MTD 139 cc OHV User manual

Safety • Operation • Maintenance • Storage • Troubleshooting
READ SAFETY RULES AND INSTRUCTIONS CAREFULLY BEFORE OPERATION
IMPORTANT:
PRINTED IN U.S.A. MTD Products Ltd., P. O. Box 1386, KITCHENER, ONTARIO N2G 4J1
139cc and 173cc
Vertical Shaft OHV Engines
for Walk Behind Mowers
04.10.09
769-03899A
OPERATOR’S MANUAL

2

This manual covers the operation and maintenance of your
engine. All information in this publication is based on the latest
product information available at the time of printing.
No part of this publication may be reproduced without written
permission.
This manual should be considered a permanent part of the
engine and should remain with it if it is resold.
This Operator’s Manual is an important part of your new engine. It will help you prepare and maintain the unit for best
performance. Please read and understand what it says.
Safe Operation Practices.........................................3
Operating the Engine...............................................5
Maintaining the Engine ............................................8
Illustrated Parts.......................................................12
Emission Control System Warranty Statement .......16
Pay special attention to safety messages and notes printed in
this manual and on the engine itself. A safety message alerts
you to potential hazards that could hurt you or others.
WARNING: Indicates a strong possibility of
severe personal injury or death if instructions
are not followed. Each safety message is
preceded by a safety symbol.
NOTE: Gives helpful information.
IMPORTANT: Indicates a possibility of equip-
ment or property damage if instructions are
not followed.
WARNING: The engine is designed to give safe and dependable service if operated according to instructions. Read
and understand the Operator’s Manual before operating the engine. Failure to do so could result in personal injury or
equipment damage.
This Operator’s Manual may cover a range of engine models. Characteristics and features discussed and/or illustrated in this manual may not be
applicable to all engine models. MTD LLC reserves the right to change product specifications, designs, and equipment without notice and without
incurring obligation.
Visit www.mtdcanada.ca or call a Customer Support Representative at 1-800-668-1238.


3
2
Safe


General Operation
1. Read this operator’s manual carefully in its entirety before
attempting to assemble this machine. Read, understand, and
follow all instructions on the machine and in the manual(s)
before operation. Keep this manual in a safe place for future
and regular reference and for ordering replacement parts.
2. Be completely familiar with the controls and the proper use of
this machine before operating it.
3. This machine is a precision piece of power equipment, not a
plaything. Therefore, exercise extreme caution at all times.
Your unit has been designed to perform one job: to mow grass.
Do not use it for any other purpose.
4. Never allow children under 14 years old to operate this
machine. Children 14 years old and over should read and
understand the instructions in this manual and should be
trained and supervised by a adult.
5. Only responsible individuals who are familiar with these rules
of safe operation should be allowed to use this machine.
6. Thoroughly inspect the area where the equipment is to be
used. Remove all stones, sticks, wire, bones, toys and other
foreign objects which could be tripped over or picked up
and thrown by the blade. Thrown objects can cause serious
personal injury.
7. Plan your mowing pattern to avoid discharge of material toward
roads, sidewalks, bystanders and the like. Also, avoid discharg-
ing material against a wall or obstruction which may cause
discharged material to ricochet back toward the operator.
8. To help avoid blade contact or a thrown object injury, stay
in the operator zone behind the handles and keep children,
bystanders, helpers and pets at least 75 feet from the mower
while it is in operation. Stop machine if anyone enters the area.
9. Always wear safety glasses or safety goggles during operation
and while performing an adjustment or repair to protect your eyes.
Thrown objects which ricochet can cause serious injury to the
eyes.
10. Wear sturdy, rough-soled work shoes and close-fitting slacks
and shirts. Shirts and pants that cover the arms and legs
and steel-toed shoes are recommended. Never operate this
machine in bare feet, sandals, slippery or light weight (e.g.
canvas) shoes.
11. Do not put hands or feet near rotating parts or under the cutting
deck. Contact with the blade can amputate hands and feet.
12. A missing or damaged discharge cover can cause blade
contact or thrown object injuries.
13. Many injuries occur as a result of the mower being pulled
over the foot during a fall caused by slipping or tripping. Do
not hold on to the mower if you are falling; release the handle
immediately.
14. Never pull the mower back toward you while you are walking. If
you must back the mower away from a wall or obstruction first
look down and behind to avoid tripping and then follow these
steps:
a. Step back from the mower to fully extend your arms.
b. Be sure you are well balanced with sure footing.
c. Pull the mower back slowly, no more than half way toward you.
d. Repeat these steps as needed.
15. Do not operate the mower while under the influence of alcohol or
drugs.
16. Do not engage the self-propelled mechanism on units so
equipped while starting engine.
17. The blade control handle is a safety device. Never attempt
to bypass its operation. Doing so makes the safety device
inoperative and may result in personal injury through contact with
the rotating blade. The blade control handle must operate easily
in both directions and automatically return to the disengaged
position when released.
18. Never operate the mower in wet grass. Always be sure of your
footing. A slip and fall can cause serious personal injury. If you
feel you are losing your footing, release the blade control handle
immediately and the blade will stop rotating within three seconds.
19. Mow only in daylight or in good artificial light. Walk, never run.
20. Stop the blade when crossing gravel drives, walks or roads.
21. If the equipment should start to vibrate abnormally, stop the
engine and check immediately for the cause. Vibration is gener-
ally a warning of trouble.
22. Shut the engine off and wait until the blade comes to a complete
stop before removing the grass catcher or unclogging the chute.
The cutting blade continues to rotate for a few seconds after the
engine is shut off. Never place any part of the body in the blade
area until you are sure the blade has stopped rotating.
23. Never operate mower without proper trail shield, discharge cover,
grass catcher, blade control handle or other safety protective
devices in place and working. Never operate mower with
damaged safety devices. Failure to do so, can result in personal
injury.
24. Muffler and engine become hot and can cause a burn. Do not
touch.
25. Never attempt to make a wheel or cutting height adjustment while
the engine is running.
26. Only use parts and accessories made for this machine by the
manufacturer. Failure to do so can result in personal injury.
27. When starting engine, pull cord slowly until resistance is felt, then
pull rapidly. Rapid retraction of starter cord (kickback) will pull
hand and arm toward engine faster than you can let go. Broken
bones, fractures, bruises or sprains could result.
28. If situations occur which are not covered in this manual, use care
and good judgment. Call customer assistance for the name of
your nearest servicing dealer.
Slope Operation
Slopes are a major factor related to slip and fall accidents which can
result in severe injury. Operation on slopes requires extra caution.
If you feel uneasy on a slope, do not mow it. For your safety, use
the slope gauge included as part of this manual to measure slopes
before operating this unit on a sloped or hilly area. If the slope is
greater than 15 degrees, do not mow it.
Do:
1. Mow across the face of slopes; never up and down. Exercise
extreme caution when changing direction on slopes.
2. Watch for holes, ruts, rocks, hidden objects, or bumps which can
cause you to slip or trip. Tall grass can hide obstacles.
WARNING: Engine Exhaust, some of its constituents, and certain vehicle components contain
or emit chemicals known to the State of California to cause cancer and birth defects or other
reproductive harm.

This symbol points
out important safety
instructions which, if
not followed, could
endanger the personal
safety and/or property
of yourself and others.
Read and follow all
instructions in this
manual before at-
tempting to operate
this machine. Failure
to comply with these
instructions may result
in personal injury. When
you see this symbol.

Your Responsibility
Restrict the use
of this power machine
to persons who read,
understand
and follow the warnings
and instructions
in this manual
and on the machine.
DANGER: This machine was built to be operated according to the rules for safe operation in this manual. As with
any type of power equipment, carelessness or error on the part of the operator can result in serious injury. This
machine is capable of amputating hands and feet and throwing objects. Failure to observe the following safety
instructions could result in serious injury or death.
continued on next page

4
3. Always be sure of your footing. A slip and fall can cause serious
personal injury. If you feel you are losing your balance, release
the blade control handle immediately, and the blade will stop
rotating within 3 seconds.
Do Not:
1. Do not mow near drop-offs, ditches or embankments, you could
lose your footing or balance.
2. Do not mow slopes greater than 15 degrees as shown on the slope
gauge.
3. Do not mow on wet grass. Unstable footing could cause slipping.
Children
Tragic accidents can occur if the operator is not alert to the presence
of children. Children are often attracted to the mower and the mowing
activity. They do not understand the dangers. Never assume that
children will remain where you last saw them.
1. Keep children out of the mowing area and under the watchful
care of a responsible adult other than the operator.
2. Be alert and turn mower off if a child enters the area.
3. Before and while moving backwards, look behind and down for
small children.
4. Use extreme care when approaching blind corners, doorways,
shrubs, trees, or other objects that may obscure your vision of a
child who may run into the mower.
5. Keep children away from hot or running engines. They can suffer
burns from a hot muffler.
6. Never allow children under 14 years old to operate a power
mower. Children 14 years old and over should read and under-
stand the operation instructions and safety rules in this manual
and should be trained and supervised by a parent.
Service
Safe Handling Of Gasoline:
1. To avoid personal injury or property damage use extreme care
in handling gasoline. Gasoline is extremely flammable and the
vapors are explosive. Serious personal injury can occur when
gasoline is spilled on yourself or your clothes which can ignite.
Wash your skin and change clothes immediately.
2. Use only an approved gasoline container.
3. Never fill containers inside a vehicle or on a truck or trailer bed
with a plastic liner. Always place containers on the ground away
from your vehicle before filling.
4. Remove gas-powered equipment from the truck or trailer and
refuel it on the ground. If this is not possible, then refuel such
equipment on a trailer with a portable container, rather than from
a gasoline dispenser nozzle.
5. Keep the nozzle in contact with the rim of the fuel tank or
container opening at all times until fueling is complete. Do not
use a nozzle lock-open device.
6 Extinguish all cigarettes, cigars, pipes and other sources of
ignition.
7. Never fuel machine indoors because flammable vapors will
accumulate in the area.
8. Never remove gas cap or add fuel while the engine is hot or run-
ning. Allow engine to cool at least two minutes before refueling.
9. Never over fill fuel tank. Fill tank to no more than ½ inch below
bottom of filler neck to provide for fuel expansion.
10. Replace gasoline cap and tighten securely.
11. If gasoline is spilled, wipe it off the engine and equipment. Move
unit to another area. Wait 5 minutes before starting the engine.
12. Never store the machine or fuel container near an open flame,
spark or pilot light as on a water heater, space heater, furnace,
clothes dryer or other gas appliances.
13. To reduce fire hazard, keep mower free of grass, leaves, or
other debris build-up. Clean up oil or fuel spillage and remove
any fuel soaked debris.
14. Allow a mower to cool at least 5 minutes before storing.
General Service:
1. Never run an engine indoors or in a poorly ventilated area.
Engine exhaust contains carbon monoxide, an odorless and
deadly gas.
2. Before cleaning, repairing, or inspecting, make certain the
blade and all moving parts have stopped. Disconnect the spark
plug wire and ground against the engine to prevent unintended
starting.
3. Check the blade and engine mounting bolts at frequent
intervals for proper tightness. Also, visually inspect blade for
damage (e.g., bent, cracked, worn) Replace blade with the
original equipment manufacture’s (O.E.M.) blade only, listed
in this manual. “Use of parts which do not meet the original
equipment specifications may lead to improper performance
and compromise safety!”
4. Mower blades are sharp and can cut. Wrap the blade or wear
gloves, and use extra caution when servicing them.
5. Keep all nuts, bolts, and screws tight to be sure the equipment
is in safe working condition.
6. Never tamper with safety devices. Check their proper operation
regularly.
7. After striking a foreign object, stop the engine, disconnect the
spark plug wire and ground against the engine. Thoroughly
inspect the mower for any damage. Repair the damage before
starting and operating the mower.
8. Never attempt to make a wheel or cutting height adjustment
while the engine is running.
9. Grass catcher components, discharge cover, and trail shield
are subject to wear and damage which could expose moving
parts or allow objects to be thrown. For safety protection,
frequently check components and replace immediately with
original equipment manufacturer’s (O.E.M.) parts only, listed
in this manual. “Use of parts which do not meet the original
equipment specifications may lead to improper performance
and compromise safety!”
10. Do not change the engine governor setting or overspeed the
engine. The governor controls the maximum safe operating
speed of the engine.
11. Check fuel line, tank, cap, and fittings frequently for cracks or
leaks. Replace if necessary.
12. Do not crank engine with spark plug removed.
13. Maintain or replace safety labels, as necessary.
14. Observe proper disposal laws and regulations. Improper
disposal of fluids and materials can harm the environment.
Do not modify engine
To avoid serious injury or death, do not modify engine in any way.
Tampering with the governor setting can lead to a runaway engine
and cause it to operate at unsafe speeds. Never tamper with
factory setting of engine governor.
Average Useful Life
According to the Consumer Products Safety Commission (CPSC)
and the U.S. Environmental Protection Agency (EPA), this product
has an Average Useful Life of seven (7) years, or 60 hours of
operation. At the end of the Average Useful Life, buy a new
machine or have the machine inspected annually by an authorized
service dealer to ensure that all mechanical and safety systems
are working properly and not worn excessively. Failure to do so can
result in accidents, injuries or death.
2
Safe



This machine is equipped
with an internal combus-
tion engine and should
not be used on or near
any unimproved forest-
covered, brushcovered or
grass-covered land unless
the engine’s exhaust
system is equipped with a
spark arrester meeting ap-
plicable local or provincial
laws (if any).
If a spark arrester is used,
it should be maintained in
effective working order by
the operator.
A spark arrester for the muf-
fler is available through your
nearest engine authorized
service dealer.
Notice regarding Emis-
sions
Engines which are certified
to comply with California
and federal EPA emission
regulations for SORE (Small
Off Road Equipment) are
certified to operate on regu-
lar unleaded gasoline, and
may include the following
emission control systems:
Engine Modification (EM)
and Three Way Catalyst
(TWC) if so equipped.

5
3





IMPORTANT: This engine is shipped without gasoline
or oil in the engine. Running the engine with insufficient
oil can cause serious engine damage and void the
engine warranty.
• Beforestartingengine,fillwithoil.Donotover-fill.Oil
capacity is about 0.6 liter (20 oz).
Use a 4-stroke, or an equivalent high detergent,
premium quality motor oil certified to meet or exceed
U.S. automobile manufacturer’s requirements for service
classification SG, SF. Motor oils classified SG, SF will
show this designation on the container.
SAE 10W-30 is recommended for general, all tem-
perature use. If single viscosity oil is used, select the
appropriate viscosity for the average temperature in your
area from the chart to the right.

1. Single Viscosity
2. Multi Viscosity
IMPORTANT: Using nondetergent oil or 2-stroke engine
oil could shorten the engine’s service life.
Check Oil Level
IMPORTANT: Be sure to check the engine on a level
surface with the engine stopped.
1. Remove the oil filler cap and wipe the dipstick clean.
See Figure 3-3.
Figure 3-1 - The major components of the engine.The shroud on your engine may differ.
Starter
Grip
Oil Fill Cap
Oil Drain
Muffler Spark Plug
Fuel Cap
Air Cleaner
Read this section before starting your lawn mower engine. Compare the illustrations in Figure 3-1 with your lawn
mower engine to familiarize yourself with the location of various controls and adjustments.
IMPORTANT
This engine is shipped
without gasoline
or oil in the engine.
Running the engine
with insufficient oil can
cause serious engine
damage and void the
engine warranty.
IMPORTANT
Using nondetergent
oil or 2-stroke engine
oil could shorten the
engine’s service life.
Be sure to check
the engine on a level
surface with the engine
stopped.
-30º -20º
10w
20w
20
30
40
20w40, 20w50
15w40, 15w50
10w40
10w30
-10º 0º
0º 20º 40º 60º 80º 100º
10º 20º 30º 40º
-20º
(ºC)
(ºF)
1
2
Starter
Grip
Oil Fill Cap
Oil Drain
Muffler Spark Plug
Fuel Cap
Air Cleaner

6
2. Insert the dipstick into the oil filler neck, but do not
screw it in.
3. If the level is low, slowly add oil to the upper limit on
the dipstick. See Figure 3-3 inset.
4. Tighten dipstick firmly before starting engine.
IMPORTANT: Do not overfill. Overfilling with oil may
cause smoking, hard starting, spark plug fouling, or oil
saturation of air cleaner.
Fuel Recommendations
Use automotive gasoline (unleaded or lowleaded
to minimize combustion chamber deposits) with a
minimum of 87 octane. Gasoline with up to 10% ethanol
or 15% MTBE (Methyl Tertiary Butyl Ether) can be used
Never use an oil/gasoline mixture or dirty gasoline.
Avoid getting dirt, dust, or water in the fuel tank.
WARNING: Gasoline is extremely flam-
mable and is explosive under certain
conditions.
Refuel in a well-ventilated area with the
engine stopped. Do not smoke or allow
flames or sparks in the area where the
engine is refueled or where gasoline is
stored.
Do not overfill the fuel tank (there
should be no fuel in the filler neck).
After refueling, make sure the tank cap
is closed properly and securely.
Be careful not to spill fuel when
refueling. Spilled fuel or fuel vapor
may ignite. If any fuel is spilled, make
sure the area is dry before starting the
engine.
Avoid repeated or prolonged contact
with skin or breathing of vapor.
Check Fuel Level
1. Clean around fuel fill before removing cap to fuel.
2. Fill tank to approximately 2 cm below lowest portion
of neck to allow for fuel expansion. Be careful not to
overfill.
IMPORTANT: Before refueling, allow engine to cool 2
minutes.
Starting The Engine
WARNING: Always keep hands and
feet clear of equipment moving parts.
Do not use a pressurized starting fluid.
Vapors are flammable.
Models equipped with a manual choke:
1. Move the choke lever on the left side of the upper
handle to START position. See Figure 3-4.
3




Always keep hands
and feet clear of equip-
ment moving parts. Do
not use a pressurized
starting fluid. Vapors
are flammable.
Figure 3-3
5PPER,EVEL
/IL&ILL#AP
$IPSTICK
Figure 3-4 - Models with a manual choke.
3
2
1
4
NOTE: Use of the choke may not necessary if the engine
is warm or the air temperature is high.
2. Standing behind the mower, depress the blade control
handle and hold it against the upper handle.
3. Pull the starter grip lightly until resistance is felt,
then pull rapidly to overcome compression, prevent
kickback and start engine. Repeat if necessary. See
Figure 3-4 .
IMPORTANT: Do not allow the starter grip to snap back
against the engine. Return it gently to prevent damage to
the starter.
4. When engine warms up, push in the choke knob .


Figure 3-5 - Models with a manual primer.
Models equipped with a primer:
1. Push the primer 3 times. Wait about two seconds
between each push. See Figure 3-5. In temperature
below 10oC (50oF), prime 5 times. After the engine
is warmed up, one prime may be needed for all
temperatures.
2. Standing behind the mower, depress the blade control
handle and hold it against the upper handle.
3. Recoil Start:
Pull the starter grip lightly until resistance is felt,
then pull rapidly to overcome compression, prevent
kickback and start engine. Repeat if necessary. See
Figure 3-5 . Do not allow the starter grip to snap
back against the engine. Return it gently to prevent
damage to the starter.
Electric Start:
Turn ignition key to the right to start the engine.
Release the key after the engine starts. See Figure
3-5.
If the engine doesn not start, it may be necessary to
re-prime the engine.
Stopping The Engine
1. Release the blade control handle. See Figure 3-5.
31
3
2
3



IMPORTANT
Do not allow the starter
grip to snap back
against the engine.
Return it gently to
prevent damage to the
starter.

8
4




Shut off the engine
before performing
any maintenance. To
prevent accidental
start-up, disconnect
the spark plug boot.
Figure 4-1
Tasks First 5 Hrs. Each Use or
Every 5 Hrs.
Every Season
or 25 Hrs.
Every Season
or 50 Hrs.
Every Season
or 100 Hrs.
Service
Dates
Check Engine
Oil
Change
Engine Oil
††
Check Air
Cleaner
Service Air
Cleaner
†
Check Spark
Plug
Service Spark
Plug
Clean Finger
Guard
Clean Around
Muffler
WARNING: Shut off the engine before
performing any maintenance. To
prevent accidental start-up, disconnect
the spark plug boot.
IMPORTANT: If engine must be tipped to transport
equipment or to inspect or remove grass, keep spark
plug side of engine up. Transporting or tipping engine
spark plug down may cause smoking, hard starting,
spark plug fouling, or oil saturation of air cleaner.
Periodic inspection and adjustment of the engine is
essential if high level performance is to be maintained.
Regular maintenance will also ensure a long service life.
The required service intervals and the kind of mainte-
nance to be performed are described in the table below.
Follow the hourly or calendar intervals, whichever occur
first. More frequent service is required when operating in
adverse conditions.

† Service more frequently when used in dusty areas.
†† Every season or 25 hours if operating under heavy load or high ambient temperature.
Oil Service
• Checkoillevelregularly.
• Besurecorrectoillevelismaintained.Checkevery
5 hours or daily before starting engine. See oil
checking procedure on page 5.
Oil Change
IMPORTANT: Be sure to check engine on a level surface
with the engine stopped. Drain the oil while the engine is
still warm to assure rapid and complete draining.
1. Remove oil fill cap and drain oil by either removing
drain plug or turning mower on its side (air cleaner
side up) and allowing oil to drain into a suitable
container. See Figure 4-1.
WARNING: Before tipping engine or
equipment to drain oil, drain fuel from
tank by running engine until fuel tank is
empty.
2. Reinstall the drain plug (if removed), and tighten it
securely.
3. Refill with the recommended oil (see page 5) and
check the oil level. See Figure 4-1.
4. Reinstall the oil fill cap securely.
Before tipping engine
or equipment to
drain oil, drain fuel
from tank by running
engine until fuel tank
is empty.
IMPORTANT
Be sure to check
engine on a level
surface with the engine
stopped. Drain the oil
while the engine is still
warm to assure rapid
and complete draining.
Oil Fill Cap
Drain
Plug
Level

9
IMPORTANT: Used motor oil may cause skin cancer
if repeatedly left in contact with the skin for prolonged
periods. Although this is unlikely unless you handle
used oil on a daily basis, it is still advisable to thoroughly
wash your hands with soap and water as soon as
possible after handling used oil.
NOTE: Please dispose of used motor oil in a manner
that is compatible with the environment. We suggest you
take it in a sealed container to your local service station
for reclamation. Do not throw it in the trash or pour it on
the ground.
Air Cleaner Service
A dirty air cleaner will restrict air flow to the carburetor.
To prevent carburetor malfunction, service the air
cleaner regularly. Service more frequently when operat-
ing the engine in extremely dusty areas.
WARNING: Never use gasoline or
low flash point solvents for cleaning
the air cleaner element. A fire or
explosion could result.
IMPORTANT: Never run the engine without the air
cleaner. Rapid engine wear will result.
1. Remove the wing bolt and the air cleaner cover.
Remove the elements and separate them. See
Figure 4-2. Replace paper element when dirty or
damaged. Replace foam element when damaged.
2. To clean foam element, separate it from the paper
element and wash in liquid detergent and water.
Allow to dry thoroughly before using. Do not oil the
foam element.
Spark Plug Service
WARNING: DO NOT check for
spark with spark plug removed. DO
NOT crank engine with spark plug
removed.
To ensure proper engine operation, the spark plug must
be properly gapped and free of deposits.
1. Remove the spark plug boot and use a spark plug
wrench to remove the plug. See Figure 4-3.
WARNING: If the engine has been
running, the muffler will be very hot.
Be careful not to touch the muffler.
2. Visually inspect the spark plug. Discard the spark
plug if there is apparent wear, or if the insulator is
cracked or chipped. Clean the spark plug with a wire
brush if it is to be reused.
3. Measure the plug gap with a feeler gauge. Correct
as necessary by bending side electrode. See Figure
4-4. The gap should be: 0.030 in.
4. Check that the spark plug washer is in good condi-
tion and thread the spark plug in by hand to prevent
cross-threading.
4




Never use gasoline
or low flash point sol-
vents for cleaning the
air cleaner element.
A fire or explosion
could result.
DO NOT check for
spark with spark plug
removed. DO NOT
crank engine with
spark plug removed.
If the engine has
been running, the
muffler will be very
hot. Be careful not to
touch the muffler.
Figure 4-2
0APER%LEMENT
&OAM%LEMENT
Figure 4-3
3PARK0LUG
3PARK0LUG"OOT
5. After the spark plug is seated, tighten with a spark plug
wrench to compress the washer.
NOTE: When installing a new spark plug, tighten 1/2 turn
after the spark plug seats to compress the washer. When
reinstalling a used spark plug, tighten 1/8-1/4 turn after
the spark plug seats to compress the washer.
IMPORTANT: The spark plug must be securely tightened.
An improperly tightened spark plug can become very hot
and may damage the engine.
Figure 4-4
%LECTRODE
IN

10
Fuel Filter Service
The fuel filter cannot be cleaned and must be replaced
once a year or every 100 operating hours; more often if
run with old gasoline.
1. Remove all fuel from tank by running engine until it
stops from lack of fuel.
2. Remove c-clamp from fuel line and remove fuel line
from tank outlet. See Fig. 4-5.
3. Pull out old fuel filter from tank outlet. Replace when
dirty or damaged.
4. Grasp new fuel filter from shouldered end and insert
it completely to the shoulder into the tank outlet. See
Fig. 4-5 inset.
5. Replace fuel line and c-clamp.
4




Accumulation of
debris around muffler
could cause a fire.
Inspect and clean
before every use.
IMPORTANT
Do not spray engine
with water to clean
because water could
contaminate fuel.
Using a garden hose
or pressure washing
equipment can also
force water into the
air cleaner or muffler
opening. Water in the
air cleaner will soak
the paper element,
and water that passes
through the element
or muffler can enter
the cylinder, causing
damage.

Engines stored over 30 days need to be drained of fuel
to prevent deterioration and gum from forming in fuel
system or on essential carburetor parts. If the gasoline in
your engine deteriorates during storage, you may need to
have the carburetor, and other fuel system components,
serviced or replaced.
1. Remove all fuel from tank by running engine until it
stops from lack of fuel.
2. Change oil. See Oil Change on page 7.
3. Remove spark plug and pour about 15 ml of engine oil
into cylinder. Replace spark plug and crank slowly to
distribute oil.
4. Clean grass and debris from around engine, under
finger guard, and under, around and behind muffler.
Touch up any damaged paint, and coat other areas
that may rust with a light film of oil.
5. Store in a clean,dry and well ventilated area away
from any appliance that operates with a flame or pilot
light, 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.
6. If possible, also avoid storage areas with high humid-
ity, because that promotes rust and corrosion.
7. Keep the engine level in storage. Tilting can cause
fuel or oil leakage.

1. Check your engine as described in the Pre-Operation
Check section of this manual on page 5.
2. If the fuel was drained during storage preparation, fill
the tank with fresh gasoline. If you keep a container
of gasoline for refueling, make certain it contains only
fresh fuel. Gasoline oxidizes and deteriorates over
time, causing hard starting.
3. If the cylinder was coated with oil during storage
preparation, the engine will smoke briefly at startup.
This is normal.
Figure 4-5

If the engine has been running, allow it to cool for at least
half an hour before cleaning. Periodically remove grass
and dirt build-up from engine. Clean finger guard and
around muffler. Clean with a brush or compressed air.
IMPORTANT: Do not spray engine with water to clean
because water could contaminate fuel. Using a garden
hose or pressure washing equipment can also force
water into the air cleaner or muffler opening. Water in
the air cleaner will soak the paper element, and water
that passes through the element or muffler can enter the
cylinder, causing damage.
WARNING: Accumulation of debris
around muffler could cause a fire.
Inspect and clean before every use.

11
NOTES:
For parts and/or
accessories refer to
customer support on
page 2.
Adressez-vous au
«Service après-vente»
à la page 2 pour
ce qui concerne
les pièces et/ou
accessoires.

12


29
26
28
14
17
10
11
18
20
15
13
21
30
9
387
1
2
19
6
5
412
27
31 32
22
23
16
25
24

13
Ref.
No./
Réf.
173 cc
Part No./
No. de
pièce
Description
Désignation
1. 951-10368 Fuel Tank Réservoir d’essence
2. 951-10855 Flywheel Shroud Déflecteur à volant
3. 951-10335 Rubber Fuel Tank Mounting
Washer
Rondelle de montage du réservoir en
caoutchouc
4. 951-10334 Oil Filler Tube Assembly Tube du filtre à huile
5. 951-10852 Dipstick Assembly Jauge à huile
6. 951-10413 Cylinder Head Complete Culasse
7. 951-10857 Short Block Assembly Bloc moteur embiellé
8. 951-10858 Stop Switch and Brake Assembly Commutateur d’arrêt et frein
9. 951-10319 Recoil Spring and Pulley Assembly Ressort du lanceur et poulie
10. 951-10344 Push Rod Kit Tige de culbuteur
11. 951-10345 Valve Kit Ensemble à soupape
12. 951-10370 Oil Drain Plug and Washer
Assembly
Orifice de vidange de l’huile et rondelle
13. 951-10854 Ignition Coil Bobine d’allumage
14. 951-10881 Carburetor Assembly Carburateur
15. 951-10307 Flywheel Key Clavette du volant
16. 951-10856 Air Cleaner Housing Assembly
Complete
Habitacle du filtre à air
17. 951-10342 Muffler Stud Assembly Support du silencieux
18. 951-10364 Fuel Line Kit – Inc. hoses, clamps
& filter
Conduite de carburant (avec boyaux,
colliers et filtre)
19. 951-10358 Fuel Filter Filtre à carburant
20. 951-10300 Fuel Cap Assembly Bouchon d’essence
21. 951-10299 Recoil Starter Assembly Démarreur à lanceur
22. 951-10298 Air Cleaner Kit Filtre à air
23. 951-10297 Air Cleaner Thumb Screw Vis de serrage à main du filtre à air
24. 951-10411 Muffler Guard Dispositif de protection du silencieux
25. 951-10403 Muffler Silencieux
26. 951-10402 Muffler Gasket /Heat Shield Joint du silencieux et bouclier thermique
27. 951-10387 Governor Return Spring Ressort de retour du régulateur
28. 951-10292 Spark Plug Bougie
29 951-10351 Spark Arrester Pare-étincelles
30 951-10880 Electric Starter Demarreur d’electrique
31 951-10823 Relay Assembly Relais
32 951-10824 Relay Harness Connector Raccord
33 951-10888 Primer Assembly Armorceur
–752Z2P70M0A Engine – Complete Moteur – complet
–951-10890 Carburetor Kit - Major Ensemble du carburateur
–951-10859 Cylinder Head Service Kit Culasse - trousse
–951-10416 Gasket Kit – Complete Ensemble de joints – complet
–951-10417 Gasket Kit – External Ensemble de joints – externes
NOTE: Parts illustrated without an identification number are non repairable.
REMARQUE : Les pièces illustrées sans identification numérique ne sont pas des éléments réparables.
For parts and/or
accessories refer to
customer support on
page 2.
Adressez-vous au
«Service après-vente»
à la page 2 pour ce qui
concerne les pièces
et/ou accessoires.
5



2P70MOA
12.12.08

14


14
29
31
24
20
30
19 18
29
15
13
11
10
12
27
22
23
16
6
5
4
21
3
2
98
7
1
25
28 17
26

15
Ref.
No./
Réf.
173 cc
Part No./
No. de
pièce
Description
Désignation
1. 951-10438 Fuel Tank Réservoir d’essence
2. 951-10369 Flywheel Shroud Déflecteur à volant
3. 951-10840 Reed Valve Assembly Soupape d’injection d’air secondaire pulsé
4. 951-10334 Oil Filler Tube Assembly Tube du filtre à huile
5. 951-10863 Dipstick Assembly Jauge à huile
6. 951-10413 Cylinder Head Complete Culasse
7. 951-10867 Short Block Assembly Bloc moteur embiellé
8. 951-10321 Stop Switch and Brake Assembly Commutateur d’arrêt et frein
9. 951-10319 Recoil Spring and Pulley Assembly Ressort du lanceur et poulie
10. 951-10344 Push Rod Kit Tige de culbuteur
11. 951-10345 Valve Kit Ensemble à soupape
12. 951-10370 Oil Drain Plug and Washer
Assembly
Orifice de vidange de l’huile et rondelle
13. 951-10366 Ignition Coil Bobine d’allumage
14. 951-10862 Carburetor Assembly Carburateur
15. 951-10307 Flywheel Key Clavette du volant
16. 951-10865 Air Cleaner Housing Assembly
Complete
Habitacle du filtre à air
17. 951-10342 Muffler Stud Assembly Support du silencieux
18. 951-10364 Fuel Line Kit – Inc. hoses, clamps
& filter
Conduite de carburant (avec boyaux,
colliers et filtre)
19. 951-10358 Fuel Filter Filtre à carburant
20. 951-10440 Fuel Cap Assembly Bouchon d’essence
21. 951-10299 Recoil Starter Assembly Démarreur à lanceur
22. 951-10298 Air Cleaner Kit Filtre à air
23. 951-10297 Air Cleaner Thumb Screw Vis de serrage à main du filtre à air
24. 951-10411 Muffler Guard Dispositif de protection du silencieux
25. 951-10775 Muffler Silencieux
26. 951-10402 Muffler Gasket /Heat Shield Joint du silencieux et bouclier thermique
27. 951-10387 Governor Return Spring Ressort de retour du régulateur
28. 951-10292 Spark Plug Bougie
29 951-10869 Roll Over Valve Assembly Soupape anti-retour
30 951-10443 Carbon Canister Cartouche à charbon actif
31 951-10773 Spark Arrester Pare-étincelles
–952Z1P70MC Engine – Complete Moteur – complet
–951-10868 Carburetor Kit - Major Ensemble du carburateur
–951-10870 Cylinder Head Service Kit Culasse - trousse
–951-10416 Gasket Kit – Complete Ensemble de joints – complet
–951-10417 Gasket Kit – External Ensemble de joints – externes
NOTE: Parts illustrated without an identification number are non repairable.
REMARQUE : Les pièces illustrées sans identification numérique ne sont pas des éléments réparables.
For parts and/or
accessories refer to
customer support on
page 2.
Adressez-vous au
«Service après-vente»
à la page 2 pour ce qui
concerne les pièces
et/ou accessoires.
5
Parts List
Pièces
détachées
1P70MOA
4.10.09

16



The U. S. EPA and MTD are pleased to explain the emissions control system warranty on your model year 2005 and
later small off-road engine. New small off-road engines must be designed, built and equipped to meet the stringent
anti-smog standards. MTD must warranty the emission control system on your engine for the period of time listed
below, provided there has been no abuse, neglect or improper maintenance of your small off-road engine.
Your emission control system may include parts such as the carburetor, air cleaner, ignition system, exhaust system,
and other associated emission-related components.
Where a warrantable condition exists, MTD will repair your small off-road engine at no cost to your including diagnosis,
parts and labor.

This emissions control system is warranted for two years. If any emission-related part on your engine is defective, the
part will be repaired or replaced by MTD.

As the small off-road engine owner, you are responsible for the performance of the required maintenance listed in your
Owner’s Manual. MTD recommends that you retain all your receipts covering maintenances on your small off-road
engine, but MTD can not deny warranty solely for the lack of receipts or for your failure to ensure the performance to
all scheduled maintenance.
As the small off-road engine owner, you should however be aware that MTD may deny your warranty coverage if your
small off-road engine or part has failed due to abuse, neglect, improper maintenance or unapproved modifications.
You are responsible for presenting your small off-road engine to an Authorized MTD Service Dealer as soon as a
problem exists. The warranted repairs should be completed in a reasonable amount of time, not to exceed 30 days.
If you have any questions regarding your warranty rights and responsibilities, you should contact a MTD Service
Representative at 1-800-668-1238 and address is MTD Products Ltd., P. O,. Box 1386, 97 Kent Avenue, Kitchener,
Ontario Canada N2 G 4J1.


This section applies to 1995 and later small off-road engines. The warranty period begins on the date the engine or
equipment is delivered to an ultimate purchaser.
 
MTD must warrant to the ultimate purchaser and each subsequent purchaser that the engine is:
1. Designed, built, and equipped so as to conform with all applicable regulations adopted by the Air Resources Board
pursuant to its authority in Chapters 1 and 2,Part 5, Division 26 of the Health and Safety Code; and
2. Free from defects in materials and workmanship that cause the failure of a warranted part to be identical in all
material respects to the part as described in the engine manufacturer’s application for certification for a period of
two years.
 
1. Any warranted part that is not scheduled for replacement as required maintenance in the written instructions
required by Subsection (c) must be warranted for the warranty period defined in Subsection (a)(2). If any such part
fails during the period of warranty coverage, it must be repaired or replaced by MTD according to Subsection (4)
below. Any such part repaired or replaced under the warranty must be warranted for the remaining warranty period.
2. Any warranted part that is scheduled only for regular inspection in the written instructions required by Subsection
(c) must be warranted for the warranty period defined in Subsection (a)(2). A statement in such written instructions
to the effect of “repair or replace as necessary” will not reduce the period of warranty coverage. Any such part
repaired or replaced under warranty must be warranted for the remaining warranty period.
3. Any warranted part that which is scheduled for replacement as required maintenance in the written instructions
required by Subsection (c) must be warranted for the period of time prior to the first scheduled replacement point
for that part. If the part fails prior to the first scheduled replacement, the part must be repaired or replaced by MTD
according to Subsection (4) below. Any such part repaired or replaced under warranty must be warranted for the
remainder of the period prior to the first scheduled replacement point for the part.
6





This emissions control
system is warranted
for two years. If any
emission-related part
on your engine is
defective, the part will
be repaired or replaced
by MTD.


4. Repair or replacement of any warranted part under the warranty provisions of this article must be performed at no
charge to the owner at a warranty station.
5. Notwithstanding the provisions of Subsection (4) above, warranty services or repairs must be provided at all MTD
distribution centers that are franchised to service the subject engines.
6. The owner must not be charged for diagnostic labor that leads to the determination that a warranted part is in fact
defective, provided that such diagnostic work is performed at a warranty station.
7. The engine manufacturer is liable for damages to other engine components proximately caused by a failure under
warranty of any warranted part.
8. Throughout the engine’s warranty period defined in Subsection (a)(2), MTD will maintain a supply of warranted
parts sufficient to meet the expected demand for such parts.
9. Any replacement part may be used in the performance of any warranty maintenance or repairs and must be
provided without charge to the owner. Such use will not reduce the warranty obligations of MTD.
10.Add-on or modified parts that are not exempted by the Air Resources Board may not be used. The use of any non-
exempted add-on or modified parts shall be grounds for disallowing a warranty claim made in accordance with this
article. The engine manufacturer shall not be liable under this article to warrant failures of warranted parts caused
by the use of non-exempted add-on or modified part.
 
 
1. Fuel Metering System
 •Coldstartenrichmentsystem(softchoke)
 •Carburetorandinternalparts
 •FuelPump
2. Air Induction System
 •Aircleaner
 •Intakemanifold
3. Ignition System
 •Sparkplug(s)
 •MagnetoIgnitionSystem
4. Exhaust System
5. Miscellaneous Items Used in Above System
 •Vacuum,temperature,position,timesensitivevalvesandswitches
 •Connectorsandassemblies
EPA-1-CA
6





This emissions control
system is warranted
for two years. If any
emission-related part
on your engine is
defective, the part will
be repaired or replaced
by MTD.

18
NOTES:
For parts and/or
accessories refer to
customer support on
page 2.
Adressez-vous au
«Service après-vente»
à la page 2 pour
ce qui concerne
les pièces et/ou
accessoires.

19
NOTES:
For parts and/or
accessories refer to
customer support on
page 2.
Adressez-vous au
«Service après-vente»
à la page 2 pour
ce qui concerne
les pièces et/ou
accessoires.

13
EPA-1-CA
5
6. Les diagnostics permettant d’établir qu’une pièce garantie est défectueuse doivent être effectués sans frais pour le proprié-
taire, à condition d’être réalisés par une station technique autorisée à offrir les services sous garantie.
7. Le fabricant du moteur est tenu responsable des dégâts aux autres pièces du moteur susceptibles d’avoir été causés par la
panne sous garantie d’une pièce garantie.
8. MTD s’engage à conserver un stock de pièces garanties suffisant pour satisfaire la demande prévue pour ces pièces pendant
la période de garantie du moteur stipulée au paragraphe (a)(2).
9. Toute pièce de remplacement peut être utilisée pour l’entretien ou la réparation sous garantie et doit être fournie gratuitement
au propriétaire. Ceci ne limite pas les obligations de garantie de MTD.
10. Les pièces complémentaires ou modifiées qui ne sont pas exemptées par le « Air Resources Board » ne peuvent toutefois
pas être utilisées. L’emploi de toute pièce complémentaire ou modifiée non exemptée sera suffisant pour rejeter une demande
d’application de la garantie en vertu de cet article. Le fabricant du moteur ne sera pas tenu, en vertu de cet article, de garantir
les pièces garanties si leur défaillance a été causée par l’utilisation d’une pièce complémentaire ou modifiée non exemptée.
(c) MTD fournira une copie de la liste suivante des pièces du système antipollution
sous garantie avec chaque moteur neuf utilisant les parties de la liste qui s’appliquent
au moteur.
1. Système de dosage du carburant
 • Systèmed’enrichissementducarburantpourdémarragesàfroid
 • Carburateuretpiècesinternes
 • Pompeàcarburant
2. Système d’admission de l’air
 • Filtreàair
 • Tubulured’admission
3. Système d’allumage
 • Bougie(s)
 • Systèmed’allumageàmagnéto
4. Système d’échappement
5. Divers articles utilisés dans le système ci-dessus
 • Soupapesdedépression,thermocontacts,soupapesdepositionnementetàactionminutéeetinterrupteurs
 • Raccordsetensembles
Déclaration
de garantie
du système
antipollution
Le système antipollu-
tion est garanti pour
une période de deux
ans. Toute pièce
annexe du système
antipollution du moteur
jugée défectueuse sera
réparée ou remplacée
par MTD.