BigDog trooper User manual

122832 REV A
BIGDOG®MOWER CO. TROOPER
General Service Manual
200 South Ridge Road
Hesston, Kansas
67062

REV A 122832
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.
WARNING
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.

122832 toc-1 REV A
General Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Big Dog Mowers®Service Program . . . . . . . . . . . . . . . . . . . . . . 1-1
Maintenance Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Warranty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Safe Servicing Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Pre-Operation Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Operation Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Operate Machine Safely. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
General Maintenance Precautions. . . . . . . . . . . . . . . . . . . . . . . 2-2
Maintenance Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Torque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Standard Torques. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Special Torques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Power Unit Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Steering Adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Steering Control Lever Stops. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Park Brake Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Belts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Hydraulic Pump Belt Adjustment . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Hydraulic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
Jackshaft Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Engine Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
General Engine Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Engine Oil and Filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Engine Air Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Fuel Evaporation System Filter . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
Fuel & Evaporative System Line Routings. . . . . . . . . . . . . . . . . 5-3
Engine RPM Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Deck Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Deck Leveling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Deck Lift Tension Spring Adjustment. . . . . . . . . . . . . . . . . . . . . 6-1
Blades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Belts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4

REV A toc-2 122832
Deck Belt Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-4
Deck Belt Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-4
Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-1
Electrical Schematic – Kawasaki 48"/52"/60" . . . . . . . . . . . . . . .7-1
Electrical Schematic – Kohler 52"/60" . . . . . . . . . . . . . . . . . . . . .7-2
Electrical Schematic – Kawasaki 36". . . . . . . . . . . . . . . . . . . . . .7-3
Neutral Switch Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-4
Operator Presence Switch Adjustment . . . . . . . . . . . . . . . . . . . .7-4
Maintenance Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-1
Maintenance Locator Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3
Maintenance Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-6
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-1

122832 1-1 REV A
GENERAL INFORMATION
Big Dog Mowers®Service Program
This manual is part of a service package for the Big Dog®
TROOPER mowers. Use of this manual in conjunction with
other Big Dog®mower and component manuals will provide
the information necessary to service and maintain the Big
Dog®TROOPER mower.
This General Service Manual is a service guide for use by
Service Technicians. It provides the necessary information
needed to perform normal maintenance requirements on
these units.
The Parts Manual provides a complete parts listing for the
unit. Use this manual when ordering parts.
The Operator's Manual provides fundamental operational
information and operational safety that is needed when oper-
ating the mower.
The component manuals are furnished by the various man-
ufacturers to be used for the troubleshooting and servicing
of their components.
Maintenance Introduction
Regular maintenance is the best prevention for downtime
or premature failure. The following pages contain suggested
maintenance information and schedules which the operator/
mechanic should follow on a routine basis.
Remain alert for unusual noises, they could be signaling 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
in the engine compartment and under the seat platform
areas; minute dust particles are abrasive to close-tolerance
engine and hydraulic assemblies.
Daily inspect mower for grass clippings and wire and 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, restrict-
ing blade and air movement and will probably show a lesser
quality of cut. 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 and scrape
the build-up from underneath.
Some repairs require the assistance of a trained service
mechanic and should not be attempted by unskilled person-
nel. Consult your Big Dog®Mowers service center when
assistance is needed.
Information included in this manual was current at the time
of printing, but subsequent production changes may cause
your machine to vary slightly in detail. Big Dog®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 service
manual contact the Customer Service Department at Big
Dog®Mowers for additional information.
Warranty
Warranty repair must be performed by a Big Dog®Mowers
Authorized Dealer before warranty credit can be allowed.

REV A 1-2 122832

122832 2-1 REV A
SAFETY
This safety alert symbol is used to call attention to a mes-
sage intended to provide a reasonable degree of PERSONAL
SAFETY for operators and other persons during the normal
operation and servicing of this equipment.
Safe Servicing Practices
Refer to the Safety section of this manual for more detailed
service safety information.
Understand correct service
Be sure you understand a service procedure before
you work on the machine.
Unauthorized modifications to the machine may
impair the function and/or safety and affect machine
life.
If it is necessary to make checks with the engine run-
ning, always use two people—with the operator at the
controls, able to see the person doing the checking.
Pre-Operation Precautions
Fuel Handling
To avoid personal injury or property damage, use
extreme care when handling gasoline. Gasoline is
extremely flammable and the vapors are explosive.
•A fire or explosion from gasoline can burn you
and others and can damage property.
Observe the usual gasoline handling precautions:
•Do not smoke while refueling. Extinguish all ciga-
rettes, cigars, pipes and other sources of ignition.
• Do not remove fuel cap or fill tank with engine run-
ning or while engine is hot. Clean up any gasoline
spills.
•If gasoline 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 igni-
tion until gasoline vapors have dissipated.
•Keep gasoline 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 appli-
ances.
•Refuel outdoors. Never refuel or drain the gaso-
line from the machine indoors.
•Never attempt to start the engine when there is a
strong odor of gasoline fumes present. Locate
and correct the cause.
•Store gasoline in an approved container and keep
it out of the reach of children. Never buy more
than a 30-day supply of gasoline.
•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 gasoline contain-
ers on the ground away from your vehicle before
filling.
•When practical, remove the machine from the
truck or trailer and refuel the machine with its
wheels on the ground. If this is not possible, then
refuel such machine on the truck or trailer using a
portable container and not a fuel dispenser noz-
zle. 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.
Gasoline is harmful or fatal if swallowed.
Avoid prolonged breathing of vapors.
•Long-term exposure to vapors can cause serious
injury and illness.
Keep gasoline away from eyes and skin.
•Keep face away from nozzle and fuel tank or fuel
container opening.
•If gasoline is spilled on clothing, change clothing
immediately.
Understand Machine Operation
Only qualified and trained personnel should operate
the equipment.
Carefully read the operator’s manual and all manuals
furnished with the attachments. Learn the location
– denotes immediate hazards which WILL result in
severe personal injury or death.
– denotes a hazard or unsafe practice which
COULD result in severe personal injury or death.
DANGER
WARNING

REV A 2-2 122832
and purpose of all controls, instruments, indicators
and labels.
Wear Protective Clothing
Do not operate or service the equipment while wearing
sandals, tennis shoes, sneakers, shorts or any type of
loose fitting clothing. Long hair, loose clothing or jew-
elry may get tangled in moving parts. Always wear
long pants, safety glasses, ear protection and safety
shoes when operating or servicing this machine.
Always wear adequate eye protection when servicing
the hydraulic system and battery, or when grinding
mower blades and removing accumulated debris.
Prolonged exposure to loud noise can cause impair-
ment or loss of hearing.
•Always wear adequate ear protection, such as
earplugs, when operating this equipment as pro-
longed 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.
Operation Precautions
Avoid Fire Hazards
Clean flammable material from machine. Prevent fires by
keeping engine compartment, top of deck, exhaust area,
battery, hydraulic lines, fuel line, fuel tank and operator’s
station clean of accumulated trash, grass clippings, and
other debris. Always clean up spilled fuel and oil.
Start Engine Safely
Avoid possible injury or death from machine runaway.
Do not start engine by shorting across starter termi-
nals.
Before you start the engine:
•Stand on the operator’s platform.
•Move control levers to the neutral/brake position.
•Move the park brake lever to the engaged park
brake position.
•Move the steering control levers to the neutral
position.
•Place the deck clutch switch in the down (deck
blades disengaged) position.
Operate Machine Safely
Refer to the unit’s operator’s manual for complete
safety information on safe machine operation.
Always maintain a safe distance from people and pets
when mowing.
Always be aware of what is behind the machine before
backing up.
Never leave machine unattended with ignition key in
switch, especially with children present.
Follow daily and weekly checklists, making sure hoses
are tightly secured and bolts are tightened.
Always keep engine and machine clean, removing
accumulated dirt, trash and other material from
machine.
Never put hands or feet under any part of the machine
while it is running.
Never attempt to start engine when there is a strong
odor of gasoline fumes present. Locate and correct
cause.
Keep all safety shields and covers in place, except for
servicing.
Do not touch hot parts of machine.
General Maintenance Precautions
Repairs or maintenance requiring engine power should
be performed by trained maintenance personnel only.
Never run the engine in an enclosed area unless
exhaust is vented to the outside. Exhaust gases con-
tain carbon monoxide which is an odorless and deadly
poison.
Unless specifically required, DO NOT have the engine
running when servicing or making adjustments to the
mower.
•Park the mower on level ground.
•Disengage the deck clutch.
•Place the steering control levers in the neutral
position.
•Place the park brake lever in the engaged park
brake position.
•Lower the deck.
•Stop the engine.
•Remove the ignition key.
•Wait for all movement to stop before adjusting,
cleaning or repairing.
•Disconnect the negative battery cable.
•Repairs or maintenance requiring engine power
should be performed by trained maintenance per-
sonnel only.
•To prevent carbon monoxide poisoning, operate
the engine in a well ventilated area only.
•Read and observe all safety warnings in this man-
ual.
Before working on or under the deck, make certain the
engine cannot be accidentally started.
Always keep belt covers on mower deck for safety as
well as for cleanliness except when changing or check-
ing the belt.

122832 2-3 REV A
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 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.
Always wear adequate eye protection when:
•servicing the hydraulic system.
•servicing the battery.
•grinding mower blades and removing accumu-
lated debris.
Never attempt to make any adjustments or repairs to
the mower drive system, mower deck or any attach-
ment while the engine is running or deck clutch is
engaged.
Exercise caution when releasing spring tension from
any of the belt idlers or when working with any of the
deck lift components.
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 appropri-
ate 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 jack
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.
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 original Big Dog®Mower replacement parts or
parts that are equivalent in overall performance.
•The mower may not comply with the appropriate
safety standards if aftermarket parts, accesso-
ries, or attachments are used.
Maintenance Precautions
Avoid Fire Hazards
Be prepared if an accident or fire should occur. Know
where the first aid kit and the fire extinguishers are
located and how to use them.
Provide adequate ventilation when charging batteries.
Do not smoke near battery.
Never check fuel level with an open flame.
Never use an open flame to look for leaks anywhere on
the equipment.
Never use an open flame as light anywhere on or
around the equipment.
When preparing engine for storage, remember that fuel
stabilizer is volatile and therefore dangerous. Seal and
tape openings after adding the inhibitor. Keep con-
tainer tightly closed when not in use.
Inspect electrical wiring for worn or frayed insulation.
Install new wiring if wires are damaged.
Prepare for Emergencies
Be prepared if a fire starts.
Keep a first aid kit and fire extinguishers available.
Keep emergency numbers for doctor, ambulance ser-
vice, hospital, and fire department near the telephone.
Prevent Battery Explosions
Battery posts, terminals, and related accessories con-
tain lead and lead compounds, chemicals known to the
State of California to cause cancer and reproductive
harm. Wash hands after handling.
Charge batteries in a well-ventilated open area, away
from sparks and flames. Unplug charger before connect-
ing or disconnecting from battery. Wear protective cloth-
ing 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 disconnect
the negative (black) battery cable(s) before dis-
connecting the positive (red) cable(s). Always
connect the positive (red) battery cable(s) before
connecting the negative (black) cable(s).
•Do not overfill the battery.

REV A 2-4 122832
•Electrolyte may overflow and damage paint, wir-
ing or structure. When cleaning the battery, use
soap and water. Be careful not to get soap and
water into the battery. Clean the battery termi-
nals with a solution of four parts water and one
part baking soda when they become corroded.
Shorts caused by battery terminals or metal tools
touching 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).
Avoid Acid Burns
Sulfuric acid in battery electrolyte is poisonous. It is
strong enough to burn skin, eat holes in clothing and
cause blindness if splashed in eyes.
Avoid the hazard by:
•Filling batteries in a well-ventilated area.
•Wearing eye protection and rubber gloves.
•Avoiding breathing fumes when electrolyte is
added.
•Avoiding spilling or contacting dripped electro-
lyte.
If you spill acid on yourself:
•Flush your skin with water.
•Apply baking soda or lime to help neutralize the
acid.
•Flush your eyes with water for 10–15 minutes.
Get medical attention immediately.
If acid is swallowed:
•Drink large amounts of water or milk.
•Then drink milk of magnesia, beaten eggs or veg-
etable oil.
•Get medical attention immediately.

122832 3-1 REV A
TORQUE
Standard Torques
The following chart lists the standard torque values for the threaded fasteners found in this manual. Torque all cap screws, nuts
and set screws to these values unless a different torque is shown in the Special Torques section.
Special Torques
NOTE:
1. Lug nuts only – It is recommended that these be
checked after the first 2 hours of operation and every
50 hours and following removal for repair or replace-
ment.
2. Engine torque values – Refer to the respective engine
owner’s manual.
3. If mounting bolt is loosened or removed, do not re-use.
Replace with a new bolt. Use only hand tools to install
this fastener.
Size ft-lbs N•m Size ft-lbs N•m
#10 32.4 IN.-LBS. 3.6 M3 12 IN.-LBS. 1.3
.250 98.4 IN.-LBS. 11.1 M4 26.4 IN.-LBS. 3
.312 204 IN.-LBS. 23 M5 54 IN.-LBS. 6.1
.375 30 40 M6 92.4 IN.-LBS. 10.4
.438 48 65 M8 222 IN.-LBS. 25
.500 73 99 M10 37 50
.562 105 143 M12 64 87
.625 145 200 M14 103 140
.750 260 350 M16 160 215
.875 420 565 M20 320 435
Size ft-lbs N-m
Wheel (lug) nuts 170 95
Blade spindle bolt top 70 95
Blade spindle bolt bottom 118 160
Electric clutch mounting bolt 345–48 61–65
Engine pulley mounting bolt 345–48 61–65
Front wheel axle bolt Tighten the nut, then back it off
until the wheel spins freely
Wheel motor hub nut 230 312
Hydraulic pump pulley screw 14 19
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.
WARNING

REV A 3-2 122832

122832 4-1 REV A
POWER UNIT MAINTENANCE
Steering Adjustments
Steering control lever neutral adjustment
The mower’s steering has been factory adjusted to elimi-
nate creeping when the steering control levers are in the neu-
tral position. However, should the mower begin to creep, the
steering control lever linkage can be adjusted.
Fine adjustment to the unit’s steering is made with the
transmission’s control rod.
Neutral is properly adjusted when the steering control
levers are in the neutral position and the drive wheels do not
rotate.
If this occurs, the steering control linkage may be adjusted
as follows:
1. Raise the rear of the mower and block with certified
jack stands. The rear wheels need to be able to rotate
freely and clear of all obstructions.
2. Chock the front tires.
3. Insert a 1/4” pin through the opening in the mower
frame and into the steering control lever. This ensures
that the steering control lever is in the neutral position.
Figure 4-1
4. Start the engine and release the park brake.
5. Observe which way the wheel(s) are rotating. If
wheel(s) are rotating forward, loosen the jam nuts on
the pump linkage rods and rotate the rod to lengthen
the steering control linkage until the wheel(s) come to
a stop. Figure 4-2
Repeat for the opposite side if necessary.
6. If wheel(s) are rotating in reverse then loosen the jam
nuts on the pump linkage rods and rotate the rod to
shorten the steering control linkage until the wheel(s)
come to a stop. Figure 4-2
Repeat for the opposite side if necessary
7. When both wheels remain in neutral, tighten the jam
nuts to lock the turnbuckles in place.
8. Remove the 1/4” pin that is holding the steering con-
trol lever in the neutral position.
9. Check to make sure all tools or obstructions are
removed from under the mower.
This procedure will require that the unit be raised
and blocked up off of the ground. It is necessary for
the wheels to rotate without coming in contact with
the floor or any object that would permit the unit to
propel itself. Stay clear and exercise caution when
rotating wheels to prevent injury. Use only appropri-
ate vehicle stands, with a minimum weight rating of
2000 pounds to block the unit up. Use in pairs only.
Follow the instructions supplied with the vehicle
stands.
Keep hands, hair, clothing, etc., clear of the cooling
fans on top of the transmissions. Exercise extreme
caution.
Untrained maintenance personnel should never
attempt to make any adjustments or repairs to the
mower’s drive system while the engine is running.
The following procedures should be performed by
trained maintenance personnel only.
WARNING
WARNING
WARNING
A. 1/4” pin B. Steering control lever
Figure 4-1
A
B

REV A 4-2 122832
10. Raise the rear of the mower and remove the jack
stands. Lower the mower.
Steering Control Lever Stops
The steering control lever stops (see Figure 4-3) are
designed to keep the pumps from bottoming out internally.
To keep the pumps from bottoming out internally use
the following procedure:
This adjustment is only required if the hydraulic pump(s) or
pump linkage rod(s) have been replaced.
NOTE: To make this adjustment the mower engine must
not be running.
NOTE: Neutral adjustment must be done before proceed-
ing.
1. Slowly move the steering control levers forward and
feel if there is some resistance on the pump control
lever before the steering handle stop contacts the
steering control lever stop screw.
2. Check one side at a time. If you sense that the pump
control lever is stopping the forward motion of the
steering control lever, then the steering control lever
stop screw needs adjusted.
3. Move the steering control lever forward until the pump
lever bottoms out.
4. Loosen the jam nut on the steering control lever stop
screw. Figure 4-4
5. Turn the steering control lever stop screw until it
makes contact with the steering handle stop. Then,
turn it an additional 1/4 turn. Tighten the jam nut.
Figure 4-4
6. Repeat for the other side.
A. Jam nuts B. Steering linkage rods
Figure 4-2
Pump damage will occur if these stops are set
incorrectly.
A
A
B
B
A
A
WARNING
A. Steering control lever
stop screw B. Steering control lever C. Steering handle stop
Figure 4-3
A. Steering control lever
stop screw B. Jam nut
Figure 4-4
A
B
C
B
A

122832 4-3 REV A
To adjust the stops for driving straight when steering
control levers are against the stops during operation:
Before considering any adjustment, check the tire air pres-
sure. Unequal tire pressure will cause the mower to drift to
one side. Refer to tire pressure information in the Tires sec-
tion for detailed information.
1. Remove the front cover.
2. Push forward on the steering control lever until it con-
tacts the steering control lever stop. Repeat for other
side.
3. Loosen the lock nut and back the speed adjusting
screw out until it does not contact the steering handle
stop. Repeat for other side. Figure 4-5
4. To determine which of the drive wheels is turning the
slowest it will be necessary to drive the machine.
•Test drive the mower on a smooth level surface.
•Start the engine.
•Release the park brake.
•Set the throttle to the full open position.
•Slowly push the steering control levers to the full
forward position.
•Determine which drive wheel is rotating faster.
•Pull the steering control levers to the neutral
position.
•Set the throttle to the slow position.
•Turn engine off.
5. Move the steering control lever on the slower speed
side forward until it makes contact with the steering
control lever stop. Turn the speed adjusting screw
down until it makes contact with the steering handle
stop (finger tight). Tighten lock nut. Figure 4-5
6. Move the steering control lever on the faster speed
side forward until it makes contact with the steering
control lever stop. Turn the speed adjusting screw
down until it makes contact with the steering handle
stop (finger tight). Using a wrench turn the adjusting
screw an additional 1/4 turn. Tighten lock nut.
Figure 4-5
7. Test drive the mower to determine if the wheels are
rotating at the same speed. If not, repeat this proce-
dure until unit drives straight.
NOTE: Since this is a hydrostatic drive, variables such as
temperature of oil, efficiency of pumps and motors, tire pres-
sure etc. may effect the consistency of the ability to rely on
the stops to drive straight without the operator making minor
steering adjustments with the control arms.
Park Brake Adjustment
Before considering any adjustment, check the tire air pres-
sure. Refer to tire pressure information in the Tires section
for detailed information.
1. Release the park brake.
2. Treadlock plate (left side) – Loosen both the carriage
bolts that hold the treadlock plate in place. Figure 4-6
Treadlock plate (right side) – Loosen both the carriage
bolts and adjust the treadlock plate until the carriage
bolts are in the middle of the slots. Tighten the
carriage bolts. Figure 4-7
3. Loosen the hardware that attaches the brake link to
the treadlock mounting bar. Adjust the brake link so
that the gap between the tire and the right treadlock
plate is .75". Tighten the hardware. Figure 4-7
4. Adjust the left treadlock plate so that the gap between
it and the tire is .75". Figure 4-6
5. Engage park brake lever. The park brake plate should
push in on the tire to prevent it from rotating.
6. If one of the treadlock plates does not fully engage the
tire then it may be necessary to readjust the treadlock
plate until it fully engages the tire.
Belts
Inspect belts frequently for wear and serviceability.
Replace a belt that shows signs of:
•severe cuts
•tears
•separation
•weather checking
•cracking
•burns caused by slipping.
A. Steering control lever
stop screw
B. Steering control lever
C. Speed adjusting screw
D. Steering handle stop
Figure 4-5
A
B
C
D

REV A 4-4 122832
Slight raveling of belt covering does not indicate failure,
trim ravelings with a sharp knife.
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 dam-
age 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.
Hydraulic Pump Belt Adjustment
The transmission drive belt tension remains constant by
means of a tension idler and spring. The spring tension
should be such that the belt does not slip under normal oper-
ating load conditions, assuming the belt is not excessively
worn or damaged. As the belt stretches and wears in, adjust-
ment may become necessary.
The proper belt tension is achieved when the tension
spring is stretched to a dimension of 7.80” ± .125”
(198.12mm ± 3.18mm) when measured from the outside of
the hook to the outside of the other hook. Figure 4-8
To increase belt tension, loosen the jam nut on the eye
bolt. Then, tighten the nut on the eyebolt until the
7.80” ± .125” (198.12mm ± 3.18mm) dimension is attained.
Lock the eyebolt in place by tightening the jam nut.
Figure 4-8
IMPORTANT: Do not over tension the spring to compen-
sate for a badly worn belt or pulley.
Inspect the belt every 100 hours and replace as needed.
Replace the belt every 400 hours or every two (2) years
whichever comes first.
Left side shown
A. Carriage bolts
B. Treadlock plate C. Slot
Figure 4-6
Right side shown
A. Carriage bolts
B. Treadlock plate
C. Hardware
D. Brake link
E. Treadlock mounting bar
F. Slot
Figure 4-7
B
A
C
B
A
CD
E
F
If the pump belt fails, loss of steering control will
occur especially when operating on a slope. If you
lose steering control while operating the mower, turn
the engine off and, if on a slope, step off of the oper-
ator’s platform to the uphill side. Inspect the
machine and involve your Big Dog®Mower Dealer to
resolve the problem before continuing to operate.
WARNING

122832 4-5 REV A
Hydraulic System
IMPORTANT: Never use hydraulic or automatic transmis-
sion fluid in this system; use only synthetic motor oil as
specified. Remember, dirt is the primary enemy of any
hydraulic system.
Check oil level in hydraulic system after every 50 hours of
operation or weekly, whichever occurs first. The hydraulic
system must be cool when checking the oil level and the
mower should be on level ground. Check more often if sys-
tem appears to be leaking or otherwise malfunctioning.
Use the hydraulic reservoir’s sight glass to check the reser-
voir fluid level. The oil level should be approximately in the
middle of the sight glass. Figure 4-9
Only use full synthetic 15W50 oil in the hydraulic system.
NOTE: The reservoir (Figure 4-10) will require approxi-
mately 1.0 U.S. gallons (3.78 liters) of full synthetic 15W50
oil when replacing the oil after an oil and filter change. Do not
overfill the reservoir.
Initial system oil and filter change must be after the first 50
hours of mower operation. Thereafter, replace filter and oil in
the reservoir annually or every 500 hours, whichever comes
first.
IMPORTANT: It is necessary to drain the system oil from
the hydraulic reservoir, using the reservoir drain plug, before
removing the hydraulic filter. Replace the drain plug before
adding system oil.
The system filter is located at the left rear of the engine.
Use a Big Dog®approved filter element only. When changing
the filter use a standard oil filter wrench. The threads are
right hand. Figure 4-11
IMPORTANT: Pre-fill the filter element with clean oil
before installing, to prevent drawing air into the system
pump.
Hydraulic Pump Flow Test
The design purpose of the Bi-Directional Flow Test Kit is to
allow the technician to isolate the pump from the wheel
motor and determine if the pump is acceptable. The follow-
A. Transmission drive belt
B. Tension spring
C. Eyebolt
D. Nut
E. Jam nut
F. 7.80” ± .125”
(198.12mm ± 3.18mm)
Figure 4-8
Hydraulic fluid escaping under pressure may have
sufficient force to penetrate skin and cause seri-
ous injury. Foreign fluid injected into the skin must
be surgically removed within a few hours by a doc-
tor, familiar with this form of injury, or gangrene
may result.
Before applying pressure to hydraulic system,
make sure all connections are tight and all hoses
and lines are in good condition. To find a leak
under pressure, use a piece of cardboard or wood
— never use your hands. Relieve all pressure in the
system before disconnecting or working on
hydraulic lines. To relieve pressure, lower all
attachments and shut off engine.
A
B
D
C
E
F
WARNING
A. Sight glass
Figure 4-9
A

REV A 4-6 122832
ing information can be used to install and test the pump by
simulating a wheel motor load.
Bi-Directional Flow Test Kit Installation
Disconnect the system hoses at the wheel motor, or sys-
tem hoses from the pump and connect the Bi-Directional
Flow Test Kit. (Special care should be taken to prevent con-
tamination debris from entering pump or wheel motor sys-
tem ports).
NOTE: Using the Bi-Directional Flow Test Kit, determina-
tion of directional flow is not necessary. The flow meter may
be connected in either direction into the forward and reverse
high pressure system lines.
NOTE: The following adapter fittings will be required when
connecting the Bi-Directional Test Kit (Excel P/N 783886 or
Hydro-Gear P/N 70661):
PG/PL Series Pumps require two 771311 adapter fittings
PJ Series Pumps require two 771311 adapter fittings
CAUTION: Ensure all fittings and hoses are attached
securely. This test is being completed on the vehicle’s high
pressure system lines. Failure to perform this properly could
result in bodily injury.
A. Hydraulic reservoir
Figure 4-10
A. Hydraulic filter
Figure 4-11
A
A
Potential for serious injury! Never work under the
machine or attachment unless it is safely sup-
ported with jack stands. To prevent possible injury
to the servicing technician and/or bystanders,
ensure the vehicle is properly secured.
•Make certain machine is secure when it is
raised and placed on the jack stands.
• 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
jack stands.
Do not attempt any adjustments with the engine run-
ning. Use extreme caution while working in or around
all vehicle linkage! High temperatures can be gener-
ated. Follow all safety procedures outlined in the
mower’s operator’s manual!
WARNING
WARNING

122832 4-7 REV A
Bi-Directional Flow Testing Procedures
1. Use approved jack stands to raise the drive wheels off
the floor.
2. Open the restriction valve all the way.
3. For the pump being tested, move the steering control
levers in full forward motion. (It will be necessary to
lock the steering control levers into full forward posi-
tion to prevent false readings).
4. Increase the engine rpms until the maximum engine
rpm is achieved.
CAUTION: Damage to the flow meter and/or re-
calibration may result from testing at input speeds that
exceed the above recommendations.
5. Operate without any load for approximately 30 sec-
onds to 1 minute. This allows the system oil tempera-
ture to rise.
NOTE: Raising the system oil temperature will make a
difference in the readings you receive. It has been
determined that to complete this test accurately, the oil
temperature must be near system operating
temperatures. Suggested temperature range 160°–210°F
(71.1°–98.9° C).
6. Tighten the flow meter restriction valve until the gauge
reads 300 psi (21 bar).
Record the flow reading on the Bi-Directional Flow Meter.
7. Increase the pressure to 1100 PSI (76 bar).
Record the flow reading on the Bi-Directional Flow Meter.
8. The acceptable gpm “flow droop” or “difference” is:
If the difference exceeds these values the pump would
not be operating efficiently and should be replaced or
repaired. See the following example.
Never work under the machine or attachment
unless it is safely supported with jack stands. To
prevent possible injury to the servicing technician
and/or bystanders, ensure the vehicle is properly
secured.
•Make certain machine is secure when it is
raised and placed on the jack stands.
• 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
jack stands.
WARNING
PG/PL (36” mowers) 1.5 gpm (5.6 l/min)
PJ (48”/52”/60” mowers) 2.0 gpm (7.6 l/min)

REV A 4-8 122832
Test Example: PG/PL or PJ Pump
300 psi (21 bar) reading 7 gpm (26 l/min) (1st reading)
1100 psi (76 bar) reading 3 gpm (11 l/min) (2nd reading)
PG/PL or PJ
300 psi (21 bar) reading 7 gpm (26 l/min) (1st reading)
1100 psi (76 bar) reading -3 gpm (11 l/min) (2nd reading)
4 gpm (15 l/min) (the difference)
Subtract the 1st reading from the 2nd.
(In this example, 4 gpm difference would indicate further pump examination).
Purging Procedures
Due to the effects air has on efficiency in hydrostatic drive
applications, it is critical that air is purged from the system.
These purge procedures should be implemented any time a
hydrostatic system has been opened to facilitate mainte-
nance or additional oil has been added to the system.
Air creates inefficiency because its compression and
expansion rates that are higher than that of oil.
Entrained air in the oil may cause the following symptoms:
1. Noisy operation.
2. Lack of power or drive after short term operation.
3. High operation temperature and excessive expansion
of oil.
Before starting, make sure the reservoir is at the proper oil
level. If it is not, fill to the vehicle manufacturer’s specifica-
tions.
RESTRICTION VALVE
BI-DIRECTIONAL
FLOW METER
CONNECTIONS TO THE
FWD/RVS LINES DIS-
CONNECTED FROM
WHEEL MOTOR
CONNECTIONSTOTHE
FWD/RVS LINES DIS-
CONNECTED FROM
WHEEL MOTOR
RESTRICTION VALVE
BI-DIRECTIONAL
FLOW METER