- � "

rf.. ... -' " . ..., ...
.•
G. < : � .
_j � m · ·a. 1.1.. "

1/.1 L�

a ···
•. I J J ·� �
... t I
1 98 8-89 DT3 5TC and DT40TC Wiring Diagram
EMERGENCY STOP SWITCH
CAP ON --- RUN
CAP OFF --- STOP
,-- --
M

AGNET
r o ____ _
IGNITION SWITCH � "'" '�' .l l� 1 1
. .
JTOI' Mn
a ��
.
10 lfAIU ,_,
I . .
L..-.-..
. J.
.- f-, [�
SPAR
I
..
O I L LEVEL
�-j� -�. RECTIFIER
COI UNIT I •••J
• �· -f+-1 • • " J, �
INDICATOR
YELLOW TuBe FUSE f20A)
0 j,� OVER HEAT SENSOR -,-_, m�. 1 Il n STARTER MOTOR � O N - IOl"C OFF - eo· c r' I � i � I � J, i R E Lt
�l r:nJ NEUTRAL swiTCH._ ·--- _ -- _ __ -- - - �� --r----1 ,
n" . J. j-'-- . :·_·.:.·:.·-�-==::_j O I L LEVEL SWITCH �� � N - ON J ; �:� • • •• • '· " - "" '"":�-:.:,tro• '---•· f---§:�.
�� .. f---.::Q-- 0 I
SPEF.OOMETEA SE NSOR � ·�· +�:n�J · � r· � � l l F.; .... ., �-.. � I � UP DOWN PT SWITCH
..
13-•
REMOTE CONTROL
BOX IMORSE)
�J:� '�"ro"�'" ' .: R E L;Y OOWN
PT MOTOR . �
1 98 8-89 DT35C and DT40C Wiring Diagram
O I L WAR N I NG LAMP�
R EST 0.5 L � ON

O I L LEV E L SWITCH
R EST 0.5 L � ON

� � L� � 81 8
ENGINE STOP SWITCH
ON - STOP O F F � RU N
r [JrJ=�r• � ·
·-
G-

81/A
�·-

EMERGENCY STOP SW ITCH
CAP ON � RUN
CAP O F F � STOP
81/A
Bii/A
81/A -+--..J

05005W69
05005W70
-
HIU
'
" ..
I G N IT ION AND ELECTRICAL SYSTEMS
1 988-89 DT35 CR and DT40CR Wiring Diagram
M AG N ETO
a � CAP CAP
I G N IT I O N SW ITCH
E M E RGE N C Y STOP SW ITCH 1.-- , -�---, .----� --,�
O N � R U N
O F F � STOP R T UBE
A R K e�G
CD��m , � f , _R E C�F I.: ' l STOf' I
I
.. , � . IQ ITAJIIT l ,�.

. '
=,J. - r-S P
..
U N IT w� r = �
r--t--. lr-=-:---W
y TUBE S E (20A)
5-61
� �l
�. 01
1
L LEV E L I N D I CATOR J � 1 O V E R H EAT SE NSOR l n '" STARTE R MOTO R RE LAY � � I R lill®..�rr .. -· l ?
� 1 � . �-r·._j ,

I . I
f �UZZE
0 I L L
C
E
H
VE L ll . iii "NEUT�:;:- - - -1- - -"L ,, r---E-:�G
��. · · Jf
SWI T �� !HI SWITCH --� ' it '" ' 'i O · C
�· ! BATT E R Y * A

;
T E R M I N A L R E S I N Q 1 2V 70AH l-- __)' '-- -----------1 *C · STARTE R MOTO R R E MOTE CONT R O L B O X (MORSE) J1H O K E SO L E N O I D
1!1 ii •
.. - � �
ITION ION
SW ITCH
� � <
-
Oil. WARNING LAW
RE'T 0 . �1-0N
� . .
1 1 • s �
m · �
:�
" U • • S
EMARGaiCY STOP SWITCH
CAP ON--RI.N
CAP OFF-STOP
lf • a
I
I'-----"
1 990-9 1 DT 40CE Wiring Diagram
@ i
81 .
p ..
.
SI
.
tEWTRAL
SWITCH
N - ON
F.R- OFF
05005W71
RECTIFIER
L--t--t- : � 8 1
- BATTERY STARTING
_L '1 T llV 70AH "' MOTOR ,!;-- •
05005W72
5-62 I G N ITION AND ELECTR ICAL SYSTEMS
1 990-9 1 DT 40CR Wiring Diagram
· · · · · · OPTION
1 990-9 1 DT 40TC Wiring Diagram
OFF -aooc
OVER HEAT
SENSOR r
ON - 101°C
CHOKE SOLENOID
ReCTIFIER
4--+-.1--- : �. 1
- BATTERY STARTING
j_ '} T tzv lOAH w woTOR ,!;----- •
05005W73
R
+ SATTE� STARTING T 12V ":J MOWR ; l l-·
05005W74
I G N ITION AND ELECTRICAL SYSTEMS 5-63
1 990-9 1 DT 40C Wiring Diagram
SPA R K PLUG
.r .r O I L L EV E L SW ITCH
R EST 0 . 5 L - ON
O I L WAR N I N G LAMP�
R E ST 0.5 L - O N
p � R ECEPTACL E
� �
E NG I NE STOP SWITCH
ON - STOP O F F • RUN
8
8 8<
ID-4--+---- •· --------:,_l �-��---- · ------�
�·.,·��t================= � er·
G
� · � E M E RG E NCY ST0' 5W ,TC" < CAP O N � R U N
O I L WAR N I N G LAMP�
R E ST 0 .5 L - ON
'

CAP O F F � STOP
1 992-98 DT40C Wiring Diagram
O I L L E V E L SWITCH
R EST 0.5 L - ON
G

� � . •.
RECEPTACLE
1 1 2V/30Wl
�· � E M E RG E NCY STOP SW'TC" < CAP O N � R UN
CAP OFF - • STOP
8!1A
05005W75
811A
R E CTI F I E R
- - - - - - OPT ION
05005W76
5-64 I G N IT ION AN D ELECTRI CAL SYSTEMS
� �
liON ION I
SW ITCH
i ! <
OIL WARNING LAAf'"
REST 0 . 51 - 0N

� ! l l
m . �
. � ::�
u � . � . .
EMARGE.NC'f STOP SWITCH
CAP ON--Rlfol
CAP OFF-STOP
. . .
I '---1--'
1 992-98 DT40CE Wiring Diagram

� i
" � ..
.
'"
.
. . .
11 '
HEWTRAL
SWITCH N - ON
F.R- OFF
- - - - - - OPTION
1 992-98 DT40CR Wiring Diagram
hrtm=:
OIL FLOW
SENSOR o
USUAL POSITION-Of'F �
I® . l lJ- - - - - - OPTION
RECTIFIER
1
j_ 'j - BATTERY STARTING T 1ZV 70AH M MOTOR � ·
05005W77
RECTIFIER
'-+-+-+-- : � ' 1
i l. .... ..... ... . . .. .
- BATTERY STARTING
...1.. 'j T lZV 70AH .. MOTOR ,!;--- •
05005W78
I G N IT IO N AND ELECTRICAL SYSTEMS
1 992-93 DT40TC Wiring Diagram
,-
-----"iMAGNETOr-----, l l 11 I I I
I 8 n· � R
ii ii :
OVERHEAT q � ��N���,ocf f. :
Off - aooc ! !
� � n r·�� . : � L n� ii: � ID ID ): e - -1-- - - - - - L---- - - -�- - - - - - -- ---
5-65
R -d.- BAnE� STAATINI3 T "V ":J MOTOR
.;, l 1--·
CHOKE SOlENOID
1 988 DT55C and DT65 C (Australia) Wiring Diagram
""'-- l�
ooc '"" •mcH �
05005W79
!OlfSI'E£0
ADJUSTMENT SWITCH
05005W29
5-66 I G N IT ION AND ELECTRICAL SYSTEMS
-�·- :·.-� : �(T£1UGtllSI'otlCH: �:���,-�6� '
. . . . . OPTION
1 988 DT55TC and DT65TC (Australia) Wiring Diagram
1 98 8 DT55C and DT65C (Except Australia) Wiring Diagram
CHOKE SOLENOID
A{C I I f i [ A &
JUGUlA lOA - - - - - - -; - - - .r--·--; _ _
. --� : : L-----�..1 ..l.
05005W30
STARTING _[' ·�:V� t � S M STARTING MOTOR
BAnERY STARTING
12V 1GAH MOTOR Rh AY
05005W31
UtERGENCY i Jf' SWHCH
CAI'ON - R U ..
CAPOFf · STO�
I G N IT ION AND ELECTRICAL SYSTEMS
1 98 8 DT55TC and DT65TC (Except Australia) Wiring Diagram
COc
SE'<-
r . f' � - 0
. . t, oo�tjl:.
5-67
05005W32
05005W33
5-68 I G N ITION AN D ELECTRI CAL SYSTEMS
......... OPTION
1 989 DT55 and DT65 Wiring Diagram
1 990-9 1 DT55 and DT65 Wiring Diagram
9 Oil .... liNING RESET SWITCH � P\.ISH -ON
-=:�=�� u -[ .. ··-·· ·-- .l'J �:;.·_-- . -=--- -------��--?"-=-- �-: - ------- ---- ------- --
05005W34
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I G N ITIO N AND ELECTRI CAL SYSTEMS 5-69
1 992 DT55 and DT65 Wiring Diagram
Otl YM.RNINO MSET SWITCH PUSH -ON
1 990-9 1 DT55HTC Wiring Diagram
05005W36
05005W37
5-70 I G N IT ION AND ELECTRI CAL SYSTEMS
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1 988 DT75 and DT85 Wiring Diagram
1 988 DT75CR and DT85CR Wiring Diagram
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05005W46
05005W47
I G N IT ION AND ELECTRICAL SYSTEMS 5-71
1 989 DT75 CR and DT85CR Wiring Diagram
01\.--NGMUT IWifCH �-�
lllMOT!COIWTIIOlBOX
1 989 DT75TC and DT85TC Wiring Diagram
Oll-IWifiiGfl[s.t:T .WITCH
PO$H - ON
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NOTE: The tachometer and trim meter are standard
equipmemts for Australian version.
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05005W48
05005W49
5-72 I G N IT ION AN D ELECTRI CAL SYSTEMS
1 990-9 1 DT75 and DT85 Wiring Diagram
05005W50
1 992-94 DT75 and DT85 Wiring Diagram
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05005W51
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6 GEAA COUNHNGCOil
IGN ITION AN D ELECTR ICAL SYSTEMS 5-73
1 995-97 DT75 and 1995-00 DT85 Wiring Diagram
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1 989-91 DT90 and DT100 Wiring Diagram
5-74 IGN ITION AN D ELECTR ICAL SYSTEMS
WIRJ: r.:mOA
1992-97 DT90 and 1992-00 DT100 Wiring Diagram
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1988-89 DT1 1 5 and DT140 Wiring Diagram
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ENGINE TEMP SENSOR
IGN ITION AN D ELECTR ICAL SYSTEMS
1 990 DT1 15 and DT140 Wiring Diagram
TR!M SENOOR
OIL W..RNING RESET SWITCH
PUSH �ON
1991-95 DT1 1 5 and DT140 Wiring Diagram
TRIM SENOOR
5-75
1996-01 DT1 15 and DT140 Wiring Diagram
OIL WARNING PTT SWITCH RESET SWITCH Oil FlOW SENSOR
CYliNDER WAll
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\2 J NEUTRAl SWITCH
18 i STARTER MOTOR RELAY
(.il THROTTLE VALVE SENSOR
l 5 l 1NJECTOR POWER SOURCE COIL � ··J CONDENSER CHARGE COIL !HIGH!
\7 I CONDENSER CHARGE COIL !LOW I
' 8 ' BATTERY CHARGE COIL
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1 996-01 DT1 1 5 and DT140 Engine Control System Wiring Diagram
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EMERGENCY
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ATMOSPHERIC
PRESS. SENSOR
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TEMP. SENSOR
AIR TEMP.
SENSOR
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I � il14)1 j � i GROUND
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1 5 . D iagnosis lamp si gnal output
16 . Ground
1 7. #1 i gnit ion signal output
1 8 . #2 ignit ion s ignal output
1 9. #3 ign it ion si gnal output
20. #4 i gn it ion si gnal output
21 . Pulser co i l i nput
22. Pu lser coi l output
23. Gear count coi l i nput
24. Gear count coi l i nput
25. Engine stop signal i nput
26. Reset switch si gnal i nput
27. Oi l flow sensor signal i nput
28. Atmospheric press. sensor signal i nput
29. Low oil level switch signal input
30. Atmospheric press. sensor power output
31 . (To ground @)
32. Buzzer signal output
33. Over rev. lamp signal output
34. Overheat lamp si gnal output
35. #1 i njector power output
36. #1 i njector ground
37. #2 injector power output
38. #2 injector ground
39. #3 i njector power output
40. #3 i njector ground
OVER HEAT -LED 41 . #4 i njector power output
DIAGNOSIS LED
42. #4 i njector ground
43. TVS power output
LOW OIL LEVE LED 44. TVS signal input
45. TVS ground
O I L F L O W L E D 46. Fuel pump ground
47. Fuel pump power output
48. Ai r temp. sensor power output
49. Air temp. sensor ground
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5-78 I G N IT ION AND ELECTRICAL SYSTEMS
1 988 DT 1 50, DT 1 75 and DT200 Wiring Diagram
05005W63
1 989-90 DT 1 50, DT 1 75 and DT200 Wiring Diagram
! RECTIFIER & REG<.RATOR g GEAR COUNT!NG CO!l
2 CYUNDER TEMP SENSOII
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1 1 OVERHEAT I. OIL WARNING BUZZER
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IGN ITION AN D ELECTR ICAL SYSTEMS 5-79
1 991-93 DT150, DT175 and DT200 Wiring Diagram
1 994-03 DT150 and 1994-00 DT200 Wiring Diagram
5-80 IGN ITION AND ELECTRICAL
DT175 and DT200 Twin Remote Control Wiring Diagram
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1990-03 DT225 Wiring Diagram
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OIL INJECTION SYSTEM 6-2
DESCR IPT ION AND O PERATION 6-2
O I L PUMP 6-2
AIR/O I L M IXING VALVE 6-2
TROUBLESHOOTING THE O I L I NJ ECTION
SYSTEM 6-2
B LEEDING THE O I L I NJECTION
SYSTEM 6-3
PROCEDURE 6-3
O I L TAN K 6-3
REMOVAL & I NSTALLATION 6-3
C LEANING & I NSPECTION 6-4
O I L PUMP 6-5
REMOVAL & I NSTALLATION 6-5
O I L L INES 6-6
O IL L INE CAUTIONS 6-6
REMOVAL & I NSTALLATION 6-6
AIR/O IL MIX ING VALVE 6-7
REMOVAL & INSTALLATION 6-7
O I L PUMP D ISCHARGE RATE 6-7
TESTING 6-7
ADJUSTMENT 6-8
O I L PUMP CONTROL ROD 6-8
ADJUSTMENT 6-8
COOLING SYSTEM 6-1 1
DESCR IPT ION AND OPERATION 6-11
WATER PUMP 6-11
THERMOSTAT 6-12
TROUBLESHOOTING THE COOL ING
SYSTEM 6-12
WATER PUMP 6-12
REMOVAL & I NSTALLATION 6-12
C LEAN ING & I NSPECTIO N 6-13
THERMOSTAT 6-13
REMOVAL & I NSTALLAT ION 6-13
C LEANING & INSPECTION 6-14
OIL INJECTION WARNING
SYSTEMS 6-1 4
DESCR IPTIO N AND OPERATION 6-14
LOW O I L LEVEL 6-14
OIL FLOW 6-14
TROUBLESHOOTING THE Olt INJECTION
WARN ING SYSTEM 6-15
O I L LEVEL SENSOR 6-1 6
TESTING 6-16
REMOVAL & INSTALLATION 6-16
O IL FLOW SENSOR 6-1 7
TESTING 6-1 7
REMOVAL & I NSTALLAT ION 6-17
C LEANING & INSPECTION 6-1 7
OVERHEAT WARNING
SYSTEM 6-1 7
DESCR IPT ION AND OPERATION 6-17
TROUBLESHOOTING THE OVERHEAT
WARN ING SYSTEM 6-17
OVERHEAT SENSOR 6-19
REMOVAL & I NSTALLATION 6-19
TESTING 6-19
SPECIFICATIONS CHARTS
O I L PUMP D ISCHARGE RATE 6-8
TROUBLESHOOTING CHARTS
O I L I NJ ECTIO N WARN ING
SYSTEM 6-15
OVERHEAT WARN ING SYSTEM 6-1 8
6-2 O I L I NJ ECTION
Oil INJECTION SYSTEM
Description and Operation
Suzuki is the originator of outboard oi l injection, introducing it to the marine
industry in 1 980. Because of years of experience in motorcycle oi l injection
technology, Suzuki applied many of those proven principles to their outboard
motors.
The o i l injection system automatically adjusts the amount of oil to a clean
burning 1 50:1 fuel/oil ratio. Then as engine rpm increases, the ratio changes
gradually to a 50: 1 mixture at fu l l throttle for greater lubrication.
OIL PUMP
• See Figures 1 and 2
The heart of oi l injection system is a precision d ie cast Mikuni oi l pump
which is gear driven directly by the engine's crankshaft. This mechanical l ink
CD Oil pump CV Driven gear
@ -Retainer
@ Oil pump control rod
Fig. 1 Exploded view of a typical oi l pump
Fig . 2 Oil flow through the powerhead
05006G07
05006G09
between engine rpm and the pump means that oi l is metered without hesitation
in exactly the correct ratio at all throttle openings. To min imize smoke and pos­
sible carbon bui ld-up at id le speeds
Once the oil leaves the Mikuni pump, it travels through o i l l i nes to distribu­
tion nozzles located downstream of the carburetor or throttle body. The nozzles
then inject the oil d irectly into the incoming air/fuel mixture. This thoroughly
mixes the oil, air and fuel before it enters the combustion chamber in order to
provide optimum lubrication.
AIR/O IL MIXING VALVE
• See Figure 3
On some models, a pre-atomization or mixing valve a l lows a small amount
of crankcase pressure to be injected into the oil l i nes just before oil reaches
the distribution nozzles. This forces thousands of tiny air bubbles into the oi l
f low before it gets to the combustion chamber. The atomized o i l stream is
therefore more un iformly distributed throughout the engine for superior l ubri­
cation.
05006G08
Fig. 3 The air/oil mixing valve accelerates the separation of the
injection oil into fine particles
Troubleshooting the O i l Injection System
Like other systems on a 2-stroke engine, the o i l injection system empha­
sizes s impl ic ity. On pre-mix engines, when enough o i l accumulated in the
crankcase it passed into the combustion chamber where it burned along with
the fue l . Since oil is a fuel just l i ke gasol ine , it burns as wel l . Un l i ke gaso­
l ine , o i l doesn't burn as efficiently and may produce b lue smoke that is seen
coming out of the exhaust. If the engine was cold, such as during in itial
start-up, oil has an even harder t ime ignit ing resulting i n excessive amounts
of smoke.
Other problems, such o i l remaining in the combustion chamber, tend to foul
spark plugs and cause the engine to misfire at idle. Most of these problems
have been al leviated by the introduction of automatic oil i njection systems.
�one of the most common problems with oil injection systems is the
use of poor quality injection oil. Poor quality oil tends to gel in the sys­
tem, clogging lines and filters.
lt is normal for a 2-stroke engine to emit some blue smoke from the exhaust.
The blue col or of the smoke comes from the burning 2-stroke o i l . An excessive
amount of blue smoke indicates too much o i l being injected into the engine. On
Suzuki engines, this is usually caused by an incorrectly adjusted injection con­
trol rod.
If the exhaust smoke is white, this is a sign of water entering the combustion
chamber. Water may enter as condensation or more seriously may enter through
a defective head gasket or cracked head. Usually white smoke from condensa­
tion wi l l disappear quickly as the engine warms.
If the exhaust smoke is black, this is a sign of an excessively rich fuel mix­
ture or incorrect spark plugs. The black col or of the smoke comes from the fuel
burning.
'
Bleeding the O i l Injection System
PROCEDURE
• See Figure 4
1 . Place the engine in the ful l upright position.
2. Remove the engine cover.
3. Connect the outboard to a fuel tank contain ing a 50:1 pre-mix fuel.
4. Fill the oi l tank to the recommended level.
�If the oil pump was removed, fill the oil lines with oil before recon­
necting them to the pump fittings.
5. Place a suitable container under the air bleed screw to catch the 2stroke oil whi le bleeding.
6. Remove any access covers and open the air bleed screw on the injection
pump 3 turns counterclockwise.
7. Start the engine and maintain engine idle speed during the bleeding
process.
�To speed the bleeding process it is possible to disconnect the oil
pump link arm and move it to the full output position.
8. Let the engine idle until the oil leaving the oil pump air bleed screw is
free of air bubbles and no air can be seen in the clear plastic o i l injection l i nes.
�on engines using solid color lines, the lines should be disconnected
an allowed to drain into a pan.
9. Stop the engine and retighten the screw.
1 0. Install the engine cover. B leed screw
05006G15
Fig. 4 On engines using solid color lines, an air bleed screw is
sometimes used to bleed the system
O I L I NJ ECTION 6-3
Oi l Tank
REMOVAL & INSTALLATION
• See accompanying i l lustrations
** WARNING I
Proper oi l l ine routing and connections are essential for correct oi l
injection system operation . The l ine connections to the powerhead
and oil pump look the same but may contain check valves of differ­
ing cal ibrations. Oil l ines m ust be instal led between the pump and
powerhead correctly and connected to the proper fittings on the
intake manifold in order for the system to operate properly.
1 . Turn the battery switch off and/or disconnect the negative battery cable.
2. Remove the engine cover.
3. Position a suitable container under the lower cowl ing to receive o i l
drained from the tank.
4. Matchmark the oil l i ne for installation reference.
5. Squeeze the o i l l ine to restrict the flow of o i l whi le pu l l i ng it free from
the fitting.
6. Remove the clamp with a pair of p l iers.
05006P27
Step 6
6-4 O I L I NJ ECTION
05005P12
Step 1 7
7 . Sl ide the clamp u p along the o i l l i ne to get i t out of the way.
8. Cap the end of the oi l l ine to prevent o i l leakage and cap the fitting at
the o i l pump to prevent dirt entering the system.
9. Remove the fasteners attaching the o i l tank to the powerhead.
1 0. Lift the o i l tank away from the powerhead slowly and disconnect the oi l
level sensor electrical harness.
1 1 . Remove the tank from the powerhead.
To install:
1 2. Position the oi l tank on the powerhead after connecting the oil level sen­
sor electrical harness.
05006P07
Step 1 6
1 3. Install the o i l tank and tighten the fasteners securely.
14. Squeeze the oil l i ne to restrict the flow of oil wh i le insta l l ing.
15 . Remove the caps and install the o i l l i ne at its original location.
** WARNING
Oi l l i nes must be reinstal led with the same type of c lamps as
removed . The use of a screw type c lamp wi l l damage the vinyl
line wh i le a tie strap will not p rovide sufficient c lamping pres­
sure.
1 6. Instal l the clamp with a pair of p l iers and push the clamp up past the r ib
on the n ipple.
1 7. Ensure a l l the original o i l l i ne protection, is put back in place.
1 8. Turn the battery switch off and/or disconnect the negative battery
cable.
1 9. Start the powerhead and bleed the air from the oil injection sys­
tem.
20. Check for proper oi l injection system function.
21 . Install the engine cover.
CLEANING & INSPECTION
One of the most common problems with oi l injection systems is the use of
poor qual ity injection oil. Poor qual ity oi l tends to gel in the system, clogging
l i nes and filters. If this is found to be the case with your system, or 1f the power­
head has been sitting in storage for a length of time, it is wise to remove the o i l
tank and clean it with solvent.
While the oil tank is removed, take the opportunity to inspect it for damage
and replace it as necessary. The o i l tank is the only source of o i l for t�e p�wer­
head. If it should leak, the powerhead wi l l eventually run out of Injection 01 1 ,
with catastrophic and costly results. Remember, there are no parts stores when
you are m i les out at sea.
Oi l Pump
REMOVAL & INSTALLATION
• See accompanying illustrations
** WARNING
Proper oil l ine routing and connections are essential for correct oil
injection system operation. The line connections to the powerhead
and oil pump look the same but may contain check valves of differ­
ing calibrations. Oil lines must be instal led between the pump and
powerhead correctly and connected to the proper fittings on the
intake manifold in order for the system to operate properly.
1 . Turn the battery switch off and/or disconnect the negative battery cable.
2 . Remove the engine cover.
3. Position a suitable container under the lower cowling to receive oi l
drained from the tank.
4. Remove the oil tank.
5. Disconnect the o i l pump control rod at the throttle lever.
6. Mark the exact location of each oi l l i ne for installation reference.
7. Remove the oil l i nes and cap the ends to prevent oil leakage.
8. Cap the fittings at the oil pump to prevent d i rt from entering the system.
9. On models equipped with banjo fittings, only remove the fittings if they
are to be replaced.
1 0. Loosen the oil pump mounting hardware.
05006P14
Step 9 Step 1 0
O I L I NJ ECTION 6-5
1 1 . Remove the o i l pump from powerhead.
12 . Carefu l ly pry the driven gear retainer and gasket loose using a putty
knife.
1 3. Remove the retainer, gasket and driven gear assembly from the powerhead.
To instal l :
14 . Clean the gasket mating surfaces thoroughly.
1 5. If the pump is to be replaced but the oil l ines reused, matchmark the
location of al l oil l i nes on the pump for installation reference.
1 6. If the pump and oil l i nes are to be replaced, ensure the oil l i nes are
f i l led with 2-stroke oi l prior to starting the powerhead.
1 7. Install the retainer and driven gear assembly on the powerhead using a
new gasket.
1 8. Position the o i l pump on the powerhead and tighten the mounting hard­
ware securely.
1 9. Connect the oil pump control rod at the throttle lever.
20. If the banjo fittings were removed, always use new gaskets during instal­
lation .
21 . Position the banjo fittings as i l lustrated and tighten securely.
22. If the o i l l i nes are to be reused, trim a small amount (% in . ) off the end
prior to connecting to ensure a t ight fit.
23. Connect the oil l i nes to their proper locations.
24. Install the oil tank.
25. Bleed the oil injection system.
26. Connect the negative battery cable and/or turn the battery switch
on .
27 . Check the oi l pump discharge rate.
28. Install the engine cover.
05006P15 05006P16
Step 1 1
6-6 O I L I NJ ECTION
Oi l lines
OIL LINE CAUTIONS
1 . Do not bend or twist the oi l l i nes when instal l ing.
2. When instal l ing cl ips, position the tabs toward the inside and make sure
they are not in contact with other parts.
3. Check the oi l l i nes, when instal led in position, do not come in contact
with rods and lever during engine operation
4. lnsall the oil sensor and oil l ines with the sensor's arrow mark pointing
to the oi l pump side.
5. Secure al l valves and sensors using their original fasteners.
6. Install hose protectors in their original positions.
7. Extreme caution should be taken not to scratch or damage oil l i nes.
8. Do not excessively compress an o i l l ine when instal l ing clamps.
9 Always use factory type clamps when instal l ing fuel l i nes. Never use
screw type clamps.
1 0. When instal l ing the oi l tank, ensure oil l i nes wil l not be pinched
between the tank and the powerhead.
REMOVAL & INSTALLATION
t See Figures 5 thru 1 2
Proper oi l l i ne routing and connections are essential for correct o i l injection
system operation. The l i ne connections to the powerhead and oil pump look
the same but may contain check valves of differing calibrations. Oil l i nes must
05006G11
be installed between the pump and powerhead correctly and connected to the
proper fittings on the intake manifold in order for the system to operate prop­
erly.
1 . Turn the battery switch off and/or disconnect the negative battery cable.
2. Remove the engine cover.
3. Position a suitable container under the lower cowling to receive o i l
drained from the tank.
4. Remove the oil tank.
5. Mark the exact location of each oil l i ne for installation reference.
6. Remove the clamps with a pair of p l iers and push the clamps up along
the o i l l i nes.
7. Cap the ends of the oil lines to prevent oil leakage and cap the fitting at
the oi l pump to prevent dirt entering the system.
To install:
8. If the oi l l i nes are to be reused, trim a small amount (% in.) off the end
prior to connecting to ensure a tight lit.
9. Ensure the oil l ines are filled with 2-stroke oil prior to starting the pow­
erhead.
1 0. Connect the oil l ines to their proper locations.
1 1 . Position the clamps using pl iers.
.,.Do not use screw type clamps as they may damage the oil lines and
cause oil leaks.
12 . Install the oil tank.
1 3. Bleed the o i l injection system.
14 . Connect the negative battery cable and/or turn the battery switch on.
15 . Check the oi l pump discharge rate.
1 6. Install the engine cover.
05006G12
CD Threadlocking compound ® Union fitting @ Washers
05006G14
Fig. 5 Some oil lines need to be posi­
tioned at specific angles to the oil pump .
Fig. 6 . . . and to the power head for
proper oil flow
Fig. 7 Some powerheads use outlet unions
for oil hose connection. Properly position
the unions for leak proof operation
05006G21
05006G01
Fig. 8 Oil hose routing schematic-DT55 and DT65 Fig. 9 Oil hose routing schemalic-DT225
05006G22
Fig. 10 Oil hose routing schematic-DT115 and DT140
05006G23
Fig. 11 Single point oil injection system hose routing schematic­
DT75 and DT85
To No. 2 intake To No. 3 intake
To No. 1 intake
Oil pump
Oil pump
Oil flow sensor
05006G24
Fig. 12 Multi point oil injection system hose routing schematic­
DT75 and DT85
O I L I NJ ECTION 6-7
Air/Oi l Mixing Valve
REMOVAL & INSTALLATION
1 . Remove the eng ine cover.
2. Position a suitable container to receive o i l discharged when the hoses are
disconnected.
3. Disconnect and plug the oil l i nes connected to the valve.
4. Remove the valve from the powerhead.
To insta l l :
5. Clean and inspect the valve. Replace as necessary.
6. Install the valve on the powerhead.
7. Connect the oil l i nes to the valve and secure them with the clamps, as
required.
8. Install the engine cover.
Oi l Pump D ischarge Rate
TESTING
DT8, DT9.9 and DT15
1. Connect the outboard to a fuel tank containing a 50:1 pre-mix fuel.
2. Disconnect the oil l i ne from the reservoir to the oi l pump.
3. Cap the line to prevent oi l from spi l l i ng during this procedure.
4. Install an engine oil measuring cylinder (09900-21 602) or equivalent
graduated cylinder on the powerhead.
5. F i l l the cylinder with o i l and bleed the o i l injection system.
6. Install a tachometer, start the engine and maintain an engine speed of
1 500 rpm.
7. Select a clean-cut value on the scale of the oil measuring cylinder as a
reference point.
8. Run the engine at 1 500 rpm for the next 5 minutes.
9. Note the amount of o i l discharged by the pump. This is the volume of
oil from your reference point to the point at the end of 5 minute period.
1 0. Compare the discharged oi l volume with the "Oil Pump Discharge Rate"
chart
,..Oil pump output test results may vary slightly depending on tempera­
ture and testing conditions.
1 1 . If the oil discharge rate is not within specification, check the injection
lines for possible leaks.
1 2. If the injection l i nes are dry, the oil pump may be faulty.
Except DT8, DT9.9 and DT15
1. Connect the outboard to a fuel tank containing a 50:1 pre-mix fuel .
2. Disconnect the oi l l i ne from the reservoir to the o i l pump.
3. Cap the l ine to prevent oi l from spi l l ing during this procedure.
4. Install an engine oil measuring cylinder (09941 -8710 or 0990-21 602)
or equivalent graduated cylinder on the powerhead.
5. F i l l the cylinder with oil and bleed the oil injection system.
6. Install a tachometer, start the engine and maintain an engine speed of
1 500 rpm.
7. Select a clean-cut value on the scale of the oil measuring cylinder as a
reference point.
8. Manually position the oil pump control rod in the fu l ly closed posi­
t ion.
9. Run the engine at 1 500 rpm for the next 5 minutes.
1 0. Note the amount of oil discharged by the pump. This is the volume of
o i l from your reference point to the point at the end of 5 minute period.
1 1 . Refill the oi l measuring cylinder.
12 . Select a clean-cut value on the scale of the oi l measuring cylinder as a
reference point.
1 3. Manually position the oi l pump control rod in the fu l ly open position.
14. Run the engine at 1 500 rpm for the next 2 minutes.
15. Note the amount of oil discharged by the pump.
1 6. Compare the discharged oi l volume from the two tests with the "Oi l
Pump Discharge Rate" chart.
6-8 O IL I NJECTION
O i l Pump Discharge Rate
Oil Pump Discharge Rate @ 1 500 rpm
Year Model Fully Closed (ml) Fully Open (ml)
1998-97 8
1 988-97 9.9
1 988-97 1 5
1 988-00 25, 30
1988-98 35, 40
1988-89 55
1988-98 65
1 988-97 75
1 988-00 85
1 998-00 90, 1 00
1 988-96 1 1 5
1996-01 1 1 5
1988-95 140
1 996-01 140
1 988-94 150
1995-03 150
1998-03 150TC
1985-03 150STC
1988-92 1 75
1 988-97 200
1998-00 200
1 990-03 225
• Oil pump output test results may vary slightly depending on
temperature and testing conditions.
1 7. If the oil discharge rate is not within specification, check the injection
lines for possible leaks.
1 8. If the injection lines are dry, the oil pump may be faulty.
ADJUSTMENT
• See Figure 13
• Oil pump control discharge adjustment should only be necessary if
the oil pump is removed for service.
Throttle linkage adjustment is an integral step in adjusting the oil control
rod.
1 . Remove the engine cover
2. Move the throttle to the wide-open position.
3. Ensure that the full-throttle mark on the oil pump control lever aligns
with the matchmark on the housing.
4. Close the throttle.
5. Ensure that the closed-throttle mark on the oil pump control lever
aligns with the match mark on the housing.
6. If the marks do not align adjust the control rod or cable as necessary.
7. On rod operated systems, disconnect the control rod from the lever.
Loosen the locknut and rotate the rod end as necessary to bring the
match marks into adjustment. Tighten the locknut and connect the control
rod.
8. On cable operated systems, loosen the locknut and rotate the cable
adjusting nut as necessary to bring the matchmarks into adjustment. Tighten
the locknut.
9. Check the oil pump discharge rate.
1 0. Install the engine cover.
1 .2-1 .8 -
1 .2-1 .8 -
1 .5-2.5 -
1 .0-1.9 1 .2-1 .7
1 .3-2.3 2.9-4.4
1 .9-3.2 3.4-5. 1
1 .9-3.2 4.0-5.9
2.2-3.7 5.0-7.5
2.2-3.7 5.9-8.7
2.5-4.5 6.0-9.0
3.8-6.8 6.5-7.9
4.4-7.9 7.6-1 1 .3
3.8-6.8 8.0-12.0
4.4-7.9 9.4-14.0
4.7-8.7 1 1 .5-1 7.2
3.4-6.0 8.1-1 2.1
12.1 -14.5 12.9-15.8
3.6-4.8 7.6-9.3
4.7-8.7 13.3-18.0
4.7-8.7 13.3-18.0
5.4-7.8 12.9-15.8
4.7-8.7 13.3-18.0
Full open
Fig. 13 Oil pump control positions when testing oil pump
discharge. Note matchmarks on pump lever and pump body
Oil Pump Control Rod .
ADJUSTMENT
Oil pump control rod adjustment should only be necessary if the oil pump
is removed for service.
Except DT55, DT65, DT11 5 and DT140
• See Figures 14, 15 and 1 6
• The throttle linkage must b e adjusted prior t o performing this
procedure. For more information on throttle linkage adjustment, refer to
the "Fuel System" section.
1 . Remove the control rod from the anchor pins on the oil pump lever
and the throttle body lever.
2. Loosen the locknuts on the control rod.
0
CD Control rod
CV Oil pump lever @ ® Carburetor lever
@
Fig. 14 Oil pump control rod adjustment- DT90, DT100 and V4
Fig. 16 Oil pump control rod adjustment-1 998-03 V6
OIL INJ ECTION 6-9
3. Adjust the control rod initial length measured between the center of
each hole in the clevis ends. Suzuki provides dimensions for the following
models:
• DT25 and DT30-3.05 in. (77.5mm)
• DT90, DT1 00 and V4-4.9 in. ( 1 24mm)
• DT175, 1 988-97 DT150 and 1 988-93 DT200-5.4 in. ( 1 37.5mm)
• 1 998-03 DT1 50-6.6 in. ( 1 68.5mm)
• 1 984-97 DT200-6.3 in. ( 1 1 3.5mm)
• 1 998-00 DT200-6.5 in. ( 1 66.0mm)
4. Install the control rod onto the anchor pins on the oil pump lever and
the throttle body lever.
5. Move the throttle to the fully closed position.
3
Fig. 15 Oil pump control rod adjustment-1988-97 V6
6-1 0 O I L I NJ ECTION
6. The clearance between the oil pump lever and the lever stop should
be 0.04 in. (1 mm).
7. If the clearance is not as specified, readjust the control rod to
achieve the proper clearance.
8. Hold the connectors and control in place and tighten the locknuts
securely.
9. The control rod clevis ends should be positioned at 90° to each other
after tightening the lock nuts.
1 0. Check for proper oil pump discharge rate.
DTSS and DT65
t See Figure 1 7
• The throttle linkage must b e adjusted prior t o performing this
procedure. For more information on throttle linkage adjustment, refer to
the "Fuel System" section.
1 . Remove the engine cover.
2. Loosen the locknuts on the control rod.
3. Move the throttle to the fully closed position.
4. The clearance between the oil pump lever and the lever stop should
be 0.04 in. (1 mm).
5. If the clearance is not as specified, adjust the control rod to achieve
the proper clearance.
DT115 and DT140
t See Figure 18
• The throttle linkage must be adjusted prior to performing this
procedure. For more information on throttle linkage adjustment, refer to
the "Fuel System" section.
[Throttle body side]
CD Oil pump control cable
® Throttle valve lever
® Cable bracket
0 Locknuts
® Lever
® Matchmark
0 Stopper
Fig. 18 Oil pump control cable adjustment-DT115 and DT140
Fig. 17 Oil pump control rod adjustment-DT55 and DT65
The oil pump is controlled by a cable on these models.
1 . Remove the engine cover.
2. Loosen the locknuts on the cable.
3. Adjust the locknuts until the lever just touches the stopper. This is the
fully closed position.
4. Readjust the locknuts to pull the lever open 0.1 2in (3mm). This is
equal to three turns of the locknuts.
5. Tighten the locknuts securely.
6. Ensure the match mark on the lever aligns with the mark on the
pump. If the marks do not align, readjust the cable length.
([) ®
[Oil pump side]
COOLING SYSTEM
Description and Operation
• See Figures 19, 20 and 21
Water cool ing is the most popular method in use to cool outboard power­
heads. A "raw-water" type pump del ivers seawater to the powerhead, circulating
it through the cylinder head(s), the thermostat, the exhaust housing, and back
down through the outboard. The water runs down the exhaust cavity and away,
either through an exhaust tube or through the propeller hub.
Routine maintenance of the cool ing system is quite important, as expensive
damage can occur if it overheats. The cooling system is so important, that many
outboards covered in this manual incorporate overheat alarm systems and
05006G25
Fig. 19 Cooling circuit diagram-inline powerhead
Port Starboard
Fig. 20 Cooling circuit diagram-V4 powerhead
O I L I NJ ECTION 6-1 1
Starboard
05006G27
Fig. 21 Cooling circuit diagram-VS powerhead
speed l imiters, in case the engine's operating temperature exceeds predeter­
mined limits.
Poor operating habits can play havoc with the cooling system. For instance,
running the engine with the water pickup out of water can destroy the water pump
impeller in a matter of seconds. Running in shallow water, kicking up debris that is
drawn through the pump, can not only damage the pump itself, but send the debris
throughout the entire system, causing water restrictions that create overheating.
WATER PUMP
• See Figure 1 6
The water pumps used o n al l Suzuki outboards are a d isplacement type water
pump. Water pressure is increased by the change in volume between the
impel ler and the pump case.
05006G28
Fig. 22 Cutaway view of a water pump with all major components
la be led
6-1 2 O I L I NJ ECTION
On most outboards, the water pump is mounted on top of the lower unit. A
driveshaft key engages a flat on the driveshaft and a notch in the impeller hub.
As the driveshaft rotates, the impel ler rotates with it.
On the DT2 and DT2.2 the water pump is mounted in a pump case instal led
on the propeller shaft between the lower unit and propeller. The pump impel lers
are secured to the propeller shaft by a pin that fits into the propeller shaft and a
simi lar notch in the impel ler hub. The propeller on other small displacement
models is secured to the drive shaft in the same manner.
THERMOSTAT
• See Figure 23
A pel let-type thermostat is used to control the flow of engine water, to pro­
vide fast engine warm-up and to regu late water temperatures. A wax pellet ele­
ment in the thermostat expands when heated and contracts when cooled. The
pellet element is connected through a piston to a valve. When the pellet element
is heated, pressure is exerted against a rubber diaphragm, which forces the
valve to open. As the pel let element is cooled, the contraction al lows a spring to
close the valve. Thus, the valve remains closed whi l e the water is cold, l imiting
circulation of water.
As the engine warms, the pellet element expands and the thermostat valve
opens, permitting water to flow through the powerhead. This opening and clos­
ing of the thermostat permits enough water to enter the powerhead to keep the
engine with in operating l imits.
Opening temperature
05006G29
Fig. 23 A pellet-type thermostat is used to control the flow of engine
water
Troubleshooting the Cooling System ·
Water cool ing is the most popular method in use on outboard engines today.
A "raw-water" pump del ivers seawater to the powerhead , c irculating it through
the cylinder head(s), the thermostat, the exhaust housing, and back down
through the outboard. The water runs down the exhaust cavity and away, either
through an exhaust tube mounted beh ind the propeller or, on the larger engines,
through the propeller hub.
Routine maintenance of the Ctloling system is quite important, as expensive
damage can occur if it overheats. The cool ing system is so important, that many
outboards covered in this manual incorporate overheat alarm systems and
speed l imiters, in case the engine's operating temperature exceeds predeter­
mined l imits.
Poor operating habits can play havoc with the cool ing system. For instance,
running the engine with the water pickup out of water can destroy the water
pump impel ler in a matter of seconds. Running in shallow water, kicking up
debris that is drawn through the pump, can not only damage the pump itself,
but send the debris throughout the entire system, causing water restrictions that
create overheating.
Symptoms of overheating are numerous and include:
• A "pinging" noise coming from the engine, commonly known as detonation
• Loss of power
• A burning smel l coming from the engine
• Paint discoloration on the powerhead in the area of the spark plugs and
cylinder heads
If these symptoms occur, immed iately seek and correct the cause. If the
engine has overheated to the point where paint has discolored, it may be too
late to save the powerhead. Powerheads in this state usually require at least par­
tial overhau I .
So what are major causes o f overheating? Well the most prevalent cause is
lack of maintenance. Other causes which are d i rectly attributable to lack of
maintenance or poor operating habits are:
• Fuel system problems causing lean mixture
• Incorrect oil mixture in fuel or a problem with the oil injection system
• Spark plugs of incorrect heat range
• Faulty thermostat
• Restricted water flow through the powerhead due to sand or s i l t
bu i ldup
• Faulty water pump impel ler
• Sticking thermostat
Water Pump
REMOVAL & INSTALLATION
Since proper water pump operation is critical to outboard operation, al l seals
and gaskets should be replaced whenever the water pump is removed . Also,
installation of a new impeller each time the water pump is disassembled is good
insurance against overheating.
,..Never turn a used impeller over and reuse it. The impeller rotates
with the driveshall and the vanes take a set in a clockwise direction.
Turning the impeller over will cause the vanes to move in the opposite
and result in premature impeller failure.
DT2 and DT2.2
,..The water pumps on the DT2 and DT.2.2 are mounted in a pump case
installed on the propeller shall between the lower unit and propeller.
The water pumps can be serviced without removing the lower unit from
the drive shall housing.
1. Remove the propeller.
2. Place a suitable container under the lower unit.
3. Remove the drain screw and drain the lubricant from the unit.
4. Remove the bolts holding the water pump case cover to the lower unit
housing and remove the cover.
5. Carefu l ly pry the impel ler from the water pump case
6. Remove the impel ler drive pin from the propeller shaft .
To i nstal l :
7. Insert impel ler drive p in in propeller shaft.
8. Install a new impeller in the pump body with a counterclockwise rotating
motion.
9. Install the pump case cover
1 0. Tighten the fasteners securely.
1 1 . Install the propeller.
12 . F i l l the lower unit with l ubricant.
13 . Place the outboard in a test tank or move the boat to a body of water.
1 4. Test the coo l ing system for proper operation.
Except DT2 and DT2.2
1 . Remove the lower unit.
2. Place the lower un it in a suitable holding fixture, keeping the unit
upright.
3. As required, remove the water tube from the pump cover .
4. Remove the water pump cover.
5. Sl ide the impel ler off the drive shaft .
6. Remove the impel ler drive pin or key from the drive shaft.
7. Careful ly pry the pump base plate and gasket assembly free of the lower
unit housing.
8. D iscard the gasket.
To instal l :
9. Clean the gasket mating surfaces thoroughly.
1 0. Install the pump base plate using a new gasket.
1 1 . Install the impel ler drive key into the drive shaft .
12 . Install a new impeller onto the drive shaft, al igning the impel ler slot with
the drive shaft key.
,..Make sure the locating pins are in place prior to installing the pump
cover.
13 . Slowly rotate the drive shaft clockwise whi le sl id ing the water pump
cover down the drive shaft. This wil l a l low the impeller to flex into the housing
in the right d i rection.
14. Coat the water pump cover bolt threads with thread locking compound.
15 . Install the lockwashers and bolts, Tightening the bolts securely.
1 6. As required, install the water tube into the pump cover .
1 7. Install the lower unit.
1 8. Place the outboard i n a test tank or move the boat to a body of
water.
1 9. Test the cooling system for proper operation .
CLEANING & INSPECTION
�When removing water pump seals, note the direction in which each
seal lip faces for proper installation reference.
Remove the drive shaft grommet, as required and water tube seal from the
pump cover. Inspect these rubber parts for wear, hardness or deterioration and
replace if necessary.
On models equipped with a water pump cover 0-ring, remove the 0-ring and
replace it.
Check the pump cover for cracks, distortion or melting and replace as
required. Clean the pump cover and base plate in solvent and blow dry with
compressed air.
1 . Throughly remove all gasket residue from the mating surfaces.
Thermostat
REMOVAL & INSTALLATION
• See accompanying i l lustrations
1 . Locate the thermostat cover on the cylinder head.
2. Remove the cover bolts.
3. Carefu l ly pry the cover from the cylinder head.
4. If the cover does not want to come loose, tap it gently with a plastic
hammer.
5. Remove the thermostat cover.
6. Remove the thermostat cover gasket.
7. Remove the thermostat from the cylinder head.
To instal l :
8. Throughly clean the gasket mating surfaces.
9. Inspect the thermostat bore for signs of corrosion. Outboards used in
salt water should be flushed with fresh water after each use to prevent corrosion
from forming.
1 0. Position the thermostat in the cylinder head.
05006P17
Step 2
O I L I NJ ECTION 6-1 3
05006P08
Step 6
6-1 4 O I L I NJ ECTION
Air breather hole
05006G31
Step 1 1
1 1 . Point the air breather hole, i f equipped, toward the end of the cylinder
head (toward the spark plugs).
12. Install the cover using a new gasket.
13 . Tighten the cover bolts securely.
CLEANING & INSPECTION
• See Figure 24
The cause o f a malfunctioning thermostat is often foreign matter stuck to the
valve seat. Inspect the thermostat to make sure it is clean and free of foreign
OIL INJECTION WARNING SYSTEMS
Description and Operation
LOW OIL LEVEL
• See Figure 25
A low oil level warning l ight and buzzer are included with most oil injected
models. The buzzer and warn ing l ight may be installed either in the instrument
panel, on the engine case or in the remote control . The light and buzzer serve a
dual function. The sending unit, located in the powerhead o i l tank, is connected
05006P30
Fig. 25 As the level of oil in the tank decreases, the float level
drops and will illuminate a low oil level lamp at a predetermined
level
05006P09
Fig. 24 Corrosion inside the thermostat bore signals a lack of main­
tenance. Always flush your outboard with fresh water, especially
after boating in salt water
matter. If necessary, test the removed thermostat for operation by immersing it
in a pot fi l led with water.
1 . With a piece of string pinched by the valve, suspend the thermostat in a
pot in such a way that the thermostat floats above the bottom of the pot.
2. Raise the water temperature.
3. If the valve opens (the thermostat releases the string and drops to the
bottom of the pot) at the temperature specified on the thermostat, the thermostat
is functioning correctly.
4. If the valve does not open (the thermostat remains hanging) at the temper­
ature specified on the thermostat, the thermostat is faulty and should be replaced.
to the warning system through the key switch. When the oil level in the tank
drops to a predetermined level, the warning light wi l l change col or to alert the
operator of a low oil condition. If the operator continues, a buzzer wi l l then
sound. After a predetermined time, the engine rpm wi l l be cut to reduce oil con­
sumption and prevent the engine from running out of oil at high speed.
,..The low oil warning system is equipped with a reset that will allow the
operator to run the engine in a low oil condition for approximately 30 min­
utes. To reset the warning system, remove the engine cover and press the
red reset button on the electrical cover with the engine running.
OIL FLOW
• See Figures 26 and 27
On some models, the in l i ne oil filter is equipped with an oil flow sensor. If
the oil flow is restricted or slows down due to an obstruction within the in l ine
� From oil tank
-----.
ON - OFF
05006G16
Fig. 26 Cutaway view of the oil flow sensor with major components
identified
05006G20
Fig. 27 If the oil flow is restricted or slows down due to an obstruc­
tion within the inline oil filter, the integral micro-switch will close
O I L I NJ ECTIO N 6-1 5
oi l fi lter, the integral micro-switch wil l close. This wi l l activate the low oi l flow
and rev l imit l ights on the mon itor. The warning buzzer will sound and the
engine speed wi l l automatically decrease.
Troubleshooting the Oi l Injection Warning System
When the oil level reaches a predetermined level in the oil tank, the oil level
monitor will turn from green to red as the switch in the oil tank senses the low
oil condition. If the operator continues to operate the outboard and the oil level
drops further, the warning buzzer wi l l begin to sound at 7 second i ntervals. All
the time, the red low oil warn ing light wil l be on. After 10 seconds of running,
the engine RPM wi l l drop and the rev. l imit l ight on the monitor wi l l come on.
If for some reason fu l l RPM is needed during a low o i l condition and the
operator does not have oi l onboard, the low oi l reset button on the engine lower
cover can be pressed with the engine runn ing. This button over-rides the rev­
l imit circu itry, but not the buzzer or l ight. The operator may continue to run with
the buzzer and light on at wide open throttle for approximately 30 minutes.
OIL INJECTION WARNING SYSTEM TROUBLESHOOTING CHART
SYMPTOM
SUZU K I MON ITOR
POSS I B LE CAUSE
B U ZZ E R O I L F L OW WATER L IM IT
Key swi tch -ON
O N
• O i l l evel i s l ower than safety
O i l l i gh t- O N level ( 1 .0 l it ) .
The buzzer and I i gh t do n o t • Poor operatin g or defective
come o n after start i ng the coo l ing water sensor.
eng i n e . • D i sconn ected coo l i ng water
sensor lead w i res.
• Defective buzzer.
• Defective mon itor.
• M al fu nction of i g n i t i o n
switc h .
• Defective reset u n i t .
Wh i l e run n i ng engine above • B locked o i l f i lter ( c l ea n or
3000 R PM , eng i n e R P M
O N O N O N
rep l ac e ) .
d rops and buzzer, f l ow, and • Defective o i l f low sw i tch .
over-rev l i m i t l ight come o n .
O i l l evei- O K • D efective o i l l evel sw i tch.
B u zzer ON O N O N O N
Over-rev control O N
O i l l evel i s l ess than 1 . 0 l i t. • D efective o i l level switch.
and l ight, buzzer and overrev do not come o n .
O i l is l ess than 1 . 0 l i t . , • D isconnected reset u n i t l ead
buzzer and l ight come o n .
O N ON
w i res.
Over- rev control does not • Defective C D I u n it.
come o n . • Defective reset u n i t.
• Shorted reset switch .
O i l is l ess than 1 . 0 l i t. and • Defective buzzer.
a l though over-rev control
ON O N
• D i sconnected i g n it ion switch
and l i gh ts works, buzzer and buzzer lead w i res.
d or� n ot sou n d .
Wh i l e operat ing engi n e at • O i l l evel i n the o i l tan k is
over 3000 R PM , engi n e l ower than safety l ev e l ( 1 .0
speed is redu ced after the O N O N ON l it ) .
buzzer sou nd s for 1 0
seconds.
The buzzer sou nds and the • Low o i l l evel .
oi l l ight stay o n even thou g h
O N O N
• D efective o i l l ev e l switch.
eng i n e speed is below 3000
R PM .
05006C02
6-1 6 O I L I NJ ECTION
Early type
Tester Teste r F load
Va lue EB lead e lead position
G reen No. 1 o n
Red No. 2 o n
Black Ye l low No. 3 o n
Orange No. 4 o n
Late type
Tester Tester
F l oat Switch
EB lead e lead 1 - 2 1 - 2 - 3 Value position position
Green No. 1 No. 1 o n
Red No. 2 No. 2 o n
Between
B l ack Orange
No. 2
No. 2 - No. 3
oo n
No. 2 No. 3 o n
Fig. 28 Testing the oil level sensor
Oi l level Sensor
TESTING
• See Figure 28
1 . Remove the oi l level sensor.
2. Connect a multi meter between the sensor terminals as i l lustrated and
continu ity.
3. Continuity should exist between the i l lustrated terminals when float is at
the designated positions.
,..Some early model sensor use a two position float that should show
continuity at the lowest position and no continuity at the upper position.
05006P29
Early type
6Q mm ]
-'--"-'� No 4 !Bottom of fto.n)
Late type 'e'
:�SWITCH NO. l iON!
-u� FLOAT NO. 1 ur -"" 00. "�'
SWITCH NO. 3 IOFFI SWITCH NO. 3 (ON) FLOAT NO. 2
r------n •·�
----() o,..,. r-----() Y1llcrw
...
Gr­
B�ok
TCH No.l
TCH No.2
SWITCH No 3
SWITCH No oi
�s� 6 Black
m Orongo
�::::: :
05006G33
4. If the sensor does not operate as specified, it may be faulty. Clean the
sensor and retest.
5. If the sensor functions properly, check the oi l level warn ing e lectrical har­
ness for opens or shorts.
REMOVAL & INSTALLATION
• See Figures 29, 30 and 31
1 . Remove the eng ine cover.
2. Label and disconnect the oi l level sensor e lectrical harness.
3. Carefu l ly pry the oil level sensor from the oil tank.
4. Careful ly remove the oil level sensor from the oil tank.
To install:
5. Place the oil level sensor in the oi l tank.
05006P03 05006P02
Fig. 29 The oil level sensor is held into
the oil tank by a rubber stopper
Fig. 30 The oil level sensor electrical har­
ness runs down the side of the oil tank
Fig. 31 The oil level sensor uses a multi­
pin and a bul let connector
O I L I NJ ECTION 6-1 7
�Tester
05006G18
05006G19 05006P05
Fig. 32 Connect a hand vacuum pump to
the sensor and check the sensor for conti­
nuity
Fig. 33 Continuity should exist when vac­
uum is applied and should not exist when
vacuum is released
Fig . 34 The oil flow sensor is located near
the bottom of the oil tank, in line with the
oil feed hose
6. Carefu l ly push the oil level rubber stopper into the oil tank.
7. Connect the oil level sensor e lectrical harness.
8 . Install the engine cover.
Oi l Flow Sensor
TESTING
• See Figures 32, 33 and 34
1 . Remove the oil flow sensor.
2. Connect a hand vacuum pump to the outlet side of the sensor and plug
the in let side of the sensor.
3. Check for continuity between the sensor terminals.
4. Continu ity should exist when vacuum is applied and should not exist
when vacuum is released.
5. If the sensor does not operate as specified, it may be faulty. Clean the
sensor and retest.
6. If the sensor functions properly, check the oi l flow warning electrical har­
ness for opens or shorts.
REMOVAL & INSTALLATION
1. Remove the engine cover.
2. Remove the oi l tank as necessary to gain access to the oi l fi lter.
3. Position a suitable container to receive oil d ischarged when the hoses
are disconnected.
4. Label and disconnect the o i l flow sensor e lectrical harness.
5. Disconnect and p lug the oil l i nes connected to the fi lter.
6. Remove the filter from the powerhead.
To instal l :
-
7. Clean and inspect the fi lter.
8. Position the filter on the powerhead.
OVERHEAT WARNING SYSTEM
Description and Operation
A overheat warn ing light and buzzer are included on most models. The
buzzer and warning light may be instal led either in the instrument panel , on the
engine case or in the remote control.
The light and buzzer serve a dual function. The sending unit, usually located
in the cylinder head, is connected to the warning system through the key switch.
When the powerhead temperature raises to a predetermined temperature, the
warning light wi l l i l luminate and the warning buzzer wi l l sound to alert the opera­
tor of an overheat condition. After a predetermined amount of time, the engine
rpm wi l l be cut to reduce the overheat condition and prevent powerhead damage.
Two types of sensors have been used to monitor for overheat conditions. The
first mon itored cooling water level in the powerhead using a float switch. If the
9 . Connect the o i l l ines to the fi lter and secure them with the clamps.
1 0. Connect the oil flow sensor e lectrical harness.
1 1 . Install the o i l tank if removed.
1 2. Install the engine cover.
CLEANING & INSPECTION
• See Figure 35
,..Some oil flow sensors cannot be disassembled for cleaning.
1 . Disassemble the oi l filter and remove the strainer.
2. C l ean the strainer in solvent and blowing it dry using compressed air.
3. Inspect the 0-ring, diaphragm and strainer for damage and replace com­
ponents as necessary.
4. Assemble the oi l filter and tighten the screws securely.
05006G17
Fig. 35 Clean the strainer by washing in solvent and blowing dry
using compressed air
switch sensed water flowing past i t , i t sent a signal to the control modul e and
the warn ing light and buzzer would remain off.
The latest style sensor uses a heat sensing bimetal switch installed in the cylinder
wall. The switch is designed to turn on at a predetermined cylinder wall temperature.
Troubleshooting the Overheat Warning System
The overheat warning system is activated should cylinder wal l temperature
become high due to insufficient cooling water. The red temperature lamp wi l l be
i l l uminated and the buzzer wi l l sound.
If the sensor detects overheating when engine speed is more than a predeter­
mined rpm, the rev. l imiter wi l l activate and the rev. l imit warning lamp wi l l also
i l luminate.
6-1 8 O I L I NJ ECTION
OVERHEAT WARNING SYSTEM TROUBLESHOOTING CHART
SYMPTOM
SUZ U K I MON ITO R
POSS I B L E CAUSE
B U ZZER O I L F L OW WATER L IMIT
The buzzer and l ight do not • Poor operating or defective
come on after starting the coo l ing water sensor.
engine. • D isconnected coo l i ng water
sensor lead wires.
• Defective buzzer.
• Defective mon itor.
• Malfu nction of ignit ion
switch.
• Defective reset un it .
The buzzer keeps sou nding • B lockage of water i ntake.
for 1 0 to 1 3 seconds after • Damaged water pump.
starting the engine and the • B locked cool i ng water c i rcu it
water l ight stays o n .
O N O N
• P oor operating or defective
• No water com i ng from coo l ing water sensor.
the d ischarge ho le . • B locked water passage.
• Water is com ing from • Defective cool i ng water
the d ischarge hole . sensor.
Wh i l e ru n n i n g en g i ne a bove • B l ocked water i n ta k e .
3000 R P M , buzzer sou nds • D am aged water p u m p .
and coo l i ng water l ight O N ON O N • Defective coo l i ng water
come on. A her 2 or 3 sensor.
seconds over- rev control • B l ocked wa ter passage .
comes o n .
Over-rev control does not • Defective reset switch.
release desp ite reset switch • Defective reset u n it.
having been pushed.
O i l levei-O K • Defective reset u n it.
R ecomm ended R PM range. ON
• Defective C D I u n it .
N o buzzer.
Over-rev control-ON
Buzzer sou nds and coo l ing • Poor operating or defective
water is norma l . O N O N O N cool ing water sensor.
Over-rev control-ON
E ngine speed is re�uced • E ng ine is over-revv ing.
after 1 0 seconds of u neven O N
engine ru n ning.
E ngine smooths out i f the
li • E ngine is over-revv ing.
thrott le is s l ightly backedoff from the fu l l -open
posit ion .
F
Wh i l e operating engine at • O i l level in the o i l tan k is
over 3 000 R PM , engine lower than safety l eve l ( 1 .0
speed is redu ced after the O N O N O N l i t ) .
buzzer sou nds for 1 0
seconds.
The buzzer sou nds and the • Blocked water intake.
water l ight is on even • Damaged water pump.
though the engine speed ON ON • Defective coo l i n g water
has been reduced to bel ow sensor.
3000 R P M . • B l ocked water passage.
05006C03
Overheat Sensor
REMOVAL & INSTALLATION
Water level Switch
1. Turn the battery switch off and/or disconnect the negative battery cable.
2. Remove the engine cover.
3. Locate the overheat sensor on the cylinder head.
4. Label and disconnect the switch harness.
5. Remove overheat sensor attaching bolts.
6. Using pl iers, grab the tongue of the sensor and twist s l ightly to remove.
To install:
7. Check the 0-ring on the end of the sensor for damage and replace as
necessary.
8. Lubricate the 0-ring and install the sensor in the cylinder head.
9. Install overheat sensor attaching bolts and tighten them securely.
1 0. Connect the switch harness.
1 1 . Turn the battery switch on and/or connect the negative battery cable.
12. Test the overheat system for proper operation.
13. Install the engine cover.
Heat Sensing Switch
t See Figures 36, 37 and 38
1 . Turn the battery switch off and/or disconnect the negative battery cable.
2. Remove the engine cover.
3. Locate the overheat sensor on the cylinder head.
4. Label and disconnect the switch harness.
5. Using p l iers, switch grab the switch at the i l l ustrated point with p l iers
and pu l l with a slight twist to remove.
To instal l :
6. Check the 0-ring on the end of the sensor for damage and replace as
necessary.
7. Lubricate the 0-ring.
8. Place a plastic tie-wrap in the sensor bore and push the sensor into the
bore.
9. When the sensor tip has reached the bottom of the bore, depress the
sensor further and hold in that position.
1 0. Slowly remove the tie-wrap to release the trapped air at the bottom of
the bore.
1 1 . If the sensor is properly instal led, it should not protrude more than 0.04
in (1 mm) above the surface.
,..If the sensor is not installed properly, it will not be seated at the bot­
tom of the bore and will not give accurate temperature readings. This
may lead to an overheat condition.
Hold with pliers here
05006G35
Fig. 36 When removing the heat sensing switch grab the switch at
the il lustrated point with pl iers and pull
O I L I NJ ECTION 6-1 9
t 05006G36
Fig. 37 Place a plastic tie-wrap in the sensor bore and push the sen­
sor into the bore
Less than
1 m m
(0 .04 i n . )
//
/
/
/
' /
.//
05006G37
Fig. 38 If the sensor is properly installed, it should not protrude
more than 0.04 in (1mm) above the surface
1 2. Connect the switch harness.
13. Turn the battery switch on and/or connect the negative battery cable.
14. Test the overheat system for proper operation.
1 5. Install the engine cover.
TESTING
Water level Switch
t See Figure 39
1. Remove the switch from the powerhead.
2. Connect a multi meter between the switch terminals and check for continuity.
3. With the float in the lower position, continuity should exist With the float
in the upper position, there should be no continuity.
4. If the sensor does not operate as specified, it may be faulty. Clean the
sensor and retest.
5. Clean the sensor as follows:
a. Inspect the float to see if it move up and down smoothly.
b. If the action is stiff, disassemble the switch and flush thoroughly with
fresh water to clean.
,..Always remove the switch pin from the left and insert it into the right
side of the switch.
6-20 O I L I NJ ECTION
Green/Yel l ow ( R ight)
Green/Red ( Left) + Teste<
Black
Fig. 39 Testing the water level switch
O F F
1
O N
05006G32
6. If the sensor functions properly, check the overheat warning e lectrical
harness for opens or shorts.
Heat Sensing Switch
t See Figure 40
1. Remove the switch from the powerhead.
2. Connect a multimeter between the switch terminals and check for continuity.
negative l3 lead
c::;;, To pocket tester
positive !3j lead
Fig. 40 Testing the heat sensing switch
05006G34
3. With the switch at room temperature, there should be no continuity.
4. Using a cigar l ighter from your vehicle, heat the end of the sensor.
,.. Take care to not touch the sensor with the cigar l ighter. Excessive
heat will damage the sensor.
5. As the sensor warms, continuity should exist.
6. If the sensor does not operate as specified, it may be fau lty.
7. If the sensor functions properly, check the overheat warning e lectrical
harness for opens or shorts.
ENGINE MECHANICAL 7-2
THE TWO-STROKE CYCLE 7-2
FLYWHEEL 7-2
REMOVAL & I NSTALLATION 7-2
I NSPECTION 7-5
POWERHEAD 7-5
REMOVAL & INSTALLATION 7-5
DISASSEMBLY & ASSEMBLY 7-15
POWERHEAD
RECONDITIONING 7-32
DETERM IN ING POWERHEAD
COND IT ION 7-32
PRIMARY COMPRESSIO N TEST 7-32
SECONDARY COMPRESSION
TEST 7-32
BUY OR REBUILD? 7-33
POWERHEAD OVERHAUL T IPS 7-33
TOOLS 7-34
CAUTIONS 7-34
CLEANING 7-34
REPA IR ING DAMAGED
THREADS 7-34
POWERHEAD PREPARATION 7-35
CYLINDER BLOCK AND HEAD 7-35
GENERAL INFORMATION 7-35
I NSPECTION 7-36
CYLINDER BORES 7-36
GEN ERAL I NFORMATIO N 7-36
I NSPECTIO N 7-37
REFIN ISH ING 7-37
PISTONS 7-37
GENERAL I NFORMATION 7-37
I NSPECTIO N 7-38
PISTON P INS 7-39
GEN ERAL I NFORMATION 7-39
I NSPECTIO N 7-39
PISTON R INGS 7-40
GEN ERAL I NFORMATION 7-40
I NSPECTION 7-41
CONNECTING RODS 7-41
GENERAL I NFORMATION 7-41
INSPECTION 7-42
THE CRANKSHAFT 7-43
GENERAL I NFORMATION 7-43
I NSPECTION 7-44
BEARINGS 7-44
GENERAL INFORMATIO N 7-44
I NSPECTION 7-45
SPECIFICATIONS CHARTS
TORQUE SPECIFICATIONS 7-46
ENGINE REBUILD ING
SPECI FICATIONS 7-49
7-2 POWER H EAD
ENGINE MECHANICAl
The Two-Stroke Cycle
The two-stroke engine can produce substantial power for its size and weight.
But why is a two-stroke so much smaller and l ighter than a four-stroke? Wel l ,
there is no valvetrain. Camshafts, valves and pushrods can really add weight to
an engine. A two-stroke engine doesn't use valves to control the air and fuel
mixture entering and exiting the engine. There are holes, called ports, cut into
the cylinder which allow for entry and exit of the fuel mixture. The two-stroke
engine also fires on every second stroke of the piston, which is the primary rea­
son why so much more power is produced than a four-stroke.
Since two-stroke engines d ischarge approximately one fourth of their fuel
unburned, they have come under close scrutiny by environmental ists. Many states
have tightened their grip on two-strokes and most manufacturers are hard at work
developing new efficient models that can meet the tough emissions standards.
Check out your state's regulations before you buy any two-stroke outboard.
The two-stroke engine is able to function because of two very simple physi­
cal laws. The first, gases will flow from an area of high pressure to an area of
lower pressure. A tire blowout is an example of this princip le . The high-pres­
sure air escapes rap idly if the tube is punctured. Second, if a gas is compressed
into a smaller area, the pressure increases, and if a gas expands into a larger
area, the pressure is decreased. If these two laws are kept in mind, the operation
of the two-stroke engine wi l l be easier understood.
Two-stroke engines util ize an arrangement of port openings to admit fuel to the
combustion chamber and to purge the exhaust gases after burning has been com­
pleted. The ports are located in a precise pattern in order for them to be opened
and closed at an exact moment by the piston as it moves up and down in the
cylinder. The exhaust port is located sl ightly higher than the fuel intake port. This
arrangement opens the exhaust port fi rst as the piston starts downward and there­
fore, the exhaust phase begins a fraction of a second before the intake phase.
Actually, the intake and exhaust ports are spaced so closely together that
both open almost simu ltaneously. For this reason, the pistons of most two­
stroke engines have a deflector-type top. This design of the piston top serves
two purposes very effectively. First, it creates turbulence when the incoming
charge of fuel enters the combustion chamber. This turbulence results in more
complete burning of the fuel than if the piston top were flat. Second, it forces
the exhaust gases from the cylinder more rapid ly.
Beginning with the piston approach ing top dead center on the compression
stroke, the intake and exhaust ports are closed by the piston, the reed valve is
open, the spark plug fires, the compressed air/fuel mixture is ignited, and the
power stroke begins. The reed valve was open because as the piston moved
upward, the crankcase volume increased, which reduced the crankcase pressure
to less than the outside atmosphere.
As the p iston moves downward on the power stroke, the combustion chamber
is fi l led with burning gases. As the exhaust port is uncovered, the gases, which
are under great pressure, escape rapidly through the exhaust ports. The piston
continues its downward movement. Pressure within the crankcase increases,
closing the reed valves against their seats. The crankcase then becomes a sealed
chamber. The air/fuel mixture is compressed ready for del ivery to the combustion
chamber. As the piston continues to move downward, the intake port is uncov­
ered. A fresh air/fuel mixture rushes through the intake port into the combustion
chamber striking the top of the piston where it is deflected along the cylinder
wal l . The reed valve remains closed until the piston moves upward again.
When the piston begins to move upward on the compression stroke, the reed
valve opens because the crankcase volume has been increased, reducing crankcase
pressure to less than the outside atmosphere. The intake and exhaust ports are
closed and the fresh fuel charge is compressed inside the combustion chamber.
Pressure in the crankcase decreases as the piston moves upward and a fresh
charge of air flows through the carburetor picking up fue l . As the piston
approaches top dead center, the spark plug ign ites the air/fuel mixture, the
power stroke begins and one fu l l cycle has been completed.
The exact time of spark plug firing depends on engine speed. At low speed
the spark is retarded, fires later than when the piston is at or beyond top dead
center. Engine timing is bui lt into the unit at the factory.
At high speed, the spark is advanced, fires earlier than when the piston is at
top dead center. On al l but the smallest horsepower outboards the timing can be
changed adjusted to meet advance and retard specifications.
Because of the design of the two-stroke engine, lubrication of the piston and
cylinder walls must be del ivered by the fuel passing through the engine. Since
gasol ine doesn't make a good lubricant, o i l must be added to the fuel and air
mixture. The trick here is to add just enough o i l to the fuel to provide lubrica­
tion. If too much o i l is added to the fuel, the spark plug can become "fouled"
because of the excessive oil within the combustion chamber. If there is not
enough oil present with the air/fuel mixture, the piston can "seize" within the
cylinder. What usually happens in this case is the piston and cylinder become
scored and scratched, from lack of lubrication. In extreme cases, the piston wi l l
turn t o l iquid and eventually disintegrate within the cylinder.
Most two-stroke engines require that the fuel and oil be mixed before being
poured into the fuel tank. This is known as "pre-mixing" the fue l . This can
become a real hassle. You must be certain that the ratio is correct. Too litt le o i l
in the fuel could cause the piston to seize to the cylinder, causing major engine
damage and completely ru in ing your weekend. Most modern two-stroke engines
have an o i l injection system that automatically mixes the proper amount of o i l
with the fuel as it enters the engine.
Flywheel
REMOVAL & INSTALLATION
DT2 and DT2.2
• See accompanying i l lustrations
1. Remove the engine cover.
2. Remove the fuel tank assembly.
3. Remove the recoil starter assembly.
4. Remove the starter cup and magneto insulator.
5. Using a flywheel holder (09930-401 1 3 for 1 988/89 models;
09930-48720 1 990 to present), hold the flywheel and loosen the retaining nut.
6. Using a flywheel rotor remover remove the flywhee l . Make sure to keep
track of the flywheel key when removing the flywheel.
05005G05
Step 5
05005G06
Step 6
To install:
7. Before installing the flywheel, thoroughly inspect the crankshaft and
flywheel tapers. These surfaces must be absolutely clean and free of oil ,
grease and dirt. Use solvent and a lint free cloth to clean the surfaces and
then blow dry with compressed air.
8. Install the flywheel key, starter cup and flywheel and flywheel bolt.
Tighten the bolt to 30-36 ft. lbs. (40-50 Nm.)
9. Install the fuel and engine cover.
DT4, DTSY, DT6 and DT8
• See accompanying illustrations
1 . Remove the engine cover from the engine.
2. Remove the built-in fuel tank (if equipped).
3. After removing the bolts, remove the recoil starter assembly.
4. Remove the starter cup. If the screws are hard to loosen, use an
impact drive to remove them.
5. Use a flywheel holder (09930-40 1 1 3) to remove the flywheel nut.
6. Use a flywheel holder and flywheel rotor remover (09930-3071 3) to
remove the flywheel.
7. Make sure to remove the flywheel key from the crankshaft.
To install :
8. Install the flywheel key into the keyway on the crankshaft. Make sure
the key is seated correctly into the keyway.
9. Install the flywheel onto the crankshaft.
1 0. Using a flywheel holder, install the flywheel nut and tighten to 32.5 ft.
lbs. (45 Nm).
1 1 . Install the starter cup onto the flywheel and tighten the screws.
1 2. Install the recoil starter.
13 . Install the fuel tank.
1 4. Install the engine cover.
Step 5
Step 6
POWERHEAD 7·3
DT9.9 and DT15
• See accompanying illustrations
1 . Remove the engine cover from the engine.
2. Remove the two nuts and disconnect the battery/starting motor
cables and the neutral switch wire (if equipped).
3. Remove the recoil starter assembly (if equipped).
4. Disconnect the wire lead extending from the stator assembly to the
rectifier assembly.
5. Remove the two bolts and remove the starter motor from the engine.
6. Using a flywheel holder (09930-4931 0), remove the flywheel nut.
7. Using a flywheel holder and the flywheel remover plate (0993030713), remove the flywheel.
Step 3
Step 6
Step 7
7-4 POWER H EAD
05005G34
Step 8
8. If any difficulty is experienced in removing the flywheel , tap the head of
the bolt with a hammer. This wi l l usually help in the removal operation.
9. Remove the key from the crankshaft keyway.
To install:
1 0. Install the key securely into the crankshaft keyway.
1 1 . Install the flywheel onto the crankshaft.
1 2. Using a flywheel holder, tighten the flywheel nut to 58-65 ft. lbs. (80-90
Nm)
1 3. Install the starter motor back onto the engine and securely tighten the
bolts (if equipped).
1 4. Reconnect the starter/battery cables and reconnect the neutral safety
switch lead wire.
1 5. Install the recoil starter assembly (if equipped)
1 6. Connect the stator wires making sure al l connections are free from cor­
rosion and are securely fastened.
1 7. Install the engine cover.
DT20, DT25 and DT30
1 . Disconnect the negative battery cable lead to prevent accidental engine
start.
2. Remove the engine cover.
3. Disconnect the wire leads in the e lectrical junction box, leading from the
stator assembly.
4. Remove the recoil starter assembly.
5. Using a screwdriver to hold the flywheel, remove the starter pul ley bolts
and l ift of the starter pu l ley.
6. Using a flywheel holder (09930-48720), remove the flywheel nut.
7. Using a flywheel holder and a flywheel remover (09930-3941 1 ) , remove
the flywheel from the engine.
To instal l :
8. Throughly clean the mating surface of the flywheel and crankshaft taper
with cleaning solvent. Install the key onto the crankshaft securely.
9. Using a flywheel holder, tighten the flywheel nut to 94-108 ft. lbs.
(1 30-150 Nm).
10. Install the starter pul ley onto the flywheel.
1 1 . Install the reco i l starter assembly.
12 . Connect the battery negative battery cable.
13. Install the engine cover.
DT35 and DT40
1 . Disconnect the negative battery cable lead to prevent accidental engine start.
2. Remove the engine cover.
3. Disconnect the wire leads in the electrical junction box and COl/control
unit holder, leading from the stator assembly.
4. Remove the recoil starter assembly.
5. Using a flywheel holder (09930-39520), remove the flywheel nut.
6. Using a flywheel holder and a flywheel remover (09930-39410), remove
the flywheel and key.
To instal l :
7. Throughly clean the mating surface of the flywheel and crankshaft taper
9. Using a flywheel holder, tighten the flywheel nut to 144.7-151 .9 ft. lbs.
(200-210 Nm).
1 0. Connect the stator wire leads to their proper connections.
1 1 . Install the starter pu l ley onto the flywheel.
12. Install the reco i l starter assembly.
13 . Connect the battery negative battery cable.
1 4. Install the engine cover.
DT55, DT65, DT75 and DT85
• See accompanying i l lustrations
1 . Remove the engine cover.
2. Remove the e lectrical junction box cover and disconnect the stator
leads.
3. Remove the flywheel cover.
4. Using a flywheel holder (09930-39520) and flywheel & propeller shaft
housing remover (09930-39410), remove the flywheel nut.
5. Using the special tools, remove the flywheel from the crankshaft.
6. Make sure to remove the flywheel key before removing the magneto case
to prevent tearing the seal.
7. Remove the magneto case from the engine.
To install:
8. Throughly clean the mating surface of the flywheel and crankshaft taper
with cleaning solvent. Install the key onto the crankshaft securely.
9. Install the flywheel onto the crankshaft.
1 0. Using a flywheel holder, tighten the flywheel nut to 144.5-152 ft. lbs.
(200-210 Nm).
1 1 . Connect the stator wire leads to their proper connections.
with cleaning solvent. Install the key onto the crankshaft securely.
8. Install the flywheel onto thew crankshaft. LS
_
te ..:.p_7 __________________ ...J
12 . Connect the battery negative battery cable.
13. Install the engine cover.
DT115 , DT140 and V4
1 . Remove the engine cover.
2. Remove the electrical junction box cover and disconnect the stator leads.
3. Remove the flywheel cover.
4. Using a flywheel holder (09930-48720), remove the flywheel nut.
5. Using a flywheel holder, flywheel remover (09930-3941 1 ) and flywheel
bolts (09930-39420), remove the flywhee l .
6. Remove the flywheel from the crankshaft.
To install:
7. Throughly clean the mating surface of the flywheel and crankshaft taper
with cleaning solvent. Install the key onto the crankshaft securely.
8. Install the flywheel onto the crankshaft.
9. Using a flywheel holder, tighten the flywheel nut to 1 81-1 88 ft. lbs.
(250-260 Nm).
1 0. Connect the stator wire leads to their proper connections.
1 1 . Connect the battery negative battery cable.
12. Install the engine cover.
V6
1 . Remove the engine cover.
2. Remove the electrical junction box cover and disconnect the stator leads.
3. Remove the flywheel cover.
4. Using a flywheel holder (09930-48720), remove the flywheel nut.
5. Using a flywheel holder, flywheel remover (09930-3941 1 ) and flywheel
bolts (09930-39420), remove the flywheel .
To install:
6. Throughly clean the mating surface of the flywheel and crankshaft taper
with cleaning solvent. Install the key onto the crankshaft securely.
7. Install the flywheel onto the crankshaft.
8. Using a flywheel holder, tighten the flywheel nut to 1 81-188 ft. lbs.
(250-260 Nm).
9. Connect the stator wire leads to their proper connections.
1 0. Connect the battery negative battery cable.
1 1 . Install the engine cover.
I NSPECTION
Check the flywheel carefu l ly for cracks or fractures.
** CAUTION
A cracked or chipped flywheel must be replaced. A damaged fly­
wheel may fly apart at high rpm , throwing metal fragments over a
large area. Do not attempt to repair a damaged flywheel .
Check tapered bore of flywheel and crankshaft taper for signs of fretting or
working.
On electric start models, check the flywheel teeth for excessive wear or damage.
Check crankshaft and flywheel nut threads for wear or damage.
Replace flywheel, crankshaft and/or flywheel nut as required.
Powerhead
REMOVAL & INSTALLATION
When removing any powerhead, it is a good idea to make a sketch or take an
instant picture of the location, routing and positioning of e lectrical harnesses,
brackets and component locations for installation reference.
,..Sometimes when attempting to remove the powerhead it won't come
loose from the adapter. The gasket may hold the powerhead. Rock the
powerhead back and forth or give it a gentile nudge with a pry bar. If the
gasket breaks loose and the powerhead still will not come loose, then
the driveshaft is seized to the crankshaft at the splines.
The following procedures assume that the outboard has been removed from
the boat and placed on a suitable work stand. If the powerhead is being
POWER H EAD 7-5
removed with the outboard sti l l mounted o n the boat and the powerhead is
equipped with an electric starter, disconnect first the negative, then the positive
battery cables to prevent accidental starting.
On some powerheads it wil l be necessary to remove attached components if
the powerhead is to be overhauled. Refer to the specific sections covering these
components for removal and installation information.
DT2 and DT2.2
• See accompanying i l lustrations
1. Remove the engine covers.
2. Turn the fuel shutoff to the OFF position. Disconnect and plug the fuel l ine.
3. Remove the fuel tank.
4. Remove the rewind starter assembly.
5. Remove the starter cup and flywheel i nsu lator.
6. Using a flywheel holder loosen and remove the flywheel nut.
7. Remove the flywheel using a flywheel pu l ler.
05007G01
Step 5
05007G02
Step 6
05007G03
Step 7
7-6 O I L I NJ ECTION
Step 12
Step 14
8. Disconnect the spark plug lead.
9. Label and disconnect the stator lead wires.
1 0. Remove the choke knob
1 1 . Remove the throttle link knob and the control panel.
1 2. Remove the carburetor and fuel shut-off valve.
1 3. Remove the bolts holding the powerhead to the driveshaft housing.
1 4. Remove the powerhead.
• If the powerhead will not come off, rotate the propeller to free the
powerhead from the driveshaft.
1 5. Remove and discard the powerhead mounting gasket.
To install:
1 6. Clean the powerhead mounting and driveshaft housing gasket
surfaces thoroughly.
1 7. Lightly coat driveshaft splines with marine grease.
1 8. Install a new powerhead new mounting gasket.
1 9. Install the powerhead, rotating the propeller as required to align
driveshaft and crankshaft splines.
20. Coat powerhead mounting bolt threads with thread locking
compound.
21 . Install the powerhead mounting bolts and tighten to specification.
22. Install the carburetor and fuel shut-off valve.
23. Install the control panel, the choke knob and the throttle link knob.
24. Connect the stator lead wires.
25. Connect the spark plug lead.
26. Install the flywheel.
27. Using a flywheel holder tighten the flywheel nut.
28. Install the starter cup and flywheel insulator.
29. Install the rewind starter assembly.
30. Install the fuel tank.
3 1 . Connect the fuel line and turn the fuel shutoff to the ON position.
32. Start the engine and make adjustments as necessary.
33. Check engine for proper operation.
34. Install the engine covers.
DT4 and DTSY
1 . Remove the engine cover.
2. Remove the fuel tank.
3. Remove the hand rewind starter.
4. Using a flywheel holder loosen and remove the flywheel nut.
5. Remove the flywheel using the flywheel puller.
6. Label and disconnect the stator and CDI unit electrical leads.
7. Remove the ignition coil and CDI unit.
8. Disconnect the throttle cable from the carburetor.
9. Loosen the hose clamp, disconnect and plug the fuel hose.
1 0 . Remove the silencer.
1 1 . Remove the carburetor.
1 2. Remove the fuel pump.
1 3. Remove the powerhead mounting bolts.
1 4. Remove the powerhead.
• If the powerhead will not come off, rotate the propeller to free the
powerhead from the driveshaft.
1 5. Remove and discard the powerhead mounting gasket.
To install:
1 6. Clean the powerhead mounting and driveshaft housing gasket
surfaces thoroughly.
1 7. Lightly coat the driveshaft splines with marine grease.
1 8. Install a new powerhead new mounting gasket.
1 9. Install the powerhead, rotating the propeller as required to align
driveshaft and crankshaft splines.
20. Coat powerhead mounting bolt threads with silicone sealer.
21 . Install the powerhead mounting bolts and tighten to specification.
22. Install the fuel pump.
23. Install the carburetor.
24. Install the silencer.
25. Connect the throttle cable top the carburetor and adjust it to
specification.
26. Install the ignition coil and CDI unit.
27. Connect the stator and CDI unit electrical leads.
28. Install the flywheel. Tighten the flywheel nut to specification.
29. Install the hand rewind starter.
30. Install the fuel tank.
3 1 . Unplug and connect the fuel hose. Using a new hose clamp, fasten
the hose properly.
32. Start the engine and make adjustments as necessary.
33. Check engine for proper operation .
34. Install the engine cover.
DT6 and DT8
t See accompanying il lustrations
1 . Remove the engine cover.
2. Remove the silencer cover.
3. Loosen the hose clamp, disconnect and plug the fuel hose.
4. Disconnect the choke knob.
Step 2
0500/GOI
Step 5 Step 7
05007G10
Step 9 Step 1 3
05007G13
Step 1 5
5 . Remove the carburetor.
6. Label and disconnect the stator and CDI unit e lectrical leads.
7. Remove the ignition coil and CDI unit.
8. Remove the fuel pump with the fuel fi lter sti l l attached.
9. Remove the hand rewind starter.
1 0. Disconnect the throttle cable from the carburetor.
1 1 . Using a flywheel holder loosen and remove the flywheel nut.
12 . Remove the flywheel using the flywheel pul ler.
13 . Remove the stator.
1 4. Remove the upper oi l seal housing.
15. Remove the powerhead mounting bolts
1 6. Remove the powerhead.
POWER H EAD 7-7
0500/GOB
05007G09
Step 8
05007G11 05007G12
Step 14
_.If the powerhead will not come off, rotate the propeller to free the
powerhead from the driveshaft.
1 7. Remove and d iscard the powerhead mounting gasket.
To instal l :
1 8. Clean the powerhead mounting and driveshaft housing gasket surfaces
thorough ly.
1 9. Lightly coat the driveshaft splines with marine grease.
20. Install a new powerhead new mounting gasket.
21 . Install the powerhead, rotating the propeller as required to al ign drive­
shaft and crankshaft splines.
22. Coat powerhead mounting bolt threads with si l icone sealer.
23. Install the powerhead mounting bolts and tighten to specificat ion .
24. Install the upper oi l seal housing.
25. Install the stator.
26. Install the flywheel .
27. Using a flywheel holder install and tighten the flywheel nut specification.
28. Connect the throttle cable to the carburetor.
29. Install the hand rewind starter.
30. Install the fuel pump using a new fuel filter.
3 1 . Install the ignition coil and CDJ unit.
32. Install the carburetor.
33. Connect the choke knob.
34. Unplug and connect the fuel hose. Using a new hose clamp, fasten the
hose properly.
35. Install the silencer cover.
36. Start the engine and make adjustments as necessary.
37. Check engine for proper operation.
38. Install the engine cover.
7-8 POWER H EAD
DT9.9 and DT15
• See accompanying i l lustrations
1. Remove the engine cover.
2. On electric start models, disconnect the e lectrical cables between the
battery and starter.
3. On o i l injected models, disconnect and plug the o i l l i ne . Remove the o i l
tank.
4. Disconnect the neutral switch.
5. Loosen the neutral starter interlock locknut and disconnect the interlock
cable from the throttle l imiter.
6. Loosen the throttle cable locknuts and disconnect the cable from the
control lever.
7. Remove the si lencer cover.
8. Remove the recoil starter assembly.
05007G15
Step 2 Step 5
05007G18
Step 7 Step 12
05007G21
Step 1 5 Step 16
9. Label and disconnect the CO l unit electrical leads.
10 . Remove the COl unit.
1 1 . Label and disconnect the neutral start switch e lectrical
lead.
12. Remove the neutral start switch.
13 . Label and disconnect the stator electrical leads.
14. Remove the rectifier assembly.
15 . Remove the starter motor relay.
1 6. Remove the starter motor.
1 7. Using a flywheel holder loosen and remove the flywheel nut.
1 8. Remove the flywheel using the flywheel pu l ler.
1 9. Remove the flywheel key.
20. Disconnect the stator e lectrical leads
21 . Remove the throttle control lever.
22. Disconnect and plug the hoses from the fuel fi lter.
05007G16
05007G17
Step 6
05007G19
Step 14
05007622 05007G23
Step 21
05007G14
Step 23 Step 24
05007G17
Step 33
23. Remove the fuel fi lter.
24. Remove the si lencer case and carburetor.
25. Remove the fuel pump.
26. Remove the nut on the backside of the starter switch assembly.
27. Unclamp the starter cable clamp and remove the grommet from the
cable. Pull the starter cable out.
28. Remove the stator assembly.
29. Remove the bolts holding the powerhead to the drivesha!t housing.
30. Remove the powerhead.
,..If the powerhead wi ll not come off, rotate the propeller to free the
powerhead from the driveshaft.
31 . Remove and discard the ptJwerhead mounting gasket.
To install :
32. Clean the powerhead mounting and drivesha!t housing gasket surfaces
thorough ly.
33. Lightly coat the drivesha!t splines with marine grease.
34. Install a new powerhead new mounting gasket.
35. Install the powerhead, rotating the propeller as required to al ign driveshalt and crankshaft spl ines.
36. Coat powerhead mounting bolt threads with si l icone sealer.
37. Install the powerhead mounting bolts and tighten to specification.
38. Install the stator assembly.
39. Install the starter cable, grommet and starter cable clamp.
40. Install the nut on the backside of the starter switch assembly.
41 . Install the fuel pump and fuel fi lter, routing the hoses properly.
42. Install the silencer case and carburetor.
43. Connect the hoses to the fuel fi lter.
44. Install the throttle control lever.
45. Install the flywheel key and flywheel .
46. Using a flywheel holder tighten the flywheel nut.
47. Install the starter motor.
48. Install the starter motor relay.
49. Install the rectifier assembly.
POWER H EAD 7-9
/
05007G15
05007G16
Step 28
05007G18
Step 41
50. Connect the stator electrical leads.
51 . Install the neutral start switch.
52. Connect the neutral start switch e lectrical lead.
53. Install the CDI unit.
54. Connect the CDI un it e lectrical leads.
55. Install the recoil starter assembly.
56. Install the si lencer cover.
57. Connect the cable to the control lever and adjust to specification.
58. Connect the interlock cable to the throttle l imiter and adjust to specifica­
tion.
59. Connect the neutral switch.
60. On e lectric start models, connect the electrical cables between the bat­
tery and starter.
61 . On oi l injected models, install the oi l tank and properly connect the oi l
l i nes.
62. Start the engine and make adjustments as necessary.
63. Check engine for proper operation.
64. Install the engine cover.
DT20, DT25 and DT30
1 . Remove the engine cover.
2. Remove the recoil starter.
3. Remvoe the e lectric parts holder and rectifier cover.
4. Disconnect the starter cable from the neutral start l ever.
5. Disconnect the negative, then the positive battery cables.
6. Disconnect the spark plug leads.
7. Remove the CDI unit from the e lectric parts holder.
8. Remove the electric parts holder.
9. Disconnect and plug the oi l hose from the o i l tank.
1 0. Remove the oil tank.
1 1 . Disconnect the throttle valve sensor, choke solenoid and id le speed
adjustment switch e lectrical leads.
1 2. Disconnect the fuel hose from the engine under cover.
7-1 0 POWER H EAD
1 3 . Remove the wiring harness stopper and disconnect the ignition coil lead
wires.
1 4. Remove the COl unit and the wiring harness assembly.
15 . Remove the si lencer cover.
16 . Disconnect the choke lever.
1 7. Remove the bolts holding the powerhead to the driveshaft housing.
18. Remove the powerhead.
�If the powerhead will not come off, rotate the propeller to free the
powerhead from the driveshaft.
1 9. Remove and d iscard the powerhead mounting gasket.
To instal l :
20. Clean the powerhead mounting and driveshaft housing gasket surfaces
thorough ly.
21 . Lightly coat the driveshaft splines with marine grease.
22. Install a new powerhead new mounting gasket.
23. Install the powerhead, rotating the propeller as required to align driveshaft and crankshaft spl ines.
24. Coat powerhead mounting bolt threads with si l icone sealer.
25. Install the powerhead mounting bolts and tighten to specification.
26. Connect the choke l ever.
27. Install the silencer cover.
28. Install the COl unit and the wiring harness assembly.
29. Install the wiring harness stopper and connect the ignition coi l lead
wires.
30. Connect the fuel hose to the engine under cover.
3 1 . Connect the throttle valve sensor, choke solenoid and id le speed adjustment switch e lectrical leads.
32. Install the oil tank.
33. Connect the oil hose to the oil tank.
34. Install the electric parts holder.
35. Install the COl unit from the e lectric parts holder.
36. Connect the spark plug leads.
37. Connect the battery cables, positive side first.
38. Connect the starter cable to the neutral start lever. Adjust to specification
39. Install the electric parts holder and rectifier cover.
40. Install the reco i l starter.
41 . Start the engine and make adjustments as necessary.
42. Check engine for proper operation.
43. Install the engine cover.
DT35 and DT40
1 . Disconnect the negative battery cable, then the positive battery
cable.
2. Remove the engine cover.
3. Disconnect the neutral start interlock cable from the throttle l imiter.
4. Label and disconnect the oi l tank e lectrical leads.
5. Disconnect and plug the oil tank hose.
6. Remove the oil tank.
7. Remove the recoil starter assembly.
8. Remove the si lencer cover.
9. Disconnect the oi l pump control rod from the carburetor.
1 0. Remove the choke knob.
1 1 . Disconnect and plug the fuel l i nes
12 . Remove the carburetor.
1 3. Disconnect the throttle control l i nk rods and remove the throttle
lever.
1 4. Disconnect the starter motor, starter relay and neutral switch electrical
leads. 15 . Remove the starter motor assembly.
1 6. Loosen the bolt in the electrical parts holder and disconnect the black
ground wire.
1 7. Label and disconnect all e lectrical leads in the electrical parts
holder.
1 8. Disconnect and plug the hoses from the fuel fi lter.
1 9. Remove the fuel fi lter.
20. Remove the flywheel.
2 1 . Remove the bolts holding the powerhead to the driveshaft housing.
22. Remove the powerhead.
�If the powerhead will not come off, rotate the propeller to free the
powerhead from the driveshaft.
23. Remove and discard the powerhead mounting gasket.
To install :
24. Clean the powerhead mounting and driveshaft housing gasket surfaces
thoroughly.
25. Lightly coat the driveshaft spl ines with marine grease.
26. Install a new powerhead new mounting gasket.
27. Install the powerhead, rotating the propeller as required to align driveshaft and crankshaft spl ines.
28. Coat powerhead mounting bolt threads with si l icone sealer.
29. Install the powerhead mounting bolts and tighten to specification.
30. Install the flywheel.
31 . Install the fuel fi lter.
32. Connect the hoses to the fuel fi lter.
33. Connect all electrical leads in the electrical parts holder.
34. Connect the black ground wire and tighten the bolt in the e lectrical parts
holder.
35. Install the starter motor assembly.
36. Connect the starter motor, starter relay and neutral switch electrical
leads.
37. Install the throttle lever and connect the throttle control l i nk rods.
38. Install the carburetor.
39. Adjust the l ink rods to specification
40. Connect the fuel l ines
41 . Install the choke knob.
42. Connect and adjust the oi l pump control rod at the carburetor.
43. Install the silencer cover.
44. Install the recoil starter assembly.
45. Install the o i l tank.
46. Connect the oil tank hose.
47. Connect the oil tank e lectrical leads.
48. Connect and adjust the neutral start interlock cable at the throttle l imiter.
49. Connect the negative battery cable, then the positive battery cable.
50. Start the engine and make adjustments as necessary.
51 . Check engine for proper operation .
52. Install the engine cover.
DT50
t See accompanying i l lustrations
1 . D isconnect the negative battery cable , then the positive battery
cable.
2. Remove the engine cover.
3. Remove the si lencer cover
05007G29
Step 3
05007G30
Step 4 Step 5
05007G33
Step 8
4. Remove the silencer case.
5. Disconnect the carburetor throttle rod.
6. Disconnect and plug the fuel hoses.
7. Remove the carburetors and choke solenoid.
8. Remove the grommet and loosen the clutch shaft double nuts.
9. Disconnect the clutch rod from the clutch shaft by driving the clutch rod
out using a drift.
10 . Remove the bolts holding the powerhead to the driveshaft housing.
1 1 . Remove the powerhead.
�If the powerhead will not come off, rotate the propeller to free the
powerhead from the driveshafl.
1 2. Remove and d iscard the powerhead mounting gasket.
To install :
13 . Clean the powerhead mounting and driveshaft housing gasket surfaces
thorough ly.
14. Lightly coat the driveshaft splines with marine grease.
1 5. Install a new powerhead new mounting gasket.
1 6. Install the powerhead, rotating the propeller as required to align driveshaft and crankshaft splines.
1 7. Coat powerhead mounting bolt threads with si l icone sealer.
18 . Install the powerhead mounting bolts and tighten to specification.
1 9. Connect the clutch rod to the clutch shaft by driving the clutch rod i n
using a drift.
20. Tighten the clutch shaft double nuts to specification.
21 . Install the grommet.
22. Install the carburetors and choke solenoid.
23. Connect the fuel hoses.
24. Connect and adjust the carburetor throttle rod.
25. Install the si lencer cover and case.
26. Connect the negative battery cable, then the positive battery cable.
27. Start the engine and make adjustments as necessary.
28. Check engine for proper operation.
29. Install the engine cover.
POWER H EAD 7-1 1
05007G31
Step 6
05007G34
Step 9
DT55 and DT65
• See accompanying i l lustrations
1 . Disconnect the negative battery cable, then the positive battery cable.
2 . Remove the engine cover.
3. Label and disconnect the e lectrical leads to the oi l level switch.
4. Disconnect and plug the oil hose.
5. Remove the oil tank.
6. Remove the power trim and tilt motor relay cover, then remove the relays
from the cylinder.
7. Remove the e lectrical parts holder cover. Label and disconnect al l elec­
trical connectors in the electrical parts holder.
8. Remove the CDI unit.
9. Disconnect the e lectrical leads from the starter motor and relay.
1 0. Remove the flywheel.
1 1 . Disconnect and p lug the fuel hose.
1 2. Remove the clutch link from the throttle control arm and the c lutch shaft
side arm.
1 3. Disconnect the water outlet hose from the engine lower cover.
1 4. Remove the bolts securing the lower under cover on each side of the
outboard.
Step 14
7-1 2 POWERHEAD
05007P21
Step 20
1 5. Remove both under covers .
1 6 . Remove the bolts ho ld ing the powerhead to the driveshalt hous­
ing.
1 7. Remove the powerhead.
,..If the powerhead will not come off, rotate the propeller to free the
powerhead from the driveshaft.
1 8. Remove and d iscard the powerhead mounting gasket.
To install:
1 9. Clean the powerhead mounting and driveshaft housing gasket surfaces
thoroughly.
20. Lightly coat the driveshaft splines with marine grease.
21 . Install a new powerhead new mounting gasket.
22. Install the powerhead, rotating the propeller as required to align driveshaft and crankshaft spl ines.
23. Coat powerhead mounting bolt threads with si l icone sealer.
24. Install the powerhead mounting bolts and tighten to specification.
25. Install both under covers and tighten the bolts securely.
26. Connect the water outlet hose to the engine lower cover.
27. Install the clutch l i nk on the throttle control arm and the clutch shalt
side arm.
28. Connect the fuel hose.
29. Install the flywheel.
30. Connect the electrical leads to the starter motor and relay.
31 . Install the CDI unit.
32. Install the e lectrical parts holder cover.
33. Connect al l e lectrical connectors in the electrical parts holder.
34. Install the power trim and tilt relays.
35. Install the power trim and tilt motor relay cover.
36. Install the oi l tank.
37. Connect the o i l hose.
38. Connect the electrical leads to the oil level switch.
39. Connect the negative battery cable, then the positive battery
cable.
40. Start the engine and make adjustments as necessary.
41 . Check engine for proper operation.
42. Install the engine cover.
DT75 and DT85
• See accompanying i l lustrations
1 . Remove the engine cover.
2. Remove the lower front cover.
05007G35
Step 2
05007G36
Step 3 Step 4
05007G39
Step 7 Step 8
05007G42
Step 1 0 Step 1 1
3. Remove the lower rear cover.
4. Disconnect the negative, then the positive battery cable.
5. Remove the battery cable clamp, disconnect the cable grommet from the
lower support housing and remove the cables.
6. Disconnect and plug the fuel hose.
7. Remove the fuel fi lter.
8. Remove the grommet on the starboard side of the driveshaft housing.
9. Remove the clutch shaft nuts.
1 0. Disconnect the clutch shaft rod by driving it out of its bore with a
dr ift.
rs .L .
'
•.�u"' . r.·L. ��� � ' ---· -� t
05007G37
05007G40
05007G43
POWER H EAD 7-1 3
/ / %;;·--. "'-'"' ... �
05007G38
Step 5
05007G41
Step 9
05007G44
Step 12
1 1 . Remove the bolts holding the powerhead to the d riveshaft housing.
1 2. Remove the powerhead using a hoist.
,..If the powerhead will not come off, rotate the propeller to free the
powerhead from the driveshaft. ·
13 . Remove and d iscard the powerhead mounting gasket.
14 . Remove the al igning dowel pins from the bottom of the powerhead.
To install:
15. C lean the powerhead mounting and driveshaft housing gasket surfaces
thoroughly.
7-1 4 POWER HEAD
05007G45
Step 1 6
1 6. Lightly coat the driveshalt sp l ines with marine grease.
1 7. Install a new powerhead new mounting gasket.
18 . Install the powerhead, rotating the propeller as required to al ign driveshalt and crankshaft splines.
19 . Coat powerhead mounting bolt threads with si l icone sealer.
20. Install the powerhead mounting bolts and tighten to specification.
21 . Install the clutch shalt rod by driving it into its bore with a drift.
22. Install the c lutch shalt nuts.
23. Install the grommet on the starboard side of the driveshalt housing.
24. Install the fuel filter.
25. Connect the fuel hose.
26. Install the battery cables and secure them with the cable clamps.
27. Install the cable grommet in the lower support housing.
28. Connect the negative battery cable , then the positive battery cable.
29. Start the engine and make adjustments as necessary.
30. Check engine for proper operation .
3 1 . Install the engine cover.
DT11 5 and DT140
1. Remove the engine cover.
2. Label and disconnect the oi l level switch electrical leads.
3. Disconnect and plug the oil hose.
4. Remove the oil tank.
5. Remove the idle speed adjustment switch, if equipped and electrical
parts holder cover.
6. Disconnect the negative, then the positive battery cables.
7. Disconnect the power trim and tilt electrical leads.
8. Remove the e lectrical parts holder assembly.
9. Disconnect and plug the fuel hose.
1 0. Remove the lower engine covers.
1 1 . Disconnect the water outlet hose.
12. Remove the bolts holding the powerhead to the driveshalt housing.
1 3. Remove the powerhead using a hoist.
,..If the powerhead will not come off, rotate the propeller to free the
powerhead from the driveshaft.
1 4. Remove and discard the powerhead mounting gasket.
15 . Remove the al igning dowel pins from the bottom of the powerhead.
To insta l l :
1 6. C lean the powerhead mounting and driveshalt housing gasket surfaces
thorough ly.
1 7. Lightly coat the driveshalt splines with marine grease.
1 8. Install a new powerhead new mounting gasket.
1 9. Install the powerhead, rotating the propeller as required to align driveshalt and crankshaft splines.
20. Coat powerhead mounting bolt threads with si l icone sealer.
21 . Install the powerhead mounting bolts and tighten to specification.
22. Connect the water outlet hose.
23. Install the lower engine covers.
24. Connect the fuel hose.
25. Install the e lectrical parts holder assembly.
26. Connect the power trim and tilt electrical leads.
27. Connect the positive, then the negative battery cables.
28. Install the idle speed adjustment switch, if equipped and e lectrical parts
holder cover.
29. Install the oi l tank.
30. Connect and plug the oil hose.
3 1 . Label and Connect the oil level switch electrical leads.
32. Install the engine cover.
V4
1 . Remove the engine top cover.
2. Remove the relay cover under the starter.
3. Remove the starter cable from the starter.
4. Disconnect the starter relay from the relay holder.
5. Remove the relay holder and bolt.
6. Disconnect the negative battery cable and the power trim and tilt motor
cable from the engine.
7. Remove the flywheel cover.
8. Remove the power trim and tilt motor relays together with the relay holder.
9. Remove the cover from the e lectrical parts holder.
1 0. Label and disconnect al l electrical leads inside the electrical parts
holder.
1 1 . Remove the bolts securing the e lectrical parts holder and remove it.
12 . Label and disconnect the ground wire from each cylinder head.
13 . Label and disconnect the o i l level switch wire leads.
14. Remove the oil tank.
15 . Disconnect and p lug the fuel hose from the fuel fi lter.
1 6. Disconnect the throttle valve sensor electrical lead, the o i l sensor e lectrical lead and the starter valve electrical lead.
1 7. Remove the lower front under cover.
18 . Remove the lower rear under cover.
1 9. Disconnect the water outlet hose.
20. Remove the bolts holding the powerhead to the driveshalt housing.
21 . Remove the c lutch connector rod pin.
22. Attach a hoist to the engine hooks and lilt the powerhead sl ightly.
,..If the powerhead will not come off, rotate the propeller to free the
powerhead from the driveshaft.
23. Disconnect the clutch lever rod from the c lutch shaft.
24. Disconnect the upper c lutch rod from the clutch shalt.
25. Remove the powerhead using a hoist.
26. Remove and discard the powerhead mounting gasket.
27. Remove the al igning dowel pins from the bottom of the powerhead.
To install:
28. C lean the powerhead mounting and driveshalt housing gasket surfaces
thoroughly.
29. Lightly coat the driveshalt spl ines with marine grease.
30. Install a new powerhead new mounting gasket.
3 1 . Install the powerhead, rotating the propeller as required to align driveshaft and crankshaft spl ines.
32. Coat powerhead mounting bolt threads with si l icone sealer.
33. Install the powerhead mounting bolts and tighten to specification.
34. Connect the upper c lutch rod to the c lutch shaft.
35. Connect the clutch lever rod to the c lutch shaft.
36. Install the c lutch connector rod pin .
37. Connect the water outlet hose.
38. Install the lower rear under cover.
39. Install the lower front under cover.
40. Connect the throttle valve sensor electrical lead, the oi l sensor e lectrical
lead and the starter valve electrical lead.
41 . Connect the fuel hose to the fuel fi lter.
42. Install the oi l tank.
43. Connect the oil level switch wire leads.
44. Connect the ground wire from each cylinder head.
45. Install the e lectrical parts holder
46. Connect al l e lectrical leads inside the e lectrical parts holder.
47. Install the cover on the electrical parts holder.
48. Install the power trim and ti lt motor relays together with the relay ho lder.
49. Install the flywheel cover.
50. Connect the negative battery cable and the power trim and ti lt motor
cable to the engine.
51 . Instal l the relay holder and bolt.
52. Connect the starter relay to the relay holder.
53. Install the starter cable to the starter.
54. Install the relay cover under the starter.
55. Start the engine and make adjustments as necessary.
56. Check engine for proper operation.
57. Install the engine cover.
V6
1 . Remove the engine cover.
2. Disconnect the negative, then the positive battery cables.
3. Remove the cover from the e lectrical parts holder.
4. Disconnect the battery cable and the power trim and ti lt motor e lectrical
leads from the powerhead.
5. Disconnect and plug the fuel hose.
6. Remove the cover from the e lectrical parts holder
7. Disconnect al l electrical leads inside the electrical parts holder, then
remove the electrical parts holder.
8. Remove the bolts holding the powerhead to the driveshaft housing.
9. Remove the lower front under cover.
1 0. Remove the lower rear under cover.
1 1 . Disconnect the water outlet hose.
12. Remove the bolts holding the powerhead to the driveshaft housing.
13. Remove the upper to lower clutch rod c levis p in .
1 4. Attach a hoist to the engine hooks and l ift the powerhead sl ightly.
�If the powerhead will not come off, rotate the propeller to free the
powerhead from the driveshaft.
15 . Disconnect the c lutch lever rod connector from the clutch shaft.
16 . Disconnect the upper clutch rod from the clutch shaft.
1 7. Remove the powerhead using a hoist.
18 . Remove and discard the powerhead mounting gasket.
19 . Remove the al igning dowel pins from the bottom of the powerhead.
To instal l :
20. C lean the powerhead mounting and driveshaft housing gasket surfaces
thoroughly.
21 . Lightly coat the driveshaft spl ines with marine grease.
22. Install a new powerhead new mounting gasket.
23. Install the powerhead, rotating the propeller as required to al ign driveshaft and crankshaft spl ines.
24. Install the upper to lower c lutch rod clevis p in .
25. Coat powerhead mounting bolt threads with s i l icone sealer.
26. Install the powerhead mounting bolts and tighten to specification.
27. Connect the water outlet hose.
28. Install the lower rear under cover.
29. Install the lower front under cover.
30. Install the electrical parts holder, then connect a l l e lectrical leads i nside
the e lectrical parts holder.
3 1 . Install the cover on the e lectrical parts holder
32. Connect the fuel hose. 33. Connect the battery cable and the power trim and tilt motor electrical
leads to the powerhead.
34. Connect the positive, then the negative battery cables.
35. Start the engine and make adjustments as necessary.
36. Check engine for proper operation.
37. Install the engine cover.
DISASSEMBLY & ASSEMBLY
DT2 and DT2.2
t See accompanying i l lustrations
1. Loosen the cylinder head nuts in several stages using a criss-cross pattern.
2. Remove the nuts and l ift the cylinder head from the cylinder block.
3. Remove and discard the cylinder head gasket.
4. Loosen the crankcase bolts in several stages using a criss-cross pattern.
5. Careful ly pry apart and separate the crankcase halves.
�If the halves resist coming apart, tap them l ightly with a plastic ham­
mer. Do not pry heavily on the crankcase halves, as severe damage may
occur.
POWER H EAD 7-1 5
05007G46
Step 1
05007G47
Step 4
05007G48
Step 5
7-1 6 POWER H EAD
05007G49
Step 6 Step 7
05007GS2
Step 1 0 Step 12
G rease here
05007GSS
Step 1 6 Step 1 7
6 . Remove the 0-ring from the crankshaft lower end.
7. To remove the rotating assembly, hold the crankshaft wh i le s l iding the
cylinder block away from the piston.
8. Remove the crankshaft thrust rings.
9. Carefu l ly pry the piston pin retainer from its groove on the piston. Then
repeat the procedure for the other side.
�The circlip will tend to fly when removed. Be ready to catching it as it
comes free.
9. Piston pin retainers are only good for one usage, discard the retainers
after removing them.
1 0. Push the piston pin from it bore in the piston using a brass drift if necessary.
�The piston pin should slide smoothly from its bore. If opposition is
felt, either the bore is out of round or the pin is bent. Inspect the com­
ponents and replace as necessary.
05007GSO
Step 9
05007G53
Step 13
Thrust Bearings
05007G56
Step 18
1 1 . Remove the piston and needle bearing from the connecting rod.
1 2. S l ide the top and bottom crankshaft o i l seals from the crank­
shaft.
To assemble:
05007GS1
05007GS4
05007G57
1 3. Install the piston and needle bearing on the connecting rod. Make sure
the arrow on the piston points to the sp l ined portion of the crankshaft (down­
ward).
14 . Push the piston p in into the piston bore using a brass drift if necessary.
1 5 . Install new piston p in retainers
16. Lubricate the seals with marine grease prior to installation.
1 7. Install the top and bottom crankshaft oi l seals with the numbers facing
the ends of the crankshaft.
18 . Install the crankshaft thrust rings.
1 9. Lubricate the rotating assembly with 2-stroke o i l prior to installa­
t ion.
Step 20 Step 21
Step 24
Step 25
20. Install the rotating assembly into the cylinder block, making sure the
crankshaft faces the correct way. The splined end of the crankshaft should
face driveshaft housing side.
2 1 . Apply marine grease to the 0-ring and the splined portion of the
crankshaft. Install the 0-ring.
22. Apply a bead of Suzuki Bond No. 4 (99000-31 030), or equivalent
sealer to the crankcase halves (shaded areas in the illustration).
23. Tighten the crankcase bolts to specification in several stages using a
criss-cross pattern.
24. Install a new cylinder head gasket noting the position of the cooling
water hole.
25. Install the cylinder head matching the waterway on the head to the
water hole on the cylinder block.
26. Tighten the cylinder head nuts to specification in several stages using
a criss-cross pattern.
27. Rotate the crankshaft several turns to check for binding. If crankshaft
does not turn freely, determine the cause and correct prior to assembling the
powerhead.
POWER H EAD 7-1 7
Step 22
DT4 and DTSY
• See Figures 1 and 2
1 . Loosen the clips and disconnect the lubrication hose from each
fitting.
2. Remove the mounting bolts and remove the rewind starter mounting
base.
3. Remove the screws and remove the water jacket cover and gasket.
4. Loosen the cylinder head bolts in several stages using a criss-cross
pattern.
5. Remove the cylinder head.
6. Loosen the crankcase bolts in several stages using a criss-cross
pattern.
7. Carefully pry apart and separate the crankcase halves.
8. To remove the rotating assembly, hold the crankshaft while sliding
the cylinder block away from the piston.
1 . Cover, cy l i nder head 8. Stopper, reed valve
2. Gasket, cyl inder head 9. Reed, valve
cover 10. Cover, water jacket
3 . Cyli nder 1 1 . Gasket, water jacket
4. Dowel pin 1 2. Cover, lower drain
5. Cover, port, R hole
6. Cover, port, L 1 3. Hose, l u brication
7 . 0 ring
Fig. 1 Exploded view of the powerhead-DT4
7-1 8 POWER H EAD
Fig. 2 Crankcase bolt tightening sequence - DT4 and DTSY
9. Carefully pry the piston pin retainer from its groove on the piston.
Then repeat the procedure for the other side.
• The circlip will tend to fly when removed. Be ready to catching it as
it comes free.
1 0. Piston pin retainers are only good for one usage, discard the
retainers after removing them.
1 1 . Push the piston pin from it bore in the piston using a brass drift if
necessary.
• The piston pin should slide smoothly from its bore. If opposition is
felt, either the bore is out of round or the pin is bent. Inspect the
components and replace as necessary.
1 2. Remove the piston from the connecting rod.
1 3. Slide the top and bottom crankshaft oil seals from the crankshaft.
To assemble:
1 4. Install the piston on the connecting rod. Make sure the arrow on the
piston points to the splined portion of the crankshaft (downward).
1 5. Push the piston pin into the piston bore using a brass drift if
necessary.
1 6. Install new piston pin retainers
1 7. Lubricate the seals with marine grease prior to installation.
1 8. Install the top and bottom crankshaft oil seals with the numbers
facing the ends of the crankshaft.
1 9. Install the crankshaft thrust washer.
20. Lubricate the rotating-assembly with 2-stroke oil prior to installation.
2 1 . Install the rotating assembly into the cylinder block, making sure the
crankshaft faces the correct way. The splined end of the crankshaft should
face driveshaft housing side.
22. The crankshaft thrust washer should fit snugly into the groove in the
cylinder block.
23. Apply marine grease to the splined portion of the crankshaft.
24. Apply a bead of Suzuki Bond No. 4 (99000-31 030), or equivalent
sealer to the crankcase halves (shaded areas in the illustration).
25. Tighten the crankcase bolts to specification in several stages using a
criss-cross pattern.
26. Install a new cylinder head gasket.
27. Install the cylinder head and tighten the cylinder head bolts to
specification in several stages using the correct torque sequence.
28. Rotate the crankshaft several turns to check for binding. If crankshaft
does not turn freely, determine the cause and correct prior to assembling the
powerhead.
DT6 and DT8
• See accompanying illustrations
1 . Loosen the cylinder head bolts in several stages using a criss-cross
pattern.
2. Remove the cylinder head.
3. Loosen the inlet case bolts in several stages using a criss-cross
pattern.
4. Remove the inlet case.
5. Remove the reed valve assembly.
Step 1
Step 3
Step 5
Step 6
05007G68
Step 8
05007G71
Step 1 2 Step 1 3
05007G90
Step 1 8
6 . Loosen the exhaust cover bolts i n several stages using a criss-cross
pattern.
7. Remove the exhaust cover.
8. Remove the lower o i l seal housing.
9. Loosen the crankcase bolts in several stages using a criss-cross pattern.
1 0. Separate the crankcase from the cylinder block.
1 1 . Careful ly pry apart and separate the crankcase halves.
1 2. Remove the rotating assembly by carefu l ly l ifting the crankshaft from the
cylinder block.
1 3. Carefu l ly pry the piston pin retainer from its groove on the piston. Then
repeat the procedure for the other side.
POWER H EAD 7-1 9
Step 9 05007G70
05007G72
0500/G/3
Step 1 5
,..The circlip will tend t o fly when removed. B e ready to catching i t a s it
comes free.
1 4. Piston pin retainers are only good for one usage, discard the retainers
after removing them.
15. Push the piston pin from it bore in the piston using a brass drift if nec­
essary.
,.. The piston pin should slide smoothly from its bore. If opposition is
fell, either the bore is out of round or the pin is bent. Inspect the com­
ponents and replace as necessary.
1 6. Remove the piston from the connecting rod.
1 7. Sl ide the top and bottom crankshaft oil seals from the crankshaft.
To assemble:
1 8. Install the piston on the connecting rod. Make sure the arrow on the pis­
tons point to the exhaust port side.
1 9. Push the piston pin into the piston bore using a brass drift i f necessary.
20. Install new piston pin retainers.
21 . Lubricate the seals with marine grease prior to installation.
22. Install the top and bottom crankshaft oil seals with the numbers faci ng
the ends of the crankshaft.
23. Install the crankshaft upper bearing, making sure the clearance between
(A) and (B) as i l lustrated is not greater than 0.02 in. (0.5mm). If the clearance is
greater, add a shim (091 60-35001 ) to decrease the distance.
24. Lubricate the rotat ing assembly with 2-stroke o i l pr ior to i nstalla­
t ion.
25. Install the rotating assembly into the cylinder block, making sure the
crankshaft faces the correct way. The spl ined end of the crankshaft should face
driveshaft housing side.
7-20 POWERHEAD
Step 26
OT6
Step 29
DT 6
DT8
Step 32
DT8
(A) &J
(A)
z;J
05007G76
05007G74
05007G75
26. The crankshaft lower bearing should fit snugly into the groove in the
cylinder block.
27. Apply marine grease to the splined portion of the crankshaft.
28. Apply a bead of Suzuki Bond No. 4 (99000-31 030), or equivalent sealer
to the crankcase halves (shaded areas in the i l lustration).
29. Install the crankcase and tighten the bolts to specification in several
stages using the proper tightening sequence.
30. Install the lower oil seal housing.
3 1 . Install the exhaust cover.
DT6
DTB
05007G77
Step 33
05007G78
Step 34
3
Step 35
32. Install the reed valve assembly making sure the reed valves face the
crankshaft.
33. nsta l l the in let case and tighten the bolts to specification in several
stages using the proper tightening sequence.
34. Install the cylinder head using a new gasket and tighten the bolts to
specification in several stages using the proper tightening sequence.
35. Rotate the crankshaft several turns to check for binding. If crankshaft
does not turn freely, determine the cause and correct prior to assembling the
powerhead.
DT9.9 and DT15
t See accompanying i l lustrations
1 . Loosen the in let case bolts i n several stages using a criss-cross pat­
tern.
2. Remove the i n let case (1 ) , inner p iece (2)and reed valve assembly
(3).
3. Remove the exhaust plate and gasket from the cylinder.
4. Remove the exhaust cover attaching bolts.
5. Insert a pry bar between the exhaust cover and cylinder block and pry
the cover to remove it. Discard the exhaust cover gasket.
6. Remove the exhaust plate and discard the gasket.
7. Loosen the cylinder head bolts in several stages using a criss-cross pattern.
0500/GSO
Step 1
Step 2
05007G81
Step 3
Step 8
05007G85
Step 9
POWER H EAD 7-21
8. Remove the cyl inder head. 1 1 the cyl inder head is hard t o remove,
use a plastic hammer to drive the dead at the placed ind icated in the i l l ustra­
t ion.
9. Loosen the crankcase bolts in several stages using a criss-cross pattern.
Then remove the crankcase.
1 0. Remove the rotating assembly by careful ly lifting the crankshaft from the
cylinder block.
1 1 . Carefu l ly pry the piston p in retainer from its groove on the piston. Then
repeat the procedure !or the other side.
,... The circlip will tend to fly when removed. Be ready to catching it as it
comes free.
1 2. Piston p in retainers are only good for one usage, d iscard the retainers
alter removing them.
13. Push the piston pin from it bore in the piston using a brass drill if nec­
essary.
,.The piston pin should slide smoothly from its bore. If opposition is
felt, either the bore is out of round or the pin is bent. Inspect the com­
ponents and replace as necessary.
1 4. Remove the piston from the connecting rod.
To assemble:
15 . Install the piston on the connecting rod. Make sure the arrow on the pistons point to the exhaust port side.
1 6. Push the piston p in into the piston bore using a brass drill if necesary.
1 7. Install new piston p in retainers.
1 8. Lubricate the seals with marine grease prior to installation.
1 9. Install the top and bottom crankshaft oil seals with the numbers lacing
the ends of the crankshaft.
20. Lubricate the rotating assembly with 2-stroke o i l prior to installa­
tion.
21 . Install the rotating assembly into the cylinder block, making sure the
crankshaft laces the correct way. The spl ined end of the crankshaft should face
driveshalt housing side.
Step 5
05007G83
05007G91
05007G89
Step 15
7-22 POWER H EAD
' '
�:��
05007G8A
Step 22 Step 24
05007G94
Step 26 Step 29
Step 31
22. The flange of the lower oi l seal should f i t snugly into the groove in the
cylinder block.
23. Apply marine g rease to the sp l ined portion of the crankshaft.
24. Apply a bead of Suzuki Bond No. 4 (99000-31 030), or equivalent sealer
to the crankcase halves (shaded areas in the i l lustration) .
25. Install the crankcase and tighten the bolts to specification in several
stages using the proper tightening sequence.
26. Install the cylinder head using a new gasket and tighten the bolts to
specification in several stages using the proper tightening sequence.
27. Install the exhaust p late using a new gasket.
28. Install the exhaust cover and tighten the attaching bolts securely.
29. Install the reed valve assembly making sure the reed valves face the
crankshaft.
30. Install the inlet case piece with the arched surface downward and fit the
tangs into the notches of the inlet case.
3 1 . Install the in let case and tighten the bolts to specification in several
stages using the proper tighten ing sequence.
05007G92
Step 25 05007G93
05007G95
05007G96
Step 30
DT25 and DT30
• See Figures 3 and 4
1 . Remove al l components stil l attached to the powerhead unti l the unit is
down to the bare cylinder block assembly
2. Remove the thermostat cover and thermostat.
3. Loosen the in let case bolts in several stages using a criss-cross pattern.
4. Remove the in let case.
5. Remove the reed valve assembly.
6. Remove the exhaust cover attaching bolts.
05007G1S
Fig. 3 Crankcase bolt tightening sequence-DT25 and DT30
0500/GH
Fig. 4 Cylinder head bolt tightening sequence-DT25 and DT30
7. Insert a pry bar between the exhaust cover and cylinder block and pry
the cover to remove it. Discard the exhaust cover gasket.
8. Remove the lower o i l seal housing attach ing bolts.
9. Insert a pry bar between the oil seal housing and cylinder block and pry
the cover to remove it. Discard the o i l seal housing gasket.
1 0. Loosen the cylinder head bolts in several stages using a criss-cross pat­
tern.
1 1 . Insert a pry bar between the cylinder head and cylinder block and pry
the head to remove it. Discard the cylinder head gasket.
12 . Loosen the cylinder head cover bolts.
13. Insert a pry bar between the cylinder head cover and the cylinder head.
Pry the head cover to remove it.
14. Loosen the crankcase bolts.
15. Insert a pry bar between crankcase and the cylinder block. Pry the
crankcase to remove it.
1 6. Remove the rotating assembly by carefu l ly l ifting the crankshaft from the
cylinder block.
1 7. Carefully pry the piston pin retainer from its groove on the piston. Then
repeat the procedure for the other side.
�The circlip will tend to fly when removed. Be ready to catching it as it
comes free.
1 8. Piston pin retainers are only good for one usage, d iscard the retainers
alter removing them.
1 9. Push the piston pin from it bore in the piston using a brass drift if nec­
essary.
�The piston pin should slide smoothly from its bore. If opposition is
felt, either the bore is out of round or the pin is bent. Inspect the com­
ponents and replace as necessary.
20. Remove the piston from the connecting rod.
To assemble:
21. Install the piston on the connecting rod. Make sure the arrow on the pistons point to the exhaust port side.
22. Push the piston pin into the piston bore using a brass drift if necessary.
23. Install new piston pin retainers.
24. Lubricate the seals with marine grease prior to installation.
25. Install the top and bottom crankshaft oil seals with the numbers lacing
the ends of the crankshaft.
26. Lubricate the rotating assembly with 2-stroke o i l prior to installation.
27. Install the rotating assembly into the cyl inder block, making sure the
crankshaft laces the correct way. The spl ined end of the crankshaft should lace
driveshaft housing side.
28. Ensure the crankshaft C-rings are fitted into their grooves in the
crankcase and the flange of the o i l seals lit snugly i nto their grooves. Check that
the bearing stopper pins are resting snugly in their cutaways.
29. Apply marine grease to the spl ined portion of the crankshaft.
POWER H EAD 7-23
30. Apply a bead o f Suzuki Bond No . 4 (99000-31 030), or equ ivalent sealer
to the crankcase halves (shaded areas in the i l l ustration).
31. Ensure the crankcase locating p ins are i nstalled prior to i nsta l l ing the
crankcase.
32. Install the crankcase and tighten the bolts to specification in several
stages using the proper tightening sequence.
33. Install the cylinder head using a new gasket. Tighten the cylinder head
and cylinder head cover bolts to specification in several stages using the proper
tightening sequence.
34. Install the exhaust cover and tighten attach ing bolts securely.
35. Install the reed valve assembly and tighten attach ing bolts securely.
36. Install the i nlet case and tighten the bolts to specification in several
stages using the proper tighten ing sequence.
37. Install the thermostat cover and thermostat.
38. Install al l previously remove al l components to the powerhead.
DT35 and DT40
• See accompanying i l lustrations
1 . Remove al l components st i l l attached to the powerhead unti l the un it is
down to the bare cylinder block assembly
2. Remove the thermostat cover and thermostat.
3. Loosen the i n let case bolts in several stages using a criss-cross pattern.
4. Remove the i n l et case.
5. Remove the reed valve assembly.
6. Remove the exhaust cover attach ing bolts.
7. Insert a pry bar between the exhaust cover and cylinder block and pry
the cover to remove it. Discard the exhaust cover gasket.
8. Remove the lower o i l seal housing attach ing bolts.
9. Insert a pry bar between the oil seal housing and cylinder block and pry
the cover to remove it. Discard the oil seal housing gasket.
1 0. Loosen the cylinder head bolts in several stages using the sequence
defined by the numbers punched into the bolt heads. Start with bolt number 1 3
and work toward bolt number 1 .
1 1 . Insert a pry bar between the cylinder head and cylinder block and pry
the head to remove it. Discard the cylinder head gasket.
12 . Loosen the cylinder head cover bolts.
13. Insert a pry bar between the cylinder head cover and the cylinder head.
Pry the head cover to remove it.
1 4. Loosen the crankcase bolts.
15 . Insert a pry bar between crankcase and the cylinder block. Pry the
crankcase to remove it.
1 6. Remove the rotating assembly by carefu l ly l ifting the crankshaft from the
cylinder block. .
1 7. Careful ly pry the piston pin retainer from its groove on the p1ston. Then
repeat the procedure for the other side.
�The circlip will tend to fly when removed. Be ready to catching it as it
comes free.
1 8. Piston pin retainers are only good for one usage, discard the retainers
alter removing them. . . . .
1 9. Push the piston p in from it bore in the p1ston us1ng a brass dn!t 1! nec­
essary.
�The piston pin should slide smoothly from its bore. If opposition is
felt, either the bore is out of round or the pin is bent. Inspect the com­
ponents and replace as necessary.
20. Remove the piston from the connecting rod.
To assemble:
21. Install the piston on the connecting rod. Make sure the arrow on the pistons point to the exhaust port side. . . .
22. Push the piston p in i nto the piston bore us1ng a brass dnft 1! necessary.
23. Install new piston p in retainers.
24. Lubricate the seals with marine grease prior to installation.
25. Install the top and bottom crankshaft oi l seals with the numbers lacing
the ends of the crankshaft.
26. Lubricate the rotating assembly with 2-stroke o i l prior to i nstallation.
27. Install the rotating assembly into the cylinder block, making sure the
crankshaft laces the correct way. The spl ined end of the crankshaft should lace
driveshaft housing side.
7-24 POWER H EAD
60 07
8
zo 4
100 09
0500/GXX
Step 31
0500/GYY
Step 32
10
6 2 4 8
0500/GZZ
Step 36
28. The flange of the middle and lower o i l seals should fit snugly into the
groove in the cylinder block.
29. Apply marine grease to the sp l ined portion of the crankshaft.
30. Apply a bead of Suzuki Bond No. 4 (99000-31030), or equivalent sealer
to the crankcase halves (shaded areas in the i l lustration).
31. Install the crankcase and tighten the bolts to specification in several
stages using the proper tightening sequence.
32. Install the cylinder head using a new gasket. Tighten the cylinder head
and cylinder head cover bolts to specification in several stages using the proper
tightening sequence.
33. Install the lower oil seal housing and tighten attaching bolts securely.
34. Install the exhaust cover and tighten attaching bolts securely.
35. Install the reed valve assembly and tighten attaching bolts securely.
36. Install the in let case and tighten the bolts to specification in several
stages using the proper tightening sequence.
37. Install the thermostat cover and thermostat.
38. Install al l previously removed components to the powerhead.
DT50
• See accompanying i l lustrations
1 . Remove al l components sti l l attached to the powerhead unti l the unit is
down to the bare cylinder block assembly
2. Loosen the cylinder head bolts in several stages using a criss-cross pattern.
3. Remove the cylinder head.
4. Remove the valve and spring from the cylinder block.
5. Loosen the i nlet case bolts in several stages using a criss-cross pattern.
6. Remove the in let case.
05007G1A
Step 2
05007G1B
Step 4
05007G1C
Step 5
Step 7
05007G1G
Step 9
05007G1F
Step 1 2 Step 13
05007G1L
Step 1 7 Step 23
7. Loosen the exhaust cover bolts in several stages using a criss-cross
pattern.
8. Remove the exhaust cover.
9. Loosen the crankcase bolts in several stages using a criss-cross pattern.
1 0. Separate the crankcase from the cylinder block.
1 1 . Remove the lower oil seal housing.
12. Remove the rotating assembly by careful ly l ifting the crankshaft from the
cylinder block.
13. Carefu l ly pry the piston pin retainer from its groove on the piston. Then
repeat the procedure for the other side.
•The circlip will tend to fly when removed. Be ready to catching it as it
comes free.
1 4. Piston pin retainers are only good for one usage, d iscard the retainers
alter removing them.
15 . Push the piston pin from it bore in the piston using a brass drift i f nec­
essary.
POWERHEAD 7-25
05007G1D
Step 1 1
05007G1E
05007G1H
05007G1J
Step 1 5
05007G1M 05007G1N
Step 24
,.. The piston pin should slide smoothly from its bore. If opposition is
felt, either the bore is out of round or the pin is bent. Inspect the com­
ponents and replace as necessary.
1 6. Remove the piston from the wnnecting rod.
To assemble:
1 7. Install the piston on the connecting rod. Make sure the arrow on the pistons point to the exhaust port side.
1 8. Push the piston pin into the piston bore using a brass drift if necessary.
19 . Install new piston p in retainers.
20. Lubricate the seals with marine grease prior to installation.
21 . Install the top and bottom crankshaft oil seals with the numbers lacing
the ends of the crankshaft.
22. Lubricate the rotating assembly with 2-stroke oi l prior to i nstallation.
23. Ensure the two thrust rings are properly i nstalled prior to insta l l ing the
rotat ing assembly.
24. Make sure there is no remain ing 0-ring compound in the i l lustrated area.
7-26 POWER H EAD
Step 26
05007G1Q
Step 28
3
05007G10
Step 30
05007G1R
Step 32
25. Install the rotating assembly into the cylinder block, making sure the
crankshaft faces the correct way. The spl ined end of the crankshaft should face
driveshaft housing side.
26. Ensure the bearing stopper pins rest snugly in the cutaways.
27. Lubricate the seals with marine grease and insta l l .
28 . I nstall the crankcase and tighten the bolts to specification i n several
stages using the proper tightening sequence.
29. Install the exhaust cover and tighten the bolts securely.
30. Install the in let case and tighten the bolts to specification in several
stages using the proper tightening sequence.
31 . Install the valve and spring into the cylinder block.
32. Install the cylinder head and tighten the bolts to specification in several
stages using the proper tightening sequence.
osoo?G1P 33. Install all components previously removed.
DT55 and DT65
• See Figures 5 and 6
1 . Remove a l l components sti l l attached to the powerhead until the unit is
down to the bare cylinder b lock assembly
2. Remove the thermostat cover and thermostat.
3. Loosen the in let case bolts in several stages using a criss-cross pattern.
4. Remove the inlet case.
Fig. 5 Crankcase bolt lightening sequence-DT55 and DT65
1 5
23
4
2 19
7 22
�-?/\���,__�9 21
13
17
05007G1U
Fig. 6 Cylinder head and cylinder head cover bolt lightening
sequence-DT55 and DT65
05007P24
5. Remove the reed valve assembly.
6. Remove the exhaust cover attach ing bolts.
7. Insert a pry bar between the exhaust cover and cylinder block and pry
the cover to remove it. D iscard the exhaust cover gasket.
8. Remove the lower o i l seal housing attach ing bolts.
9. Insert a pry bar between the oil seal housing and cylinder block and pry
the cover to remove it. D iscard the oil seal housing gasket.
10 . Loosen the cylinder head bolts in several stages using a criss-cross pat­
tern.
1 1 . Insert a pry bar between the cylinder head and cylinder block and pry
the head to remove it. Discard the cylinder head gasket.
1 2. Loosen the cylinder head cover bolts.
13. Insert a pry bar between the cylinder head cover and the cylinder head.
Pry the head cover to remove it.
1 4. Loosen the crankcase bolts.
15 . Insert a pry bar between crankcase and the cylinder block. Pry the
crankcase to remove it.
1 6. Remove the rotating assembly by carefu l ly l ifting the crankshaft from the
cylinder block.
1 7. Careful ly pry the piston pin retainer from its groove on the piston. Then
repeat the procedure for the other side.
,.. The circlip will tend to fly when removed. Be ready to catching it as it
comes free.
18 . Piston p in retainers are only good for one usage, discard the retainers
after removing them.
1 9. Push the piston pin from it bore in the piston using a brass drift if nec­
essary.
,..The piston pin should slide smoothly from its bore. If opposition is
felt, either the bore is out of round or the pin is bent. Inspect the com­
ponents and replace as necessary.
20. Remove the piston from the connecting rod.
To assemble:
21 . Install the piston on the connecting rod. Make sure the arrow on the pistons point to the exhaust port side.
22. Push the piston pin into the piston bore using a brass drift if necessary.
23. Install new piston pin retainers.
24. Lubricate the seals with marine grease prior to installation.
25. Install the top and bottom crankshaft o i l seals with the numbers facing
the ends of the crankshaft.
26. Lubricate the rotating assembly with 2-stroke o i l prior to installation.
27. Install the rotating assembly into the cylinder block, making sure the
crankshaft faces the correct way. The spl ined end of the crankshaft should face
driveshaft housing side.
28. Ensure the crankshaft C-rings are fitted i nto their grooves in the
crankcase and the flange of the oil seals fit snugly into their grooves.
29. Check that the bearing stopper pins are resting snugly in their cutaways.
30. Apply marine grease to the splined portion of the crankshaft.
31 . Apply a bead of Suzuki Bend No. 4 (99000-31 030), or equivalent sealer
to the crankcase halves (shaded areas in the i l lustration).
32. Ensure the crankcase locating pins are installed prior to instal l ing the
crankcase.
33. Install the crankcase and tighten the bolts to specification in several
stages using the proper tightening sequence.
34. Install the cylinder head using a new gasket. Tighten the cylinder head
and cylinder head cover bolts to specification in several stages using the proper
tighten ing sequence.
35. Install the exhaust cover and tighten attach ing bolts securely.
36. Install the reed valve assembly and tighten attach ing bolts securely.
37. Install the in let case and tighten the bolts to specification in several
stages using the proper tightening sequence.
38. Install the thermostat cover and thermostat.
39. Install al l previously remove al l components to the powerhead.
DT75 and DT85
t See Figures 7, 8, 9 and 1 0
1 . Remove a l l components sti l l attached to the powerhead unti l the unit is
down to the bare cylinder block assembly
2. Remove the thermostat cover and thermostat.
POWER H EAD 7-27
05007G1W
Fig. 7 Crankcase bolt tightening sequence-1988-92 DT55 and DT65
8
4
2
6
1 0
1 4
1 3
9
5
3
7
1 1
Fig. 8 Crankcase bolt tightening sequence-1993-97 DT55 and DT65
05007G1Y
Fig. 9 Cylinder head and cylinder head cover bolt tightening
sequence-1988-92 DT55 and DT65
7-28 POWER H EAD
1 3 1 2 6 2 4 8 1 0 I
1 4 3 5 1 1 9 7
Fig. 10 Cylinder head and cylinder head cover bolt tightening
sequence-1993-97 DT55 and DT65
05007G1Z
3. Loosen the in let case bolts i n several stages using a criss-cross pattern.
4. Remove the inlet case.
5. Remove the reed valve assembly.
6. Remove the exhaust cover attaching bolts.
7. I nsert a pry bar between the exhaust cover and cylinder block and pry
the cover to remove it. Discard the exhaust cover gasket.
8. Remove the lower oil seal housing attaching bolts.
9. Insert a pry bar between the oil seal housing and cylinder block and pry
the cover to remove it. Discard the oil seal housing gasket.
1 0. Loosen the cylinder head bolts in several stages using a criss-cross pat­
tern.
1 1 . I nsert a pry bar between the cylinder head and cylinder block and pry
the head to remove it. Discard the cylinder head gasket.
12 . Loosen the cylinder head cover bolts.
13. Insert a pry bar between the cylinder head cover and the cylinder head.
Pry the head cover to remove it.
14. Loosen the crankcase bolts.
1 5. I nsert a pry bar between crankcase and the cylinder block. Pry the
crankcase to remove it.
1 6. Remove the rotating assembly by carefu l ly lifting the crankshaft from the
cylinder block.
1 7. Careful ly pry the piston pin retainer from its groove on the piston. Then
repeat the procedure for the other side.
�The circlip will tend to fly when removed. Be ready to catching it as it
comes free.
18. Piston pin retainers are only good for one usage, discard the retainers
after removing them.
1 9. Push the piston pin from it bore in the piston using a brass drift if nec­
essary.
�The piston pin should slide smoothly from its bore. If opposition is
felt, either the bore is out of round or the pin is bent. Inspect the com­
ponents and replace as necessary.
20. Remove the piston from the connecting rod.
To assemble:
21. Install the piston on the connecting rod. Make sure the arrow on the pistons point to the exhaust port side.
22. Push the piston p in into the piston bore using a brass drift if necessary.
23. Install new piston pin retainers.
24. Lubricate the seals with marine grease prior to installation.
25. Install the top and bottom crankshaft oil seals with the numbers facing
the ends of the crankshaft.
26. Lubricate the rotating assembly with 2-stroke oi l prior to instal lation .
27. Install the rotating assembly into the cylinder block, making sure the
crankshaft faces the correct way. The spl ined end of the crankshaft should face
driveshaft housing side.
28. Ensure the crankshaft C-rings are fitted into their grooves in the
crankcase and the flange of the oil seals fit snugly into their grooves. Check that
the bearing stopper pins are resting snugly in their cutaways.
29. Apply marine grease to the splined portion of the crankshaft.
30. Apply a bead of Suzuki Bond No. 4 (99000-31 030), or equivalent sealer
to the crankcase halves (shaded areas in the i l lustration).
31 . Ensure the crankcase locating pins are installed prior to instal l ing the
crankcase.
32. Install the crankcase and tighten the bolts to specification in several
stages using the proper tightening sequence.
33. Install the cylinder head using a new gasket. Tighten the cylinder head
and cylinder head cover bolts to specification in several stages using the proper
tightening sequence.
34. Install the exhaust cover and tighten attaching bolts securely.
35. Install the reed valve assembly and tighten attaching bolts securely.
36. Install the inlet case and tighten the bolts to specification in several
stages using the proper tightening sequence.
37. Install the thermostat cover and thermostat.
38. Install al l previously removed components to the powerhead.
DT1 1 5 and DT140
• See Figures 1 1 and 1 2
1 . Remove a l l components sti l l attached to the powerhead unti l the unit is
down to the bare cylinder block assembly
2. Remove the si lencer cover and then the si lencer case.
3. Loosen the i n let case bolts in several stages using a criss-cross pattern.
4. Remove the inlet case.
5. Remove the reed valve assembly.
6 . Remove the exhaust cover attaching bolts.
7. Insert a pry bar between the exhaust cover and cylinder block and pry
the cover to remove it. Discard the exhaust cover gasket.
8. Loosen the cylinder head bolts in several stages using a criss-cross pat­
tern.
9. Insert a pry bar between the cylinder head and cylinder block and pry
the head to remove it. Discard the cylinder head gasket.
1 0. Loosen the crankcase bolts.
1 1 . Insert a pry bar between crankcase and the cylinder block. Pry the
crankcase to remove it.
12 . Remove the rotating assembly by careful ly lifting the crankshaft from the
cylinder block.
13. Careful ly pry the piston pin retainer from its groove on the piston. Then
repeat the procedure for the other side.
7
1 9
5
1 5
--+<�====�--���-25
9 -{�������27
05007G2G
Fig. 11 Crankcase bolt tightening sequence- DT115 and DT140
30-------
29 --H.��:::::::---
3 1---+"i'f:.'.l),),'j �1(-4� 28-----;�
8--+---+�
26---1--4"'1
1 6
1 9
4--�������-3 \\�+---22
1 2 7
20 rH--+---2 1 27====t�ii����:t===1 5
25 1 7 1 4
6
23
2
1 0
24
1 8 ____ _..,.
05007G2F
Fig. 12 Cylinder head lightening sequence- DT115 and DT140
,.. The circlip will tend to fly when removed. Be ready to catching it as it
comes free.
1 4. Piston pin retainers are only good for one usage, discard the retainers
after removing them.
15 . Push the piston pin from it bore in the piston using a brass drift if nec­
essary.
,..The piston pin should slide smoothly from its bore. If opposition is
felt, either the bore is out of round or the pin is bent. Inspect the com­
ponents and replace as necessary.
16 . Remove the piston from the connecting rod.
To assemble:
1 7. Install the piston on the connecting rod. Make sure the arrow on the pistons point to the exhaust port side.
1 8. Push the piston pin into the piston bore using a brass drift if necessary.
1 9. Install new piston p in retainers.
20. Lubricate the seals with marine grease prior to installation.
21 . Install the top and bottom crankshaft o i l seals with the numbers faci ng
the ends of the crankshaft.
22. Lubricate the rotating assembly with 2-stroke o i l prior to installation.
23. Firmly insert crankshaft locating pins.
24. Install the rotating assembly into the cyl inder block, making sure the
crankshaft faces the correct way. The spl ined end of the crankshaft should face
driveshaft housing side.
25. Firmly fit the bearing races onto the locating p ins with punch mark
stamped on the circumference of the bearings d i rected upwards.
26. Check if the projection of spacer is in the hole of crankcase correctly.
27. Make sure that the flange of the upper o i l seal fit snugly i nto the groove
provided in crankcase.
28. Check to be sure the bearing stopper p in is resting snugly in the cut­
away.
29. Also make sure that the C-ring is fitted i nto groove in the crankcase.
30. Make sure that the flange of oil seal housing fits snugly into the groove
provided in crankcase.
3 1 . Apply marine grease to the spl ined portion of the crankshaft.
32. Apply a bead of Suzuki Bond No. 4 (99000-31030), or equivalent sealer
to the crankcase halves (shaded areas in the i l lustration).
33. Install the crankcase and tighten the bolts to specification in several
stages using the proper tightening sequence.
34. Install the cylinder head using a new gasket. Tighten the cylinder head
and cylinder head cover bolts to specification in several stages using the proper
tightening sequence.
35. Install the exhaust cover and tighten attaching bolts securely.
POWERHEAD 7-29
36. Install the reed valve assembly and tighten attach ing bolts securely.
37. Install the in let case and tighten the bolts to specification in several
stages using the proper tightening sequence.
38. Install all previously removed components to the powerhead.
V4
• See accompanying i l lustrations
1 . Remove all components sti l l attached to the powerhead until the unit is
down to the bare cylinder block assembly.
2. Remove the exhaust cover bolts.
3. Using a pry bar, remove the exhaust cover and plate.
4. Remove the s i lencer cover.
5. Position the power un it with the case and si lencer facing downwards on
a level surface so that it wi l l not fall over.
,..Place a thick rubber sheet under the silencer to prevent scratching the
surface.
6. Remove the cylinder head bolts.
7. Tap on the cylinder head with a plastic hammer to remove.
8. Remove the oil seal housing.
9. Remove the hexagon cylinder bolts.
1 0. Remove the crankcase nuts.
1 1 . Pul l ing upward carefu l ly and slowly, remove each cylinder head.
1 2. Carefu l ly pry the piston pin retainer from its groove on the piston. Then
repeat the procedure for the other side.
,..The circlip will tend to fly when removed. Be ready to catching it as it
comes free.
1 3. Piston pin retainers are only good for one usage, discard the retainers
after removing them.
14. Push the piston pin from it bore in the piston using a brass drift if nec­
essary.
,..The p iston pin should slide smoothly from its bore. If opposition is
felt, either the bore is out of round or the pin is bent. Inspect the com­
ponents and replace as necessary.
15 . Remove the piston from the connecting rod.
1 6. Place the crankcase on a wooden stand.
1 7. Remove the in let cases with the reed valves.
1 8. Remove the c lutch shaft.
1 9. Remove the crankcase bolts and lift the rotating assembly out from the
crankcase.
To assemble:
20. Lubricate the seals with marine grease prior to i nstal lation.
21 . Install the top and bottom crankshaft o i l seals with the numbers facing
the ends of the crankshaft.
22. Lubricate the rotating assembly with 2-stroke o i l prior to installation.
05007G2E
Step 1 6
7-30 POWER H EAD
C l i p
1 1 9 7 13 3 6 80 0 680 0 �
ill/ 0� 0 0 0 0 � 0 0 4 16 6 14 8 10 12
Step 23
05007G2A
Step 31
Upside
t Step 33
05007G2N
Step 37
23. Install the middle bearing on the crankshaft with the c l ip covering both
spl it faces of the bearing.
24. Install the rotating assembly into the cylinder block, making sure the
crankshaft faces the correct way The spl ined end of the crankshaft should face
driveshalt housing side.
25. Firmly fit the bearing races onto the locating pins with punch mark
stamped on the c ircumference of the bearings di rected upwards.
26. Ensure the flanges of the upper o i l seal fit snugly into the groove pro­
vided in crankcase.
27. Check to be sure that the under bearing stopper pi n is resting snugly in
the cutaway.
28. Make the "C" ring is fitted into groove in the crankcase.
29. Check to be sure that the end gap of the seal rings face up.
30. Apply marine grease to
-
the sp l ined portion of the crankshaft.
31 . Install the crankcase and tighten the crankcase nuts to specification
using the proper tightening sequence.
_.After the crankcase has been assembled, turn the crankshaft to see
whether it makes any abnormal noise. If the crankshaft makes any
abnormal noise, disassemble the crankcase to find the trouble.
32. Install the piston on the connecting rod. Make sure the arrow on the pistons point to the exhaust port
side.
33. Push the piston pin into the piston bore using a brass drift if necessary.
34. Install new piston p in retainers.
35. Install a new cylinder head gasket and hold it i n place with a light film of
grease.
36. Install each cylinder head onto the cylinder block and snug each bolt to
hold the cylinders in place.
37. Install the cylinder/crankcase assembly p late (0991 2-68720) and tighten
the bolts to the specified torque using the proper sequence.
38. Tighten the hexagon cylinder bolts to specification using a criss-cross
tightening sequence.
39. Install the cylinder head and tighten the cylinder head bolts to specifica­
tion using the proper tightening sequence.
05007G2B
Step 32 05007G2H
12
11
05007G2D
05007G2C
Step 39
40. Install the o i l seal housing and tighten the bolts to specification.
41 . Install the exhaust cover and plate. Tighten the exhaust cover bolts to
specification.
42. Install al l components previously removed from the cyl inder block.
V6
t See accompanying i l lustrations
1 . Remove all components sti l l attached to the powerhead until the un it is
down to the bare cylinder block assembly.
2. Remove the exhaust cover bolts.
3. Using a pry bar, remove the exhaust cover and plate.
4. Remove the s i lencer cover.
5. Position the power unit with the case and silencer facing downwards on
a level surface so that it wi l l not fall over.
_.Place protective padding under the inlet case to prevent scratching
the surface.
6. Remove the cylinder head bolts.
7. Tap on the cylinder head with a plastic hammer to remove.
8. Remove the o i l seal housing.
9. Remove the hexagon cylinder bolts.
1 0. Pu l l i ng upward carefu l ly and slowly, remove each cylinder head.
1 1 . Carefu l ly pry the piston pin retainer from its groove on the piston. Then
repeat the procedure for the other side.
_.The circlip will tend to fly when removed. Be ready to catching it as it
comes free.
1 2. Piston pin retainers are only good for one usage, d iscard the retainers
alter removing them.
1 3. Push the piston pin from it bore in the piston using a brass drift if necessary.
_.The piston pin should slide smoothly from its bore. If opposition is
felt, either the bore is out of round or the pin is bent. Inspect the com­
ponents and replace as necessary.
POWERHEAD 7-31
Cl ip
1 9 15 to 14 18
Step 21
05007G2A
Step 29
Upside
t \
Step 31
05007G2N
Step 35
1 4. Remove the piston from the connecting rod.
15. Place the crankcase on a fabricated wooden stand.
16 . Remove the in let cases with the reed valves.
1 7. Remove the crankcase bolts and l ift the rotating assembly out from the
crankcase.
To assemble:
1 8. Lubricate the seals with marine grease prior to instal lation .
1 9. Install the top and bottom crankshaft oi l seals with the numbers facing
the ends of the crankshaft.
20. Lubricate the rotating assembly with 2-stroke oil prior to instal lation.
21 . Install the middle bearing on the crankshaft with the clip covering both
split faces of the bearing.
22. Install the rotating assembly into the cylinder block, making sure the
crankshaft faces the correct way. The splined end of the crankshaft should face
driveshaft housing side.
23. Firmly fit the bearing races onto the locating pins with punch mark
stamped on the circumference of the bearings d irected upwards.
24. Ensure the flanges of the upper o i l seal fit snugly into the groove pro­
vided in crankcase.
25. Check to be sure that the under bearing stopper pin is resting snugly in
the cutaway.
26. Make the "C" ring is fitted i nto groove in the crankcase.
27. Check to be sure that the end gap of the seal rings face up.
28. Apply marine grease to the sp l ined portion of the crankshaft.
05007G2L
05007G2M
Step 30
20
19
05007G2J
05007G2K
Step 37
29. Install the crankcase and tighten the crankcase nuts to specification
using the proper tightening sequence.
•After the crankcase has been assembled, turn the crankshaft to see
whether it makes any abnormal noise. If the crankshaft makes any
abnormal noise, disassemble the crankcase to find the trouble.
30. Install the piston on the connecting rod. Make sure the arrow on the pistons point to the exhaust port side.
31 . Push the piston pin into the piston bore using a brass drift i f necessary.
32. Install new piston p in retainers.
33. Install a new cylinder head gasket and hold it in place with a light film of
grease.
34. Install each cylinder head onto the cylinder block and snug each bolt to
hold the cylinders in place.
35. Install the cylinder/crankcase assembly plate (09912-68720) and tighten
the bolts to the specified torque using the proper sequence.
36. Using a special socket (0991 1 -78730), tighten the cylinder bolts to
specification using a criss-cross tightening sequence.
37. Install the cylinder head and tighten the cylinder head bolts to specifica­
tion using the proper tightening sequence.
38. Install the oil seal housing and tighten the bolts to specification.
39. Install the exhaust cover and plate. Tighten the exhaust cover bolts to
specification.
40. Install all components previously removed from the cylinder block.
7-32 POWER HEAD
POWERHEAD RECOND ITIONING
Determining Powerhead Condition
Anything that generates heat and/or friction wi l l eventually burn or wear out
(for example, a l ight bulb generates heat, therefore its life span is l imited). With
this in mind, a running powerhead generates tremendous amounts of both; fric­
tion is encountered by the moving and rotating parts inside the powerhead and
heat is created by friction and combustion of the fuel. However, the powerhead
has systems designed to help reduce the effects of heat and friction and provide
added longevity. The oil injection system combines oil with the fuel to reduce
the amount of friction encountered by the moving parts inside the powerhead,
whi le the cool ing system reduces heat created by friction and combustion. If
either system is not maintained, a break-down will be inevitable. Therefore, you
can see how regular maintenance can affect the service life of your powerhead.
There are a number of methods for evaluating the condition of your power­
head. A secondary compression test can reveal the condition of your pistons,
piston rings, cylinder bores and head gasket(s). A primary compression test can
determine the condition of all engine seals and gaskets. Because the 2-stroke
powerhead is a pump, the crankcase must be sealed against pressure created on
the down stroke of the piston and vacuum created when the piston moves
toward top dead center. If there are air leaks into the crankcase, insufficient fuel
wi l l be brought into the crankcase and into the cylinder for normal combustion.
PRIMARY COMPRESSION TEST
Because the 2-stroke powerhead is a pump, the crankcase must be sealed
against pressure created on the down stroke of the piston and vacuum created
when the piston moves toward top dead center. If there are air l eaks into the
crankcase, insufficient fuel wi l l be brought into the crankcase and into the cylin­
der for normal combustion.
�If it is a very small leak, the powerhead will run poorly, because the
fuel mixture will be lean and cylinder temperatures will be hotter than
normal .
Ai r leaks are possible around any seal, 0-ring, cylinder block mating surface
or gasket. Always replace 0-rings, gaskets and seals when service work is per­
formed.
If the powerhead is running, soapy water can be sprayed onto the suspected
sealing areas. If bubbles develop, there is a leak at that point. Oil around sealing
points and on ignition parts under the flywheel indicates a crankcase leak.
The base of the powerhead and lower crankshaft seal is impossible to check
on an installed powerhead. When every test and system have been checked out
and the bottom cylinder seems to be effecting performance, then the lower seal
should be tested.
Adapter plates available from tool manufacturers to seal the in let, exhaust
and base of the powerhead. Adapter plates can also be manufactured by cutting
metal block off p lates from pieces of plate steel or aluminum. A pattern made
from the gaskets can tJe used for an accurate shape. Seal these p lates using
rubber or s i l icone gasket making compound.
1 . Install adapter p lates over the intake ports and the exhaust ports to com­
pletely seal the powerhead.
�when installing the adapter plates, make sure to leave the water
jacket holes open.
2. Into one adapter, place an air fitting which will accept a hand air pump.
3. Using the hand pump (or another regulated air source), pressurize the
crankcase to five pounds of pressure.
4. Spray soapy water around the lower seal area and other sealed areas
watching for bubbles which indicate a leaking point.
5. Turn the powerhead upside down and fil l the water jacket with water. If
bubbles show up in the in the water when a positive pressure is applied to the
crankcase, there may be cracks or corrosion holes in the cool ing system pas­
sages. These holes can cause a loss of cool ing system effectiveness and lead to
overheating.
6. After the pressure test is completed, pull a vacuum to stress the seals in
the opposite direction and watch for a pressure drop.
7. Note the leaking areas and replace the seals or gaskets.
SECONDARY COMPRESSION TEST
• See Figure 1 3
The actual pressure measured during a secondary compression test i s not as
important as the variation from cylinder to cylinder. On multi-cylinder power­
heads, a variation of 15 psi or more is considered questionable. On single
cyl inder powerheads, a drop of 15 psi from the normal compression pressure
you established when it was new is cause for concern (you did do a compres­
sion test on it when it was new, didn't you?).
�If the powerhead been in storage for an extended period, the piston
rings may have relaxed. This will often lead to initially low and mis­
leading readings. Always run an engine to operating temperature to
ensure that the reading you get is accurate.
1 . Disable the ignition system by removing the lanyard cl ip. If you do not
have a lanyard, take a wire jumper lead and connect one end to a good engine
ground and the other end to the metal connector inside the spark plug boot,
using one jumper for each plug wire. Never simply disconnect all the plug wires.
** CAUTION
Removing al l the spark plugs and cranking over the powerhead can
lead to an explosion if raw fuel/oi l sprays out of the plug holes. A
plug wire could spark and ignite this mix outside of the combustion
chamber if it isn't grounded to the engine.
2. Remove al l the spark p lugs and be sure to keep them in order. Carefu l ly
inspect the plugs, looking for any inconsistency in coloration and for any sign
of water or rust near the tip.
3. Thread the compression gauge into the No. 1 spark-plug hole, taking
care to not crossthread the fitting.
4. Open the throttle to the wide open throttle position and hold it there.
�some engines allow only minimal opening if the gearshift is in neu­
tral, to guard against over-revving.
5. Crank over the engine an equal number of times for each cylinder you
test, zeroing the gauge for each cylinder.
6. If you have e lectric start, count the number of seconds you count. On man­
ual start, pul l the starter rope four to five times for each cylinder you are testing.
7. Record your readings from each cylinder. When al l cylinders are tested,
05003P25
Fig . 13 The actual pressure measured during a secondary compres­
sion test is not as important as the variation from cylinder to cylin­
der
compare the readings and determine if pressures are within the 1 5 psi criterion.
8. I! compression readings are lower than normal !or any cylinders, try a
"wet" compression test, which wi l l temporarily seal the piston rings and deter­
mine if they are the cause of the low reading.
9. Using a can of logging oi l , log the cyl inder with a c ircular motion to dis­
tribute o i l spray al l around the perimeter of the piston. Retest the cyl inder.
a. I! the compression rises noticeably, the piston rings are sticking. You
may be able to cure the problem by decarboning the powerhead.
b. I! the dry compression was really low and no change is evident during
the wet test, the cylinder is dead. The piston and/or are worn beyond specifi­
cation and a powerhead overhaul or replacement is necessary.
10 . I! two adjacent cylinders on a multi-cyl inder engine give a s imi larly low
reading then the problem may be a faulty head gasket. This should be suspected
if there was evidence of water or rust on the spark plugs from these cylinders.
Buy or Rebuild?
• See Figures 14 and 1 5
Now that you have determined that your powerhead i s worn out, you must
make some decisions. The question o! whether or not a powerhead is worth
05003P03
Fig. 14 The question of whether or not a powerhead is worth
rebuilding is largely a subjective matter and one of personal worth.
This powerhead is not worth much in its present condition
05003P04
Fig. 15 A burned piston like this one will be replaced during an
overhaul. The condition which caused the hole in the top of the pis­
ton must be identified and corrected or the same thing will happen
again
POWER HEAD 7-33
rebui ld ing is largely a subjective matter and o n e o f personal worth. I s the power­
head a popular one, or is it an obsolete model? Are parts available? Is the out­
board it's being put into worth keeping? Would it be less expensive to buy a new
powerhead, have your powerhead rebuilt by a pro, rebuild it yourself or buy a
used powerhead? Or would it be simpler and less expensive to buy another out­
board? I! you have considered al l these matters and more and have stil l decided
to rebu i ld the powerhead, then it is time to decide how you wi l l rebui ld it.
,.. The editors at Seloc® feel that most powerhead machining should be
performed by a professional machine shop. Don't think of it as wasting
money, rather, as insurance that the job has been done right the first
time. There are many expensive and specialized tools required to per­
form such tasks as boring and honing a powerhead. Even inspecting the
parts requires expensive micrometers and gauges to properly measure
wear and clearances. Also, a machine shop can deliver to you clean and
ready to assemble parts, saving you time and aggravation. Your maxi­
mum savings will come from performing the removal, disassembly,
assembly and installation of the powerhead and purchasing or renting
only the tools required to perform the above tasks. Depending on the
particular circumstances, you may save 40 to 60 percent of the cost
doing these yourself.
A complete rebuild or overhaul o! a powerhead involves replacing or recon­
ditioning all of the moving parts (pistons, rods, crankshaft, etc.) with new or
remanu!acturerd ones and machin ing the non-moving wearing surfaces o! the
block and heads. Unfortunately, this may not be cost effective. For instance,
your crankshaft may have been damaged or worn, but it can be machined !or a
min imal lee.
So, as you can see, you can replace everyth ing inside the powerhead, but, it
is wiser to replace only those parts which are really needed and, if possible,
repair the more expensive ones.
Powerhead Overhaul Tips
• See Figure 1 6
Most powerhead overhaul procedures are fairly standard. I n addition to spe­
cif ic parts replacement procedures and specifications tor your individual power­
head, this section is also a guide to acceptable rebui ld ing procedures. Examples
of standard rebu i ld i ng practice are given and should be used along with specific
details concerning your particular powerhead.
Competent and accurate mach ine shop services wi l l ensure maximum perfor­
mance, rel iab i l ity and powerhead life. In most instances it is more profitable !or
the do-it-yourself mechanic to remove, c lean and i nspect the component, buy
the necessary parts and del iver these to a shop !or actual machine work.
Much of the assembly work (crankshaft, bearings, pistons, connecting rods
and other components) is wel l within the scope of the do-it-yourself mechanic's
05007P28
Fig. 16 Much of the assembly work (crankshaft, bearings, pistons,
connecting rods and other components) is well within the scope of
the average do-it-yourself mechanic's tools and abi lities
7-34 POWER HEAD
tools and abi l ities. You wi l l have t o decide for yourself the depth of involvement
you desire in a powerhead repair or rebuild.
TOOLS
The tools required for a powerhead overhaul or parts replacement wil l
depend on the depth of your involvement. With a few exceptions, they wi l l be
the tools found in an average do it yourselfer's tool kit. More in-depth work wi l l
require some or al l of the following:
• A dial ind icator (reading in thousandths) mounted on a un iversal base
• Micrometers and telescope gauges
• Jaw and screw-type pul lers
• Scraper
• Ring groove c leaner
• Piston ring expander and compressor
• Ridge reamer
• Cylinder hone or g laze breaker
• Plastigage®
• Powerhead stand
The use of most of these tools is i l lustrated in this section . Many can be
rented for a one-time use from a local parts store or tool supply house.
Occasional ly, the use of special tools is necessary. See the information on
Special Tools and the Safety Notice in the front of this book before substituting
another tool.
CAUTIONS
Aluminum is extremely popular for use in powerheads, due to its low weight.
Observe the following precautions when handling aluminum parts:
• Never hot tank aluminum parts, the caustic hot tank solution wi l l eat the
aluminum
• Remove al l aluminum parts (identification tag, etc.) from powerhead parts
prior to hot tanking
• Always coat threads lightly with oil or anti-seize compounds before instal­
lation, to prevent seizure
• Never overtighten bolts or spark plugs especially in aluminum threads
When assembling the powerhead, any parts that wi l l be exposed to frictional
contact must be prelubed to provide lubrication at in itial start-up. Any product
specifically formulated for this purpose can be used.
When semi-permanent (locked, but removable) installation of bolts or nuts is
desired, threads should be cleaned and coated with Loctite® or another similar,
commercial non-hardening sealant.
CLEANING
Before the powerhead and its components are inspected, they must be thor­
oughly c leaned. You wi l l need to remove any varnish, oil sludge and/or carbon
deposits from all of the components to insure an accurate inspection. A crack in
the block or cylinder head cart easily become overlooked if hidden by a layer of
sludge or carbon.
Most of the cleaning process can be carried out with common hand tools
and readi ly available solvents or solutions. Carbon deposits can be chipped
away using a hammer and a hard wooden chisel. Old gasket material and var­
nish or sludge can usually be removed using a scraper and/or cleaning solvent.
Extremely stubborn deposits may require the use of a power dri l l with a wire
brush. Always follow any safety recommendations given by the manufacturer of
the tool and/or solvent. You should always wear eye protection during any
cleaning process involving scraping, chipping or spraying of solvents.
�If using a wire brush, use extreme care around any critical machined
surfaces (such as the gasket surfaces, bearing saddles, cylinder bores,
etc . ) . USE OF A WIRE BRUSH IS NOT RECOMMENDED ON ANY ALUMI·
NUM COMPONENTS.
An alternative to the mess and hassle of cleaning the parts yourself is to drop
them off at a local machine shop. They wi l l , more than l ikely, have the necessary
equipment to properly clean all of the parts for a nominal fee.
** CAUTION
Always wear eye protection during any cleaning process involving
scraping, chipping or spraying of solvents.
Remove any plugs or pressed-in bearings and carefully wash and degrease
a l l of the powerhead components including the fasteners and bolts. Small parts
should be placed in a metal basket and al lowed to soak. Use pipe c leaner type
brushes and clean al l passageways in the components.
Use a ring expander to remove the rings from the pistons. C lean the piston
ring grooves with a ring groove c leaner or a piece of broken ring. Scrape the
carbon off of the top of the piston. You should never use a wire brush on the
pistons. After preparing al l of the piston assembl ies in this manner, wash and
degrease them again.
REPAIRING DAMAGED THREADS
• See Figures 1 7 , 18 , 1 9, 20 and 21
Several methods of repairing damaged threads are available. Heli-Coi l®,
Keenserts® and Microdot® are among the most widely used. All involve basically
the same principle-dri l l ing out stripped threads, tapping the hole and
instal l ing a prewound insert-making welding, plugging and oversize fasteners
unnecessary.
Two types of thread repair inserts are usually supplied: a standard type for
most inch coarse, inch fine, metric course and metric fine thread sizes and a
spark lug type to fit most spark plug port sizes. Consult the individual tool man­
ufacturer's catalog to determine exact appl ications. Typical thread repair kits wi l l
contain a selection of prewound threaded inserts, a tap (corresponding to the
outside diameter threads of the insert) and an installation tool. Spark plug
inserts usually differ because they require a tap equipped with p i lot threads and
a combined reamer/tap section. Most manufacturers also supply bl ister-packed
thread repair inserts separately in addition to a master kit containing a variety of
taps and inserts p lus installation tools.
Before attempting to repair a threaded hole, remove any snapped, broken or
damaged bolts or studs. Penetrating oil can be used to free frozen threads. The
offending item can usually be removed with locking p l iers or using a screw/stud
extractor. After the hole is c lear, the thread can be repaired, as shown in the
series of accompanying i l lustrations and in the kit manufacturer's instructions.
DAMAGED
THREADS
TCCS3039
Fig. 17 Damaged bolt hole threads can be replaced with thread
repair inserts
TCCS3040
Fig. 18 Standard thread repair insert (left) and a spark plug thread
insert
POWER H EAD 7-35
0 ' ,,�
TCCS3043
TCCS3042 TCCS3041
Fig. 1 9 Drill out the damaged threads with
the specified size bit. Be sure to drill com­
pletely through the hole or to the bottom
of a blind hole
Fig. 20 Using the kit, tap the hole to
receive the thread insert. Keep the tap
well oiled and back it out frequently to
avoid clogging the threads
Fig. 21 Screw the insert onto the installer
tool until the tang engages the slot.
Thread the insert into the hole until it is
V.-112 turn below the top surface, then
remove the tool and break of the tang
using a punch
Powerhead Preparation
To properly rebu i ld a powerhead, you must first remove it from the outboard,
then disassemble and inspect it. Ideally you should place your powerhead on a
stand. This affords you the best access to the components. Follow the manufac­
turer's directions for using the stand with your particular powerhead.
Now that you have the powerhead on a stand, it's time to strip it of all but the
necessary components. Before you start disassembl ing the powerhead, you may
want to take a moment to draw some pictures, fabricate some labels or get some
containers to mark and hold the various components and the bolts and/or studs
which fasten them. Modern day powerheads use a lot of little brackets and cl ips
which hold wiring harnesses and such and these holders are often mounted on
studs and/or bolts that can be easily mixed up . The manufacturer spent a lot of
time and money designing your outboard and they wouldn't have wasted any of
it by haphazardly placing brackets, c l ips or fasteners. If it's present when you
disassemble it, put it back when you assemble it, you wi l l regret not remembering that little bracket which holds a wire harness out of the path of a rotating
part.
You should begin by unbolting any accessories attached to the powerhead.
Remove any covers remaining on the powerhead. The idea is to reduce the pow­
erhead to the bare necessities (cylinder head(s), cylinder block, crankshaft, pis­
tons and connecting rods), plus any other 'in block' components.
Cylinder Block and Head
GENERAL INFORMATION
• See Figures 22 thru 27
The cylinder block is made of aluminum and may have cast-in iron cylinder
l i ners. it is the major part of the powerhead and care must be given to this part
when service work is performed. Mishandling or improper service procedures
05007P67
Fig. 22 The cylinder block . . . Fig. 23 . . . crankcase half . . .
05007P68
Fig. 24 . . . and cylinder head make up
the major components of the cylinder
assembly
05007P16
Fig. 25 In this cylinder, an exhaust port
can be seen above the level of the piston.
The inlet port is on the opposite side of
the cylinder wall , below the piston
05007P31
Fig. 26 The cylinder block and crankcase
half are machined to fit together perfectly.
They provide a cradle for the spinning
crankshaft
05007P32
Fig. 27 To seal the ends of the cylinder
assembly around the crankshaft, 0-rings
are installed around the end caps and
neoprene seals are installed inside the
cap and seal against the crankshaft
7-36 POWERHEAD
performed o n this assembly may make scrap out o f a n otherwise good casting.
The cylinder assembly casting and other major castings on the outboard are
expensive and need to be cared for accordingly.
There are three parts to the cylinder assembly, the cylinder block, the cylinder
head and the crankcase half. The cylinder block and crankcase half are married
together and line bored to receive the crankshaft bearings, reed blocks and on some
powerheads sealing rings. After this operation they are treated as one casting.
,..Remember that anything done to the mating surfaces during service
work will change the inner bore diameter for the main bearings, reed
blocks and sealing rings and possibly prevent the block and crankcase
mating surfaces from sealing.
The only service work a l lowed on the mating surface is a lapping operation
to remove nicks from the service. Careful ly guard this surface when other ser­
vice work is being performed. The different sealing materials used to seal the
mating surfaces are sealing strips, sealing compound and Loctite®.
Since the 2-stroke powerhead operates like a pump with one in let and one
outlet for each cylinder, special sealing features must be designed into the cylin­
der assembly to seal each individual cylinder in a mu lti-cylinder powerhead.
Each inlet manifold must be completely sealed both for vacuum and pressure.
One way of doing this internally is with a labyrinth seal, which is located
between two adjacent cylinders next to the crankshaft. it may be of aluminum or
brass, formed in the assembly and machined with small circular grooves run­
ning very close to a machined area on the crankshaft. The tolerance is so close
that fuel residue puddling in the seal effectively completes the seal between the
cylinder block and crankcase halves against the crankshaft. Crankcase pres­
sures are therefore retained to each individual cylinder. No repair of the labyrinth
seal is made. If damage has occurred to the seal, the main bearings have
al lowed the crankshaft to run out and rub.
Another method of internal sealing between the crankcases is with seal rings.
These rings are instal led in grooves in the crankshaft. When the crankshaft is
installed, the sealing rings mate up to and seal against the web in the cylinder
block crankcase halves and crankshaft. Sealing rings of different thickness are
available for service work. The side tolerance is close, so puddled fuel residue
will effectively complete the seal between crankcases and crankshaft.
To seal the ends of the cylinder assembly around the crankshaft, 0-rings are
instal led around the end caps and neoprene seals are instal led inside the cap
and seal against the crankshaft.
I NSPECTION
t See Figures 28, 29 and 30
Everytime the cylinder head is removed, the cylinder head and cylinder block
deck should be checked for warping. Do this with a straight edge or a surface
block. If the cylinder head or cylinder block deck are warped, the surface should
05007P63
Fig. 28 Everytime the cylinder head is removed, the cylinder head
and cylinder block deck should be checked for warping using a
straight edge and a feeler gauge
5
I
6 7 8
3 �==���������--�--�����
4
05007G2Z
Fig. 29 When inspecting components for warping, check in multiple
directions
05007P87
Fig. 30 To help prevent bolts from seizing due to corrosion, coat
threads with a good antiseize compound
be machined flat by a competent machine shop. Minor warpage may be cured
by using emery paper in a figure eight motion on a surface block until the sur­
face is true.
Inspect the cylinder head and cylinder block for cracks and damage to the bolt
holes caused by galvanic corrosion. On models which do not use a cylinder head,
check the cylinder dome for holes or cracks caused by overheating and pre-igni­
tion. The spark plug threads may also be damaged by overtorquing the spark plug.
Quite often the small bolts around the cylinder block seal ing area are seized
by corrosion. If white powder is evident around the bolts, stop. Galvanic corro­
sion is probably seizing the shank of the bolt and possibly the threads as wel l .
Putting a wrench on them may just twist the head off, creating one b ig mess.
Know the strength of the bolt and stop before it breaks. If it does break, don't
reach for an easy out, it won't work.
A good way to service these seized bolts is with local ized heat (from a heat gun,
not a torch) and a good penetrating oi l . Heat the aluminum casting, not the bolt.
This releases the bolt from the corrosive grip by creating c learance between the
bolt, the corrosion and the aluminum casting. Be careful because too much heat
wil l melt the casting. Many bolts can be released in this way, preventing dril l ing out
the total bolt and heli-coiling the hole or tapping the hole for an oversize bolt.
To help prevent bolts from seizing due to corrosion, coat threads with a good
antiseize compound.
Cyl inder Bores
GENERAL INFORMATION
The purpose of the cylinder bore is to help lock in combustion gases, pro­
vide a guided path for the piston to travel within, provide a lubricated surface for
the piston rings to seal against and transfer heat to the coo l ing system. These
functions are carried out through all engine speeds. To function properly the
cylinder has to have a true machined surface and must have the proper finish
instal led on it to retain lubricant.
INSPECTION
• See Figures 31 and 32
The roundness of the cylinder d iameter and the straightness of the cylinder
wall should be inspected careful ly. Micrometer readings should be taken at sev­
eral points to determine the cylinder condition. Start at the bottom using an out­
side m icrometer or dial bore gauge. By starting at the bottom, below the area of
ring travel , cylinder bore d iameter can be determined and a determination can
be made it the powerhead is standard or has been bored oversize. Take the sec­
ond measurement straight up from the first in the area of the ports and note that
the cylinder is larger here. This is the area where the rings ride and it has worn
sl ightly. Take the thi rd measurement within a hall inch of the top of the cylinder,
straight up from where the second measurement was taken. These three mea­
surements should be repeated with the measuring i nstrument turned goo clock­
wise.
Alter the readings are taken, you wi l l have enough information to access the
cylinder condition. This wi l l tell you it the rings can simply be replaced or it the
cylinder wi l l need to be overbored. Whi le measuring the cylinder, you should
also be noting it there is a cross-hatched pattern on the cylinder wal ls. Also
note any sculling or deep scratches.
05007G2Y
Fig. 31 The roundness of the cylinder diameter and the straightness
of the cylinder wall should be inspected using a dial bore gauge
05007G2X
Fig. 32 Readings should be taken at several points to determine the
cylinder condition. Start at the bottom and work your way to the top
POWER H EAD 7-37
REFINISHING
If the cylinder is out of round, worn beyond specification, scored or deeply
scratched, reboring will be necessary. If the cylinder is within specification, i t
can be deglazed with a f lex hone and new r ings installed.
,..Some cylinders are chrome plated and require special service proce­
dures. Consult a qualified machine shop when dealing with chrome
plated cylinders.
Almost all engine block rel in ish ing must be performed by a mach ine shop.
If the cyl inders are not to be rebored, then the cyl i nder glaze can be removed
with a bal l hone. When removing cyl i nder glaze with a ball hone, use a l ight
or penetrating type o i l to l ubr icate the hone. Do not a l low the hone to run dry
as this may cause excessive scoring of the cyl i nder bores and wear on the
hone. If new pistons are required, they w i l l need to be installed to the con­
necting rods. This should be performed by a machine shop as the pistons
must be instal led in the correct relationship to the rod or engine damage can
occur.
When deglazing, it is i mportant to retain the factory surface of the cylinder
wal l . The cross-hatched patter on the cylinder wall is used to retain oil and seal
the rings. As the piston rings move up and down the wal l , a g laze develops. The
hone is used to remove this g laze and reestablish the basket weave pattern. The
pattern and the finish is has a sat in look and makes an excellent surface for
good retention of 2-stroke oil on the cylinder wal l .
There is nothing magic about the crosshatch angle but there should be one
simi lar to what the factory used. (approximately 20-40°). Too steep an angle or
too flat a pattern is not acceptable and as it is not good for ring seating. Since
the hone reverses as it is being pushed down and pu l led up the cylinder wal l ,
many d illerent angles are created. Mult iple criss-crossing angles are the secret
for longevity of the cylinder and the rings. The pattern al lows 2-stroke o i l to
flow under the piston ring bearing surface and prevents a metal-to-metal contact
between the cyl i nder wal l and piston ring. The satin f inish is necessary to pre­
vent early break-in scuffing and to seat the ring correctly.
After the cylinder hone operation has been completed, one very important job
remains. The grit that was developed in the machin ing process must be thor­
oughly c leaned up. Grit l eft in the powerhead wi l l find its way into the bearings
and piston rings and become embedded into the piston skirts, ellectively grind­
ing away at these precision parts. Relate this to emery paper applied to a piece
of steel or steel against a grinding stone. The el!ect is removal of material from
the steel . Grit left in the powerhead wi l l damage internal components in a very
short time.
Wip ing down the cylinder bores with an oil or solvent soaked rag does not
remove grit. C l eaning must be thorough so that al l abrasive grit material has
been removed from the cylinders. I! is important to use a scrub brush and
plenty of soapy water. Remember that aluminum is not safe with al l cleaning
compounds, so use a mild dish washing detergent that is designed to remove
grease. Alter the cylinder is thought to be clean, use a white paper towel to test
the cylinder. Rub the paper towel up and down on the cylinder and look for the
presence of gray calor on the towel . The gray calor is grit. Re-scrub the cylinder
unti l it is perfectly clean and passes the paper towel test. When the cylinder
passes the test, immed iately coat it with 2-stroke oil to prevent rust from form­
ing.
,..Rust forms very quickly on clean, oil free metal. Immediately coat all
clean metal with 2-stroke oil to prevent the formation of rust.
Pistons
GENERAL INFORMATION
• See Figures 33, 34, 35 and 36
Piston are the moveable end of a cyl inder. The cylinder bore provides a
guided path for the piston allowing a small c learance between the piston skirt
and cylinder wal l . This c learance a l lows for piston expansion and controls pis­
ton rock within the cylinder.
Modern piston design is such that the head of the piston d i rects i ncoming
fuel toward the top of the cylinder and outgoing exhaust to the exhaust port in
the cylinder wal l . Th is design is called a deflector type piston head. The deflec­
tor dome deflects the incoming fuel upward to the spark plug end of the cylin­
der, partially cool ing the cylinder and spark plug t ip. I! also purges the spent
7-38 POWER H EAD
05003P49 05007P44
Fig. 33 A hole placed in the side of the
piston, commonly referred to as the piston
boss, is used to mount the piston to the
piston pin
Fig. 34 The piston has machined grooves
in which the rings are installed. They are
carried along with the piston as it travels
up and down the cylinder wall
05007P59
Fig. 35 There is one small pin in each ring
groove to prevent the ring from rotating
- -
JJ:�;;;;r=�---� -- -��
- - --
05007G2W
Fig. 36 Piston diameter should be measured at a specific position
on the p iston which the manufacturer will specify
gases from the cylinder. I n essence, the incoming fuel charge is chasing out the
exhaust gases from the cylinder.
Not al l p iston designs are of the deflector head type. Other pistons have a
small convex crown on the piston head. In this case, port design aids in di rect­
ing the incoming fuel upward. The piston head bears the brunt of the combus­
tion force and heat. Most of the heat is transferred from the piston head through
the rings to the cylinder wall and then on to the cool ing system.
The piston design can be round, cam ground or barrel shaped. The cam
ground design a l lows !or expansion of the piston in a contro l led manner. As the
piston heats up, expansion take place and the piston moves out along the piston
pin becoming more round as it warms up. Barrel shaped pistons rock very
s l ightly in the bore which helps to keep the rings free.
The piston has machined ring grooves in which the rings are instal led. They
are carried along with the piston as it travels up and down the cylinder wal l .
There is one small p in in each ring groove to prevent the ring from rotating. The
p iston skirt is the bearing area !or thrust and rides on the cylinder wall o i l film.
The side thrust of the piston is dependent upon piston pin location. I! the pin is
in the center of the piston, then there wi l l be more thrust. I! the pin is o!!set a
few thousandths of an inch from the center of the piston, there wi l l be less
thrust. A used piston wi l l have one side of the piston skirt show more signs of
wear than the opposite side_ The side showing wear is the major thrust side.
Thrust is caused by the pendu lum action of the rod following the crankshaft
rotation , which pul ls the rod out from under the piston. The combustion pres­
sure therefore pushes and thrusts the piston skirt against the cylinder wall.
Some heat is also transferred at this point. The other skirt receives only minor
pressure_ Some pistons have small grooves circl ing the skirts to retain o i l in the
critical area between the skirt and the cylinder wal l .
I NSPECTION
• See Figures 37 and 38
The piston needs to be inspected !or damage. Check the head !or erosion
caused by excessive heat, lean mixtures and out of specification timing/syn­
chron izat ion. Examine the r ing land area to see if it is flat and not rounded
over. Also look !or burned through areas caused by preignit ion. Check the
skirt !or scoring caused by a break through of the o i l f i lm, excessive cyl inder
wal l temperatures, incorrect t iming/synchron ization or inadequate lubrica­
t ion.
To measure the piston diameter, p lace an outside micrometer on the piston
skirt at the specified location. All pistons in a given powerhead should read the
same. Check the specifications !or p lacement of the micrometer when measur­
ing pistons. Generally there is a specific place on the piston. This is especially
true of barrel shaped pistons that are larger in the middle than they are at the
top and bottom.
I! the piston looks reasonably good alter cleaning, take a close look at
the r ing lands. Wear may develop on the bottom of the r ing lands. Th is
wear is usual ly uneven, causing the r ing to push on the h igher areas and
loads the r ing u nevenly when inertia is the greatest. Such uneven support
of the ring wi l l cause ring breakage and the piston wi l l need to be re­
placed.
When instal l ing a new ring in the groove, measure the ring side clearance
against specification. Also check the see if the ring pins are there and that they
have not loosened. Measure the skirt to see if the piston is col lapsed.
05003P07
Fig. 37 This piston is severely scored from lack of lubrication and
should not be reused
05007P15
Fig. 38 Pistons should be installed with the arrow facing the exhaust
port
Piston Pins
GENERAL INFORMATION
• See Figures 39, 40, and 41
A hole p laced in the side of the piston, commonly referred to as the p iston
boss, is used to mount the p iston to the p iston pin. The combustion pressure
is transferred to the piston pin and connecting rod bearing, then on to the
crankshaft where it is converted to rotary motion. The pin is fitted to the pis­
ton bosses. The piston p in is the i nner bearing race for the bearing mounted
in the small end of the connecting rod. This transfers the combustion pres­
sures into the connecting rod and a l lows the rod to swing with a pendulum­
l i ke action.
Piston pins are secured into both piston bosses. All have retainers and in
addition some use a press fit to secure the pin. There are some models which
use a slip fit. These may require special installation techniques.
Another type of pin fitting is loose on one side and tight on the other. This
type aids in removal of the pin without collapsing the piston. With this design,
always press on the pin from the loose boss side. The piston is marked on the
inside of the piston skirt with the word "loose" to identify the loose boss.
05007P45
Fig. 39 The holes in the bottom of this piston pin bore provide oiling
to the piston pin . . .
POWER H EAD 7-39
a similar hole i n the connecting rod also oils the pin
05007P37
Fig. 41 This piston uses a floating pin design. Once the retainers
are removed, the pin should slide out easily
Always press with the loose side up and press the p in all the way through and
out. When insta l l ing, press with the loose side up.
I n a l l pressing operations, set the piston in a cradle block to support the
piston. Some pistons require heating to expand the piston bosses so the pin
can be pressed out without collapsing the piston. Other pistons just have a sl ip
fit .
INSPECTION
• See Figures 42, 43, 44, 45 and 46
Check the piston pin retainer grooves for evidence of the retainers moving as
they may have been distorted. Always replace the retainers once they have been
removed. If there is evidence of wear in any of these areas, the piston should be
replaced.
Inspect piston pin for wear in the bearing area. Rust marks caused by water
wil l leave a needle bearing imprint. Chatter marks on the p in indicate that the
piston pin should be replaced. If these marks are not too heavy, they may possi­
bly be cleaned with emery paper for loose needle bearings or crocus c loth for
caged bearings.
If the piston pin checks out visual ly, measure its outside diameter and com­
pare that measurement with the inside diameter of the piston pin bore. Proper
clearance is vital to providing enough lubrication.
7-40 POWER H EAD
05007P83
Fig. 42 Measuring the p iston pin bore inside diameter. This reading
will be compared with the piston pin outside diameter to determine
pin-to-bore clearance
05007P70
05007P71
Fig. 43 Measuring the p iston pin outside diameter with an outside
micrometer at the point where the pin al igns with the piston pin
bore . . .
05007P38
Fig. 44 . . . and also at the point where
the pin aligns with the connecting rod bore
Fig. 45 Typical caged b