Yamakoyo YK250 User manual

Welcome to use YAMAKOYO gasoline engine.
This manual is dealing with the operation and maintenance of
YAMAKOYO gasoline engine.
Please read it carefully as it will instruct you how to operate safely.
Keep this owner's manual handy, so you can refer to it at any time.
This owner's manual is considered a permanent part of the engine and
should remain with the engine if resold.
The information and specifications included in this publication were in
effect at the time of approval for printing.
Only the D Type is equipped for both electric and manual starting.
Indicates serious injury or death will result if
instructions are not followed.
DANGER
Pay special attention to these symbols and any
instructions that follow:
NOTICE
Indicates a strong possibility that serious injury or
death could result if instructions are not followed.
Indicates a possibility that minor injury can result
if instructions are not followed.
Indicates that equipment or property damage can
result if instructions are not followed.
WARNING
CAUTION
NOTE: Gives helpful information.
If a problem should arise, or if you have any questions about your engine,
consult your engine dealer.

1. ENGINE SAFETY
2. COMPONENTS & CONTROL LOCATIONS
3. CONTROLS
4. CHECK BEFORE OPERATION
5. OPERATION
6. MAINTENANCE
7. STORAGE/TRANSPORTING
8. TROUBLESHOOTING
9. TECHNICAL & CONSUMER INFORMATION
10. SPECIFICATIONS
11. WIRING DIAGRAMS
12. OPTIONAL PARTS
BATTERY
CONTENTS
1
2
3
5
6
10
21
25
26
32
35
37
37

1. ENGINE SAFETY
IMPORTANT SAFETY INFORMATION
Most accidents with engines can be prevented if you follow all instructions in this manual
and on the engine. Some of the most common hazards are discussed below, along with
the best way to protect yourself and others.
Owner Responsibilities
Refuel With Care
Gasoline is extremely flammable, and gasoline vapor can explode. Refuel outdoors, in a
well-ventilated area, with the engine stopped. Never smoke near gasoline, and keep other
flames and sparks away. Always store gasoline in an approved container. If any fuel is
spilled, make sure the area is dry before starting the engine.
Hot Exhaust
Carbon Monoxide Hazard
Exhaust gas contains poisonous carbon monoxide. Avoid inhalation of exhaust gas. Never
run the engine in a closed garage or confined area.
Other Equipment
Review the instructions provided with the equipment powered by this engine for any
additional safety precautions that should be observed in conjunction with engine startup,
shutdown, operation, or protective apparel that may be needed to operate the equipment.
ENGINE SAFETY
The engines are designed to give safe and dependable service if operated according
to instructions. Read and understand this owner's manual before operating the engine.
Failure to do so could result in personal injury or equipment damage.
Know how to stop the engine quickly, and understand the operation of all controls.
Never permit anyone to operate the engine without proper instructions.
Do not allow children to operate the engine. Keep children and pets away from the
area of operation.
The muffler becomes very hot during operation and remains hot for a while after
stopping the engine. Be careful not to touch the muffler while it is hot. Let the engine
cool before storing it indoors.
To prevent fire hazards and to provide adequate ventilation for stationary equipment
applications, keep the engine at least 3 feet (1 metre) away from building walls and
other equipment during operation. Do not place flammable objects close to the engine.

2. COMPONENTS & CONTROL LOCATIONS
2
COMPONENTS & CONTROL LOCATIONS
FUEL FILLER CAP
FUEL TANK
OIL DRAIN PLUG
OIL FILLER CAP/DIPSTICK
IGNITION SWITCH
STARTER GRIP
SPARK PLUG
THROTTLE LEVER
MUFFLER
AIR CLEANER
RECOIL STARTER
CHOKE LEVER
FUEL VALVE LEVER

3. CONTROLS
Fuel Valve Lever
The fuel valve opens and closes the passage between the fuel tank and the carburetor.
The fuel valve lever must be in the ON position for the engine to run.
When the engine is not in use, leave the fuel valve lever in the OFF position to prevent
carburetor flooding and to reduce the possibility of fuel leakage.
Throttle Lever
The throttle lever controls engine THROTTLE LEVER speed.
Moving the throttle lever in the directions shown makes the engine run faster or slower.
Engine Switch
The engine switch enables and disables the ignition system.
The engine switch must be in the ON position for the engine to run.
Turning the engine switch to the OFF position stops the engine.
3
CONTROLS
OFF
0N0N
OFF......
FUEL
VALVE
LEVER
THROTTLE
LEVER
SLOWSLOW
FASTFAST

Choke Lever
The choke lever opens and closes the choke valve in the carburetor.
The CLOSE position enriches the fuel mixture for starting a cold engine.
The OPEN position provides the correct fuel mixture for operation after starting, and for
restarting a warm engine.
Some engine applications use a remotely-mounted choke control rather than the
engine-mounted choke lever shown here.
Recoil Starter Grip
Pulling the starter grip operates the recoil starter to crank the engine.
4
CHOKE LEVER
OPEN
......OPEN
CLOSECLOSE
STARTER GRIP
ALL ENGINEEXCEPT DTYPE
ON
OFF
ENGINE SWITCH
CONTROLS

4. CHECK BEFORE OPERATION
IS YOUR ENGINE READY TO GO?
For your safety, and to maximize the service life of your equipment, it is very important
to take a few moments before you operate the engine to check its condition. Be sure
to take care of any problem you find, or have your servicing dealer correct it, before
you operate the engine.
Before beginning your properation checks, be sure the engine is level and the engine
switch is in the OFF position.
Check the General Condition of the Engine
Check the Engine
Check the engine oil level. Running the engine with a low oil level can cause engine
damage.
The Oil Alert system (applicable engine types) will automatically stop the engine before
the oil level falls below safe limits. However, to avoid the inconvenience of an unexpected
shutdown, always check the engine oil level before startup.
Check the air filter. A dirty air filter will restrict air flow to the carburetor, reducing engine
performance.
Check the fuel level. Starting with a full tank will help to eliminate or reduce operating
interruptions for refueling
Check the Equipment Powered by This Engine
Review the instructions provided with the equipment powered by this engine for any
precautions and procedures that should be followed before engine startup.
5
CHECK BEFORE OPERATION
WARNING
Improperly maintaining this engine, or failing to
correct a problem before operation, could cause
a malfunction in which you could be seriously
injured.
Always perform a properation inspection before
each operation, and correct any problem.
Look around and underneath the engine for signs of oil or gasoline leaks.
Remove any excessive dirt or debris, especially around the muffler and recoil starter.
Look for signs of damage.
Check that all shields and covers are in place, and all nuts, bolts, and screws are
tightened.

5. OPERATION
SAFE OPERATING PRECAUTIONS
Before operating the engine for the first time, please review the IMPORTANT SAFETY
INFORMATION and the chapter titled BEFORE OPERATION.
Review the instructions provided with the equipment powered by this engine for any
safety precautions that should be observed in conjunction with engine startup, shutdown,
or operation.
STARTING THE ENGINE
1. Move the fuel valve lever to the ON position.
2. To start a cold engine, move the choke lever to the CLOSE position.
To restart a warm engine, leave the choke lever in the OPEN position.
Some engine applications use a remotely-mounted choke control rather than the
engine-mounted choke lever shown here.
6
OPERATION
WARNING
Carbon monoxide gas is toxic. Breathing it can cause
unconsciousness and even kill you. Avoid any areas
or actions that expose you to carbon monoxide.
FUEL VALVE
LEVER
ON
ON

3. Move the throttle lever away from the SLOW position, about 1/3 of the way toward
the FAST position.
Some engine applications use a remotely-mounted throttle control rather than the
engine-mounted throttle lever shown here.
4. Turn the engine switch to the ON position.
5. Operate the starter.
RECOIL STARTER (all engine types):
Pull the starter grip lightly until you feel resistance, then pull briskly.
7
HIGH
THROTTLE LEVER
SLOW
LOW
ON
OFF
ENGINE SWITCH
CHOKE LEVER
CLOSE OPEN
OPERATION

6. If the choke lever has been moved to the CLOSE position to start the engine,
gradually move it to the OPEN position as the engine warms up.
STOPPING THE ENGINE
To stop the engine in an emergency, simply turn the engine switch to the OFF position.
Under normal conditions, use the following procedure.
1. Move the throttle lever to the SLOW position.
Some engine applications use a remotely-mounted throttle control rather than the
engine-mounted throttle lever shown here.
8
Return the starter grip gently.
THROTTLE LEVER
SLOW
OPEN
CHOKE LEVER
STARTER GRIP
OPERATION

2. Turn the engine switch to the OFF position.
3. Turn the fuel valve lever to the OFF position.
SETTING ENGINE SPEED
Position the throttle lever for the desired engine speed.
Some engine applications use a remotely-mounted throttle control rather
than the engine-mounted throttle lever shown here.
For engine speed recommendations, refer to the instructions provided with
the equipment powered by this engine.
9
FUEL VALVE
LEVER
THROTTLE
LEVER
SLOWSLOW
FASTFAST
OFF
ON
OFF
ENGINE SWITCH
OPERATION

6. MAINTENANCE
THE IMPORTANCE OF MAINTENANCE
Good maintenance is essential for safe, economical, and trouble-free operation. It will
also help reduce air pollution.
To help you properly care for your engine, the following pages include a maintenance
schedule, routine inspection procedures, and simple maintenance procedures using basic
hand tools. Other service tasks that are more difficult, or require special tools, are best
handled by professionals and are normally performed by a technician or other qualified
mechanic.
The maintenance schedule applies to normal operating conditions. If you operate your
engine under unusual conditions, such as sustained high-load or high-temperature
operation, or use in unusually wet or dusty conditions, consult your servicing dealer for
recommendations applicable to your individual needs and use.
MAINTENANCE SAFETY
Some of the most important safety precautions are as follows: However, we cannot warn
you of every conceivable hazard that can arise in performing maintenance. Only you can
decide whether or not you should perform a given task.
Safety Precautions
Make sure the engine is off before you begin any maintenance or repairs. This will
10
WARNING
Improperly maintaining this engine, or failure to correct
a problem before operation, can cause a malfunction in
which you can be seriously hurt or killed.
Always follow the inspection and maintenance
recommendations and schedules in this owner's manual.
WARNING
Failure to properly follow maintenance instructions and
precautions can cause you to be seriously hurt or killed.
Always follow the procedures and precautions in the
owner's manual.
MAINTENANCE

eliminate several potential hazards:
Read the instructions before you begin, and make sure you have the tools and skills
required.
To reduce the possibility of fire or explosion, be careful when working around gasoline.
Use only a nonflammable solvent, not gasoline, to clean parts. Keep cigarettes, sparks
and flames away from all fuel-related parts.
Remember that your servicing dealer knows your engine best and is fully equipped to
maintain and repair it.
To ensure the best quality and reliability, use only new, genuine parts or their equivalents
for repair and replacement.
MAINTENANCE SCHEDULE
11
Carbon monoxide poisoning from engine exhaust.
Be sure there is adequate ventilation whenever you operate the engine.
Burns from hot parts.
Let the engine and exhaust system cool before touching.
Injury from moving parts.
Do not run the engine unless instructed to do so.
Emission-related items.
Replace the paper element type only.
(1) Service more frequently when used in dusty areas.
REGULAR SERVICE PERIOD
Performed at every indicated month
or operating hour interval, whichever
comes first.
ITEM
Each
use
First
month or
20 Hrs.
Every 3
months or
50 Hrs.
Every 6
months or
100 Hrs.
Every
year or
300 Hrs.
Engine oil Check level
Change
Check
Clean
Replace
Air cleaner
Sediment Cup
Spark plug Check-Clean
Replace
Clean
Spark arrester
(optional parts)
Idle speed Check-Adjust
Check-Adjust
Clean
Clean
Clean
Check
Valve clearance
Fuel tank and strainer
Combustion chamber
Fuel line
(2)
(2)
(2)
After every 300 Hrs. (2)
Every 2 years (Replace if necessary) (2)
(1)
MAINTENANCE

(2) These items should be serviced by your servicing dealer unless you have the proper
tools and are mechanically proficient. Refer to manual for service procedures.
REFUELING
With the engine stopped, remove the fuel tank cap and check the fuel level. Refill the
tank if the fuel level is low.
Refuel in a well-ventilated area before starting the engine. If the engine has been
running, allow it to cool. Refuel carefully to avoid spilling fuel. Do not fill above the fuel
strainer shoulder. After refueling, tighten the fuel tank cap securely.
Never refuel the engine inside a building where gasoline fumes may reach flames or
sparks. Keep gasoline away from appliance pilot lights, barbecues, electric appliances,
power tools, etc.
Spilled fuel is not only a fire hazard, it causes environmental damage. Wipe up spills
immediately.
Fuel tank capacities
YK-250/300/400:0.66Gal.(2.5L)
YK-550(E), YK-550(E)L, YK-550(E)R:0.95Gal.(3.6L)
YK-600(E):1.2Gal.(4.5L)
YK-650(E), YK-650(E)L, YK-650(E)R:0.95Gal.(3.6L)
YK-800(E), YK-800(E)L, YK-800(E)R:1.6Gal.(6.0L)
YK-900(E), YK-900(E)L, YK-900(E)R:1.6Gal.(6.0L)
YK-1200(E):1.8Gal.(7.0L)
YK-1100(E), YK-1100(E)L, YK-1300(E), YK-1300(E)L, YK-1500(E), YK-1500(E)L:1.7Gal.(6.5L)
12
WARNING
Gasoline is highly flammable and explosive. You can be
burned or seriously injured when handling fuel.
Stop the engine and keep heat, sparks, and flame away.
Handle fuel only outdoors.
Wipe up spills immediately.
MAXIMUM FUEL LEVEL
MAINTENANCE

FUEL RECOMMENDATIONS
Use unleaded gasoline with a pump octane rating of 86 or higher.
These engines are certified to operate on unleaded gasoline. Unleaded gasoline produces
fewer engine and spark plug deposits and extends exhaust system life.
Never use stale or contaminated gasoline or an oil/gasoline mixture. Avoid getting dirt
or water in the fuel tank.
Occasionally you may hear a light "spark knock" or "pinging" (metallic rapping noise)
while operating under heavy loads. This is no cause for concern.
If spark knock or pinging occurs at a steady engine speed, under normal load, change
brands of gasoline. If spark knock or pinging persists, see an authorized servicing dealer
ENGINE OIL LEVEL CHECK
Check the engine oil level with the engine stopped and in a level position.
1. Remove the filler cap/dipstick and wipe it clean.
Running the engine with persistent spark knock or pinging can cause engine
damage.
Running the engine with persistent spark knock or pinging is considered misuse,
and the Distributor's Limited Warranty does not cover parts damaged by misuse.
13
Fuel can damage paint and plastic. Be careful not to spill fuel
when filling your fuel tank. Damage caused by spilled fuel is
not covered under warranty.
NOTICE
NOTICE
FILLER CAP/DIPSTICK
LOWER LIMIT
UPPER LIMIT
MAINTENANCE

2. Insert and remove the dipstick without screwing it into the filler neck. Check the oil
level shown on the dipstick.
3. If the oil level is low, fill to the edge of the oil filler hole with the recommended oil.
4. Screw in the filler cap/dipstick securely.
The Oil Alert system (applicable engine types) will automatically stop the engine before
the oil level falls below safe limit. However, to avoid the inconvenience of an unexpected
shutdown, always check the engine oil level before startup.
ENGINE OIL CHANGE
Drain the used oil while the engine is warm. Warm oil drains quickly and completely.
1. Place a suitable container below the engine to catch the used oil, and then remove
the filler cap/dipstick and the drain plug.
2. Allow the used oil to drain completely, and then reinstall the drain plug, and tighten
it securely.
Please dispose of used motor oil in a manner that is compatible with the environment.
We suggest you take used oil in a sealed container to your local recycling center or
service station for reclamation. Do not throw it in the trash; pour it on the ground; or
down a drain.
3. With the engine in a level position, fill to the outer edge of the oil filler hole with the
recommended oil.
Engine oil capacities
Running the engine with a low oil level can cause engine damage.
The Oil Alert system (applicable engine types) will automatically stop the engine before
the oil level falls below the safe limit.
However, to avoid the inconvenience of an unexpected shutdown, fill to the upper limit,
and check the oil level regularly.
YK-250/300:0.37 US qt(0.35L)
YK-400, YK-550/650(E), YK-550/650(E)L, YK-550/650(E)R:0.63 US qt(0.6L)
YK-800/900/1100//1200/1300/1500(E), YK-800/900(E)R:1.2 US qt(1.1L)
YK-800/900(E)L, YK-1100/1300/1500(E)L:1.2 US qt(I.IL)
14
Running the engine with a low oil level can cause engine
damage.
NOTICE
MAINTENANCE

4. Screw in the filler cap/dipstick securely.
REDUCTION GEAR OIL (Only on equipped model)
< 1/2 reduction with automatic centrifugal clutch >
1. Remove the oil filler cap and wipe the dipstick clean.
2. Insert the dipstick into the filler neck but do not screw it in.
3. If the level is low, fill to the upper level mark with the same oil recommended for
the engine.
SERVICING YOUR ENGINE
ENGINE OIL RECOMMENDATIONS
Oil is a major factor affecting performance and service life. Use 4-stroke automotive
detergent oil.
Oil capacity Of YK-550/650/800/900(E)R:500CC
15
FILLER CAP/
DIPSTICK
OIL LEVEL
DRAIN BOLT
DRAIN BOLT
DIPSTICK/FILLER CAP
UPPER LEVEL
MAINTENANCE

SAE 10W-30 is recommended for general use. Other viscosities shown in the chart may
be used when the average temperature in your area is within the recommended range.
The SAE oil viscosity and service classification are in the API label on the oil container.
We recommend that you use API SERVICE Category SE or SF oil.
AIR FILTER INSPECTION
Remove the air cleaner cover and inspect the filter. Clean or replace dirty filter elements.
Always replace damaged filter elements. If equipped with an oil-bath air cleaner, also
check the oil level.
AIR CLEANER SERVICE
A dirty air filter will restrict air flow to the carburetor, reducing engine performance.
16
SAE Viscosity Grades
AMBIENT TEMPERATURE
5W-30
10W-30
30
-20 0 20 40 60 80 100F
-30 -20 -10 0 10 20 30 40
PAPER
FILTER
ELEMENT
FOAM
FILTER
ELEMENT
FILTER
MAINTENANCE

If you operate the engine in very dusty areas, clean the air filter more often than
specified in the MAINTENANCE SCHEDULE.
Dual-Filter-Element Types
1. Remove the wing nut from the air cleaner cover,
and remove the air cleaner cover.
2. Remove the wing nut from the air filter, and remove
the filter.
3. Remove the foam filter from the paper filter.
4. Inspect both air filter elements, and replace them if
they are damaged. Always replace the paper air
filter element at the scheduled interval.
5. Clean the air filter elements if they are to be reused.
Paper air filter element: Tap the filter element several times on a hard surface to
remove dirt, or blow compressed air [not exceeding 30 psi (207 kPa)] through the
filter element from the inside. Never try to brush off dirt; brushing will force dirt into
the fibers.
Foam air filter element: Clean in warm soapy water, rinse, and allow drying thoroughly.
Or clean in nonflammable solvent and allow drying. Dip the filter element in clean
engine oil, and then squeeze out all excess oil. The engine will smoke when started
if too much oil is left in the foam.
6. Wipe dirt from the inside of the air cleaner base and cover, using a moist rag. Be
careful to prevent dirt from entering the air duct that leads to the carburetor.
7. Place the foam air filter element over the paper element, and reinstall the assembled
air filter. Be sure the gasket is in place beneath the air filter. Tighten the air filter
wing nut securely.
8. Install the air cleaner cover, and tighten the cover wing nut securely.
Operating the engine without an air filter, or with a damaged air filter, will allow dirt to
enter the engine, causing rapid engine wear. This type of damage is not covered by the
Distributor's Limited Warranty.
17
NOTICE
AIR
CLEANER
COVER
PAPER
FILTER
ELEMENT
FOAM
FILTER
ELEMENT
GASKET
MAINTENANCE