YARDMAX 154FS-1 User manual

Gasoline Engine
Owner’s Manual
154F(D)S-1/156F(D)S-1

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.
READ THIS OWNER’S MANUAL CAREFULLY. Pay special attention to these
symbols and any instructions that follow:
Indicates serious injury or death will result if instructions are not
followed.
Indicates a strong possibility that serious injury or death could
result if instructions are not followed.
Indicates a possibility that minor injury or an result if instructions
are not followed.
Indicates that equipment or property damage can result if
instructions are not followed.
NOTE: Gives helpful information.
If a problem should arise, or if you have any questions about your engine, consult
your engine dealer.

CONTENTS
- 1 -
CONTENTS
1.ENGINE SAFETY.......................................................................................................2
2.COMPONENTS & CONTROL LOCATIONS……………………………………........…3
3.CONTROLS................................................................................................................4
4.CHECK BEFORE OPERATION .................................................................................6
5.OPERATION.................................................................................................................8
6.MAINTENANCE………………………………………………………... ..........................11
7.STORAGE/ TRANSPORTING………….………………………………………………….17
8.TECHNICAL & CONSUMER INFORMATION …..……………………….…….…….…19
9.ENGINE PARAMETER…………………………………………………………….………..22
10. WIRING DIAGRAMS………………………………………………………………………..23

ENGINE SAFETY
- 2 -
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
⚫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 far away from the
area of operation.
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
⚫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 meter) away from building walls and
other equipment during operation. Do not place flammable objects close to the engine.
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.

COMPONENTS & CONTROL LOCATIONS
- 3 -
Priming pump
2. COMPONENTS&CONTROLLOCATIONS
OIL DRAIN PLUG
MUFFLER
FUEL TANK
RECOIL STARTER
CHOKE LEVER
AIR box
SPARK PLUG
OIL DIPSTICK
CYLINDER
HEAD COVER
IGNITION SWITCH
STARTER GRIP
STARTER MOTOR
FUEL FILLER CAP

CONTROLS
- 4 -
3. CONTROLS
1) Engine Switch
The engine switch enables and disables the ignition system.
The engine switch key must put in for the engine to run.
Putting out the engine switch key stops the engine.
2) 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.
Choke lever
The engine switch
key
Open
Close
Open
Close

CONTROLS
- 5 -
3) Recoil Starter Grip And Starter Motor
Pulling the starter grip or using the starter motor operates the recoil starter to crank the
engine.
Don’t let the lever suddenly rebound, lightly put the lever back.
4）Priming pump
The Priming Pump supply more fuel to the carburetor when starting the engine in the low
temperature.
When you put the Priming Pump ,you should not put more than three times.
Engines applied in snow blowers, are suggested using between -30°C to
4.4°C. If it operates below or above this temperature scope, engines
couldn't start or work normally.
CAUTION
Starter grip
OR
starter switch

CHECK BEFORE OPERATION
- 6 -
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.
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 preoperation
inspection before each operation,
and correct any problem.
Before beginning your preoperation checks, be sure the engine is level and the engine
switch is out off the key hole.
1) Check the General Condition of the Engine
⚫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.
2) Check oil
When stopping the engine at horizontal place, check the oil
1) Take the oil dipstick and clean
2) Insert the oil dipstick in and check the oil lever without screwing down.
3) If the oil is too low, add the recommenced oil in the high safe limits position.
4) After finishing, reassemble and screw the oil dipstick down.
CAUTION

CHECK BEFORE OPERATION
- 7 -
Running the engine with a low oil level can cause engine
damage，so always check the engine oil level before startup.
3) Check fuel
First stop the engine, open the fuel cover, and check oil level., if the oil level is too low, add
the fuel to full, after finishing, screw the fuel cover down.
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. Don’t add the fuel over the shoulder
of the carburetor when fueling (maximum oil level).
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 volume：1.4 L
Recommended octane rating over 90 unleaded gasoline for unleaded gasoline, can make
carbon deposit muck less and enhance exhaust system service life
Don’t use used and contaminated or gasoline with oil , Avoid the dirt and water entering
into fuel tank.
4)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.
Lower limit
Maximum
fuel oil level
Upper limit
Oil
dipstick

OPERATION
- 8 -
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.
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.
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) Put the engine switch in the key hole.
The engine switch
key

OPERATION
- 9 -
2) To start a cold engine, move the choke lever to the “ON”position.
To start a warm engine, turn the choke lever to the “OFF"position.
“
Operate the starter.
RECOIL STARTER (all engine types):
Pull the starter grip lightly until you feel resistance, then pull briskly.
Return the starter grip gently.
Don’t let starting lever suddenly rebound, and lightly put the lever back.
ELECTRIC STARTER (some engine types):
Plug the plug cap in electrical source carefully, then press the starter.
When the engine running, pull out the plug cap from the electric source.
To prevent damaging the electric starter, run it no more than 10
times at intervals of 5 seconds on, then 5 seconds off .If the engine
does not start after this series of attempts, allow the starter to cool
for at least 40 minutes before trying to start it again. If the engine still does not
start, take the engine to an Authorized Service Dealer for service.
CAUTION
Starter grip
Choke
lever
Open
Close
Open
Close

OPERATION
- 10 -
3) 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.
starting the Engine, carefully note the following:
Due to engine work in low-temprature,engine can marm up more
than 30 s .If inconsistent engine speeds are experienced when
Choke Lever is rotated OPEN Position:
1) Move Choke Lever to Mid-Point Between OPEN and CLOSE Posintions and
allow Engine to develop additional operating heat.
2) After Engine has warmed up,move Choke Lever to OPEN Posintion
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.
Pull out the engine switch.
Choke lever
The engine
switch key
Open
Close
CHOKEL VALVE POSITION SYMBOL

MAINTENANCE
- 11 -
6. MAINTENANCE
THE IMPORTANCE OF MAINTENANCE
Good maintenance is essential for safe, economical, and trouble-free operation. It will also
help reduce air pollution.
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.
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.
Safety Precautions
⚫Make sure the engine is off before you begin any maintenance or repairs. This will
eliminate several potential hazards:
◼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.
⚫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.

MAINTENANCE
- 12 -
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
REGULAR SERVICE PERIOD
Each
use
First month or
20 Hrs.
Every 3
months
or 50
Hrs.
Every 6
months
or 100
Hrs.
Every
year or
150 Hrs.
Engine oil
Check
level
○
Change
○
○
Sediment Cup
Clean
○
Spark plug
Clean
○
Replac
e
Valve clearance
Check-
Adjust
○(2)
Cover comp head
Clean
After every 150 Hrs. (2)
Fuel tank and fuel
filter
Clean
Every 2 years (Replace if necessary) (2)
Fuel line
Check
Every 2 years (Replace if necessary) (2)
⚫mission-related items.
（2）These items should be serviced by your servicing dealer unless you have the proper
tools and are mechanically proficient.
REFUELING
With the engine stopped, remove the fuel tank cap and check the fuel level. Refill the tank
if the fuel level is low.
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.

MAINTENANCE
- 13 -
Fuel tank volume：1.4 L
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 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.
under warranty.
FUEL RECOMMENDATIONS
Use unleaded gasoline with a pump octane rating of 86 or higher,You can also use
other fuels, such as ethanol gasoline
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.
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.

MAINTENANCE
- 14 -
RENEWING ENGINE OIL
Check the engine oil level with the engine stopped and in a level position.
1. Remove the filler cap/dipstick and wipe it clean.
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.
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 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 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.
Lower limit
Oil
dipstick
Upper limit

MAINTENANCE
- 15 -
Engine oil capacities:
154F(D)S-1/156F(D)S-1: 0.35 L
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.
4. Screw in the filler cap/dipstick securely.
ENGINE OIL RECOMMENDATIONS
Using the proper type and weight of oil in the engine is extremely important, as is
daily checking of oil level oil, or using dirty oil, will cause premature engine wear and
failure.
Oil Type
When the ambient temperature is under -25℃, SAE 0W-30/40 is recommended for
general use; when the ambient temperature is above -25℃but under 4.4℃, SAE 5W-30
or 0W-30/40 is recommended for general use. The SA oil viscosity and service
classification are in the API label on the oil container. We recommend that you useAPI
SERVICE Category SF or higher class oil.
Drain bolt
and Sealing
washer
Oil upper limit
Oil dipstick

MAINTENANCE
- 16 -
SPARK PLUG
Recommended spark plugs: E7RTC or other equivalents.
An incorrect spark plug can cause engine damage.
1. Disconnect the spark plug cap, and remove any dirt from around the spark plug area.
2. Remove the spark plug with a spark plug wrench.
3. Inspect the spark plug. Replace it if the electrodes are worn, or if the insulator is cracked
or chipped.
4．Measure the spark plug electrode gap with a suitable gauge.The gap should be 0.028
-0.031 in (0.70 - 0.80 mm). Correct the gap, if necessary,
5. Install the spark plug carefully, by hand, to avoid cross-threading.
6. After the spark plug seats, tighten with a spark plug wrench to compress the water.
If reinstalling the used spark plug ，tighten 1/8 - 1/4 turn after the spark plug seats.
If installing a new spark plug, tighten 1/2 turn after the spark plug seats.
A loose spark plug can overheat and damage the engine. Over
tightening the spark plug can damage the threads in the cylinder
head.
7. Assemble spark plug.
Spark plug wrench

STORING YOUR ENGINE
- 17 -
7. STORING ENGINE
Storage Preparation
Proper storage preparation is essential for keeping your engine trouble free and looking
good. The following steps will help to keep rust and corrosion from impairing your engine’s
function and appearance, and will make the engine easier to start after storage.
Cleaning
If the engine has been running, allow it to cool for at least half an hour before cleaning.
Clean all exterior surfaces, touch up any damaged paint, and coat other areas that may
rust with a light film of oil.
⚫Using a garden hose or pressure washing equipment can force water into the
air cleaner or muffler opening. Water in the air cleaner will soak the air filter,
and water that passes through the air filter or muffler can enter the cylinder,
causing damage.
⚫Water contacting a hot engine can cause damage. If the engine has been
running, allow it to cool for at least half an hour before washing.
Storage Precautions
1、DRAINING CARBURETOR
1)、Place a container underneath the carburetor, and use funnel for oil not spattering, close
fuel cock.
2）、 Remove the drain plug and sediment cup, then, open the fuel cock.
3）、 Immediately reassemble sediment cup and drain bolt after fuel completely draining.
And screw down.
Spring
Bolt

STORING YOUR ENGINE
- 18 -
2、Change the engine oil.
3、Remove the spark plugs.
4、Pour a tablespoon (5-10 cc) of clean engine oil into the cylinder.
5、Pull the starter rope several times to distribute the oil in the cylinder.
6、Reinstall the spark plugs.
7、Pull the starter rope slowly until resistance is felt. This will close the valves so
moisture cannot enter the engine cylinder. Return the starter rope gently.
8、Put the out case on the engine and place in the ventilated and dry area.
If your engine will be stored with gasoline in the fuel tank and carburetor, it is important to
reduce the hazard of gasoline vapor ignition. Select a well-ventilated storage area away
from any appliance that operates with a flame, such as a furnace, water heater, or clothes
dryer. Also avoid any area with a spark-producing electric motor, or where power tools are
operated.
If possible, avoid storage areas with high humidity, because that promotes rust and
corrosion.
Be sure all fuel has been drained from the fuel tank, to reduce the possibility of fuel
leakage.
Position the equipment so the engine is level. Tilting can cause fuel or oil leakage.
With the engine and exhaust system cool, cover the engine to keep out dust. Ahot engine
and exhaust system can ignite or melt some materials. Do not use sheet plastic as a dust
cover. A nonporous cover will trap moisture around the engine, promoting rust and
corrosion.
If equipped with a battery for an electric starter, recharge the battery once a month while
the engine is in storage. This will help to extend the service life of the battery.
Removal from Storage
Check your engine as described in the chapter CHECK BEFORE OPERATION.
If the fuel was drained during storage preparation, fill the tank with fresh gasoline. If you
keep a container of gasoline for refueling, be sure that it contains only fresh gasoline.
Gasoline oxidizes and deteriorates over time, causing hard starting.
If the cylinders were coated with oil during storage preparation, the engine may smoke
briefly at startup. This is normal.
TRANSPORTING
If the engine has been running, allow it to cool for at least 15 minutes before loading the
engine-powered equipment on the transport vehicle.Ahot engine and exhaust system can
burn you and can ignite some materials.
Keep the engine level when transporting to reduce the possibility of fuel leakage.