MTD YARD-MAN 12A-979L401 User manual

OPERATOR’S MANUAL
IMPORTANT: Read safety rules and instructions carefully before operating equipment.
Warning: This unit 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 arrester meeting
applicable local or state laws (if any). If a spark arrester 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 arrester for the muffler is available through your nearest engine authorized
service dealer or contact the service department, P.O. Box 368022 Cleveland, Ohio 44136-9722.
MTD PRODUCTS INC. P.O. BOX 368022 CLEVELAND, OHIO 44136-9722
FORM NO. 770-10075A
(8/99)
PRINTED IN U.S.A.

TABLE OF CONTENTS
Content Page
Maintaining Safety.3
Slope Gauge.6
Assembling Your Lawn Mower.7
Know Your Lawn Mower.8
Operating Your Lawn Mower.9
Making Adjustments.11
Maintaining Your Lawn Mower.13
Storing Your Lawn Mower.16
Troubleshooting.17
Parts List.18
FINDING MODEL NUMBER
This Operator’s Manual is an important part of your new lawn mower. It will help you assemble, prepare and
maintain the unit for best performance. Please read and understand what it says.
Before you start assembling your new equipment, please locate the model plate on the
equipment and copy the information from it in the space provided below. The information on the
model plate is very important if you need help from our Customer Support Department or an
authorized dealer.
You can locate the model number by looking down at the rear of the deck. A sample model plate is
explained below. For future reference, please copy the model number and the serial number of the
equipment in the space below.
z'
(Model Number)
MTD PRODUCTS INC
CLEVELAND, OHIO 44136
Copy the model number here:
Copy the serial number here:
CALLING CUSTOMER SUPPORT
If you have difficulty assembling this product or have any questions regarding the controls, operation or
maintenance of this unit, please call the Customer Support Department.
Call 1- (330) 220-4MTD (4683) or 1- (800)-800-7310 to reach a Customer Support
representative. Please have your unit’s model number and serial number ready when you
call. See previous section to locate this information. You will be asked to enter the serial
number in order to process your call.
2

SECTION 1: MAINTAINING SAFETY
This Warning 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 your lawn mower. Failure to comply with these instructions may result in
personal injury. When you see this symbol, heed its warning.
DANGER: Your lawn mower 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 lawn mower is capable of amputating hands and feet and throwing objects.
Failure to observe the following safety instructions could result in serious injury or death.
WARNING: The Engine Exhaust from this product contains chemicals known to the State of
California to cause cancer, birth defects or other reproductive harm.
General Operation
• Read, understand, and follow all instructions in the
operator’s manual and on the machine before
starting. Keep this manual in a safe place for future
and regular reference and for ordering replacement
parts.
• Only allow responsible individuals familiar with the
instructions to operate the machine. Know controls
and how to stop the machine quickly.
• Do not put hands or feet under cutting deck or near
rotating parts.
• Clear the area of objects such as rocks, toys, wire,
etc., which could be picked up and thrown by the
blade. A small object may have been overlooked
and could be accidentally thrown by the mower in
any direction and cause injury to you or a
bystander. To help avoid a thrown objects injury,
keep children, bystanders and helpers at least 75
feet from the mower while it is in operation. Always
wear safety glasses or safety goggles during
operation or while performing an adjustment or
repair, to protect eyes from foreign objects. Stop the
blade(s) when crossing gravel drives, walks or
roads.
• Be sure the area is clear of other people before
mowing. Stop machine if anyone enters the area.
• Never carry passengers.
• Disengage blade(s) before shifting into reverse and
backing up. Always look down and behind before
and while backing.
• Be aware of the mower and attachment discharge
direction and do not point it at anyone. Do not
operate the mower without either the entire grass
catcher or the chute guard in place.
• Slow down before turning. Operate the machine
smoothly. Avoid erratic operation and excessive
speed.
• Never leave a running machine unattended. Always
turn off blade(s), place transmission in neutral, set
park brake, stop engine and remove key before
dismounting.
• Turn off blade(s) when not mowing.
Stop engine and wait until blade(s) comes to a
complete stop before (a) removing grass catcher or
unclogging chute, or (b) making any repairs,
adjusting or removing any grass or debris.
Mow only in daylight or good artificial light.
Do not operate the machine while under the
influence of alcohol or drugs.
Watch for traffic when operating near or crossing
roadways.
Use extra care when loading or unloading the
machine into a trailer or truck. This unit should not
be driven up or down a ramp onto a trailer or truck
under power, because the unit could tip over,
causing serious personal injury. The unit must be
pushed manually on a ramp to load or unload
properly.
Never make a cutting height adjustment while
engine is running if the operator must dismount to
do so.
Wear sturdy, rough-soled work shoes and close-
fitting slacks and shirts. Do not wear loose fitting
clothes or jewelry. They can be caught in moving
parts. Never operate a unit in bare feet, sandals, or
sneakers.
Check overhead clearance carefully before driving
under power lines, wires, bridges or low hanging
tree branches, before entering or leaving buildings,
or in any other situation where the operator may be
struck or pulled from the unit, which could result in
serious injury.
Disengage all attachment clutches, thoroughly
depress the brake pedal, and shift into neutral
before attempting to start engine.
Your mower is designed to cut normal residential
grass of a height no more than 10". Do not attempt
to mow through unusually tall, dry grass (e.g.,
pasture) or piles of dry leaves. Debris may build up
on the mower deck or contact the engine exhaust
presenting a potential fire hazard.
Slope Operation
Slopes are a major factor related to loss of control
and tip-over accidents which can result in severe
injury or death. All slopes require extra caution. If
you cannot back up a slope or feel uneasy on it, do
not mow it.
3

• 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° as shown on the slope
gauge, do not operate this unit on that area or
serious injury could result.
Do:
• Mow up and down slopes, not across.
• Remove obstacles such as rocks, limbs, etc.
• Watch for holes, ruts or bumps. Uneven terrain
could overturn the machine. Tall grass can hide
obstacles.
• Use slow speed. Choose a low enough gear so that
you will not have to stop or shift while on the slope.
Always keep machine in gear when going down
slopes to take advantage of engine braking action.
• Follow the manufacturer’s recommendations for
wheel weights or counterweights to improve
stability.
• Use extra care with grass catchers or other
attachments. These can change the stability of the
machine.
• Keep all movement on the slopes slow and gradual.
Do not make sudden changes in speed or direction.
Rapid engagement or braking could cause the front
of the machine to lift and rapidly flip over backwards
which could cause serious injury.
• Avoid starting or stopping on a slope. If tires lose
traction, disengage the blade(s) and proceed slowly
straight down the slope.
Do Not:
• Do not turn on slopes unless necessary; then, turn
slowly and gradually downhill, if possible.
• Do not mow near drop-offs, ditches or
embankments. The mower could suddenly turn over
if a wheel is over the edge of a cliff or ditch, or if an
edge caves in.
• Do not mow on wet grass. Reduced traction could
cause sliding.
• Do not try to stabilize the machine by putting your
foot on the ground.
• Do not use grass catcher on steep slopes.
Children
Tragic accidents can occur if the operator is not alert to
the presence of children. Children are often attracted to
the machine and the mowing activity. Never assume
that children will remain where you last saw them,
• Keep children out of the mowing area and in
watchful care of an adult other than the operator.
• Be alert and turn machine off if children enter the
area.
• Before and when backing, look behind and down for
small children.
• Never carry children, even with the blades off. They
may fall off and be seriously injured or interfere with
the safe machine operation.
• Never allow children under 14 years old to operate
the machine. Children 14 years and over should
only operate machine under close parental
supervision and proper instruction.
• Use extra care when approaching blind corners,
shrubs, trees or other objects that may obscure your
vision of a child or other hazard.
• Remove key when machine is unattended to
prevent unauthorized operation.
Service
• Use extreme care in handling gasoline and other
fuels. They are extremely flammable and the vapors
are explosive.
• Use only an approved container.
• Never remove fuel cap or add fuel with the engine
running. Allow engine to cool at least two minutes
before refueling.
• Replace fuel cap securely and wipe off any spilled
fuel before starting the engine as it may cause a fire
or explosion.
• Extinguish all cigarettes, cigars, pipes and other
sources of ignition.
• Never refuel the machine indoors because fuel
vapors will accumulate in the area.
• Never store the fuel container or machine inside
where there is an open flame or spark, such as a
gas hot water heater, space heater or furnace.
• Never run a machine inside a closed area.
• To reduce fire hazard, keep the machine free of
grass, leaves or other debris build-up. Clean up oil
or fuel spillage. Allow machine to cool at least 5
minutes before storing,
• Before cleaning, repairing or inspecting, make
certain the blade and all moving parts have
stopped. Disconnect the spark plug wire, and keep
the wire away from the spark plug to prevent
accidental starting,
• Check the blade and engine mounting bolts at
frequent intervals for proper tightness. Also, visually
inspect blade for damage (e.g., excessive wear,
bent, cracked). Replace with blade which meets
original equipment specifications.
• Keep all nuts, bolts and screws tight to be sure the
equipment is in safe working condition.
• Never tamper with safety devices. Check their
proper operation regularly. Use all guards as
instructed in this manual.
• After striking a foreign object, stop the engine,
remove the wire from the spark plug and thoroughly
inspect the mower for any damage. Repair the
damage before restarting and operating the mower.
• Grass catcher components are subject to wear,
damage and deterioration, which could expose
moving parts or allow objects to be thrown. For your
safety protection, frequently check components and
replace with manufacturer’s recommended parts
when necessary.
4

Mower blades are sharp and can cut. Wrap the
blade(s) or wear gloves and use extra caution when
servicing blade(s).
Check brake operation frequently. Adjust and
service as required.
Muffler, engine and belt guards become hot during
operation and can cause a burn. Allow to cool down
before touching.
Do not change the engine governor settings or
overspeed the engine. Excessive engine speeds
are dangerous.
Observe proper disposal laws and regulations.
Improper disposal of fluids and materials can harm
the environment and the ecology.
Prior to disposal, determine the proper method to
dispose of waste from your local Environmental
Protection Agency. Recycling centers are
established to properly dispose of materials in an
environmentally safe fashion.
Use proper containers when draining fluids. Do not
use food or beverage containers that may mislead
someone into drinking from them. Properly dispose
of the containers immediately following the draining
of fluids.
DO NOT pour oil or other fluids into the ground,
down a drain or into a stream, pond, lake or other
body of water. Observe Environmental Protection
Agency regulations when disposing of oil, fuel,
coolant, brake fluid, filters, batteries, tires and other
harmful waste.
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. Some of the safety labels on the equipment are
reproduced below. Take a moment to study these labels before operating the unit. Always maintain
safety while operating or sen/icing the equipment.
TO REDUCE THE RISK OF INJURY,
DO NOT OPERATE MOWER UNLESS
DISCHARGE CHUTE COVER OR GRASS
CATCHER IS IN ITS PROPER PLACE.
A DANGER
AVOID SERIOUS INJURY OR DEATH
• KEEP HANDS AND FEET AWAY FROM
ROTATING PARTS.
• REMOVE OBJECTS THAT CAN BE THROWN
BY THE BLAOE IN ANY DIRECTION.
WEAR SAFETY GLASSES.
» DO NOT MOW WHEN CHILDREN OR OTHERS
ARE AROUND.
• USE EXTRA CAUTION ON SLOPES. DO NOT MOW
SLOPES GREATER THAN 15 . MOW ACROSS NEVER
UP ANO OOWN. NEVER PULL MOWER CLOSE TO
YOUR FEET, LOOK OOWN AND BEHIND BEFORE
AND WHILE MOVING BACKWARDS.
READ OPERATOR'S MANUAL. KEEP SAFETY DEVICES (BLADE CONTROL.
TRAILING SHIELD, DISCHARGE COVER, ETC.) IN PLACE AND WORKING.
5

SECTION 2: SLOPE GAUGE
Use this page as a guide to determine slopes where you may not operate safely. Do not operate your lawn mower
on such slopes.
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6

SECTION 3: ASSEMBLING YOUR LAWN MOWER
IMPORTANT: This unit is shipped without gasoline or oil
in the engine. Be certain to service engine with gasoline
and oil as instructed in the separate engine manual
before operating your mower.
NOTE: Reference to right or left hand side of the mower
is observed from the operating position.
Removing Unit From Carton
• Remove staples, break glue on top flaps, or cut
tape at carton end and peel along top flap to open
carton.
• Remove loose parts if included with unit (i.e.,
operator’s manual, oil, etc.)
• Cut along corners, lay carton down flat, and remove
packing material.
• Roll or slide unit out of carton and check carton
thoroughly for loose parts.
Disconnecting Spark Plug Wire
• Before setting up your lawn mower, disconnect the
spark plug wire from the spark plug and ground to a
bolt on the engine. See Figure 1.
Setting Up Your Lawn Mower
• Remove grass bag from unit and set it aside.
• Lift up and pull back on the upper handle to raise
the handle into the operating position. Make
certain the lower handle is seated securely into the
handle mounting brackets. Tighten the wing nuts
on each side of the handle (carriage bolts must be
seated properly into the handle) See Figure 2.
NOTE: Your mower Is shipped with the handle in the
higher height position. If you wish to lower the height of
the handle, refer to the Adjustment Section at this time.
• Remove the hairpin clips from the outer hole in the
weld pins on the handle mounting brackets. Using a
pair of pliers, squeeze one leg of the lower handle
against the handle mounting bracket. Insert the
hairpin clip into the inner hole on the weld pin.
Repeat on other side. See Figure 3.
• Fasten the cables to the lower handle with the two
cable ties found on the lower handle. Be sure to
insert the post on the cable ties into the holes
provided on the lower handle. These holes may be
found on either the inside or outside of the handles.
Pull the cable ties tight and trim off the excess.
See Figure 4.
NOTE: Make certain the drive cable is routed around
the outside and above the lower handle so it does not
interfere with attaching the grass bag.
7

Figure 5
• The rope guide, which is connected to the support
rod, is located on the right side of lower handle.
See Figure 5.
• With the spark plug wire disconnected and
grounded, hold the blade control handle against the
upper handle, and pull the starter rope out of the
engine. Release the blade control handle. Slip the
starter rope into the rope guide.
SECTION 4: KNOW YOUR LAWN MOWER
Read this operator’s manual and safety rules before operating your lawn mower. Compare the illustrations in Figure
6 with your lawn mower to familiarize yourself with the location of various controls and adjustments. Save this
manual for future reference.
WARNING: The operation of any lawn mower can result in foreign objects being thrown into the
operator’s eyes and causing severe eye damage. Always wear safety glasses while operating the
mower, or while performing any adjustments or repairs on it.
Figure 6
Recoil Starter
The recoil starter is attached to the right lower handle.
Stand behind the unit and pull the recoil starter to start
the unit. See Figure 6.
Blade Control Handle
The blade control handle is located on the upper handle
of the mower. The blade control handle must be
depressed in order to operate the unit. Release blade
control handle to stop engine and blade. See Figure 6.
WARNING: This blade control mechanism
is a safety device. Never attempt to bypass
its operations.
Cutting Height Adjustment Lever
The cutting height adjustment lever is located above
the left rear wheel. To adjust the cutting height, refer to
the Adjustment Section in this manual. See Figure 6.
Drive Clutch Control
The drive clutch control is located on the upper handle.
Squeeze the drive control to engage the drive system.
Release the clutch control to disengage the drive
system. Release the clutch control to slow down when
approaching an obstacle, making a turn, or stopping.
See Figure 6.
Shift Lever
The shift lever is located on the drive clutch control
housing on the upper handle. This lever is used to
select the forward speed of the mower. When changing
speed selection, release the drive clutch control. See
Figure 6.
NOTE: Move the shift lever only when the engine is
running. Changing the shift lever setting with the engine
off can cause damage to the mower.
8

Engine Controls
See the separate engine manual for the location and
function of the controls on the engine.
Stopping Engine
• Release blade control handle to stop the engine
and the blade.
• Disconnect spark plug wire and ground it to the
post on the engine.
WARNING: Before using your lawn mower,
again refer to the Safety Section in this
manual. Always be careful.
SECTION 5: OPERATING YOUR LAWN MOWER
Towards Better Mower Performance
1. Read this manual in its entirety before you start
the lawn mower. Instructions given here have
been designed for maintaining safety while
getting the best performance from your mower.
Follow the instructions closely.
2. Pour fresh, clean gasoline into the mower’s gas
tank until the tank Is full. Do not use gasoline
that is more than 30 days old.
3. Always use a fuel stabilizer. It will double the life
of the gasoline used.
4. Make sure to connect the mower’s spark plug
wire before trying to start the engine.
5. Add engine oil to the oil fill on the mower engine.
Check the dipstick and add more if necessary.
Remember that the oil level has to touch the fill
line.
6. Locate the primer decal near the primer bulb on
the engine, and read its instruction. Using your
thumb, press the primer bulb slowly as many
times as the decal advises.
7. Hold control handle down and pull rope firmly to
start the engine.
8. Set cutting height adjustment lever to middle
setting and mow a single pass on your lawn;
then adjust to desired height for a closer cut.
9. When bagging the grass clippings, remove
mulch plug/cover and store.
10. When mulching, remove the grass bag and
store. Insert the mulch plug/cover on the mower.
11. In heavy growing season, it may be necessary
to mow lawn twice weekly. Clumps of grass
clippings left behind on the lawn usually means
that the grass is too high to mulch.
12. Before storing the lawn mower for the winter,
use stabilizer-treated fuel and run the tank dry.
13. Thirty days before sfart of the new season,
check the air filter, spark plug and blade on the
lawn mower, and replace if needed.
For more details about proper lawn care, visit our website at www.Yardman.com
WARNING: Keep hands and feet away
from chute area on the cutting deck. The
operation of any lawn mower can result in
foreign objects being thrown into the
eyes, which can result in severe eye
damage. Always wear safety glasses or
eye shields.
NOTE: For shipping purposes your mower is set with
the wheels in a low cutting height position. For best
results raise the cutting position until it is determine
which height is best for your lawn. See the adjustment
section for details.
Gas and Oil Fill-Up
Service the engine with gasoline and oil as instructed in
the separate engine manual packed with your mower.
Read instructions carefully.
WARNING: Never fill fuel tank indoors with
engine running or untii the engine has
been allowed to cool for at least two
minutes after running.
Before Starting Your Mower
• Attach spark plug wire to spark plug. Make certain
the metal cap on the end of the spark plug wire is
fastened securely over the metal tip on the spark
plug.
• Check for proper drive clutch operation using the
NEUTRAL ADJUSTMENT TEST.
Neutral Adjustment Test
To perform the neutral adjustment test answer the
following questions.
• With the drive clutch control released, push mower
forward and pull It backward. Does it move freely?
9

• Squeeze the drive clutch control and pull the
mower backward. Do the rear wheels lock?
• Is the drive clutch control cable free of kinks or
sharp bends?
• If you answered “yes” to all three questions, your
mower passed the test and you can start your
mower.
• If you answered “no” to any of the three questions,
you will have to adjust the drive clutch control in the
ADJUSTMENT SECTION.
Starting Engine
• Prime engine as instructed in the separate engine
manual packed with your unit.
• Your lawn mower may be equipped with a constant
speed throttle, which is set at full throttle for best
performance.
• Stand behind the mower and squeeze the blade
control handle against the upper handle.
• Grasp recoil starter handle and pull rope out slowly
until engine reaches the start of compression cycle
(rope will pull slightly harder at this point). Let the
rope rewind slowly. Pull rope with a rapid,
continuous, full arm stroke. Keeping a firm grip on
the starter handle, let the rope return to the starter
slowly.
Using Your Lawn Mower
Be sure that the lawn is clear of stones, sticks, wire, or
other objects which could damage the lawn mower or
the engine. Such objects could be accidently thrown by
the mower in any direction and cause serious personal
injury to the operator and others.
For best results, do not cut wet grass because it tends
to stick to the underside of the mower, preventing
proper discharge of grass clippings, and could cause
you to slip and fall. New grass, thick grass, or wet grass
may require a narrower cut.
For a healthier lawn, never cut off more than one-third
of the total length of the grass. Your lawn should be cut
in the fall as long as there is growth. This mower is
designed to be operated at full throttle to give you the
best cut and do the most effective job of mowing or
mulching.
WARNING: If you strike a foreign object,
stop the engine. Remove wire from the
spark plug, thoroughly inspect the mower
for any damage, and repair the damage
before restarting and operating the
mower. Extensive vibration of the mower
during operation is an indication of
damage. The unit should be promptly
inspected and repaired.
Mulching
For effective mulching, do not cut wet grass because it
tends to stick to the underside of the deck, preventing
proper mulching of grass clippings. New or thick grass
may require a narrower cut. The ground speed should
be adjusted to the condition of the lawn. If mowing has
been delayed and the grass has been allowed to grow
in excess of 4”, mulching is not recommended. Mow
using the grass bag to reduce the grass height to 3 1/4”
maximum before mulching.
Attaching The Grass Bag
• Remove wing nuts holding the mulching baffle or
side discharge chute in place and remove from unit.
• Replace with grass bag adapter, while making
sure the inner lip of attachment goes under the
edge of the deck. Secure with wing nuts previously
removed. See Figure 7.
• Lift chute door on the grass bag adapter and slide
grass bag onto the adapter. See Figure 8.
NOTE: The chute door has been designed to move the
starter rope out of the way of the bag when the chute
door is opened.
10

Emptying the Grass Bag
• While holding the grass bag by both the rear handle
and the lower handle, lift the grass bag straight up
off the adapter. The chute door will move the rope
out of the way of the bag.
• Continue to hold the lower handle and raise the
rear of the grass bag up toward your chest. The
grass bag will open and the grass clippings will
disperse. See Figure 9.
• When replacing the grass bag, be sure the top of
the bag rests on the wire support between the
handles.
Attaching Side Discharge Chute
• Remove mulching baffle or grass bag adapter from
unit by disconnecting wing nuts.
• Attach side discharge chute to unit and secure with
wing nuts. See Figure 10.
SECTION 6: MAKING ADJUSTMENTS
WARNING: Do not at any time make any
adjustments without first stopping engine
and disconnecting spark plug wire.
Cutting Height Adjustment
Your mower is shipped with the cutting height in the
lowest position. The cutting height adjustment lever is
located above the left rear wheel. To adjust the cutting
height, pull the lever out and away from the mower and
then move it forward or backward to select a new
cutting height. See Figure 11.
NOTE: For rough or uneven lawns, move the height
adjustment lever to a higher position. This will help stop
scalping
Handle Height Adjustment
Your mower is shipped with the handle in the higher
height position. To lower the height proceed as follows:
• Remove the starter rope from the rope guide.
• Remove the upper handle by removing the hand
knobs and carriage bolts. Lay the upper handle out
of the way, being careful not to bend or kink the
cables.
• Remove the hairpin clips from the weld pins on the
handle brackets. Press out on the legs of the lower
handle. Remove lower handle from the mower.
11

• Turn lower handle around so the notch on the
bottom of the lower handle is facing forward.
Reassemble, placing the bottom holes in the
handle over the weld pins in the handle mounting
bracket.See Figure 12.
• Reassemble the upper handle to the lower handle.
• Place the hairpin clips in the inner holes in the weld
pins and attach the starter rope as instructed in the
Assembly Section.
Drive Clutch Control Adjustment
The drive clutch control adjustment wheel is located in
the drive clutch control handle housing and is used to
tighten or loosen the drive belt. You will have to adjust
the drive clutch control if any of the following happens:
• The mower does not propel itself with the drive
clutch engaged.
• The mower’s drive wheels hesitate with the drive
clutch engaged.
To resolve the above problems, rotate the adjustment
wheel with your fingers. Clockwise to tighten the cable
and counter-clockwise to loosen the cable. See Figure
13 .
NOTE: For some people the drive clutch control may
not be in a comfortable position. You can adjust the
handle out by tightening the adjustment wheel.
Shift Lever Cable Adjustment
Periodic adjustment of the six speed shift cable may be
required due to normal wear on the cable. Adjustment
is needed if all six speeds do not work.
The adjustable cable bracket is located on the left side
of the mower beside the engine.
• Start engine and place speed control lever in the
sixth speed position. See Figure 14.
• Stop engine and disconnect spark plug wire and
ground it against engine.
* Loosen hex nut which secures the adjustable cable
bracket. See Figure 15.
• Push back on the adjustable cable bracket and
tighten hex nut.
Figure 13
12

SECTION 7: MAINTAINING YOUR LAWN MOWER
General Recommendations
• Always observe safety rules when performing any
maintenance.
• The warranty on this lawn mower does not cover
items that have been subjected to operator abuse
or negligence. To receive full value from the
warranty, operator must maintain the lawn mower
as instructed in this manual.
• Changing of engine governed speed will void
engine warranty.
• Some adjustments will have to be made
periodically to maintain your unit properly. All
adjustments in the Making Adjustments section of
this manual should be checked at least once each
season.
• Periodically check all fasteners and make sure
these are tight.
• Follow the maintenance schedule under Customer
Responsibilities to get quality performance from
your lawn mower.
Customer Responsibilities
MAINTENANCE c? ^ # SERVICE
SCHEDULE / /• A c? / DATES
_r ccT <c/ o ^_
PRODUCT
Lubricate wheels
—
Lubricate blade control
Clean deck
S
Blade care
Bi
ENGINE
Change oil
H
Replace air filter
■
Clean engine
B
Check spark plug
. J/
B
Check spark arrester (if any)
■ J/
■
1
■
■ ■ ■ ■
Lubrication
WARNING: Always stop engine and
disconnect spark plug wire before
cleaning, lubricating or doing any kind of
service work on the lawn mower.
Blade Control: Lubricate the pivot points on the blade
control handle at least once a season with light oil. The
blade control must operate freely in both directions.
See Figure 16.
Wheels: Lubricate the wheels at least once a season
with light oil (or motor oil). If the wheels are removed for
any reason, lubricate the surface of the axle bolt and
inner surface of the wheel with light oil. See Figure 16.
Engine: Follow the separate engine manual packed
with you unit for lubrication instructions.
13

Maintenance
Blade
Adapter
Blade Bell
Support
Hex Bolt
Figure 17
NOTE: When tipping the unit, empty the fuel tank and
keep the spark plug side of engine up. Never tip the
mower more than 90 degrees and do not leave the
mower tipped for any length of time. Oil can drain into
the upper part of the engine causing a starting problem.
Engine
Refer to the separate engine manual for all engine
maintenance instructions.
• Maintain engine oil as instructed in the separate
engine manual packed with your unit.
• Service air cleaner every 25 hours under normal
conditions. Poor engine performance and flooding
usually indicate that the air cleaner should be
serviced. To service the air cleaner, refer to the
separate engine manual packed with your unit.
• The spark plug should be cleaned and the gap
reset once a season. Spark plug replacement is
recommended at the start of each mowing season.
• Clean the engine regularly with a cloth or brush.
Keep the cooling system (blower housing area)
clean to permit proper air circulation which is
essential to engine performance and life. Be certain
to remove all grass, dirt, and combustible debris
from muffler area.
Deck
The underside of the mower deck should be cleaned
after each use to prevent a buildup of grass clippings,
leaves, dirt, or other matter. If this debris is allowed to
accumulate, it will invite rust and corrosion, and may
prevent proper mulching, discharge, or bagging. The
deck may be cleaned by tilting the mower and scraping
clean with a suitable tool (make certain the spark plug
wire is disconnected).
IMPORTANTiWe do not recommend the use of a
pressure washer or garden hose to clean your unit. The
use of water will result in shorten life and reduce
serviceability.
Cutting Blade Removal, Replacement, and Sharpening
• When removing the cutting blade for sharpening or
replacement, protect your hands with a pair of
heavy gloves or use a heavy rag to hold the blade.
• Remove the bolt and the blade bell support which
hold the blade and the blade adapter to the engine
crankshaft. See Figure 17.
• Remove the blade and the adapter from the
crankshaft.
WARNING: Periodically inspect the blade
adapter for cracks, especially if you strike
a foreign object. Replace when necessary.
WARNING: Periodically inspect the biade
adapter for cracks, especially if you strike
a foreign object. Replace when necessary.
When sharpening the blade, follow the original angle of
grind as a guide. It is extremely important that each
cutting edge receives an equal amount of grinding to
prevent an unbalanced blade. An unbalanced blade will
cause excessive vibration when rotating at high
speeds. It may cause damage to the mower, and could
break causing personal injury.
The blade can be tested by balancing it on a round
shaft screwdriver. Remove metal from the heavy side
until it balances evenly. It is recommended that the
blade always be removed from the adapter when
testing for balance. Before reinstalling the blade and
the blade adapter to the unit, lubricate the engine
crankshaft and the inner surface of the blade adapter
with light oil.
• Be sure to install the blade with the side of the
blade marked “Bottom” (or with part number) facing
the ground when the mower is in the operating
position.
• Slide the blade adapter onto the engine crankshaft.
• Place the blade on the adapter. Be certain the
blade is aligned and seated on the blade adapter
flanges.
• Place blade bell support on blade. Make sure the
notches on the blade bell support are aligned with
small holes in the blade.
• Replace hex bolt and tighten hex bolt to torque: 450
in. lbs. min., 600 in. lbs. max.
NOTE: To ensure safe operation of your mower, the
blade bolt must be checked periodically for correct
torque.
Drive Belt Removal and Replacement
• Disconnect the spark plug wire and ground it
against the engine.
• Drain the fuel tank or place a piece of plastic
beneath the cap to prevent gasoline leakage.
• Place shift lever in the first position and tip the
mower on its side.
14

• Remove the center bolt which secures the blade to
the crankshaft followed by blade bell support,
blade, and blade adapter.
• Move the cutting height adjustment to the highest
position.
• Remove the three hex screws holding the baffle to
the deck and pivot baffle towards the rear of the
mower. See Figure 18.
Figure 18
• Remove the hex bolt from the rear of unit holding
the transmission to the mower housing.
See Figure 19.
Figure 19
• Tilt the transmission forward and loosen the idler
pulley bolt and lock nut half a turn. See Figure 20.
• Using a pair of pliers, pull back and rotate belt
keeper bracket from the slot on the idler pulley.
• Slide the belt out from between the belt keeper
bracket and the idler pulley.
• Squeeze the belt together and push it forward,
while pressing the control arm inward towards the
deck and remove the six speed cable from the slot.
See Figure 20.
• Pivot the control arm down away from the pulley
and belt.
• Lift off the lower pulley assembly and remove the
old belt from around the crankshaft. See Figure 20.
Baffle
Figure 20
15

• Place the new belt over the transmission pulley.
Start the belt in the pulley groove and rotate the
pulley until the belt is seated in the transmission
pulley. Refer to Figure 20.
• Place the belt between the idler pulley and the belt
keeper bracket.
• Using pliers, rotate the belt keeper bracket so that it
snaps into slot on the idler bracket.
• Tighten the idler pulley bolt and lock nut half a turn.
• Place the belt between the two pulley halves on the
crankshaft. Make sure to route the belt inside the
belt guard pin. See Figure 21.
IMPORTANT: When replacing the belt, do not disas¬
semble the lower pulley assembly.
• Pinch both sides of the belt together so that the belt
is not in the pulley groove, and the lower pulley can
be pushed towards the engine. See Figure 22.
• Pivot the control arm back to its original position
and reinstall the six-speed cable into the slot. See
Figure 23.
• Check and make sure the belt is routed inside the
pulley halves and the belt guard pin.
• Reinstall the bolt securing transmission to rear
mower housing.
• Pivot the baffle back to its original position and
secure with three hex screws earlier removed.
• Lightly lubricate the inside of the blade adapter and
reinstall the spacer, wave washer, blade adapter
assembly, and blade in the correct order.
• Tighten the hex bolt to secure the blade to torque:
450-600 in. lbs.
SECTION 8: STORING YOUR LAWN MOWER
The following steps should be taken to prepare your
lawn mower for storage.
• Clean and lubricate mower thoroughly as described
in the lubrication instructions.
IMPORTANTiWe do not recommend the use of a
pressure washer or garden hose to clean your unit. The
use of water will result in shorten life and reduce
serviceability.
• Refer to engine manual for correct engine storage
instructions.
• Coat mower’s cutting blade with chassis grease to
prevent rusting.
• Store mower in a dry, clean area. Do not store next
to corrosive materials, such as fertilizer.
NOTE: When storing any type of power equipment in a
poorly ventilated or metal storage shed, care should be
taken to rust-proof the equipment. Using a light oil or
silicone, coat the equipment, especially cables and all
moving parts.
16

SECTION 9: TROUBLESHOOTING
Problem
Cause
Remedy
Engine fails to start
1. Blade control handle disengaged.
2. Spark plug wire disconnected.
3. Fuel tank empty or stale fuel.
4. Blocked fuel line.
5. Faulty spark plug.
6. Engine flooded
1. Engage blade control handle.
2. Connect wire'to spark plug.
3. Fill tank with clean, fresh gasoline.
4. Clean fuel line.
5. Clean, adjust gap, or replace.
6. Crank engine with throttle in FAST
position.
Engine runs erratic
1. Spark plug wire loose.
2. Blocked fuel line or stale fuel.
3. Vent in gas plugged.
4. Water or dirt in fuel system.
5. Dirty air cleaner.
6. Carburetor out of adjustment.
1. Connect and tighten spark plug wire.
2. Clean fuel line; fill tank with clean, fresh
gasoline
3. Clear vent.
4. Drain fuel tank. Refill with fresh fuel.
5. Clean air cleaner.
6. Adjust carburetor.
Engine overheats
1. Engine oil level low.
2. Airflow restricted.
3. Carburetor not adjusted properly.
1. Fill crankcase with proper oil.
2. Remove blower housing and clean.
3. Adjust carburetor.
Occasional skip (hesitates)
at high speed
1. Spark plug gap too close.
1. Adjust gap to .030”.
Idles poorly
1. Spark plug fouled, faulty or gap too
wide.
2. Carburetor improperly adjusted.
3. Dirty air cleaner.
1. Reset gap to .030” or replace spark
plug.
2. Adjust carburetor.
3. Clean air cleaner.
Excessive vibration
1. Cutting blade loose or unbalanced.
2. Bent cutting blade.
1. Tighten blade and adapter. Balance
blade.
2. Replace blade.
Mower will not mulch grass
1. Engine speed too low.
2. Wet grass.
3. Excessively high grass.
4. Dull blade.
1. Set throttle between 3/4 and full throttle.
2. Do not mow when grass is wet; wait
until later to cut.
3. Mow once at a high cutting height, then
mow again at desired height or make a
narrower cutting path.
4. Sharpen or replace blade.
Uneven cut
1. Wheels not positioned correctly.
2. Dull blade.
1. Place all four wheels in same height
position.
2. Sharpen or replace blade.
NOTE: For repairs beyond the minor adjustments listed above, contact your nearest authorized service dealer.
17

Model 979
Ref.
No.
Part No. Part Description
Ref.
No.
Part No.
Part Description
1. 710-0134 Carriage Screw 1/4-20 x .62
41. 732-0842
Trail Shield Wire
2. 710-0654A Scr. TT: 3/8-18:1.00
42. 611-0064
Fr. Axle Ass’y.
3.
710-0703 Scr. 1/4-20 X .750 43.
710-1241
Hx Scr. Wash Hd. Hi.-Lo.
4. 712-0397 Wing Nut 1/4-20
44. 710-1242
Scr. Torx, Truss Hi.-Lo.
5. 723-0233
Nut, Push .25 I.D.x .50O.D. 45.
714-0104
Cotter Pin .072 x 1.12 Lg.
6.
736-0204
Wash. FI. .334 I.D.x .62x 03
46. 731-1829
Fr. Axle Cover, Yellow
7. 782-0078A Deck-21”
47.
736-0286 Bowed Washer
8. 710-0653
Scr. TT. 1/4-20 x .375 48.
741-0492A
Bush. Block .505 Dia. x .62
9. 710-0969 Scr. HL. 1/2-14 X .750
49. 782-0565
Control Arm
10. 731-1828 Baffle
50. 734-1978
Wheel 8x2 Link, Yellow
11. 638-0012
Rear Axle Ass y
51. 734-1981
Wheel 9x2 Link Yellow, SIv.
12. 682-0531 Pivot Arm Ass'y
52.
736-0105 Spr. Wash. .401 x .870 x .063
13.
682-7526 Trans. Axle Ass’y
53. 736-0504
Wave Wash .510 x .750 x .017
14. 682-7528 Chain Cover Ass’y
54.
738-0102
Shidr Scr .498 x 1.445 x3/8-16
15.
710-0653
Scr. TT 1/4-20 x .375
55. 10622B
Spring, Ratchet, Plastic
16. 710-0751
Cap Screw HH 1/4-20 x.620 56. 748-0381 Pawl - R.H.
17.
710-0896 Scr. AB 1/4-14 X .625
57.
748-0188B
Pawl - L.H. (Not Illustrated)
18.
710-1315 Scr. 3/8 116 X .25 58. 16855 Ratchet Pawl Plate
19. 711-0835 Clevis Pin .50 Dia. x 4.82 Lg. 59.
738-0137A
Scr. Shid. .340 x .285
20. 713-0453 Chain-Endls. #48 .500P x 24L
60. 712-0414
Top Lock Tab Weld Nut 1/4-20
21. 714-0474 Cotter Pin .1250.D. X .75
61.
731-1426 Hubcap -Yellow
22. 720-0223 Grip
62.
710-1237
Screw .620 Hx. Sit. Wsh.
23.
732-0803A Spring Lever 63. 751B213146 Casing Clamp, Throttle
24. 732-0832 Torsion Spring
64. 725-0157
Cable Tie
25. 736-0270 Bell Wash. .285 x .75 x .082 65.
710-0604
Hex Scr. 5/16-18
26. 736-0369 FI. Wash..508 I.D. 1.000 x.020 66. 754-0460 V-Belt
27.
738-0529 Nut Shid. .825 Dia. x .165 Lg.
67. 742-0741
21” Mulching Blade
28.
741-0324 Hx.FIg. Brg..506 I D. x .590 L. 68. 753-0609
Blade Adapter Kit
29. 741-0522 Hx.FIg. Brg. .506 I.D. x.715 L. 69. 736-0524A
Blade Bell Suport
30. 741-0978 Hx. SIv. Brg..504 I D. x .830 L. 70.
710-1257
Hex Bolt 3/8-24x2.5”Lg.
31. 748-0318 Wheel Rachet
72.
735-0639
Spark Plug Insulator
32.
750-0151 Spa. .550 I.D. x/750 O.D. 73.
731-1832
Side Discharge Chute
33. 750-0515 Spa. .51 D. X.70O.D.X38L.
74.
731-1833 Mulch Cover
34. 750-0807 Spa. .385 X .624 x .700 75.
631-0066 Rear Chute Ass’y w/ Door
35. 750-1056 ShId. Spa. .385 I.D. X .715 Lg.
76. 731-1713A
Discharge Chute
36. 782-0568 Brkt. - Ht. Adj. Spring
77.
747-0965
Pivot Rod
37.
682-3052 Handle Brkt. Ass’y. R.H. 78. 732-0819
Torsion Spring
38. 682-3053
Handle Brkt. Ass'y. L.H.
79. 726-0111
Push Cap
39. 710-1348 Scr. AB 1/4-14 X .500
80. 731-1874
Chute Door
40. 731-1901 Trail Shield
19