BigDog Alpha MP Operator's Manual

BigDog® Mowers Alpha MP

Operator's Manual

605046 REV A

200 South Ridge Road
Hesston, Kansas
67062

TABLE OF CONTENTS

General Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

To The New Owner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Using This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Warranty Registration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Model And Serial Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Parts And Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Safety Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Safety And Instructions Decals . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Safe Operating Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Safe Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Using A Ramp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Slope Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Children . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Safety Start Interlock System . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Engine Starting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Stopping The Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Moving Mower With Stalled Engine . . . . . . . . . . . . . . . . . . . . . . 3-6

Mower Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Deck Cutting Height Adjustment . . . . . . . . . . . . . . . . . . . . . . . 3-10

Anti-Scalp Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10

Maintenance & Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Safe Servicing Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Service Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Service Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Torque Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Electrical System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Hydraulic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

605046 toc-1 REV A

Fuel and Evaporative Emissions Control System . . . . . . . . . . . .4-4

Engine Oil And Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5

Engine Air Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

General Engine Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5

Fuel Evaporation System Filter . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Belts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Mower Blade Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-6

Mower Blade Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Seat Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Steering Control Lever Adjustment . . . . . . . . . . . . . . . . . . . . . . .4-7

Maintenance Locator Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1

Product Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

REV A toc-2 605046

GENERAL INFORMATION

This manual applies to the following BigDog® Mowers

equipment lines:

BigDog

®

Mowers Alpha MP

To The New Owner

The purpose of this manual is to assist owners and operators
in maintaining and operating your BigDog
it carefully; information and instructions furnished can help you
achieve years of dependable performance.

A separate Engine Owner’s Manual is included with your
owner’s packet which contains additional engine information
that will not be repeated in this manual. It is the owner’s
responsibility to make certain that the operators and mechanics
read and understand the engine owner’s manual before
attempting to operate or repair the engine.

The decals are designed to give the operator brief information
needed in the daily operation and service of the machine. These
decals are not intended to be used in place of this manual but
instead are to be used as an extension of this manual. These
decals should not be removed or obliterated. Replace these
decals if they become unreadable.

It is the owner’s responsibility to make certain that the
operators and mechanics read and understand this manual and
all decals before operating this machine. It is also the owner’s
responsibility to make certain that the operators and mechanics
are qualified and physically able individuals, properly trained in
the operation of this equipment. All operators and mechanics
must become familiar with the safe operation of the equipment,
operator controls and decals.

IMPORTANT: The owner/user can prevent and is responsi-

ble for accidents or injuries occurring to themselves, other peo­ple or property.

Never let children or untrained people operate or service the
equipment. Local regulations may restrict the age of the
operator.

For more detailed maintenance and adjustment information
refer to the proper General Service Manual for your machine.
Refer to the “Product Literature” section of this manual for
information on how to attain these manuals.

®

Mower. Please read

Using This Manual

General operation, adjustment and maintenance guidance is
outlined for both the experienced and novice BigDog
user. Operating conditions vary considerably and cannot all be
addressed individually. Through experience, however, operators
should find no difficulty in developing good operating skills
suitable to most conditions.

®

Mowers

Directions used in this manual, for example RIGHT or LEFT,
refer to directions when in operator position and facing forward,
unless otherwise stated.

Photographs and illustrations used were current at the time of
printing, but subsequent production changes may cause your
machine to vary slightly in detail. BigDog

®

Mowers reserves the
right to redesign and change the machine as deemed necessary,
without notification. If a change has been made to your machine
which is not reflected in this operator’s manual, or the parts
manual, see your BigDog

®

Mowers Dealer for current

information and parts.

Warranty Registration

Your BigDog® Mowers Dealer must register the unit on-line
within ten (10) days following date of purchase to validate your
warranty protection. As the new equipment owner, you should
confirm that your BigDog
mower with BigDog

®

Mowers Dealer has registered your

®

Mowers.

Be sure to register the mower plus each attachment that
displays a model and serial identification number plate with
BigDog

®

Mowers.

IMPORTANT: Any unauthorized modification, alteration,

or use of non-approved attachments voids the warranty and
releases BigDog

®

Mowers from any liability arising from subse­quent use of this equipment. Do not use or operate any attach­ment not approved by BigDog

®

Mowers.

Model And Serial Number

Mower model and serial numbers are found on the serial

identification plate, located on the left mower frame side rail.

These numbers are required when the unit is registered with
BigDog Mowers. They will also assure you of the correct
service parts when replacement becomes necessary.

Parts And Service

Use original BigDog® Mower replacement parts only. These
parts are available through your local BigDog
To obtain prompt, efficient service, always provide the
following information when ordering parts:

1. Correct part description.

2. Correct part number.

3. Correct model number.

4. Correct serial number.

All warranty repair and service must be handled through an
authorized BigDog

®

Mower Dealer. Arrangements should be

made through your local service center.

®

Mower Dealer.

605046 1-1 REV A

The Engine Owner’s Manual provides information regarding the U.S. Environmental Protection Agency (EPA)
and the California Emission Control Regulation of emission systems, maintenance and warranty.

Keep Engine Owner’s Manual with your unit. Should the Engine Owner’s Manual become damaged or
illegible, replace immediately. Replacements may be ordered per the information found in the Product
Information section of the owner’s manual.

Federal law and California State law prohibit the following acts or the causing thereof:

1. The removal or rendering inoperative by any person other than for purposes of maintenance,
repair, replacement, of any device or element of design incorporated into any equipment for the
purposes of emissions control prior to or after its sales or delivery to the ultimate purchaser or
while it is in use, or

2. The use of the equipment after such device or element of design has been removed or rendered
inoperative by any person.

WARNINGWARNING

The engine exhaust from this product

contains chemicals known to the state

of California to cause cancer, birth

defects or other reproductive harm.

NOTICE OF REQUIREMENT OF SPARK ARRESTER MUFFLER

This equipment may create sparks that can start fires around dry vegetation. California Public Resources Code
Section 4442.6 provides that it is unlawful to use or operate an internal combustion engine on any forest-covered,
brush-covered, or grass-covered land unless the engine is equipped with a spark arrester maintained in effective
working order. A spark arrester is a device constructed of nonflammable materials specifically for the purpose of
removing and retaining carbon and other flammable particles over 0.0232 of an inch in size from the exhaust flow of
an internal combustion engine that uses hydrocarbon fuels or which is qualified and rated by the United States
Forest Service. Other states or federal areas may have similar laws. The Operator Should Contact Local Fire
Agencies For Laws or Regulations Relating to Fire Prevention Requirements. THIS EQUIPMENT DOES NOT HAVE
A SPARK ARRESTER AND YOU SHOULD CONTACT YOUR AUTHORIZED DEALER FOR THE PURCHASE OF
A SPARK ARRESTER.

Inspect spark arrester daily; replace every 500 hours or as needed.

REV A 1-2 605046

SAFETY PRECAUTIONS

DANGER

WARNING

WARNING

M

A

X

O

F

1

0

%

E

T

H

A

N

O

L

I

N

F

U

E

L

I

G

H

E

R

T

H

A

N

E

1

0

F

U

E

L

V

O

I

D

S

W

A

R

R

A

N

T

Y

H

This safety alert symbol is used to call attention to a message

intended to provide a reasonable degree of PERSONAL
SAFETY for operators and other persons during the normal
operation and servicing of this equipment.

– denotes immediate hazards which WILL result in
severe personal injury or death.

• It is also the owner’s responsibility to make certain that
the operators and mechanics are qualified and physically
able individuals, properly trained in the operation of this
equipment.

• All operators and mechanics must become familiar with
the safe operation of the equipment, operator controls
and decals.

• Never let children or untrained people operate or service
the equipment. Local regulations may restrict the age of
the operator.

• The owner/user can prevent and is responsible for acci­dents or injuries occurring to themselves, other people or
property.

• The owner should also ensure that the operators/mechan­ics know that they are responsible for their own safety as
well as the safety of other persons within the vicinity.
Remember, the operator is responsible for accidents or
hazards occurring to other people or their property.

– denotes a hazard or unsafe practice which COULD
result in severe personal injury or death.

This manual uses two other words to highlight information.

IMPORTANT calls attention to special mechanical information
and NOTE emphasizes general information worthy of special
attention.

All operators and mechanics should read this manual, and be
instructed about safe operating and maintenance procedures. If
the operators or mechanics cannot read and understand English,
it is the owner’s responsibility to explain this material to them.

Improper use or maintenance by the operator or owner can
result in injury. To reduce the potential for injury, comply with
these safety instructions and always pay attention to the safety
alert symbol “”, which means DANGER or WARNING ­“personal safety instructions.” Failure to comply with the
instructions may result in personal injury or death.

Incorrect usage of this mower may result in severe injury.
Personnel operating and maintaining it should be trained in
the proper use and should read the manuals completely and
thoroughly before attempting to set-up, operate, adjust, or
service this mower.

Safety And Instructions Decals

The decals are designed to give the operator brief information
needed in the daily operation and service of the mower. These
decals are not intended to be used in place of this manual but
instead are to be used as an extension of this manual. These
decals should not be removed or obliterated. Replace these
decals if they become unreadable.

• It is the owner’s responsibility to make certain that the
operators and mechanics read and understand this manual
and all decals before operating this mower.

605046 2-1 REV A

Specific safety warning decals are located on the equip­ment near the immediate areas of potential hazards. These
decals should not be removed or obliterated. Replace
them if they become non-readable.

The following illustrations show the various safety decals that
are located on the mower. A brief explanation, for those
requiring one, is shown to help the operator understand the
meanings of these decals.

•

Read Operator’s Manual and Safety Warning Decals before
attempting to operate this machine.

• Do not smoke while refueling.

• Do not remove the fuel tank cap or fill tank with engine running

or while the engine is hot.

• Allow engine to cool before storing machine inside a building.

• Store away from open flame or spark if there is fuel in tank.

• Clean up any gasoline spills.

• Do not refuel while in enclosed trailer or other enclosed areas.

• Maximum of 10% ethanol (E10) in fuel. Fuels with greater than

10% ethanol, (such as E15, E20 and E85) voids warranty. Fuels

with greater than 10% ethanol are not approved for use and

such illegal use could cause equipment failure and pose a fire

hazard.

602041

If you lose steering control while operating the machine, place the steering
control levers in the park brake position immediately. Inspect the machine and

involve your dealer to resolve the problem before continuing to operate.

If pump belt fails, steering control will be lost. Refer to owner’s manual for
inspection and replacement intervals and refer to above paragraph for
emergency procedures.

600899

601967

785220

785139

604222

604221

Part Number 602041
WARNING:
Hot surface!

• Keep a safe distance from the machine.

WARNING: Fire!

• Clean flammable material from

machine. Prevent fires by keeping
engine compartment, top of deck,
exhaust area, battery, fuel line, fuel
tank and operator’s station clean of

Part Number 600899

Part Number 601967

accumulated trash, grass clip­pings, and other debris. Always
clean up spilled fuel and oil.

• If you loose steering control while operating the machine,

place the steering control levers in the park brake position
immediately. Inspect the machine and involve your dealer to

Fast - Forward

Fast - Forward

resolve the problem before continuing to operate.

• If pump belt fails, steering control will be lost. Refer to owner’s

manual for inspection and replacement intervals and refer to
above paragraph for emergency procedures.

Slow Slow

Park Brake Position

WARNING:Thrown objects!

• Always maintain a safe distance from

people and pets when mowing.

• Always stop machine if someone enters

the area.

• Inspect area to be mowed for hazards

such as rocks, metal objects and other
debris which may be thrown or entan­gled by mower blades. Remove these
objects before mowing.

WARNING:Thrown objects!

• Never operate the mower deck with side

deflector damaged, altered, removed or
in raised position, except when the
entire grass catcher attachment or
mulching system is being used.

Part Number 604222

DANGER:
Rotating blades, pulleys & belts

Fast - Reverse

Part Number

785220

DANGER:
Rotating blades, pulleys & belts

• Keep shields and covers in

place while machine is in oper­ation

• Keep hands, feet and clothing

away from rotating pulleys and
belts.

Fast - Reverse

Part Number

785139

REV A 2-2 605046

Part Number 604221

• Keep shields and covers in

place while machine is in oper­ation

• Keep hands, feet and clothing

away from rotating pulleys and
belts.

601815

• Do not overfill battery.

• Electrolyte may overflow and damage

paint, wiring or structure. When clean­ing the battery, use soap and water. Be
careful not to get soap and water into
the battery. Use soda mixed in water
to clean corrosion off the terminals.

• Always wear eye protection when

checking the battery, acid can cause
serious injury to skin and eyes. If con­tact occurs, flush area with clean
water and call physician immediately.
Acid will also damage clothing.

• Avoid skin con-

tact with battery
acid

• Do not allow open flame near the

battery when charging.

• Hydrogen gas forms inside the

battery. This gas is both toxic and
flammable and may cause an
explosion if exposed to flame.
Always remove the negative
ground first and replace it last.

604889

Part Number 604889

C

M

D

F

L

B

G

H

E

K

J

I

A

Part Number 601815

DANGER: Battery Hazards!

A. Fast
B. Slow
C. Choke
D. Mower blade engage/disengage switch
E. Ignition switch - insert key

F. OFF
G. ON
H. Engine start position

I. Wear ear protection, eye protection and safety shoes

when operating this equipment.

605046 2-3 REV A

J. Read Operator’s Manual before attempting to operate

this machine.

K. Before starting the engine:

• Read Operator’s Manual

• Disengage mower blades

• Place control levers in park brake position

L. For maximum electric clutch life engage at 1/2 - 3/4

throttle position.

M. For maximum electric clutch life disengage at low throttle

position.

601981

601981

1.

2.

Part Number 601981

WARNING: Read Operator ’s Manual and decals before attempting

to operate this machine.

WARNING: Roll over!

• Mow a safe distance (minimum of 10 feet) away from drop-offs,

retaining walls, drainage ditches, embankments, water, and
other types of hazards to avoid a wheel dropping over the edge
or to avoid the ground from breaking away.

WARNING: Back over!

• Do not carry passengers.

• Always stop machine if someone enters the area.

• Always be aware of what is behind the machine before backing

up. Do not mow in reverse unless absolutely necessary. Always
look down and behind before and while backing up.

WARNING: Roll over!

• Slow down before turning.

• Do not operate on slopes greater than 15 degrees.

• Keep all movement on slopes slow and gradual. Never make

sudden changes in speed and direction.

• Do not mow on slopes above a retaining wall or drop-off.

WARNING: Ejection!

• Do not operate on slopes greater than 15 degrees.

• Keep all movement slow and gradual when going up or down

slopes.

• Do not remove or modify stabilizer wheels or injury can result.

WARNING: Loss of traction/control on slopes!

• Shut off blades.

• Back slowly down the slope when loss of traction occurs.

REV A 2-4 605046

1. Hold this sheet of paper in front of you. Make sure that Line A is horizontal.

2. Align Line B with a vertical surface such as pole, tree or building.

3. Fold the paper along the slope guide lines (C, D or E).

4. Align the closest slope guide line with the ground slope. This will give you a close estimation of the ground slope to be

mowed.

Slope Guide Lines

Line B

D (10o)

C (5

o

)

E (15

o

)

Line A

Slope Guide

Use this diagram when determining the degree of slope to be mowed.

605046 2-5 REV A

REV A 2-6 605046

OPERATION

Safe Operating Practices

This product is capable of amputating hands and feet and
throwing objects. Always follow all safety instructions to avoid
serious injury or death.

Safe Operation

 Evaluate the terrain to determine what accessories and

attachments are needed to properly and safely perform
the job. Only use accessories and attachments approved
by the manufacturer.

 Never leave a running mower unattended. Always stop

on level ground, disengage deck clutch, place steering
control levers in park brake position, stop the engine, and
remove ignition key before leaving operator’s seat for
any reason. Wait for engine and all moving parts to come
to a complete stop before leaving the mower for any rea­son including emptying the catcher or unclogging the
chute.

 Do not change the engine governor setting or overspeed

the engine. Operating the engine at excessive speed may
increase the hazard of personal injury.

 Always remain seated while operating mower.
 Always keep safety shields and covers in place, except

for servicing.

 Always maintain a safe distance from people and pets

when mowing. Always stop mower if someone enters the
area.

 Always operate mower in daylight or with adequate

working lights.

 Follow daily and weekly checklists, making sure hoses

are tightly secured and bolts are tightened.

 Always observe traffic laws while driving mower from

one location to another. Watch for traffic when operating
near or crossing roadways.

 Always be alert for hazards such as rocks, metal objects

and other debris which may be thrown or entangled by
mower blades. Watch out for holes or deep depressions.

 Never operate the mower when there is a risk for light-

ning.

 Inspect area to be mowed for hazards such as rocks,

metal objects and other debris which may be thrown or
entangled by mower blades. Remove these objects before
mowing.

 Always inspect mower for damage after striking a foreign

object. If damage is found, repair mower immediately. Be
sure to stop on level ground, disengage deck clutch, set
park brake, stop the engine, and remove the ignition
switch key when leaving the operator’s seat to inspect
damage.

 Always wear adequate ear protection, such as earplugs,

when operating this equipment as prolonged exposure to
uncomfortable or loud noises can cause impairment or
loss of hearing. Do not wear radios or music headphones
while operating the machinery. Safe operation requires
your full attention.

 Do not operate the equipment while wearing sandals, ten-

nis shoes, sneakers, shorts or any type of loose fitting
clothing. Do not use a towel as a headband or neck wrap
and do not hang a towel from the waist. Long hair, loose
clothing or jewelry may get tangled in moving parts.
Always wear long pants, safety glasses, ear protection
and safety shoes with slip-resistant soles when operating
this mower.

 Always be aware of what is behind the mower before

backing up. Never mow in reverse. Always look down
and behind before and while backing up.

 Never push forward suddenly on your steering control

levers while the mower is in rearward motion because
mower may tip backwards.

 Never pull back suddenly on your steering control levers

while the mower is in forward motion.

 When mowing in reverse, push forward slowly on the

steering control levers and avoid sudden movement.
Rapid movement of the steering control levers in either
direction could result in a reaction of the mower that can
cause serious injury.

 Never operate a poorly maintained mower.
 Never attempt high speed maneuvering, especially in

crowded or congested areas.

 Never allow persons to operate this mower without

proper instruction or allow children to operate mower.
Allow only responsible adults who are familiar with
these instructions to operate this mower.

 Never put hands or feet under any part of the mower

while it is running.

 Never carry passengers.
 Never direct discharged material toward anyone. Avoid

discharging material against a wall or obstruction. Mate­rial may ricochet back towards the operator. Always dis­engage the mower blades and wait for them to stop
before crossing gravel drives, walks or roads.

 Always keep clear of the mower blades and attachments

during their operation.

 Do not use any unauthorized attachment or modify the

mower.

 Turn off mower blades when not mowing.
 Slow down before turning.
 Stop the engine before removing the grass catcher or

unclogging the discharge chute. Never clear the discharge
chute with the engine running. Turn off the engine and be
sure the blades have stopped before cleaning. Use a stick
to clear a plugged discharge area. Never use your hand!

 Do not operate the mower if you are fatigued, sick or

while under the influence of alcohol or drugs, if your are
pregnant or under 18 years old.

 Poor posture or operating the mower for extended periods

of time may lead to fatigue or injury, resulting in loss of
mower control. Occasionally, stop the mower and get off
the seat to stretch and relax.

 Exercise extreme caution when loading or unloading the

mower onto a trailer or truck.

605046 3-1 REV A

 Always wear safety goggles or safety glasses with side

shields when operating the mower.

 Data indicates that operators, age 60 years and above, are

involved in a large percentage of riding mower-related
injuries. These operators should evaluate their ability to
operate the mower safely enough to protect themselves
and others from serious injury.

 Follow the manufacturer’s recommendation for wheel

weights or counterweights.

 If any attachment or additional weight is mounted on the

rear of the unit, any rapid movement of the control levers
in either direction could result in a reaction of the mower
that can cause serious injury.

 Clean flammable material from mower. Prevent fires

by keeping engine compartment, top of deck, exhaust
area, battery, fuel line, fuel tank and operator’s sta­tion clean of accumulated trash, grass clippings, and
other debris. Always clean up spilled fuel and oil.

 Prevent fires by keeping the engine and exhaust areas

clear of grass clippings and other debris. Do not back
mower into flammable materials.

Using A Ramp

 Use extreme caution when loading and unloading a

mower onto a truck or trailer with a ramp.

 Use only a single, full width ramp; do not use individual

ramps for each side of the unit. Having a full width ramp
provides a surface for the mower frame to contact if the
unit starts to tip backwards. It also reduces the risk of a
wheel going off and the mower tipping over.

 Do not exceed a 15 degree angle between the ramp and

the ground or between the ramp and the trailer or truck.

 Avoid sudden acceleration when on a ramp.

Slope Operation

Slopes are a major factor in loss-of-control and tip-over

accidents, which can result in severe injury or death. All
slopes require extra caution. If you cannot back the mower
up the slope or if you feel uneasy on the slope; do not mow it.
REMINDER: Only operate on slopes of 15 degrees or less.

 Use extreme caution when operating on slopes.

• Be extremely careful changing directions on a
slope. Slow down.

• Do not operate where the mower could slip or tip.

• Turn slowly

• Turn on the most level part of the slope

• To maximize traction, it is better to turn the front of
the mower uphill, rather than downhill. If drive

tires lose traction, steering control is lost which
could cause serious injury or death.

• If it becomes necessary to turn downhill, turn
slowly and gradually, if possible.

 Watch for holes, ruts, bumps, rocks or other hidden

objects. Uneven terrain could overturn the mower. Tall
grass can hide obstacles.

 Remove obstacles such as rocks, tree limbs, etc.
 Keep all movement on slopes slow and gradual. Do not

make sudden changes in speed or direction.

 Avoid starting and stopping on a slope. If tires lose trac-

tion, disengage the mower blades and proceed slowly
straight down the slope.

 Mow a safe distance (minimum of 10 feet) away from

drop-offs, retaining walls, drainage ditches, embank­ments, water, and other types of hazards to avoid a wheel
dropping over the edge or to avoid the ground from
breaking away. This will reduce the risk of the mower
suddenly rolling over causing serious injury or death.

 Use a walk behind, push mower or hand-held trimmer on

slopes and near drop-offs, retaining walls, drainage
ditches, embankments and water to avoid mower rollover
and serious injury or death.

 Do not mow on wet grass. Slippery conditions reduce

traction which could cause sliding and loss of control.

 Do not tow on slopes. The weight of the towed equip-

ment may cause loss of traction and loss of control.

 Do not try to stabilize the mower by putting your foot on

the ground.

 If the mower’s tires lose traction when operating on

slopes, disengage the blades, place the control levers in
the park brake position, stop the engine, remove ignition
switch key, and get help.

 Never make sudden starts, stops, turns, or reverse direc-

tion, especially when maneuvering on slopes. The steer­ing is designed for sensitive response. Rapid movement
of the control levers in either direction could result in a
reaction of the mower that can cause serious injury.

 Never stop suddenly while backing down slopes. This

action may result in a reaction of the mower that can
cause serious physical injury.

 The BigDog

®

mower is capable of operating horizontally
(traverse) on moderately steep slopes. When operating on
slopes up to 15 degrees, be aware of any conditions that
may cause the mower drive tires to lose traction resulting
in a possible loss of control of the mower. An operator
should not operate on a slope until he is thoroughly
familiar with the equipment.

Do not operate on slopes greater than 15 degrees.

Refer to the Slope Guide, when determining the degree of
slope to be mowed.
It is strongly recommended that the operator drive the
mower off of the slope, using extreme caution, if any sign
of loss of traction is detected. Wait until the condition
that caused the problem is resolved before attempting to
operate on the slope again.
Terrain conditions can affect traction resulting in possible
loss of control of the mower. Some of the conditions to be
aware of are:

1. Wet terrain

2. Depressions in the ground; i.e. holes, ruts, washouts

3. Mounds of dirt

4. Soil type; i.e. sand, loose dirt, gravel, clay

5. Grass type, density, and height

6. Extremely dry conditions of grass

7. Tire pressure
The attachments mounted to the mower will also affect
the way it handles on a slope. Be aware that each attach­ment’s characteristics vary.

REV A 3-2 605046

Do not tow on slopes. The weight of the towed equip­ment may cause loss of traction and loss of steering con­trol.
Another consideration to safe mowing on slopes is to be
aware of what is located at the bottom of the slope.
Extreme caution should be used when there is a hazard
located at the bottom of the slope. Some examples are:

1. Water; i.e. lake, river

2. Cliffs, retaining walls

3. Roads, highways

4. Buildings

5. Rocks
These are just a few examples of situations when caution
must be used when operating on a slope. There are many
other possibilities too numerous to mention. Just remem­ber to always exercise extreme caution when operating
on any slope.

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. Never assume that children
will remain where you last saw them.

 Never leave the mower unattended with the ignition key

in switch, especially with children present.

 Children or bystanders may be injured if they move or

attempt to operate the mower while it is unattended.
Always disengage the deck clutch, place the control
levers in park brake position, stop the engine, and remove
the ignition key when leaving operator’s seat.

 Keep children out of the mowing area and under the

watchful care of a responsible adult other than the opera­tor.

 Be alert and turn the mower off if children enter the area.
 Before and while 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 safe
mower operation. Children who have been given rides in
the past may suddenly appear in the mowing area for
another ride and be run over or backed over by the
mower.

 Never allow children to operate the mower.
 Never allow children or others in or on towed equipment.
 Use care when approaching blind corners, shrubs, trees,

the end of a fence or other objects that may obscure
vision.

605046 3-3 REV A

Control Panel

A

C

D

B

E

WARNING

Shown with steering control

levers in neutral position

Steering control lever

Shown with steering control
levers in park brake position

A. Deck clutch switch
B. Ignition switch
C. Throttle
D. Choke
E. Hour meter

Figure 3-1

IMPORTANT: When access is required under the seat plat-

form and the seat is equipped with the optional arm rests, make
certain to place the control arms in the park brake position and
pivot the arm rests upward before placing the seat platform in
the full forward position to prevent arm rest damage.

A. Deck clutch switch (Figure 3-1) — this switch engages

the deck. Pull the switch up to engage and push switch
down to disengage the clutch.

IMPORTANT: For additional clutch information refer
to the Mower deck operation section of this manual.

B. Ignition switch (Figure 3-1) — a three position switch:

“OFF”, “RUN”, and “START”. With key inserted, rotate
it clockwise to “START” position; release key when
engine starts, and switch will automatically return to the
RUN position.

C. Throttle control (Figure 3-1) — a cable is linked to the

engine throttle for controlling engine speed. Move lever
forward to increase engine rpm, move lever rearward to
decrease engine rpm.

D. Choke control (Figure 3-1) — a cable is linked to

manually operate the engine choke. When the lever is in
the down position, the choke is in the “OFF” (run)
position. When the knob is pulled up, the choke is in the
“ON” (start) position. Do not operate the machine in the
“ON” (start) position.

E. Electronic hour meter (Figure 3-1) — registers 1/10

hour increments up to 9,999.9 total hours. Connected to
the ignition switch, the meter records the accumulative
time while the ignition key is switched to the RUN
position.

steering control levers are in the park brake position the
mower will not move when the engine is on and drive
pumps are operating

.

The parking brake may not hold the mower if parked on a
slope. Block or chock the machine when parked on a
slope.

B. Deck lift pedal (Figure 3-4) — the deck lift pedal is used

to raise or lower the deck. Push on the pedal to raise the
deck and then place the deck height locking pin into the
desired cutting height hole.
Push the deck lift pedal to raise the deck when going over
obstructions.

Figure 3-2

Controls

A. Steering control levers (Figure 3-2 & Figure 3-3) —

these levers control the mower’s speed, direction,
stopping, and park brake. These levers are used to steer,
accelerate, decelerate and change direction. When the

REV A 3-4 605046

Figure 3-3

Figure 3-4

Deck lift pedal

Lights

WARNING

WARNING

system:

1. The operator must be on the seat when testing the seat
switch.

2. Set both steering control levers in the park brake position.

3. Start the engine and allow it to warm up to operating

temperature.

4. With the deck clutch switch down and the steering
control levers in the park brake position, slowly raise off
of the seat. The engine should continue to run.

5. With the deck clutch switch up and/or the steering control
levers in the neutral position, slowly raise off of the seat.

The engine should stop.

6. If the engine fails to stop when the deck clutch switch is

up or one or both of the steering control levers is up and
the operator is off the seat, check the function of the seat
switch. If the seat switch is not operating properly (is not
opening or closing) and if the cause can not be
determined, replace the seat switch.
If the problem cannot be located, contact your BigDog
Mowers Dealer.

®

Lights

The BigDog® Alpha MP comes equipped with operating
lights mounted in the front mower frame. There is no dedicated
“ON/OFF” switch for these lights. These lights come on when
the ignition switch is in the “RUN” position and go off when the
ignition switch is in the “OFF” position. Figure 3-5

Figure 3-5

Safety Start Interlock System

The mower is equipped with a safety start interlock system
consisting of the park brake switches, seat switch, and deck
clutch switch.

Check the mower’s safety start interlock system daily,
prior to operation. This system is an important mower safety

feature. It should be repaired immediately if it malfunctions.
The machine incorporates a separate seat switch which will stop
the engine when the operator is unseated for any reason while
the mower is operating. This is a safety feature designed to
prevent runaway or accidental entanglement. To inspect the

The safety interlock system should always function per
steps 4 and 5. If it does not function properly, it should be
corrected immediately. Do not operate machine without a
properly functioning seat safety switch.

Engine Starting

The mower’s safety start interlock system is also designed to
protect the operator and others from accidental injury due to
unintentional engine starting. The engine starting motor will not
engage until:

1. Steering control levers are in the park brake position.

2. Deck clutch switch is in the down (OFF) position.

The safety interlock system must not be disconnected or
bypassed. Doing so could cause the machine to operate
unexpectedly resulting in personal injury.

NOTE: The operator’s seat is equipped with a separate

safety switch. If for any reason the operator should become
unseated when the steering control levers are not in the park
brake position (park brake switches are disengaged) or the deck
clutch switch is engaged the engine will stop.

The following steps are the correct procedures for starting the
engine. If difficulty is encountered, contact the BigDog
Mowers Dealer in your area.

1. Before starting mower each day, perform daily pre­operation checking. (See Safety Start Interlock System
section.)

2. Make sure the steering control levers are in the park
brake position and deck clutch switch is disengaged.
Only start the engine from the operator’s position.

®

605046 3-5 REV A

3. Use chokewhen engine is cold, or if warm engine fails to

WARNING
DANGER

Bypass valve rod

(Left rod shown)

Bypass valve rod shown in operating position

Slot

start within 5 seconds of cranking. Avoid flooding and
operate engine without choking as soon as possible.

4. Set throttle at approximately 1/2 open position.

5. Insert key in ignition switch and rotate full clockwise to

engage starting motor. Release key when engine starts.
IMPORTANT: The engine starter should not be operated
for periods longer than 30 seconds at a time. An interval
of at least two minutes should be allowed between such
cranking periods to protect the starter from overheating
and burn-out.

6. Perform test to make sure safety start interlock system is
operating properly. Refer to Safety Start Interlock System
section.

7. Allow the engine to idle a few minutes before advancing
the throttle and/or engaging the deck clutch.

Stopping The Engine

Use the following procedure to shut off the engine after

operating the equipment.

1. Place the steering control levers in the park brake
position.

2. Throttle the engine back to low idle, then disengage the
deck clutch. Refer to Mower deck operation section for
more details.

3. Let the engine run at low idle for a couple of minutes.

4. Rotate the ignition key counter-clockwise to the “OFF”

position. Remove the key from switch before leaving the
mower.

Moving Mower With Stalled Engine

If it becomes necessary to move the mower when the engine

is inoperative, the transaxles are equipped with bypass valves.

Before moving the unit, pull out on the bypass valve rod until
the notch in the rod hooks over the edge of the slot. This places
the bypass valves in the disengaged position. The valve rod is
located per Figure 3-6.

The steering control levers must be placed in the neutral
position, to release the park brakes, so that the mower can be
moved.

Do not tow the machine. Move it by hand or use a winch to
load on a trailer for transporting.

When transporting on another vehicle, the mower should be
facing forward and it must be secured.

IMPORTANT: Always make certain the two bypass valves

are returned to their operating position before running the
mower following repairs.

Allow engine exhaust manifold to cool before engaging
or disengaging the bypass valves. The bypass valve rods
are located close to the exhaust system.

Figure 3-6

Mower Operation

Driving the mower

Never make sudden stops or reverse direction, especially
when maneuvering on a slope. The steering is designed
for sensitive response. Rapid movement of the control
levers in either direction could result in a reaction of the
mower that can cause serious injury.

After starting engine, engage the steering control levers and

steer as follows:

To go for war d, push steering control levers forward an equal

distance (Figure 3-7).

To go in reverse, pull steering control levers rearward an

equal distance (Figure 3-7).

To turn left, move the right steering control lever farther

forward from neutral than the left steering control lever.

To turn right, move the left steering control lever farther
forward from neutral than the right steering control lever.
(Figure 3-7)

Zero radius turn, move one steering control lever forward
and the other steering control lever back of neutral. This will
allow the drive wheels to counter-rotate. (Figure 3-7)

To stop or decrease speed, move steering control levers to
neutral. When going forward pull back gently on steering
control levers. When going in reverse push forward gently on
steering control levers.

For emergency stop, when traveling forward or rearward,
place the steering control levers in the park brake position

REV A 3-6 605046

immediately.

DANGER

WARNING

FORWARD TRAVEL

FRONT OF MOWER FACES THIS DIRECTION

ZERO RADIUS TURN

FORWARD TRAVEL
RIGHT TURN

REVERSE TRAVEL
RIGHT TURN

REVERSE TRAVEL

N = NEUTRAL POSITION

Direction of arrows indicate direction of mower

movement

N

N

N

N

N

N

N

N

N

N

When moving in the rearward direction push forward
gently on steering control levers and avoid sudden move­ment. Any sudden movement could cause the front of the
mower to come off of the ground resulting in possible
loss of control, causing serious injury or death.

To make a three point turn to the right, move the left
steering control lever farther forward from neutral than the right
steering control lever and start the turn. Next, pull back on the
steering control levers until they are past neutral and the
machine starts to go rearward. Pull the right steering control
lever farther rearward from neutral than the left steering control
lever until the rear of the machine has pivoted around. Then,
push the steering control levers forward until they are both past
neutral and the machine starts to go forward. Push the left
steering control lever farther forward from neutral than the right
steering control lever and finish the turn. (Figure 3-8)

Always be aware of what is behind the machine before
backing up. Do not mow in reverse unless absolutely nec­essary. Always look down and behind before and while
backing up.

IMPORTANT: Rapid movement of steering control levers

is not recommended as damage to the hydraulic system compo­nents may occur.

To increase speed, increase steering control lever’s distance
from neutral. The farther forward steering control levers are
from neutral, the faster the mower will travel forward. The
farther back steering control levers are from neutral, the faster
the mower will go in reverse.

605046 3-7 REV A

Figure 3-7

Step 1

THREE POINT TURN

Step 2

Step 3

R

ig

h

t

c

o

n

t

r

o

l

l

e

v

er

L

e

f

t

c

o

n

t

r

o

l

l

e

v

e

r

N

e

u

t

r

a

l

R

i

g

h

t

c

o

n

t

r

o

l

l

e

v

e

r

L

e

f

t

c

o

n

t

r

o

l

l

e

v

e

r

N

e

u

t

r

a

l

Neutral

Left control leverRight control lever

DANGER

WARNING

WARNING

WARNING

Operating suggestions

Prior to operating the mower the operator should be thor­oughly familiar with the proper use and operation of the
equipment, should read the manual completely and thor­oughly, and should have attempted slow moving maneu­vers to become familiar with the operation of the
equipment before attempting normal speed operation. An
inexperienced operator should not mow on slopes or on
uneven terrain.

If you lose steering control while operating the
machine, place the steering control levers in the park
brake position immediately. Inspect the machine and
involve your BigDog

®

Mower Dealer to resolve the

problem before continuing to operate.

Figure 3-8

The unit’s steering control levers are very responsive:
Easy does it! For smooth operation, move the levers
slowly, avoiding sudden movement. Skill and ease of
operation come with practice and experience. The
machine can spin very rapidly. Use caution when making
turns and slow down before making sharp turns.

Inexperienced operators may have a tendency to oversteer and
lose control. Slow-moving (low engine rpm - idle) practice
maneuvers on a flat open area are recommended to become
familiar with these characteristics before attempting normal
speed operation.

Sharp depressions or raised obstacles (such as gutters or
curbs) should not be directly approached at high speed in
an attempt to “jump” them as the operator could be
thrown from the equipment. Approach at a slow speed
and angle one drive wheel at the obstruction. Continue at
an angle until the wheel clears and then pivot the opposite
wheel around.

When turning on soft wet turf, keep both wheels rolling either
forward or backward. Pivoting on one stopped wheel can
damage turf. This is especially important when mowing.

Mower performance is at maximum when the throttle is set at
full rpm. This gives maximum power to the drive wheels and
deck when needed. Use the control levers to control ground
speed rather than engine rpm.

Keep blades sharp. Many professional mowing companies

REV A 3-8 605046

DANGER

WARNING
DANGER

WARNING

Discharge

chute

NOTE: Discharge chute may

vary from this illustration

have additional sets of blades and change blades twice a day:
once in the morning and again at noon. Many problems with
incorrect cutting patterns are due to dull blades or blades which
have been sharpened incorrectly. Information on sharpening
blades is listed in this manual’s maintenance section. In
addition, most communities have individuals or companies
which specialize in sharpening mower blades. Blade sharpness

should be checked daily.

Never work with blades while engine is running or deck
clutch switch is engaged (on). Always place deck clutch
switch in the disengaged position, place steering control
levers in the park brake position and turn engine off and
disconnect negative battery cable. Block up mower when
you must work under it. Wear gloves when handling
blades. Always check for blade damage if the mower
strikes a rock, branch or other foreign object during mow­ing!

Use high blade speed. Your mower is designed to operate at
full throttle. The throttle setting directly controls blade speed.
The highest blade speed generally gives the best cut.

Direct grass discharge to the right, away from the unmowed
area. Select a mowing pattern that directs grass discharge
toward the outside, not toward the center, of the mowing area.
Generally, this means using a pattern utilizing left turns
because side discharge is to the right. In any case, avoid
throwing grass discharge onto unmowed area because grass is
then mowed “twice”. Mowing twice puts an unnecessary load
on the unit and reduces mowing efficiency.

When mowing a lawn for the first time cut grass slightly
longer than normal to avoid scalping uneven terrain. When
possible, it is best to use the cutting height that was used in the
past. When cutting grass taller than six inches, you may want to
mow the lawn twice to achieve a better quality of cut.

During normal mowing cut only about 1/3 of the grass
blade. Cutting more than that is not recommended unless grass

is sparse or it is the end of the mowing season.

Alternate the mowing direction to keep the grass growing
straight and for better dispersion of the clippings.

Remember, grass grows at different rates at different times
of the year. Mow more often in the early spring to maintain the
same cutting height. As the growth rate slows in midsummer,
mow less frequently. If you cannot mow at a regular interval,
mow at a high cutting height; then mow again two days later at a
lower cutting height.

Raise the cutting height of the mower if the cutting width of
the mower is wider than the previous mower. This ensures that
uneven turf is not cut too short.

Raise the cutting height of the mower if the grass if slightly
taller than normal or if it contains a high degree of moisture.
Then mow it again with the cutting height set lower.

If the machine’s forward motion must be stopped while
mowing, a clump of grass clippings may drop onto your lawn.
To avoid this, move onto a previously cut area with the blades
engaged.

Never direct the discharge of material from the mower
deck toward bystanders. Do not operate the mower with­out either the discharge chute or the entire grass collec­tion system in place. Figure 3-9

Figure 3-9

Never attempt to make any adjustments to the mower
deck while the engine is running or with the deck drive
clutch engaged. Mower blades cannot be seen and are
located very close to deck housing. Fingers and toes can
be cut off instantly.

Deck clutch operation

Before beginning operation, check to make sure the deck
clutch switch is engaging and disengaging the blades
properly.

Make sure that the area around and under the deck is clear
and that there are no bystanders in the immediate area
before proceeding.

To check the deck clutch switch:

1. Start the engine and engage the deck clutch.

2. With the deck clutch switch up (clutch engaged) and the

engine running, listen to confirm that the mower blades
are rotating.

3. Now, push the deck clutch switch down (clutch
disengaged), and with the engine running, listen to
confirm that the blades have stopped rotating.

4. If the mower blades continue to rotate with the deck
clutch switch down, discontinue operation immediately
and contact your BigDog

®

Mowers Dealer.

605046 3-9 REV A

Clutch life will be maximized if these procedures are

Transport lever

Pin

Cutting height holes

Anti-scalp

wheel

Adjusting

holes

followed.

1. Engage the clutch only when the throttle is set at

approximately 2/3 throttle and there is no load on the
blades. After clutch engagement, advance the engine
throttle to full rpm.
Engaging the deck clutch at high engine rpm or when
under heavy load (in tall grass, for example) can cause
belts and/or electric clutch to slip, resulting in premature
wear or possible damage.

2. Disengage the clutch only when the throttle is set at less

than 1/2 throttle.

Never disengage the clutch with the engine running at
high rpm. Setting the throttle to less than 1/2 throttle
when disengaging the clutch will help extend clutch life.

Warranty will not be allowed for deck clutches that fail due

to improper engagement and disengagement practices.

Deck Cutting Height Adjustment

Deck cutting height is adjustable in 1/4” (6.4mm) increments.

Step on the deck lift pedal and latch the transport lever in the
deck transport position. Pull the adjusting pin out of the hole
that it is in and insert it into the desired cutting height hole. Step
on the deck lift pedal to release the transport lever. Figure 3-10

Step on the deck lift pedal and raise the deck to its highest
position and latch the transport lever in place when transporting
the unit.Figure 3-10

Anti-Scalp Wheels

Anti-scalp wheels are standard on this mower. These anti­scalp wheels are designed to minimize scalping when mowing
on rough uneven terrain. Figure 3-11

Anti-scalp wheels can be installed in two positions. With the
wheel installed in the bottom hole, the wheel is located 1.60”
(40.6mm) below the mower blades. This setting is preferred
when mowing at cutting heights of 2-1/2” (63.5mm) or higher.
When the wheel is mounted in the top hole, it is located .70”
(17.8mm) below the mower blades. This is the acceptable
setting for mowing at cutting heights of 1-1/2” (38.1mm) or
higher.

Figure 3-10

Figure 3-11

REV A 3-10 605046

MAINTENANCE & ADJUSTMENTS

Safe Servicing Practices

This product is capable of amputating hands and feet and
throwing objects. Always follow all safety instructions to avoid
serious injury or death.

Service Precautions

 Unless specifically required, DO NOT have engine run-

ning when servicing or making adjustments to mower.
Park the machine on level ground. Place steering control
levers in the park brake position, disengage deck clutch,
lower deck, remove ignition switch key and disconnect
negative battery cable before doing any maintenance.
Wait for all movement to stop before adjusting, cleaning
or repairing. Repairs or maintenance requiring engine
power should be performed by trained maintenance per­sonnel only. To prevent carbon monoxide poisoning, be
sure proper ventilation is available when engine must be
operated in an enclosed area. Read and observe safety
warnings in front of manual.

 Before working on or under the deck, make certain

engine cannot be accidentally started. Shut engine off,
remove ignition switch key and disconnect negative bat­tery cable for maximum safety. Repairs or maintenance
requiring engine power should be performed by trained
maintenance personnel only.

 Except when changing or checking the belt, always keep

belt covers on mower deck for safety as well as for clean­liness.

 Use a stick or similar instrument to clean under the

mower making sure that no part of the body, especially
arms and hands are under the mower.

 Keep your machine clean and remove any deposits of

trash and clippings, which can cause engine fires and
hydraulic overheating as well as excessive belt wear.
Clean up oil or fuel spillage. Allow machine to cool
before storing.

 Clean flammable material from machine. Prevent

fires by keeping the engine compartment, top of the
deck, exhaust area, battery, fuel line, fuel tank and
operator’s station clean of accumulated trash, grass
clippings, and other debris. Always clean up spilled
fuel and oil.

 Always wear adequate eye protection when servicing the

hydraulic system and battery, or when grinding mower
blades and removing accumulated debris.

 Use extra caution when handling gasoline and other

fuels. They are flammable and vapors are explosive.

 Never attempt to start the engine when there is a strong

odor of gasoline fumes present. Locate and correct the
cause.

 Never remove the fuel cap or refuel the mower while

engine is running or while engine is hot; never refuel near
an open flame or near devices which can create a spark.
Refuel outdoors. Never refuel or drain the fuel from the
machine indoors.

 Never run the engine in an enclosed area unless exhaust

is vented to the outside. Exhaust gases contain carbon
monoxide which is an odorless and deadly poison.

 Never attempt to make any adjustments or repairs to the

mower drive system, mower deck or any attachment
while the mower engine is running or deck clutch is
engaged. Repairs or maintenance requiring engine power
should be performed by trained maintenance personnel
only.

 Never work under the machine or attachment unless it is

safely supported with jack stands. Make certain machine
is secure when it is raised and placed on the jack stands.
The jack stands should not allow the machine to move
when the engine is running and the drive wheels are
rotating. Use only certified jack stands. Use only appro­priate jack stands, with a minimum weight rating of 2000
pounds (907 kg) to block the unit up. Use in pairs only.
Follow the instructions supplied with the vehicle stands.

 Exercise caution when releasing spring tension from any

of the belt idlers or when working with any of the deck
lift components.

 Do not touch hot parts of machine.
 Keep nuts and bolts tight, especially the blade attachment

bolts. Keep equipment in good working condition.

 Never tamper with safety devices. Check their proper

operation regularly.

 Stop the engine before removing the grass catcher or

unclogging the discharge chute. Never clear the discharge
chute with the engine running. Turn off the engine and be
sure the blades have stopped before cleaning. Use a stick
to clear a plugged discharge area. Never use your hand!

 Grass collection system components are subject to wear,

damage and deterioration, which could expose moving
parts or allow objects to be thrown. Frequently check
components and replace with manufacturer’s recom­mended parts, when necessary.



Exercise caution when working under the deck as the
mower blades are extremely sharp. Wrap the blade(s) or
wear gloves and use extra caution when servicing them.

 Use only genuine BigDog

ensure that original standards are maintained.

®

Mowers replacement parts to

Service Introduction

Regular maintenance is the best prevention for costly
downtime or expensive, premature repair. The following pages
contain suggested maintenance information and schedules
which the operator should follow on a routine basis. For more
detailed information order the correct Parts Manual and General
Service Manual for your unit. Refer to the Product Literature
section of this manual.

Remain alert for unusual noises, which could signal a
problem. Visually inspect the machine for any abnormal wear or
damage. A good time to detect potential problems is while
performing scheduled maintenance service. Correcting the
problem as quickly as possible is the best insurance.

Clear away heavy build-up of grease, oil and dirt, especially

605046 4-1 REV A

in the engine and under the seat platform areas; minute dust

WARNING

WARNING

WARNING

WARNING

particle are abrasive to close-tolerance engine and hydraulic
assemblies.

Inspect mower daily for grass clippings and wire or string
tangles. The underside of the mower deck will collect a build-up
of grass clippings and dirt, especially when grass is wet or has
high moisture content. This build-up will harden, restricting
blade and air movement and will probably show a poorer quality
of cutting. Therefore it should be removed routinely.

To do this it will be necessary to raise and block the deck
using jack stands or blocks in the full up position. Scrape the
build-up from underneath.

Some repairs require the assistance of a trained service
mechanic and should not be attempted by unskilled personnel.
Consult your BigDog
is needed.

®

Mowers service center when assistance

Torque Values

Particular attention must be given to tightening the drive
wheel lug nuts and blade spindle bolts. Failure to cor­rectly torque these items may result in the loss of a wheel
or blade, which can cause serious damage or personal
injury.

Torque values are given below:

Ft-lbs. N-m

Wheel (lug) nuts . . . . . . . . . . . . . . . . . 70 . . . . . . . . 95

Blade spindle bolt top . . . . . . . . . . . . . 73 . . . . . . . . 95

Blade spindle bolt bottom . . . . . . . . . . 118 . . . . . . . . 160

Lug nuts only - It is recommended that these be checked after
the first 2 hours of operation, initially, every 50 hours and
following removal for repair or replacement.

For all other torques refer to the mower’s General Service
Manual for standard torque chart. See Product Literature
section for ordering information.

For engine torque values, see engine owner’s manual.

Tires

It is important for level mowing that the tires have the same
amount of air pressure. The recommended pressures are:

Drive wheels . . . . . . . . . . . . . . . . . . . . . 8-12 psi (55-83 KPa)

Front wheels . . . . . . . . . . . . . . . . . . . . . 8-12 psi (55-83 KPa)

Recommended battery size is a garden tractor BCI group U1R
with 225 or better cranking AMP rating. A maintenance-free
battery is recommended. Otherwise, follow battery
manufacturer’s maintenance, safety, storing and charging
specifications.

Battery posts, terminals, and related accessories contain
lead and lead compounds, chemicals known to the State
of California to cause cancer and reproductive harm.
Wash hands after handling.

Charge batteries in an open well-ventilated area, away
from sparks and flames. Unplug charger before connect­ing or disconnecting from battery. Wear protective cloth­ing and use insulated tools.

• Avoid skin and clothing contact with battery acid.

• Always wear eye protection when checking the bat­tery. Acid can cause serious injury to skin and eyes.
If contact occurs, flush area with clean water and
call a physician immediately. Acid will also damage
clothing.

• Do not drink the battery electrolyte.

• Do not allow open flame near the battery when
charging.

• Hydrogen gas forms inside the battery. This gas is
both toxic and flammable and may cause an explo­sion if exposed to flame. Always remove the nega­tive ground first and replace it last.

• Do not overfill the battery.

• Electrolyte may overflow and damage paint, wiring
or structure. When cleaning the battery, use soap
and water. Be careful not to get soap and water into
the battery. Clean the battery terminals with a solu­tion of four parts water and one part baking soda
when they become corroded.

If you wish to use non-pneumatic tires on your BigDog
mower the tires must be an approved tire purchased from
BigDog
mower equipped with unapproved non-pneumatic tires.

®

Mowers. Warranty claims will be denied on any

Lubrication

Use SAE multi-purpose grease.

Electrical System

The electrical system is a 12 volt, negative ground.

REV A 4-2 605046

®

WARNING

Shorts caused by battery terminals or metal tools touch-

WARNING

Master fuse

housing

WARNING

Expansion

tank

Filter

Transmission

ing metal mower components can cause sparks. Sparks
can cause a battery gas explosion which will result in per­sonal injury.

• Prevent the battery terminals from touching any
metal mower parts when removing or installing the
battery.

• Do not allow metal tools to short between the bat­tery terminals and metal mower parts.

Incorrect battery cable routing could cause damage to the
mower and battery cables. This can cause sparks which
can cause a battery gas explosion which will result in per­sonal injury.

•Always disconnect the negative (black) battery
cable(s) before disconnecting the positive (red)
cable(s).

•Always connect the positive (red) battery cable(s)
before connecting the negative (black) cable(s).

The hydraulic expansion tank is located in front of the engine

and under the operator’s platform. Figure 4-2

Check oil level in hydraulic system after every 50 hours of
operation or weekly, whichever occurs first. Check more often if
system appears to be leaking or otherwise malfunctioning.

Fluid level should be at the “Full Cold” line on the expansion
tank. Use only SAE 20W50 SL/SM service motor oil.

Initial system oil and filter change must be after the first 75
hours of use or 1 year whichever comes first. Thereafter, replace
filter and oil in each transmission every 2 years or 200 hours,
whichever comes first. NOTE: The filter guard must be
removed to access filter.

Each transmission’s filter is located per Figure 4-3. A
standard oil filter wrench is used to change filter, threads are
right handed. Use a BigDog

®

Mowers approved filter element

only.

When washing the mower, direct the spray away (espe­cially if using a power washer) from the transmission’s
seals to prevent water intrusion and to ensure component
performance

Master in-line fuse

These mowers have a master in-line fuse in the electrical
system. This is the main fuse to protect the complete electrical
system. It is located under the seat platform and next to the
solenoid. Figure 4-1

Figure 4-1

Figure 4-2

Hydraulic System

This mower is equipped with two integrated hydrostatic
transmissions. Figure 4-2

IMPORTANT: Never use hydraulic or automatic transmis-

sion fluid in this system; use only motor oil as specified.
Remember, dirt is the primary enemy of any hydraulic system.

605046 4-3 REV A

Figure 4-3

Fuel and Evaporative Emissions Control

WARNING
DANGER

WARNING

WARNING

System

The fuel and evaporative emissions control system for this

mower is EPA compliant. Use only BigDog
replacement parts.

Your evaporative emission control system may include parts

such as: fuel tanks, fuel lines, fuel line fittings, fuel caps, carbon
canisters, canister mounting brackets, carburetor purge port
connection, filters, vapor hoses, clamps, control valves, control
solenoids, electronic controls, vacuum control diaphragms,
purge valves, liquid/vapor separator and other associated
components.

Modifying or Tampering with the evaporative emissions

control system or the fuel system is prohibited. Federal law

and California State law prohibit the following acts or the
causing thereof:

1. The removal or rendering inoperative by any person other
than for purposes of maintenance, repair, replacement, of
any device or element of design incorporated into any
equipment for the purposes of emissions control prior to
or after its sales or delivery to the ultimate purchaser or
while it is in use, or

2. The use of the equipment after such device or element of
design has been removed or rendered inoperative by any
person.

Use of replacement parts not equivalent to the original
parts may result in system failure and pose a safety haz­ard.

®

Mowers approved

• Allow engine to cool before storing machine inside
a building.

• Keep fuel away from open flame or spark and store
machine away from open flame or spark or pilot
light such as on a water heater or appliances.

• Use extreme care when handling gasoline and other
fuels. They are extremely flammable and vapors are
explosive. A fire or explosion from fuel can burn
you and others and can damage property.

• Refuel outdoors. Never refuel or drain the fuel from
the machine indoors.

• Never attempt to start engine when there is a strong
odor of gasoline fumes present. Locate and correct
cause.

• Store fuel in an approved container and keep it out
of the reach of children. Never buy more than a 30
day supply of fuel.

• Do not fill fuel containers inside a vehicle or on a
truck or trailer bed with interior carpets or plastic
truck bed liners. Always place fuel containers on
the ground away from your vehicle before filling.

• When practical, remove gas powered equipment
from the truck or trailer and refuel the equipment
with its wheels on the ground. If this is not possible,
then refuel such equipment on the truck or trailer
using a portable container and not a fuel dispenser
nozzle. If a fuel dispenser nozzle must be used,
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.

• Never use gasoline for cleaning parts.

• Read and observe safety precautions elsewhere in
this manual.

To avoid personal injury or property damage, use
extreme care in handling fuel. Fuel is extremely flam­mable and the vapors are explosive.

Observe usual fuel handling precautions

• Do not smoke while refueling. Extinguish all ciga­rettes, cigars, pipes and other sources of ignition.

• Do not remove fuel cap or fill tank with engine
running or while engine is hot. Clean up any fuel
spills.

• If fuel is spilled, do not attempt to start the engine
but move the machine away from the area of spill­age and avoid creating any source of ignition until
fuel vapors have dissipated.

REV A 4-4 605046

• Gasoline is harmful or fatal if swallowed.

• Long-term exposure to vapors can cause serious
injury and illness.

• Avoid prolonged breathing of vapors.

• Keep face away from nozzle and gas tank or fuel
container opening.

• Keep gas away from eyes and skin.

• If fuel is spilled on clothing, change clothing imme­diately.

The fuel tank is located under the seat platform with the filler

neck and fuel cap located in the left side fender. Figure 4-4

Remove the fuel cap slowly.

When threading the fuel cap onto the filler neck, tighten the
cap until it begins to click, then, continue to turn it until at least
three clicks are heard.

IMPORTANT: Do not overfill the fuel tank. The fuel tank

should be filled no higher than the bottom of the fill neck.

The fuel system is designed to leave room for the fuel to expand

WARNING

WARNING

Fuel cap

Oil drain hose

Oil drain valve

with fuel temperature changes.

Overfilling fuel tank may cause the following:

• Engine damage

• Fire hazard!

Use regular unleaded gasoline with an octane rating of 87 or
higher. Maximum of 10% ethanol (E10) in fuel. Fuels with
greater than 10% ethanol, (such as E15, E20 and E85) voids
warranty. Fuels with greater than 10% ethanol are not approved
for use and such illegal use could cause equipment failure and
pose a fire hazard.

Refer to the engine owner’s manual for fuel specification
requirements.

IMPORTANT: After the new oil filter has been installed,

clean up any oil which may have spilled onto the engine plate,
muffler, and heat shield.

Draining the engine oil :

1. Locate the oil drain valve on the lower right side of the
engine.

2. Locate the oil drain hose that was supplied with the
machine. Be sure to clean and clear it of debris that might
block the flow of the engine oil. Figure 4-5

3. Attach one end of the hose onto the oil drain valve nipple.
Make sure the hose is pushed all the way onto the valve.

4. Position the loose end of the hose forward and down in
front of the right side transmission so that it can drain
into a suitable oil drain container.

5. With the hose in position, use a 10 mm wrench or socket
and open the valve approximately 4 turns in the
counterclockwise direction. Allow 10 minutes for engine
oil to adequately drain.

6. After oil is drained, close the valve by turning it in the
clockwise direction until it is fully closed.

7. Once the valve is closed, carefully remove the oil drain
hose and clean up any spilled oil.
IMPORTANT: All oil drips or spills must be cleaned off
of the exhaust system before operating the machine.

8. Clean the oil drain hose and store it appropriately. Figure
4-5

Figure 4-4

Engine Oil And Filter

If the engine has been running and is up to operating tem­perature, allow the engine to cool before changing the oil.
Engine and engine oil will be very hot, so be very careful
when changing oil and wear the appropriate protective
gear to avoid being burned or exposed to engine oil.

Check engine oil daily and after every 4 hours of operation.
Mower must be on a level surface when checking oil. Refer to
engine manual and maintenance schedule for oil recommenda­tion and capacities.

Change the engine oil and filter after the first 5 hours of oper­ation and then per the engine manufacturer’s recommendations
after that. If mower is being operated in extremely dirty condi­tions, then it is recommended oil be changed more frequently.

605046 4-5 REV A

Figure 4-5

Engine Air Filter

Perform engine air filter maintenance per the Maintenance

Schedule shown elsewhere in this manual.

General Engine Maintenance

Detailed instructions and recommendations for break-in and
regular maintenance are specified in the Engine Owner’s
Manual. Please refer to this manual for engine servicing,
lubricating oil levels with quality and viscosity
recommendations, bolt torques, etc. The engine warranty is
backed by the manufacturer. Special attention should be paid to
applicable data which will not be duplicated here.

Fuel Evaporation System Filter

WARNING

Fuel evaporation

system filter

WARNING

WARNING

WARNING

All BigDog® Alpha MP mowers have a fuel evaporation
system filter. This filter must be checked and replaced every 100
hours or annually whichever comes first. Figure 4-6

Figure 4-6

efficiency and well groomed turf. Keep the blades sharp. A dull
blade will tear rather than cut the grass, leaving a brown ragged
top on the grass within a few hours. A dull blade also requires
more power from the engine.

Replace any blade which is bent, cracked or broken.

Never attempt to straighten a bent blade by heating, or
weld a cracked or broken blade as the blade may break
and cause serious injury. Replace worn or damaged
blades.

Never work with blades while engine is running or deck
clutch switch is engaged (on). Always place deck clutch
switch in the disengaged position, place steering control
levers in the park brake position and turn engine off and
disconnect negative battery cable. Block up mower when
you must work under it. Wear gloves when handling
blades. Always check for blade damage if mower
strikes a rock, branch or other foreign object during mow­ing!

Belts

Inspect belts frequently for wear and serviceability. Replace a
belt that shows signs of severe cuts, tears, separation, weather
checking and cracking, or burns caused by slipping. Slight
raveling of belt covering does not indicate failure, trim ravelings
with a sharp knife.

If the pump belt fails, loss of control will occur especially
when operating on a slope. If you lose steering control

while operating the machine, place the steering con­trol levers in the park brake position immediately.
Inspect the machine and involve your BigDog
ers Dealer to resolve the problem before continuing to
operate.

Inspect the belt pulley grooves and flanges for wear. A new
belt, or one in good condition, should never run against the
bottom of the groove. Replace the pulley when this is the case,
otherwise the belt will lose power and slip excessively.

Never pry a belt to get it on a pulley as this will cut or damage
the fibers of the belt covering.

Keep oil and grease away from belts, and never use belt
dressings. Any of these will destroy the belt composition in a
very short time.

Mower Blade Maintenance

Check the mower blades daily, they are the key to power

REV A 4-6 605046

®

Mow-

Always wear adequate eye protection when grinding
mower blades.

Mower Blade Removal

Use a 15/16” wrench to remove the 5/8” cap screw holding

the blade to the spindle shaft from underneath. NOTE: A blade
holding tool (part number 381442) is available from BigDog
Mowers. It is designed to prevent the blades from rotating when
they are being removed or installed on the spindle. Contact your
BigDog

(Figure 4-7). Touch-up sharpening can be done with a file

commercial balancing tool is available through most hardware
supply stores, or balancing can be done by placing the blade on
an inverted line punch or 5/8” bolt. Blade should not lean or tilt.
Spin the blade slowly, blade should not wobble. If blade is out
of balance, true it up before reinstalling.

(Figure 4-8 & Figure 4-9). Replace any distorted blade.

undercut threads. Torque bolts on spindles to 118 foot-pounds
(160.0 N-m) when reinstalling blades.

compression load on the blades. Replace the cup washers if they
are cracked or flattened.

®

Mowers dealer for more information.

Sharpen the blades on a grinder following pattern as shown

Check the blades for balance following grinding. A

Lay the blade on a flat surface and check for distortion

Do not re-use spindle bolts which have stripped, worn or

Properly compressed cup washers maintain the correct

®

IMPORTANT: The blade sail (curved part) must be point-

WARNING

WARNING

Resharpening

pattern

Do not sharpen to original pattern (below). It is

easier to get a straight cutting edge following

the resharpening pattern shown above.

Original edge

Warped Blade (Replace)

Straight Blade

Cutting

plane

Comparison of Warped and Straight Blades

Cutting edge

Twisted Blade Edge

(replace)

Cutting edgeCutting Plane

Straight Blade Edge

End view of blades, comparing

twisted and straightened blades

Cap

screw

ing upward toward the inside of the deck to ensure proper cut-

ting.

IMPORTANT: When mounting blades, rotate them after

installation to ensure blade tips do not touch each other or sides

of the mower.

Failure to correctly torque the bolt may result in the loss
of the blade which can cause serious injury.

Figure 4-9

Seat Adjustment

Mower blades are sharp and can cut. Wrap the blade(s) or
wear gloves and use extra caution when servicing them.

The seat on the BigDog® Alpha MP mower can be adjusted
forward and rearward by pivoting the seat platform up and
forward. Then, loosen the four cap screws on the underneath
side of the seat platform. Position the seat where you have the
best control of the machine and are the most comfortable and
then tighten the cap screws.

Figure 4-7

605046 4-7 REV A

Figure 4-8

Figure 4-10

Steering Control Lever Adjustment

The steering control levers can be adjusted for operator
comfort. By loosening the cap screws that attaches the upper
control lever to the lower lever (Figure 4-11), the upper control
lever can be pivoted to fit the operator’s personal preference.

The steering control levers can also be adjusted up and down.
Remove the cap screws and slide the upper control lever up or
down and align the holes in it with the holes in lower lever. Re-

install the cap screws and tighten.

Upper

control

lever

Lower

control

lever

Cap screw

The steering control levers should be adjusted so that they

align with each other when in the neutral position.

Figure 4-11

REV A 4-8 605046

Maintenance Schedule

Refer to Figure 4-12, Figure 4-13, Figure 4-14, & Figure 4-15

SERVICE AT

INTERVALS INDICATED

Verify safety start interlock system Prior to each use

Visually inspect unit for loose hardware and/or damaged parts Prior to each use

Visually inspect tires Prior to each use

Check oil level, engine (1) Prior to each use or every 4 hours

Clean air intake screen (4) Prior to each use or every 4 hours

Check fuel level Prior to each use

Blades - sharpen & securely fastened Prior to each use

Discharge chute - securely in place & in lowest position Prior to each use

Check tire pressure with a gauge Prior to each use

Clean engine and transaxle compartment After each use

Change engine oil & filter (1)(3) X

Check battery connections X

Clean engine exterior (a) X

Replace air cleaner paper element (4) X

Check pump & deck belt tension and condition (5) X

Check fuel system (6) X

Check fuel tank grommet (6) X

Tighten lug nuts on wheels (2) X

Change fuel filter (6) X

Replace fuel evaporation system filter (7) X

WEEKLY

OR 40

HOURS

ANNUALLY

OR 100
HOURS

NOTES:

1. Initial oil change is after 5 hours of operation. Thereafter, change oil after every 40 hours operation. Change more often under dusty or dirty conditions and dur-

ing hot weather periods.

2. Torque initially and after first 2 hours of operation.

3. Change engine oil filter per the engine manufacturer’s recommendations. Refer to Engine Owner’s Manual for recommendations and other maintenance items..

4. Service more often under dusty or dirty conditions.

5. Pump drive belt only - Inspect every month and replace if worn or cracking is noticed. Otherwise, replace every 2 years.

6. Check fuel system for any crack or leaks including, but not limit to, fuel line hoses, fuel valve, vent line hoses, vent valve, vapor valve, carbon canister, and

grommets. Replace as needed.

7. More often under dusty or dirty conditions and during hot weather.

REFERENCES:

A. Refer to engine owner’s manual for engine service information.
NOTE: After completing maintenance cycle (100 hours), repeat cycle.

605046 4-9 REV A

Maintenance Locator Chart

Figure 4-12

6

5

8

11

3

12

8

9

4

1

7

2

9

13

10

15

14

15

16

1. Engine Oil Fill & Dipstick

2. Fuel Filter

3. Engine Air Cleaner

4. Engine Oil Drain Valve

5. Battery

6. Fuel Tank

7. Engine Oil Filter

8. Park Brake Switch (2)

9. Drive Tire

10. Pump Belt

11. Engine Air Intake Screen

12. Front Wheel Tires

13. Hydraulic Oil Expansion Tank

14. Deck Belt

15. Blades

16. Fuel Evaporation System Filter

Figure 4-13 Figure 4-14

REV A 4-10 605046

Figure 4-15

TROUBLESHOOTING

The majority of operating problems that occur with a system can be traced to improper adjustments or delayed service. A
consistently applied preventative maintenance program, as outlined in the Maintenance section of this manual, will prevent many
problems. The following chart is designed to help you locate a problem by suggesting probable causes and the recommended
solutions.

SYMPTOMS PROBABLE CAUSES

Starting motor does not

crank

The engine will not start,

starts har d or fails to kee p

running

Engine:

Runs with continuous mis-

firing or engine runs

unevenly or erratically

Loss of power or system

will not operate in either

direction

Air cooled engine over-

heating

Low engine oil pressure Low oil level Add oil

High oil consumption Numerous Contact your Dealer

Mower jerky when starting

or operates in one direc-

tion only

Steering control levers not
in park brake position or
switch not adjusted

Deck clutch switch
engaged

Weak or dead battery Recharge or replace

Electrical connections are
corroded or loose

15 amp fuse is blown Replace the 15 amp fuse

For additional causes See engine manual

No fuel or line plu gged Fill tank or replace line (See

There is incorrect fuel in the
fuel system

There is dirt in the fuel filter Replace the fuel filter

Dirt, water or stale fuel in
the fuel system

The choke is not on Move the choke lever to

Numerous See engine manual

Numerous See engine manual

Restrictions in air cleaner Service air cleaner

Poor compression Contact your Dealer

Steering linkage needs
adjustment

Tow valve open Close tow valve

The traction drive belt is
worn, loose or broken

For additional causes See engine manual

Air intake screen or cooling
fins clogged

For additional causes See engine manual

Oil diluted or too light Change oil and check for

Failed oil pump Contact your Dealer

Steering control linkage
needs adjustment

Loose steering linkage Tighten linkage

Transaxle component faulty Contact your Dealer

SUGGESTED

REMEDIES

Place steering control
levers in park brake posi­tion or re-adjust switch

Disengage clutch switch

Check the electrical con­nections

Fuel System section for
more details)

Drain the tank and replace
the fuel with the proper type

Contact your Dealer

ON

Adjust linkage

Install a new traction drive
belt

Clean screen and fins

source of contamination

Adjust linkage

SYMPTOMS PROBABLE CAUSES

Mower creeps when
steering control levers are
in neutral

Mower circles or veers in
one direction

Mower creeps when park­ing brake engaged

There is abnormal vibra­tion

Blades do not rotate The deck drive belt is worn,

Uneven cutting height The blade(s) are not sharp Sharpen the blades

Steering linkage needs
adjustment

Steering linkage needs
adjustment

Loose steering linkage Tighten linkage

Tires improperly inflated Adjust air pressure to 8 - 12

Transaxle component faulty Contact your Dealer

Steering linkage out of
adjustment

Brakes need adjustment Adjust parking brakes

The engine mounting bolts
are loose

The engine pulley, idler pul­ley or blade pulley is loose

The engine pulley is dam­aged

The cutting blade(s) is/are
bent or unbalanced

A blade mounting bolt is
loose

Spindle bearing is worn or
loose

A blade spindle is bent Contact your Dealer

loose or broken

The deck drive belt is off
the pulley

Electric clutch is not engag­ing

A cutting blade(s) is/are
bent

The deck is not level Level the deck per the

An anti-scalp wheel is not
set correctly

The underside of the deck
is dirty

Tires improperly inflated Adjust air pressure to 8 - 12

A blade spindle is bent Contact your Dealer

SUGGESTED

REMEDIES

Adjust linkage

Adjust linkage

psi (55 - 83 KPa)

Adjust steering linkage

Tighten the engine mount­ing bolts

Tighten the appropriate pul­ley

Contact your Dealer

Install new cutting blade(s)

Tighten the blade mounting
bolt

Replace or tighten spindle
bearing

Install a new deck drive belt

Install the deck drive belt
and check for a reason

Check and/or replace 15
amp fuse.
Contact your Dealer

Install new cutting blade(s)

Deck leveling section of the
General Service Manual

Adjust the height of the
anti-scalp wheel

Clean the underside of the
deck

psi (55 - 83 KPa)

605046 5-1 REV A

REV A 5-2 605046

STORAGE

WARNING

When storing the unit at the end of the mowing season, the
mower, engine, and battery should have the following items
serviced before storage.

If the mower has been stored for an extended period of time,
follow the new season preparation steps before beginning
operation.

General mower preparation for storage

1. Remove all grass, dirt, and trash from mower and cutting
units.
IMPORTANT: Wash the machine with a mild detergent
and water. Do not pressure wash the machine. Avoid
excessive use of water, especially near the control panel
and engine.
Clean mower and deck and touch up all scrapes with
touch-up paint.

2. Install new air filter per Engine Owner’s Manual.

3. Check thoroughly for any worn or damaged parts that

need replacing and order them from your dealer.

4. Thoroughly lubricate machine, according to the
Maintenance section.

5. Block mower up so weight is off tires. Check tire
pressure and inflate to proper operating pressure.
NOTE: Do not deflate tires.

6. Perform separate engine and battery preparation as listed
below.

7. Store mower in a clean, dry place.

Preparation of engine for storage

When the engine is to be unused for long periods, proceed as

follows:

1. Run the engine for a minimum of 15 minutes.

2. Drain the oil from the crankcase while the engine is still

warm.

3. Refill with fresh oil of the proper viscosity.

4. Drain the fuel tank and run the engine until it stops from

lack of fuel. Gasoline evaporates if left in the carburetor
for long periods, forming gum and varnish deposits in the
carburetor. These deposits will cause engine flooding and
loss the previous 100 hours.

5. Remove the spark plugs and pour a tablespoon of engine
oil into each spark plug hole. Install plugs, but do not
reconnect plug leads.

6. Crank the engine with the starter at least a dozen
revolutions to distribute oil over the cylinder walls and
valve mechanism.

7. Clean the exterior surface of the engine. Spread a light

film of oil over any exposed metal surfaces of the engine
that are subject to corrosion.

8. Clean dirt and chaff from the cylinders and fins, blower
housing and muffler.

9. Check the oil filler cap and fuel tank caps to make certain
they are securely in place.

10. Refer to the engine manual for more information.

Preparation of battery for storage

When the machine is to be unused for long periods, it is best
to disconnect the battery and remove it from the unit. At this
time perform the following battery maintenance:

1. Remove the battery from machine.

2. Clean the battery, terminals, and cable connectors.

3. Charge the battery, if necessary.

4. Store the battery in a cool, dry place (do not expose to

freezing temperatures).

5. Always keep the battery fully charged. Especially
important to prevent battery damage when the
temperature is below 32°F (0°C).

New season preparation

Before starting the mower following post season storage, the

following service is required:

1. Clean mower, removing trash and dirt accumulation.

2. Check engine oil and hydraulic oil levels.

3. Fill fuel tanks with fresh fuel. Run machine at half speed

for 5 minutes, checking operation of steering control
lever. Stop engine and check for oil leaks, loose fittings
and so forth.

At start of new season always check that fresh oil has
been added to machine. If oil is drained at season’s end
and not replaced, engine damage will result.

4. Tighten any bolts that have loosened and make sure all
hair pins, cotter pins and clevis pins are in place.

5. Install all safety shields and review safety precautions
listed in this manual.

6. Check and inflate tires to 8-12 psi (55-83 KPa).

7. Install fully charged battery and attach the battery cables.

8. Refer to engine manual for more information.

605046 6-1 REV A

PRODUCT LITERATURE

If you would like to view or print a copy of the product manuals (Operator’s Manual, Parts Manual, or General Service Manual) for

these mowers go online to www.bigdogmowers.com and click on the MANUALS button.

Contact your local BigDog

®

Mower dealer if you require another engine manual.

REV A 6-2 605046

INDEX

PAGE PAGE

Anti-scalp wheels ..................................................3-10

Belts

.........................................................................4-6

Children

Control Panel

Controls

Deck clutch operation

Deck cutting height adjustment

Driving the mower

Electrical system

Engine air filter

Engine oil & filter

Engine starting

Fuel and evaporative emissions control system

Fuel evaporation system filter

General engine maintenance

...................................................................3-3

...........................................................3-4

...................................................................3-4

.............................................3-9

............................3-10

...................................................3-6

.....................................................4-2

........................................................4-5

.....................................................4-5

........................................................3-5

...4-4

................................4-6

.................................4-5

New season preparation

Operating suggestions

Parts and service

................................................... 1-1

........................................ 6-1

........................................... 3-8

Preparation of battery for storage

Preparation of engine for storage

Safe Operating Practices

Safe Operation

....................................................... 3-1

Safe servicing practices

Safety and Instructions Decals

Safety start interlock system

Seat adjustment

..................................................... 4-7

Service introduction

Service precautions

Slope guide

Slope Operation

............................................................. 2-5

..................................................... 3-2

....................................... 3-1

......................................... 4-1

............................. 2-1

................................. 3-5

............................................... 4-1

............................................... 4-1

......................... 6-1

......................... 6-1

General mower preparation for storage

Hydraulic system

Lubrication

Maintenance locator chart

Model and serial number

Moving mower with stalled engine

Mower blade maintenance

Mower blade removal

Mower operation

.....................................................4-3

...............................................................4-2

....................................4-10

........................................1-1

.........................3-6

.....................................4-6

.............................................4-6

.....................................................3-6

................6-1

Steering control lever adjustment

Stopping the engine

Tires

........................................................................ 4-2

To the new owner

Torque values

Using a Ramp

Using this manual

Warranty registration

............................................... 3-6

................................................... 1-1

......................................................... 4-2

......................................................... 3-2

................................................... 1-1

............................................. 1-1

......................... 4-7

605046 i-1 REV A