MTD 478-SUC Owner’s Manual

Safe Operation Practices • Set-Up • Operation • Maintenance • Troubleshooting • Warranty

OperatOr’s Manual

277cc, 357cc & 420cc OHV Horizontal Shaft Engine

WARNING

READ AND FOLLOW ALL SAFETY RULES AND INSTRUCTIONS IN THIS MANUAL

BEFORE ATTEMPTING TO OPERATE THIS MACHINE.

FAILURE TO COMPLY WITH THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.

MTD LLC, P.O. BOX 361131 CLEVELAND, OHIO 44136-0019

Printed In USA

Form No. 769-11494

(May 10, 2016)

To The Owner

Thank You

This Operator’s Manual is an important part of your new engine. It will help you prepare and maintain the engine for the best
performance. Please read and understand the contents before operating the engine.

Table of Contents

1

Safe Operation Practices ........................................ 3

Safety Symbols ........................................................ 5

Set-Up ....................................................................... 6

Controls & Features ................................................. 9

Operation ................................................................10

Maintenance ...........................................................13

Troubleshooting .....................................................19

Replacement Parts ................................................ 20

Emission Statement/Warranty .............................21

Spanish ................................................................... 23

Record Product Information

Before operating your new engine, please locate the model plate
on the engine and record the information in the provided area

to the right. This information will be necessary, should you seek
technical support via our web site or with your local dealer.

Model NuMber/Serial NuMber

/

Customer Support

Please do NOT return the machine to the retailer or dealer without first contacting our Customer Support Department.

If you have difficulty with this product or have any questions regarding the controls, operation, or maintenance of this
engine, you can seek help from the experts. Choose from the options below:

◊ Visit us on the web at www.mtdproducts.com

See How-to Maintenance and Parts Installation Videos at www.mtdparts.com/KnowledgeCenter

◊ Call a Customer Support Representative at [phone] or [phone]

◊ Write us at MTD LLC • P.O. Box 361131 • Cleveland, OH • 44136-0019

2

Important Safe Operation Practices

WARNING! 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 attempting to operate the equipment. Failure to
comply with these instructions may result in personal injury. When you see this symbol.

HEED ITS WARNING!

CALIFORNIA PROPOSITION 65

WARNING! Engine Exhaust, some of its constituents, and certain vehicle components

contain or emit chemicals known to State of California to cause cancer and birth defects
or other reproductive harm.

DANGER! This engine was built to be operated according to the safe operation practices in

this manual. As with any type of power equipment, carelessness or error on the part of the
operator can result in serious injury. Failure to observe the following safety instructions
could result in serious injury or death.

2

Training

1. Read, understand and follow all instructions on the engine
and in the manual(s) before attempting to assemble and
operate. Keep this manual in a safe place for future and
regular reference and for ordering replacement parts.

2. Be familiar with all controls and their proper operation.
Know how to stop the engine and disengage them quickly.

3. Never allow children under 14 years of age to operate the
engine. Children 14 and over should read and understand
the instructions and safe operation practices in this manual
and be trained and supervised by an adult.

4. Never allow adults to operate the machine without proper
instruction.

5. Keep the area of operation clear of all persons, particularly
small children and pets. Stop machine if anyone enters the
area.

Preparation

1. Wear sturdy, rough-soled work shoes and close fitting
slacks and shirts. Loose fitting clothes or jewelry can be
caught in the moving parts. Never operate the machine in
bare feet or sandals.

2. Disengage clutch levers and shift (if equipped) into neutral
(“N”) before starting the engine.

3. Never leave the engine running while unattended.

4. Never attempt to make any adjustments while the engine
is running, except where specifically recommended in the
operator’s manual.

Safe Handling of Gasoline:

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 and/or your clothes which can
ignite. Wash your skin and change clothes immediately.

1. When adding fuel, turn engine OFF and let engine cool at
least 2 minutes before removing the gas cap.

2. Fill fuel tank outdoors or in well ventilated area.

3. Use only an approved gasoline container.

4. 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.

5. If possible, 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.

6. 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.

3

7. Do not overfill fuel tank. Fill tank to full as indicated by
the fuel level indicator installed inside of the fuel tank or
marked on the tank. Do not over-fill to allow space for fuel
expansion. On some models, a fuel level indicator may NOT
be present, in this instance, fill the tank no more than 1/2
inch below the bottom of the filler neck to allow space for
fuel expansion.

8. Replace fuel cap and tighten until the cap ratchets.

9. If gasoline is spilled, wipe it off the engine and the
equipment. Move the machine to another area. Wait five
minutes before starting the engine.

10. To reduce fire hazards, keep the machine free of grass ,
leaves or other debris build up. Clean up oil or fuel spillage
and remove any fuel-soaked debris.

11. Keep gasoline away from sparks, open flames, pilot lights,
heat, and other ignition sources.

12. Never fuel equipment indoors because flammable vapors
will accumulate in the area.

13. Extinguish all cigarettes, cigars, pipes, and other sources of
ignition.

14. Check fuel line, tank, cap, and fittings frequently for cracks
or leaks. Replace if necessary.

Operation

1. When starting the engine, make sure spark plug, muffler,
and fuel cap are in place.

2. Do not crank engine with spark plug removed.

3. If fuel spills, wait until it evaporates before starting engine.

4. Allow muffler, engine cylinder, and fins to cool before
touching.

5. Keep children away from hot or running engines. They can
suffer burns from a hot muffler.

6. Remove accumulated combustibles from muffler and
cylinder area.

7. Operate equipment with all guards in place.

8. Keep hands and feet away from rotating parts.

9. Tie up long hair and remove jewelry.

10. Do not wear loose-fitting clothing, dangling drawstrings or
items that could become caught.

11. When starting the engine, pull cord slowly until resistance
is felt, then pull rapidly (if not electric start).

12. Remove all external equipment/engine loads before
starting engine.

13. Direct coupled equipment components such as, but not
limited to blades, impellers, pulleys, sprockets, etc., must
be securely attached.

Maintenance & Storage

1. Keep the engine in safe working order

2. Allow the engine to cool at least five minutes before
storing. Never tamper with safety devices. Check their
proper operation regularly.

3. Check bolts and screws for proper tightness at frequent
intervals to keep the engine in safe working condition.
Visually inspect the engine for any damage.

4. Before cleaning, repairing or inspecting; stop the
engine and make certain all moving parts have stopped.
Disconnect the spark plug wire and ground it against the
engine to prevent unintended starting.

5. Do not change the engine governor settings or over-speed
the engine. The governor controls the maximum safe
operating speed of the engine.

6. Maintain and replace safety and instruction labels as
necessar y.

7. Always refer to the operator’s manual for important details
if the machine is to be stored for an extended period of
time.

8. If the fuel tank has to be drained, do this outdoors.

9. Observe proper disposal laws and regulations for gas, oil,
etc. to protect 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.

Notice Regarding Emissions

Engines which are certified to comply with California and federal
EPA emission regulations for SORE (Small Off Road Equipment)
are certified to operate on regular unleaded gasoline, and
may include the following emission control systems: Engine
Modification (EM), Oxidizing Catalyst (OC), Secondary Air
Injection (SAI) and Three Way Catalyst (TWC) if so equipped.

Spark Arrestor

WARNING! This machine is equipped with an

internal combustion engine and should not be used
on or near any unimproved forest-covered, brush
covered or grass-covered land unless the engine’s
exhaust system is equipped with a spark arrestor
meeting applicable local or state laws (if any).

If a spark arrestor is used, it should be maintained in effective
working order by the operator. In the State of California the
above is required by law (Section 4442 of the California Public
Resources Code). Other states may have similar laws. Federal laws
apply on federal lands.
A spark arrestor for the muffler is available through your
nearest engine authorized service dealer or contact the service
department, P.O. Box 361131 Cleveland, Ohio 44136-0019.

4 Section 2 — important Safe operation practiceS

Safety Symbols

This page depicts and describes safety symbols that may appear on this product. Read, understand, and follow all instructions on the
machine before attempting to assemble and operate.

Symbol Description

READ THE OPERATOR’S MANUAL(S)
Read, understand, and follow all instructions in the manual(s) before attempting to
assemble and operate.

WARNING—GASOLINE IS FLAMMABLE
Allow the engine to cool at least two minutes before refueling.

WARNING— CARBON MONOXIDE
Never run an engine indoors or in a poorly ventilated area. Engine exhaust contains carbon
monoxide, an odorless and deadly gas.

WARNING— ELECTRICAL SHOCK
Do not use the engine’s electric starter in the rain.

WARNING— HOT SURFACE
Engine parts, especially the muffler, become extremely hot during operation. Allow engine
and muffler to cool before touching.

WARNING! 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.

SAVE THESE INSTRUCTIONS!

5Section 2 — important Safe operation practiceS

Set-Up

Fill

between

high (H)
and low

(L) marks

3

Oil & Fuel Specifications

IMPORTANT: The engine is shipped without gasoline in the

engine. See the following instructions for adding gasoline.

IMPORTANT: Some engines are shipped with oil already in

the engine, others without oil already in the engine. It is very
important to check the oil level before operating the engine and
to add oil if necessary. Running the engine with insufficient oil
can cause serious engine damage and void the engine warranty.

Oil Recommendations

Before starting engine, fill with motor oil, capacity is 1100 ml/37.2
oz. Refer to viscosity chart in Figure 3-1 for oil recommendations.
Do not over-fill. 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 of a minimum level SJ (higher letter ratings are
acceptable such as SL and SM grades). Motor oil will display this
designation on the container.

NOTE: Do not use non-detergent oil or 2-stroke engine oil. It
could shorten the engine’s service life.

Checking Oil Level on Engines with Quarter-Turn Oil Fill Caps

NOTE: Be sure to check the oil while on a level surface with the
engine stopped.

To avoid engine damage, it is important to:

• Check oil level before each use and every 5 operating
hours when engine is warm. Check oil level more
frequently during engine break-in.

• Keep oil level between “H” and “L” marks on dipstick.
See Figure 3-2.

• Be sure oil fill cap/plug is tightened securely when
checking.

1. Remove the oil filler cap/dipstick and wipe the dipstick
clean. See Figure 3-2.

2. Insert the cap/dipstick into the oil filler neck, and tighten
the cap until seated.

3. Remove the oil filler cap/dipstick. If the level is low, slowly
add oil until oil level registers between high (H) and low (L),
Figure 3-2.

4. Replace and tighten cap/dipstick firmly before starting
engine.

NOTE: Do not overfill. Overfilling with oil may cause smoking,
hard starting, or spark plug fouling.

NOTE: DO NOT allow oil level to fall below the “L” mark on the
dipstick. Doing so may result in equipment malfunctions or
damage.

NOTE: To change the oil on your engine, see the Maintenance
Section of this manual.

Figure 3-1

Checking Oil Level

Some engines will have a quarter-turn oil fill/dipstick cap, others
may have a threaded oil fill/dipstick cap. Follow the instructions
next that apply to your engine model.

6

Figure 3-2

Checking Oil Level on Engines with Threaded Oil Fill Caps

Fill
between
high
and low
marks

NOTE: Be sure to check the oil while on a level surface with the
engine stopped.

To avoid engine damage, it is important to:

• Check oil level before each use and every 5 operating
hours when engine is warm. Check oil level more
frequently during engine break-in.

• Keep oil level between “H” and “L” marks on dipstick.
See Figure 3-3.

• Be sure to rest oil fill cap on the threads when
checking. Do not tighten down oil fill cap when
checking the oil on threaded oil fill cap engines.

1. Remove the oil filler cap/dipstick and wipe the dipstick
clean. See Figure 3-3.

2. Insert the cap/dipstick into the oil filler neck, but do not
screw it in.

3. Remove the oil filler cap/dipstick. If the level is low, slowly
add oil until oil level registers between high (H) and low (L),
Figure 3-3.

4. Replace and tighten cap/dipstick firmly before starting
engine.

NOTE: Do not overfill. Overfilling with oil may cause smoking,
hard starting, or spark plug fouling.

NOTE: DO NOT allow oil level to fall below the “L” mark on the
dipstick. Doing so may result in equipment malfunctions or
damage.

NOTE: To change the oil on your engine, see the Maintenance
Section of this manual.

Filling Oil Sump

1. Be sure the engine is upright and level.

2. Remove the oil fill cap dipstick from oil filler tube by
rotating counter-clockwise and lifting the dipstick out of
the engine. Wipe the dipstick clean with a shop rag.

3. Insert oil fill cap dipstick back into oil filler tube. On
quarter-turn oil fill caps, tighten by rotating the cap
clockwise until firmly seated.

NOTE: Some units may have a threaded dipstick. In this
instance, insert the cap/dipstick into the oil filler neck, but
do not screw it in to check.

4. Loosen and remove the oil fill cap dipstick from the oil
filler tube. Note the oil level, if oil reading on the dipstick is
below the “L” mark, slowly add oil to reach the “FULL” level.
See Figure 3-2 or Figure 3-3, whichever is applicable.

5. Insert oil fill cap dipstick back into oil filler tube. Tighten by
rotating the cap clockwise until firmly seated.

6. Wipe away any spilled oil.
NOTE: To change the oil, see Checking and Changing Oil

instructions in the Maintenance Section of this manual.

Figure 3-3

7Section 2 — Set-Up

Fuel Recommendations

CAUTION: Operating the engine with E15 or E85

fuel, an oil/gasoline mixture, dirty gasoline, or
gasoline over 30 days old that has not been
stabilized using a fuel additive, may result in
damage to your engine’s carburetor. Subsequent
damage would not be covered under the
manufacturer’s warranty.

Use automotive gasoline (unleaded or low leaded 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.

DO NOT use E15 or E85 gasoline.

WARNING! Gasoline is extremely flammable 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. 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.

Electrical Power

WARNING! DO NOT pull starter rope with engine

running. Doing so may VOID YOUR WARRANTY.

CAUTION: The extension cord can be any length,

but must be rated for 15 amps at 125 volts, grounded
and rated for outdoor use.

NOTES: When connecting power cord always
connect power cord to switch box on engine first;
then into outlet. See Figure 3-4.

Determine what type of power source outlet you will be
connecting the power cord to, before you start your engine.
See Engines with Electric Starters instructions in the Operation
Section of this manual.

Adding Fuel

WARNING! An adult should fuel this engine. NEVER
allow children to refuel this engine. Gasoline (fuel)
vapors are highly flammable and can explode. Fuel
vapors can spread and be ignited by a spark or flame
many feet away from engine. To prevent injury or
death from fuel fires, follow these instructions:

• DO NOT use leaded fuel.

• Fuel must be fresh and clean. NEVER use fuel left over
from last season or stored for long periods.

• NEVER mix oil with fuel.

• DO NOT use fuel containing Methanol (Wood
Alcohol)

1. Before refueling, allow the engine to cool for two minutes.

2. Be sure engine is outdoors and in a well-ventilated area.

3. Clean area around the fuel fill cap and remove the fuel fill cap.

4. Using an approved red GASOLINE container, add fuel
slowly, being careful to avoid spilling.

5. Replace the fuel cap and tighten securely. Wipe up spilled
fuel before starting engine. If fuel is spilled DO NOT start
engine. Move machine away from area of spillage. Avoid
creating any source of ignition until fuel vapors are gone.

6. Be sure fuel valve, if present, is open.

Figure 3-4

8 Section 2— Set-Up

Controls and Features

Starter Handle

Primer Bulb

Muffler

Muffler

Oil Drain

Air Filter Cover

Electric Starter

Inlet & Button

Air Filter

Thumb Screws

Oil Drain

Fuel Fill

Fuel Fill

Oil Fill/Dipstick

Oil Fill/Dipstick

Fuel Shut-Off

Control

Choke

Choke

Key

Throttle

Throttle

4

Throttle

The throttle control is located on the rear of the engine. It
regulates the speed of the engine and will shut off the engine
when moved into the STOP position.

Choke

Activating the choke closes the choke plate on the carburetor
and aids in starting the engine.

Fuel Shut-Off Control

If equipped, is used for controlling the flow of fuel between
usage and transport/storage.

Primer Bulb

Pressing the primer bulb forces fuel directly into the engine’s
carburetor to aid in starting a “Cold” engine.

Oil Drain

Removing the oil drain plug will drain the oil from the engine.

Oil Filler Cap & Dipstick

Remove the oil cap to check the oil level and add oil.

Figure 4-1

Fuel Fill

Remove the cap to add fuel.

Electric Starter Inlet

Requires the use of a three-prong outdoor extension cord and a
120V power source/wall outlet.

Recoil Starter Handle

This handle is used to manually start the engine.

Electric Starter Button

Pressing the button on the top of the electric starter switch
engages the engine’s electric starter when plugged into a 120V
power source.

Key

The key is a safety device. It must be fully inserted in order for the
engine to start. Remove the key when the snow thrower is not in
use.

Important: Do not turn the key in an attempt to start the

engine. Doing so may cause it to break.

9

Operation

ChokeRun

Fast Slow/Idle Engine Off

Primer

5

Pre-Operation Check

IMPORTANT: The engine is shipped without gasoline or oil in

the engine. See the Set-Up Section of this manual for instructions
on adding oil and gasoline.

For your safety, and in order to maximize the service life of this
equipment, it is very important to check its condition before you
operate this engine. Make certain to service, correct or fix any
problem that might be identified before attempting to operate
this engine.

WARNING! Improperly maintaining this engine, or

failure to correct any problem before operation can
cause a malfunction which could result in serious
injury or even death.

Always perform a pre-operation inspection before
each operation, and correct any problem.

Before you start the engine, always check the following items:

1. Fuel Recommendations (See Set Up Section)

2. Checking Oil Level (See Set Up Section)

3. Air filter (if equipped) (See Maintenance Section)

4. General Overall Inspection. Check for any fluid leaks or
discharges, and loose or damaged parts.

5. Check the owner’s manual provided with the equipment
that is powered by this engine. Review the owner’s manual
for any precautions and procedures that should be
followed before starting the engine.

Starting the Engine

WARNING! Always keep hands and feet clear of

moving parts. Do not use a pressurized starting
fluid. Vapors are flammable.

WARNING! An adult should start the engine. Only

allow children to start the engine if an adult has
determined they are experienced and capable of
such operation.

WARNING! If you are unable to start this engine

after following instructions in this manual, contact
you authorized MTD Service Dealer. To avoid serious
burn injuries or damage to your engine, DO NOT
attempt to start or troubleshoot this engine in any
other way. for example:

• DO NOT use starting fluid.

• DO NOT spray flammable vapors into the
carburetor.

• DO NOT put flammable liquids into carburetor.

• DO NOT operate engine or pull on starter rope
with spark plug removed. Fuel can spray from
spark plug hole and ignite.

NOTE: Allow the engine to warm up for a few minutes after

starting. The engine will not develop full power until it reaches
operating temperatures.

Familiarize yourself with the engine symbols shown in Figure 5-1
before attempting to start this engine. If this engine is remotely
controlled by the equipment it is powering, be sure to familiarize
yourself with the equipment Operator’s Manual as well.

Figure 5-1

NOTE: The following starting instructions are for several different
types of engines. In order to locate the instructions that apply to
your engine, first determine what type of starter you have. If you
have an electric starter, see Engines With Electric Starters. If you
have a manual recoil starter, see Engines with Recoil Starters later
in this section.

Engines With Electric Starters

If you have a manual recoil starter, see Engines with Recoil
Starters later in this section.

WARNING! DO NOT pull the starter handle while
the engine is running.

WARNING! The electric starter is equipped with
a 120V A.C. Power Plug designed to operated
with a grounded extension cord and on 120V A.C.
household current. It must be properly grounded
at all times to avoid the possibility of injury or death
from electrical shock.

a. Determine if your house wiring has a Ground Fault

Interrupted (G.F.I.) Three-Wire Grounded System; if
you are not sure, ask a Licensed Electrician.

b. If your house wiring does not have a G.F.I. Three-

Wire Grounded System, DO NOT USE THIS ELECTRIC
STARTER UNDER ANY CONDITION.

10

c. If your house wiring is grounded and a G.F.I.

three-Prong Wall Receptacle is not available at the
location where your starter will be used, one must
be installed by a Licensed Electrician BEFORE USING
THE ELECTRIC STARTER!

1. To avoid carbon monoxide poisoning, be sure engine is
outdoors in a well-ventilated area.

2. Be sure fuel valve, if present (see equipment Operator’s
Manual instructions) is open and all switches are on.

NOTE: If your engine is equipped with a 12V battery­operated electric starter, proceed Step 5.

3. Plug an extension cord into the outlet located on the
engine’s surface. Plug the other end of extension cord
into a three-prong 120-volt, grounded, AC outlet in a well­ventilated area.

CAUTION: The extension cord can be any length,

but must be rated for 15 amps at 125 volts, grounded
and rated for outdoor use.

IMPORTANT: When connecting the power cord, always

connect the power cord to the switch box on the engine first;
then into the outlet.

4. Move engine speed control, if equipped, in the “Fast”
position.

5. If equipped, set the choke control to “FULL CHOKE”
position.

6. Hold the primer bulb in for one full second each time you
press it.

• Make sure you cover the vent hole with your
thumb.

• Prime between 3 and 5 times.

IMPORTANT: DO NOT operate an electric starter for more than

5 seconds during each attempt.

NOTE: DO NOT use the primer bulb to restart a warm
engine after a short shutdown. Doing so will flood the
engine and may result in equipment malfunction.

NOTE: If restarting a warm engine after a short shutdown,
move the engine speed control (if equipped) the “FAST”
position and move the choke control to the “NO CHOKE”
position.

7. Push the starter button to start the engine.

NOTE: If the engine fails to start after 3 attempts, repeat
steps 1 through 8.

8. When the engine starts:

• Release the starter button.

• Move the choke control to 1/2 “CHOKE” position
until the engine runs smoothly.

• Next, move the choke control to the NO CHOKE
position.

9. Move the engine speed control (if equipped) to the desired
speed in the “RUN” range.

NOTE: If the engine starts but falters when the choke
control is moved to the “NO CHOKE” position:

• Momentarily move choke control back to “FULL
CHOKE” position.

• Next, move the choke control to “1/2 CHOKE”
position until engine runs smoothly.

• Finally, move the choke control to the NO
CHOKE position.

If the engine dies after choke control is moved to “NO CHOKE”
position, repeat steps 5 through 10 to restart engine.

10. If the engine fails to start after 3 attempts in the “NO
CHOKE” position, move the choke control to “FULL CHOKE”
position and start engine.

NOTE: When disconnecting the power cord, always
disconnect the power cord from the outlet first; then
disconnect the power cord from the switch box on the
engine.

11. Disconnect the power cord form the outlet.

12. Disconnect the power cord form the switch box on the
engine.

13. If engine does not start after following steps 1 through
12, contact your Authorized MTD Service Dealer. DO NOT
attempt to troubleshoot this engine in any other way.

Engines with Recoil Starters

If you have an electric starter, see Engines with Electric Starters
earlier in this section.

WARNING! DO NOT pull starter rope with engine
running. Doing so may VOID YOUR WARRANTY.

1. To avoid carbon monoxide poisoning, be sure engine is
outdoors in a well-ventilated area.

2. Be sure fuel valve, if present (see equipment Operator’s
Manual instructions) is open and all switches are on.

3. Move the engine speed control, if equipped, to the “FAST”
position.

4. If equipped, set the choke control to “FULL CHOKE”
position.

5. Hold the primer bulb in for one full second each time you
press it.

• Make sure you cover the vent hole with your
thumb.

• Prime between 3 and 5 times.

NOTE: DO NOT use the primer bulb to restart a warm
engine after a short shutdown. Doing so will flood the
engine and may result in equipment malfunction.

NOTE: If restarting a warm engine after a short shutdown,
move the engine speed control (if equipped) the “FAST”
position and move the choke control to the “NO CHOKE”
position.

6. Operate equipment control to release engine brake or
clutch, if equipped (see equipment Operator’s Manual).

WARNING! When pulling the starter rope, the

rope can unexpectedly jerk back toward the engine
causing serious injury. To avoid this risk, carefully

11Section 5 — oper ation

follow these instructions:

7. Grasp the starter cord handle.

• Pull rope out slowly until you feel drag.

• Without allowing the rope to retract, continue
pulling the rope with one rapid full arm stroke.

• Return the rope slowly to the original position.

NOTE: Following the instructions listed in the steps above avoids
potential damage to the recoil mechanism.

If the recoil starter handle is frozen and will not operate the
engine, proceed as follows:

• Pull as much rope out of the starter as possible.

• Release the starer handle and let it snap back
against the starter to break up ice’; these two
steps should only be done when the starter is
frozen.

8. If the engine fails to start after 3 attempts repeat steps 1
through 7 and try again.

9. When the engine starts:

• Move the choke control to 1/2 “CHOKE” position
until the engine runs smoothly.

• Next, move the choke control to the NO CHOKE
position.

10. Move the engine speed control (if equipped) to the desired
speed in the “RUN” range.

NOTE: If the engine starts but falters when the choke
control is moved to the “NO CHOKE” position:

• Momentarily move choke control back to “FULL
CHOKE” position.

• Next, move the choke control to “!/2 CHOKE”
position until engine runs smoothly.

• Finally, move the choke control to the NO
CHOKE position.

If the engine dies after choke control is moved to “NO CHOKE”
position, repeat steps 3 through 10 to restart engine.

11. If the engine fails to start after 3 attempts in the “NO
CHOKE” position, move the choke control to “FULL CHOKE”
position and start engine.

12. If engine does not start after following steps 1 through
11, contact your Authorized MTD Service Dealer. DO NOT
attempt to troubleshoot this engine in any other way.

Stopping the Engine & Short Term Storage

Stop engine in accordance with the equipment Operator’s
Manual.

WARNING! To avoid unsupervised engine

operation, especially by children, NEVER leave the
engine unattended while running. Always turn off
the engine after use and remove the ignition key, if
equipped.

WARNING! NEVER store the engine with fuel in the

fuel tank inside a building with potential sources of
ignition such as hot water tank and space heaters,
clothes drivers, electric motors, etc.

Stopping The Engine

1. If operating the engine in the snow or rain, run the engine
for a few minutes to help dry off any moisture.

2. Move the equipment control, if present (see Equipment
Owner’s Manual), engine control lever or ignition switch to
“STOP” or “OFF” position.

3. Remove ignition key, if provided (see equipment Operator’s
Manual).

NOTE: Removing the key will reduce the possibility of
unauthorized starting of the engine while equipment is not
in use.

WARNING! NEVER store the engine with fuel in the

fuel tank inside a building with potential sources of
ignition such as hot water tank and space heaters,
clothes dryers, electric motors, etc.

After the Engine is Stopped

WARNING! To prevent the possible freeze-up of

engine controls, follow instructions with engine
STOPPED, listed below:

1. Wipe all snow and moisture from the engine control lever
and choke areas.

2. Move the equipment control, if present, (see equipment
Operator’s Manual), engine control lever or ignition switch
back and forth several times and leave the control in the
“STOP” or “OFF” position.

3. Move the engine choke back and forth several times and
leave in the “FULL CHOKE” position.

4. Be sure the Fuel Shut-Off Valve, , if present, is off.

12 Section 5— operation

Maintenance

Maintenance Schedule

6

First 5 Hours

Check Engine Oil Level

Change Engine Oil

Check Air Cleaner (If so equipped)

Service Air Cleaner (If so equipped)

Check Spark Plug

Replace Spark Plug

Clean Engine Shroud (If so equipped)

Clean around muer

Replace Fuel Filter (If equipped)

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 maintenance to be performed are described
in the table above. Follow the hourly or calendar intervals,
whichever occur first. More frequent service is required when
operating in adverse conditions.

P P

Each Use or
Every 5 Hrs.

Every Season

or 25 Hours

Every Season

or 50 Hours

Every Season

or 100 Hours

Service Dates

P

P

P

P

P
P
P

P

NOTE: Do not use non-detergent oil or 2-stroke engine oil. It
could shorten the engine’s service life.

WARNING! Shut off the engine before performing

any maintenance. To prevent accidental start-up,
disconnect the spark plug boot.

NOTE: 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.

WARNING! If the engine has been running, the

muffler will be very hot. Be careful not to touch the
muffler.

Oil Recommendations

Refer to viscosity chart in Figure 6-1 for oil recommendations.
Do not over-fill. 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 of a minimum level SF or SG (higher letter ratings
are acceptable such as SJ, SL and SM grades). Motor oil will
display this designation on the container.

Figure 6-1

13

Checking and Changing the Oil

Spark Plug

Spark Plug

Boot

To avoid engine damage, it is important to:

• Check oil level before each use and every 5 operating hours

• Change the oil after the first 5 operating hours and every

Oil Fill Cap and Dipstick

1. Carefully disconnect the spark plug wire and keep it away

2. Be sure that the fuel fill cap is on and securely tightened.

3. Be sure to find correct oil drain plug location, if present

4. Clean area around the oil drain plug.

5. Place an approved recyclable oil container under the oil

6. Remove the Oil drain plug. See Figure 6-3.

when the engine is warm.

50 operating hours thereafter. Engine should still be warm
but NOT hot from recent use.

WARNING! Before tipping engine or equipment to

drain oil, drain fuel from tank by running engine
until fuel tank is empty.

from the spark plug. Refer to Figure 6-2 for spark plug
location.

• Keep the disconnected spark plug wire securely
away from the metal parts where arcing could
occur.

• Carefully attach the spark plug wire to the
grounding post, if provided.

Figure 6-2

(see the equipment Operator’s Manual instructions for
additional information).

drain plug.

WARNING! 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.

Oil

Drain

Figure 6-3

7. Tip engine to position the oil flow, so it will drain from the
lowest point on the engine.

8. Drain the oil into an approved recyclable oil container.
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.

9. Install the oil drain plug and tighten securely.

10. Clean area around the oil drain plug.

11. Remove the oil fill cap dipstick.

12. Fill with the recommended Oil. See Figure 6-1.
NOTE: DO NOT overfill oil filler. Doing so may result in oil

carry-over to the equipment and cause malfunction or
damage.

NOTE: DO NOT allow oil level to fall below and “L” mark on
dipstick. Doing so may result in equipment malfunction or
damage.

13. Wipe away any spilled oil.

14. Check the oil level by installing the Oil Fill Cap/Dipstick.

• For threaded Oil Fill Cap/Dipstick models, rest
the cap on the threads, do not tighten down the
cap to check the oil level.

• For quarter-turn Oil Fill Cap/Dipstick models,
tighten down the cap to check the oil level.

NOTE: See the Set-Up section earlier in this manual for
detailed instructions on identifying and checking the oil on
each of these specific engine models.

15. Remove the oil filler cap/dipstick. If the level is low, slowly
add oil until oil level registers between high (H) and low (L),
Fig. 3-2 and 3-3 in the Set-Up section.

16. Repeat Steps 14 & 15 to be sure that the correct oil level has
been achieved.

17. Once the proper oil level has been confirmed, install the Oil
Fill Cap/Dipstick. Tighten securely.

14 Section 6— Maintenance