Scag Power Equipment STT-31BSD User manual

MODEL STT-31BSD
OPERATOR’S MANUAL
THIS MANUALCONTAINS THE OPERATING
INSTRUCTIONS AND SAFETY INFORMA-
TION FOR YOUR SCAG MOWER. READING
THIS MANUAL CAN PROVIDE YOU WITH
ASSISTANCE IN MAINTENANCE AND AD-
JUSTMENT PROCEDURES TO KEEP YOUR
MOWER PERFORMING TO MAXIMUM EFFI-
CIENCY. THE SPECIFIC MODELS THATTHIS
BOOK COVERS ARE CONTAINED ON THE
INSIDECOVER. BEFORE OPERATINGYOUR
MACHINE, PLEASE READ ALL THE INFOR-
MATION ENCLOSED.
PART NO. 03153
PRINTED10/04
PRINTED IN USA
©2004
SCAGPOWEREQUIPMENT
DIVISION OF METALCRAFT OF MAYVILLE, INC.

FAILURE TO FOLLOW SAFE OPERATING PRACTICES
MAY RESULT IN SERIOUS INJURY.
* Keep all shields in place, especially the grass discharge chute.
* Before performing any maintenance or service, stop the machine and
remove the spark plug wires and ignition key.
* Ifa mechanism becomes clogged,stop the engine beforecleaning.
* Keep hands, feet and clothing away from power-driven parts.
* Read this manual completely as well as other manuals that came
withyourmower.
* Keep others off the tractor (only one person at a time)
REMEMBER -YOUR MOWER IS ONLY AS SAFE ASTHE OPERATOR!
Hazard control and accident prevention are dependent upon the awareness,
concern, prudence, and proper training of the personnel involved in the
operation, transport, maintenance, and storage of the equipment.
This manual covers the operating instructions
and illustrated parts list for:
STT-31BSD with a serial number of A7400001 to A7499999
SMST-61A with a serial number of A7500001 to A7599999
SMST-72A with a serial number of A7600001 to A7699999
Always use the entire serial number listed on the serial number
tag when referring to this product.
WARNING:

I
TABLE OF CONTENTS
SUBJECT PAGE
Section 1 - General Information
1.1 Introduction .............................................................................................................................1
1.2 Directional Reference.............................................................................................................1
1.3 Servicing the Engine and DriveTrain Components ................................................................1
Section 2 - Safety Information
Symbols ............................................................................................................................... 2-3
2.1 Introduction .............................................................................................................................4
2.2 SignalWords ...........................................................................................................................4
2.3 Before Operation Considerations ...........................................................................................4
2.4 Operation Considerations ........................................................................................................5
2.5 Roll Over Protection System ..................................................................................................6
2.6 Maintenance Considerations ...................................................................................................8
2.7 Safety and Instructional Decals ..............................................................................................9
Section 3 - Specifications ....................................................................................................10-11
Section 4 - Operating Instructions
4.1 Controls and Instrument Identification ..................................................................................12
4.2 Safety Interlock System........................................................................................................13
4.3 Initial Run-In Procedures......................................................................................................14
4.4 Starting the Engine ................................................................................................................14
4.5 Ground Travel and Steering ..................................................................................................14
4.6 Engaging the Deck Drive .....................................................................................................15
4.7 HillsideOperation .................................................................................................................16
4-8 Parking the Mower ...............................................................................................................16
4.9 After Operation ....................................................................................................................16
4.10 Removing Clogged Material .................................................................................................17
4.11 Moving Mower with Engine Stopped ...................................................................................17
4.12 Recommendations for Mowing .............................................................................................17
4.13 Adjusting Cutting Height .......................................................................................................18
Section 5 -Troubleshooting Cutting Conditions.............................................................. 19-21

II
TABLE OF CONTENTS (CONT'D)
SUBJECT PAGE
Section 6 - Adjustments
6.1 Parking Brake Adjustment ....................................................................................................22
6.2 TravelAdjustments ...............................................................................................................22
6.3 Throttle Control and ChokeAdjustments..............................................................................24
6.4 BeltAdjustment ....................................................................................................................24
6.5 BeltAlignment ......................................................................................................................24
6.6 Cutter Deck Adjustments .....................................................................................................25
Section 7 - Maintenance
7.1 Maintenance Chart ...............................................................................................................28
7.2 LubricationFitting Points ......................................................................................................29
7.3 Hydraulic System ..................................................................................................................31
7.4 EngineOil .............................................................................................................................32
7.5 Engine Fuel System ..............................................................................................................33
7.6 EngineAir Cleaner................................................................................................................33
7.7 Battery ..................................................................................................................................33
7.8 Drive Belts ............................................................................................................................35
7.9 Cutter Blades ........................................................................................................................35
7.10 Tires ......................................................................................................................................36
7.11 Cutter Deck Gearbox ...........................................................................................................36
7.12 CoolingSystem .....................................................................................................................37
7.13 Body, Deck, Hopper and Upholstery ....................................................................................38
Section 8 - Illustrated Parts List
Notes ..............................................................................................................................................39
SMST 61"Adv., 72"Adv. Cutter Decks ................................................................................... 40-41
Cutter Deck Controls................................................................................................................ 42-43
Sheet Metal Components.......................................................................................................... 44-45
STT Roll Over Protection......................................................................................................... 46-47
Deck Drive Components .......................................................................................................... 48-49
Radiator, Coolers & Engine Brackets.................................................................................50-51
Brake & Steering Components..........................................................................................52-53
Fuel & Hydraulic System ......................................................................................................... 54-55
Electrical System ...................................................................................................................... 56-57
Hydraulic Pump Assembly - BDP-21L .................................................................................... 58-59
Wire Harness, STT-31BSD ............................................................................................................60
Replacement Decals................................................................................................................. 61-62
Warranty Statement............................................................................................. Inside Back Cover

1
GENERAL INFORMATION
1.1 INTRODUCTION
Your mower was built to the highest standards in the
industry. However, the prolonged life and maximum
efficiency of your mower depends on you following the
operating, maintenance and adjustment instructions in this
manual.
If additional information or service is needed, contact
your Scag Power Equipment Dealer.
We encourage you to contact your dealer for repairs. All
Scag dealers are informed of the latest methods to
service this equipment and provide prompt and efficient
service in the field or at their service shop. They carry a
full line of Scag service parts.
USE OF OTHER THAN ORIGINAL SCAG
REPLACEMENT PARTS WILL VOID THE
WARRANTY.
When ordering parts, always give the model and serial
number of your tractor. The serial number plate is
located where shown in Figure 1-1.
For pictorial clarity,some illustrations and figures
in this manual may show shields, guards or plates
open or removed. Under no circumstances should
your mower be operated without these devices in
place.
All information is based upon product information
available at the time of approval for printing. Scag
Power Equipment reserves the right to make
changes at any time without notice and without
incurring any obligation.
1.2 DIRECTION REFERENCE
The “Right” and “Left”, “Front” and “Rear” of the
machine are referenced from the operator’s right and left
when seated in the normal operating position and facing
the forward travel direction.
1.3 SERVICING THE ENGINE AND DRIVE
TRAIN COMPONENTS
The detail servicing and repair of the engine, hydraulic
pumps and gearboxes are not covered in this manual;
only routine maintenance and general service instructions
are provided. For service of these components during
the limited warranty period, it is important to contact your
Scag dealer or find a local authorized servicing agent of
the component manufacturer. Any unauthorized work
done on these components during the warranty period
may void your warranty.
Section 1
Figure 1-1Tractor Serial Number Plate Location
390S0137A
SERIAL NUMBER
PLATE LOCATION
R
MODEL
SERIAL
DivisionofMetalcraftofMayville,Inc.
Mayville,Wisconsin53050
PatentsIssuedandPending
MANUFACTUREDUNDERONEORMORE
OF THEFOLLOWINGPATENTS:
PATENTS PENDING
4,487,006
4,885,903
4,920,733
4,967,543
4,991,382
4,998,948
5,118,617
5,826,416
5,832,708
5,865,018
WARNING:
USE ONLY SCAG APPROVED ATTACHMENTS
AND ACCESSORIES.
Attachments and accessories manufactured by companies
otherthanScagPowerEquipmentarenotapprovedforuse
on this machine.
Scag approved attachments and accessories:
GC-STT(p/n 9049, 9039)
GC-STT-CS (p/n 9053, 9041)
Mulch Plate (p/n 9261, 9262)
Hurricane Mulch (p/n 9266, 9267)
Cup Holder (p/n 9240)
STT Hitch (p/n 9242)
STT Bumper (p/n 9256)
STT - Suspension Seat (p/n 9270)
STT - Lights (p/n 9279)
Tiger Striper (p/n 9269)
Blade Buddy (p/n 9212)

2
CE Mark
Transmission
Choke
On/Start Spring Tension on Idler
Oil
Off/Stop
SYMBOL DESCRIPTION
SYMBOL DESCRIPTION
ISO Symbols
SpinningBlade
48071S
Parking Brake
WARNING
FALLING HAZARD
USE ONLY SCAG APPROVED
RIDING ATTACHMENTS
SEE OPERATOR'S MANUAL
481109
FallingHazard

3
Slow
Fast
Cutting Element - Engage
Cutting Element - Basic Symbol
Cutting Element - Disengage
Continuously Variable - Linear
Read Operator's Manual
Keep Bystanders Away
Pinch Point
481039S
SYMBOL DESCRIPTION SYMBOL DESCRIPTION
Hourmeter/Elapsed Operating Hours
Thown Object Hazard

4
SAFETY INFORMATION
2.1 INTRODUCTION
Your mower is only as safe as the operator.
Carelessness or operator error may result in serious
bodily injury or death. Hazard control and accident
prevention are dependent upon the awareness, concern,
prudence, and proper training of the personnel involved in
the operation, transport, maintenance and storage of the
equipment. Make sure every operator is properly trained
and thoroughly familiar with all of the controls before
operating the mower. The owner/user can prevent and is
responsible for accidents or injuries occuring to
themselves, other people or property.
READ THIS OPERATOR’S MANUAL BEFORE
ATTEMPTING TO START YOUR MOWER.
A replacement manual is available from your authorized
Scag Service Dealer or by contacting Scag Power
Equipment, Service Department at P.O. Box 152,
Mayville, WI 53050 or via the Internet at
www.scag.com. The manual for your machine can be
downloaded by using the model and serial number or use
the contact form to make your request. Please indicate
the complete model and serial number of your Scag
product when requesting replacement manuals.
2.2 SIGNAL WORDS
This symbol means “Attention! Become Alert! Your
Safety is Involved!" The symbol is used with the
following signal words to attract your attention to safety
messages found on the decals on the machine and
throughout this manual. The message that follows the
symbol contains important information about safety. To
avoid injury and possible death, carefully read the
message! Be sure to fully understand the causes of
possible injury or death.
Signal Word:
It is a distinctive word found on the safety decals on the
machine and throughout this manual that alerts the
viewer to the existence and relative degree of the
hazard.
The signal word “WARNING” denotes that a hazard
exists on or near the machine that can result in injury or
death if proper precautions are not taken.
The signal word “DANGER” denotes that an extremely
hazardous situation exists on or near the machine that
could result in high probability of death or irrepairable
injury if proper precautions are not taken.
CAUTION:
The signal word “CAUTION” is a reminder of safety
practices on or near the machine that could result in
personal injury if proper precautions are not taken.
Your safety and the safety of others depends significantly
upon your knowledge and understanding of all correct
operating practices and procedures of this machine.
2.3 BEFORE OPERATION
CONSIDERATIONS
1. NEVER allow children to operate this riding mower.
Do not allow adults to operate this machine without
proper instructions.
2. DO NOT mow when children and/or others are
present. Keep children out of the mowing area and
in the watchful care of a responsible adult other than
the operator. Be alert and turn machine off if a child
enters the area.
3. Clear the area to be mowed of objects that could be
picked up and thrown by the cutter blades.
4. DO NOT carry passengers.
5. DO NOT operate the machine under the influence
of alcohol or drugs.
WARNING:
Section 2

5
9. Keep the machine and attachments in good operating
condition. Keep all shields and safety devices in
place. If a shield, safety device or decal is defective
or damaged, repair or replace it before operating the
machine.
This machine is equipped with an interlock system
intended to protect the operator and others from
injury. This is accomplished by preventing the
engine from starting unless the deck drive is
disengaged, the parking brake is on, the steering
control levers are in the neutral position and the
operator is in the seat. The system shuts off the
engine if the operator leaves the seat with the deck
driveengagedand/or the steering control levers are
not in the neutral postion and the parking brake is
not engaged. Never operate equipment with the
interlock system disconnected or malfunctioning.
10. Be sure the interlock switches are functioning
correctly.
11. Fuel is flammable; handle it with care. Fill the fuel
tank outdoors. Never fill it indoors. Use a funnel or
spout to prevent spillage. Clean up any spillage
before starting the engine.
12. DO NOT add fuel to a running or hot engine. Allow
the engine to cool for several minutes before adding
fuel.
13. Keep flammable objects (cigarettes, matches, etc.),
open flames and sparks away from the fuel tank and
fuel container.
14. Equipment must comply with the latest requirements
per SAE J137 and/or ANSI/ASAE S279 when
driven on public roads.
If the mower is driven on public roads, it must
comply with state and local ordinances as well as
SAE J137 and/or ANSI / ASAE S279
requirements. Contact your local authorities for
regulations and equipment requirements.
15. DO NOT operate without the side discharge chute
installed and in the down position or with an optional
grass catcher or mulch plate completely installed.
16. Check the blade mounting bolts at frequent intervals
for proper tightness.
17. Make sure all hydraulic fluid connections are tight
and all hydraulic hoses and lines are in good condition
before starting the machine.
2.4 OPERATION CONSIDERATIONS
1. Know the function of all controls and how to stop
quickly.
2. Reduce speed and exercise extreme caution on
slopes and in sharp turns to prevent tipping or loss of
control. Be especially cautious when changing
directions on slopes.
DO NOT operate on steep slopes. To check a slope,
attempt to back up it (with the cutter deck down). If
the machine can back up the slope without the
wheels slipping, reduce speed and use extreme
caution. ALWAYS FOLLOW OSHA APPROVED
7. DO NOT wear loose fitting clothing. Loose
clothing, jewelry or long hair could get tangled in
moving parts. Do not operate the machine wearing
shorts; always wear adequate protective clothing
including long pants. Wearing safety glasses, safety
shoes and a helmet is advisable and is required by
some local ordinances and insurance regulations.
8. Operator hearing protection is recommended,
particularly for continuous operation of the mower.
Wear suitable hearing protection. Prolonged
exposure to loud noise can cause hearing
impairment or loss.
2.3 BEFORE OPERATION
CONSIDERATIONS (CONT'D)
6. If the operator(s) or mechanic(s) cannot read English
or Spanish, it is the owner's responsibility to explain
this material to them.
Section 2
WARNING:
OPERATION.
-NOTE-
WARNING:

6
Section 2
2.4 OPERATION CONSIDERATIONS
(CONT'D)
3. To prevent tipping or loss of control, start and stop
smoothly, avoid unnecessary turns andtravelatreduced
speed.
4. When using any attachment, never direct the discharge
of material toward bystanders or allow anyone near
the machine while in operation.
5. Before attempting to start the engine, with the operator
in the seat, disengage power to the cutter deck, place
the steering control levers in the neutral position and
engage the parking brake.
6. If the mower discharge ever plugs, shut off the engine,
remove the ignition key, and wait for all movement to
stop before removing the obstruction.
DO NOT use your hand to dislodge the clogged
discharge chute. Use a stick or other device to
remove clogged material.
7. Be alert for holes, rocks, roots and other hidden hazards
in the terrain. Keep away from any dropoff. Beware
ofoverheadobstructions(lowlimbs, etc.), underground
obstacles(sprinklers,pipes,treeroots,etc.). Cautiously
enter a new area. Be alert for hidden hazards.
8. Disengage power to cutter deck before backing up.
Do not mow in reverse unless absolutely necessary
andthenonlyafterobservationoftheentireareabehind
the mower.
9. DO NOT turn sharply. Use care when backing up.
10. Disengage power to cutter deck before crossing roads,
walks or gravel drives.
11. Mowonlyin daylight or good artificial light.
12. NEVER raise the deck with the blades engaged.
13. Takeallpossibleprecautionswhenleavingthemachine
unattended, such as disengaging the mower, lowering
theattachments, setting the parking brake, stoppingthe
engine, and removing the key.
14. Disengagepower to theattachments when transporting
or when not in use.
15. The machine and attachments should be stopped and
inspected for damage after striking a foreign object,
and damage should be repaired before restarting and
operating the machine.
DO NOT touch the engine or the muffler while
the engine is running or immediately after
stopping. These areas may be hot enough to
cause a burn.
DO NOT run the engine inside a building or a
confined area without proper ventilation. Exhaust
fumes are hazardous and could cause death.
16. Keep hands and feet away from cutter blades and
moving parts. Contact can injure.
17. Use care when loading or unloading the machine onto
a trailer or truck.
18. Usecarewhenapproachingblindcorners,shrubs,trees,
or other objects that may obscure vision.
WARNING: WARNING:
CAUTION:
2.5 ROLL OVER PROTECTION SYSTEM
WARNING:
Seat belt must be securely fastened during
operation. Failure to do so could cause
serious injury or loss of life.

7
Section 2
This mower has been designed for good traction and
stabilityunder normalmowingconditions. However,caution
must be used when traveling on slopes, especially when
the grass is wet. Do not mow on wet grass. Wet grass
reduces traction and steering control.
Any or all parts of the Roll Over Protection System MUST
NOTbe removed. Failure to adhere to this guideline could
result in injury or death.
The potential exposure of this seat belt to severe
enviromental conditions make it crucial to inspect the seat
belt system regularly.
It is recommended that the seat belt be inspected on a
daily basis for signs of damage.Any seat belt system that
shows cuts, fraying, extreme or unusual wear, significant
discolorationdueto UV exposure, dirt or stiffness, abrasion
to the seat belt webbing, or damage to the buckle, latch
plate, hardware or any other obvious problem should be
replacedimmediately.
1. Check the full length of the seat belt webbing for cuts,
wear, fraying, dirt and stiffness. See Figure 2-1.
2. Check the seat belt webbing in areas exposed to ultra
violet rays from the sun or extreme dust or dirt. If the
originalcolorof the webbing in these areas isextremely
faded and/or is packed with dirt, the physical strength
ofthiswebbingmayhavedeteriorated.Ifthiscondition
exists, replace the seat belt system.
3. Check the buckle and latch for proper operation and
determine if the latch plate is exessively worn,
deformed, or of the buckle is damaged or cracked.
See Figure 2-1.
WARNING:
Failure to properly inspect and maintain the
seat belt can cause serious injury or loss of
life.
Reduce speed when turning, operating on slopes,
slick or wet surfaces. Allow extra distance to stop.
Stay off of slopes too steep for safe operation. To
check a slope, attemp to back up it (with the cutter
deck down). If the machine can not back up the
slope without the wheels slipping, do not operate
the machine on this slope.
ALWAYS travel up or down the slope whenever
possible. Never across the slope.
DO NOT mow near drop-offs, ditches or
embankments. The machine could suddenly roll
over if a wheel goes over the edge or if the edge
caves in.
Operate the machine smoothly, no sudden turns,
starts or stops on a slope.
NEVER tow on slopes. The weight of the towed
equipment may cause loss of traction and loss of
control.
DO NOT permit untrained personnel to operate
the machine.
WARNING:
INSPECT WEBBING
INSPECT BUCKLE
& LATCH
Figure 2-1 Seat Belt Inspection

8
11. Use jack stands to support components when
required.
12. Carefully release pressure from components with
stored energy.
13. Let the engine cool before storing.
14. DO NOT store the machine near an open flame.
15. Shut off fuel while storing or transporting.
16. DO NOT store fuel near flames or drain indoors.
17. Charge batteries in an open well ventilated area,
away from spark and flames. Unplug charger before
connecting or disconnecting from battery. Wear
protective clothing and use insulated tools.
Hydraulic fluid is under high pressure. Keep
body and hands away from pinholes or nozzles
that eject hydraulic fluid under high pressure.
If you need service on your hydraulic system,
please see your authorized Scag dealer. If
hydraulic fluid is injected into the skin, it must
be surgically removed within a few hours by a
doctor or gangrene may result.
2.6 MAINTENANCE CONSIDERATIONS &
STORAGE
1. Never make adjustments to the machine with the
engine running unless specifically instructed to do so.
If the engine is running, keep hands, feet, and
clothing away from moving parts.
2. Disengage drives, lower implement, set parking
brake, stop engine and remove key or disconnect
spark plug wire to prevent accidental starting of the
engine when servicing or adjusting the machine.
Wait for all movement to stop before adjusting,
cleaning or repairing.
3. Disconnect battery or remove spark plug wire before
making any repairs. Disconnect the negative
terminal first and the positive last. Reconnect the
positive first and the negative last.
4. Keep all nuts, bolts and screws tight, to ensure the
machine is in safe working condition. Check blade
mounting bolts frequently to be sure they are tight.
5. Do not change the engine governor settings or
overspeed the engine. See the engine operator's
manual for information on engine settings.
6. To reduce fire hazard, keep the cutting units, drives
muffler and engine free of grass, leaves, excessive
grease, oil and dirt.
WARNING:
Section 2
Figure 2-2. STT-BSD With Roll Over
Protection System.
7. Park the machine on level ground and engage the
parking brake.
8. NEVER allow untrained personnel to service the
machine.
9. Use care when checking blades. Wrap the blade(s)
or wear gloves and use caution when servicing
blades. Only replace blades. NEVER straighten or
weld blades.
10. Keep all parts in good working condition. Replace all
worn or damaged decals.

9
Section 2
2.7 SAFETY AND INSTRUCTIONAL DECALS
WARNING
INSTALL BELT COVER BEFORE
OPERATING MACHINE
READ OPERATOR'S MANUAL 481039
390S0150E- Rev 1
481568
FORWARD
REVERSE
FR
482710
482290
482286
482285
481039
482834
483046

10
Section 3
SPECIFICATIONS
SCAG “SABRE TOOTH TIGER” ZERO-TURN RIDER
MODEL: STT– 31BSD
ENGINE
GeneralType: HeavyDutyIndustrial/CommercialTurboChargedDiesel
Brand: BriggsDaihatsu VanguardLiquidCooled31HP
Model: DM950D
Horsepower: 31HP@3600RPM
Type: water cooled 4 cycle, overhead valve, 3 cylinder, diesel engine
Displacement: 952cc
Cylinders: 3 inline sleeves
Governor: High-speed flyweight governor, runs faster than engine crankshaft, provides precision
speedgoverning and asteady low idle,3600 rpm (±100rpm),idle set at1700 rpm
AirIntakeGroup: Canister type air filter system.
ExhaustGroup: Singleexhaustcanistermuffler
FuelInjection: Distributorinjectionpump
OilPumpGroup: PositivedisplacementGerotor™oilpumpwithremoteoilfilter,capacity3.2U.S.quarts
(3.0ltrs)withoilfilter
ValveGroup: Overhead
Electrical/ChargingSystem: 12 volt battery with alternator, solid state ignition with key start, 40 amp regulated
charging system, solenoid shift type starter
ENGINE DECK
FuelTank: 10 gallon (38.0 litres) seamless polyethylene tank with fuel gauge cap
DriveWheels/Tires: 24x12-12four-plypneumatic tubeless,radius edge, offset rims toimprove operator’sview
ParkingBrake: Lever operated interlocked parking brake prevents operation with parking brake engaged
Frame: Compact tractor frame with structural steel tubing construction
DRIVE SYSTEM
Type: Hydro drive with two variable displacement pumps and two cast iron motors for
independent control of each drive wheel
HydroPumps: Two Hydro-Gear ModelBDP 21Lpumps with dumpvalves for movement without running
engine
Drive Wheel Motors: Two 23 cubic inch cast-iron high torque wheel motors
TransmissionBeltIdler: Self-adjusting, self-tightening, sealed bearings
HydroFluidCoolingGroup: 6qt. capacity nylon fluid reservoir,uses SAE20W50 fluid and 10 micronfilter
Steering/TravelControl: Twin lever fingertip steering control with gas shock dampeners for smooth, responsive
control to each wheel
Axles: 1-1/4" heavy-duty, tapered motor shafts
Wire Harness: 14gaugewire
SafetyGroup: Seatactuatedenginekill,neutralinterlock,mowerengagement(BBC)switch,parking
brake
InstrumentPanel: Voltmeter, water temperature gauge, oil pressure gauge, key switch, throttle, fuses, BBC
switch (hourmeter located at rear of machine), glow plug indicator, water separator
indicator
ForwardGroundSpeedRange: 0to10.5mph
Reverse Ground Speed Range: 0to5.0mph
Date of Issue: October, 2004
Specifications Subject To Change Without Notice
-NOTE-
The machine will travel at 10.5 mph for
transport purposes. For best cutting
performance the forward travel speed
should be adjusted depending on the
cutting conditions.

11
Section 3
SPECIFICATIONS (CON'T)
SCAG “SABRE TOOTH TIGER” ZERO-TURN RIDER
MODEL: STT– 31BSD
CUTTER DECK
Type: SMST-72A ("Advantage") & SMST-61A ("Advantage") - Floating, adjustable anti-
scalping, hybrid design combines out-front and belly-mount designs. "Advantage" -
special extended front edge allows Bahia or other tough grasses to enter the deck
standing upright for a clean cutting.
Construction: 10-gauge steel top reinforced with 7 gauge support plate, deck skirt is 7 gauge steel
True Cutting Width: 72"cutterdeck=71.5 inches(181.6cm);61"cutterdeck=61.0"(155.0cm)
Cutting Height Adjustment: Foot-operated pedal adjustment from operator’s seat,
1" to 6" in 1/4" increments
CutterBlades: 72" = Three (3) 24" blades; 61" = Three (3) 21" blades
CutterDeckDrive: Drive shaft to 90 degree gear box
BladeEngagement: Electric blade engagement clutch with control panel knob
DischargeOpening: Extra wide 11.5" discharge opening with spring loaded discharge chute
Caster Wheels: 13 x 5 x 6 caster wheels with tapered roller bearing pivots
Spindles: Heavy duty 1-1/8" top dimension spindle shaft, cast housing, taper roller bearing, low
maintenance with top access grease fitting and grease overfill relief poppet
SpindlePulleys: Split Steel with easily removed taper hubs
CutterDeckBelts: B-section with Kevlarcord
Anti-ScalpRollers: Two front,tworear4-1/2"adjustable, two rear 12"fixed
ADDITIONAL SPECIFICATIONS
Seat: Thick padded seat cushions with special springs. Padded arm rests, lever adjustment
forward and back.
APPROXIMATE DIMENSIONS
72" 61"
Length: 92.0" 89.5"
TrackingWidth: 56.0” 56.0"
Width: 83.0” 73.0"
Width (with discharge chute up): 73.0” 63.0"
Height: 43.0” 43.0"
TurningRadius: zero radius turning zero radious turning
Weight: 1635lbs. 1600lbs.
PRODUCTIVITY
The following chart will aid you in determining how many acres your Scag mower will cut per day.
The chart is an estimate based on 8 hours per day cutting time at 7 MPH with an allowance for overlap and turns calculated in.
CuttingWidth: 61" 72"
AcresPer Day: 27 32
Date of Issue: October, 2004
Specifications Subject To Change Without Notice

12
Section 4
OPERATING INSTRUCTIONS
Do not attempt to operate this mower unless you
have read this manual. Learn the location and
purpose of all controls and instruments before you
operate this mower.
4.1 CONTROLS AND INSTRUMENT
IDENTIFICATION
Before operating the mower, familiarize yourself with all
mower and engine controls. Knowing the location,
function and operation of these controls is important for
safe and efficient operation of the mower.
1. Ignition Switch (Figure 4-1). The ignition switch
is used to start the engine and has three positions;
OFF, ON, and START.
CAUTION:
2. Water Seperator Indicator (Figure 4-1). Amber
indicator turns on when the Water Seperator is full
and needs to be cleaned out.
3. Mower Deck Switch (Figure 4-1). Used to
engage and disengage the mower drive system.
Pulling up on the switch will engage the deck drive.
Pushing down on the switch will disengage the deck
drive.
4. Glow Plug Indicator (Figure 4-1). Yellow
indicator turns off when the glow plugs have been
properly heated after the ignition switch is turned on.
5. Engine Throttle Control (Figure 4-1). Used to
control the engine speed. Pushing the lever forward
increases engine speed. Pulling the lever back
decreases engine speed. Full back position is the
IDLE position. Full forward is the cutting position.
Figure 4-1 Controls and Instruments
H
aljalefjairjf;o3rf
af krjf ;wso rgf
aljalef j airjf;o3rf
aljalefjairjf;o3rf
OFF
OFF
OFF
LEFT STEERING
CONTROL
HOURMETER
FUEL GAUGE
DUMP VALVE
FUSES
ENGINE
THROTTLE
CONTROL
RIGHT STEERING
CONTROL
DECK LIFT
DECK RELEASE
BSD2005CONTROLS
PARKING BRAKE
CONTROL
CUTTING HEIGH
T
ADJUSTMENT
WATER TEMPERATURE
MOWER DECK SWITCH
OIL PRESSURE
IGNITION SWITCH
VOLTMETER
GLOW PLUG INDICATOR
C
WATER SEPARATOR
INDICATOR
SEAT BELT

13
Section 4
6. Voltmeter (Figure 4-1). Indicates the condition of
the charging system. When the engine is running, in
normal operating conditions, the needle should be in
the 12 to 14 volt range.
7. Oil Pressure (Figure 4-1). Indicates engine oil
pressure. Reference the engine operator's manual
for further information.
8. Hourmeter (Figure 4-1). Indicates the number of
hours the engine has been operated. It operates
whenever the engine is running. It can be used to
keep track of maintenance intervals and the amount
of time required to perform various tasks.
9. Fuse Holders (Figure 4-1). There are two 20-
amp fuses and one 40-amp fuse that protect the
mower’s electrical system. To replace fuses, pull
fuse out of the socket and install a new fuse.
10. Left Steering Control (Figure 4-1). Used to
control the mower's left wheel when traveling
forward or reverse.
11. Right Steering Control (Figure 4-1). Used to
control the mower's right wheel when traveling
forward or reverse.
12. Parking Brake Control (Figure 4-1). Used to
engage and disengage the parking brakes. Pull the
lever back to engage the parking brakes. Push the
lever forward to disengage the parking brakes.
13. Fuel Tank Gauge (Figure 4-1). Indicates the
amount of fuel in the fuel tank.
14. Dump Valve Control Levers (Figure 4-2).
Located on the hydraulic pumps, used to “free-
wheel” the mower. Rotating the levers clockwise
until they stop allows the unit to move under
hydraulic power. The levers must be in this position
and torqued to 10ft/lbs during operation of the
mower. Rotating the levers counter-clockwise
allows the mower to be moved by hand (free-
wheeling).
15. Deck Lift Foot Lever (Figure 4-1). Used to raise
and lower the cutter deck.
Figure 4-2 DumpValve Control
16. Cutting Height Adjustment (Figure 4-1). Used
to set the cutter deck at the desired cutting height.
17. Deck Release Lever (Figure 4-1). Used to lock
the cutter deck in the transport position. Push the
foot pedal forward and lift up on the release lever to
release the cutter deck for normal mowing.
18. Temperature Gauge (Figure 4-1). Indicates the
operating temperature of the engine.
19. Seat Belt (Figure 4-1). Used to secure the
operator. Seat belt must be worn at all times during
operation.
4.2 SAFETY INTERLOCK SYSTEM
The mower is equipped with a safety interlock system
that prevents the engine from starting unless the deck
drive is disengaged, the parking brake is engaged, the
steering control levers are in the neutral position and the
operator is in the seat. The interlock system shuts off
the engine if the operator leaves the seat with the
steering control levers not in the neutral position and/or
the cutter blades engaged and the parking brake not
engaged.
WARNING:
Never operate the mower with the interlock
system disconnected or malfunctioning. Do
not disengage or bypass any switch; injury to
yourself and others or property damage could
result.
390S0141BSG
DUMP VALVE
CONTROL

14
Section 4
4.3 INITIAL RUN-IN PROCEDURES (First
Day of Use or Approximately 10 Hours)
1. Check all belts for proper alignment and wear at 2, 4
and 8 hours.
2. Change the engine oil and oil filter after the first 5
hours of operation. (See Section 7.4.)
3. Check hydraulic oil level in reservoir. (See Section
7.3.)
4. Check for loose hardware. Tighten as needed.
6. Move the engine throttle control to about half engine
5. Check interlock system for proper operation. (See
Section 4.2.)
6. Check tire pressure. Adjust pressure if necessary.
(See Section 7.10)
4.4 STARTINGTHE ENGINE
DO NOT USE STARTING FLUIDS. Use of starting
fluids in the air intake system may be potentially
explosive or cause a“runaway” engine condition
that could result in engine damage and/or personal
injury.
1. Before initial start or after running out of fuel, you
must prime the fuel pump located on the right side of
the engine. Pump the primer pump until it can no
longer be depressed.
2. Be sure the fuel shutoff valve, located behind the
operator's seat, is completely open. (See Section 7.5
Page 30)
3. Sit in the operator’s seat, fasten seat belt and place
the steering control levers in the neutral position.
4. Engage the parking brake.
5. Place the PTO switch in the disengaged position.
CAUTION:
speed.
7. Turn the ignition key to the on position until the
yellow indicator for the glow plugs goes out. Then
turn the ignition key to the START position and
release the key as soon as the engine starts. Do not
hold the key in the START position for more than 15
seconds at a time. Allow at least 60 seconds
between each cranking attempt to prevent
overheating of the starter motor. Prolonged cranking
can damage the starter motor and shorten battery
life.
8. Allow engine to warm before operating the mower.
4.5 GROUND TRAVEL AND STEERING
-IMPORTANT-
If you are not familiar with the operation of a
machine with lever steering and/or hydrostatic
transmissions, the steering and ground speed
operations should be learned and practiced in
an open area, away from buildings, fences, or
obstructions. Practice until you are comfortable
with the handling of the machine before
attempting to mow. Learn the operation on flat
ground before operating on slopes.
-IMPORTANT-
Start practicing with a slow engine speed and
slow forward travel.
Learn to feather the steering controls to obtain
a smooth operating action.
Practice operating the mower until you are
comfortable with the controls before proceeding
to mow.
Forward Travel
To travel forward with the mower, disengage the parking
brake and slowly push the steering control levers forward
an equal distance. The further the steering control levers
are pushed forward, the greater the forward speed will
be. To increase the speed, push the steering control
levers further forward and to decrease the speed, pull the
steering control levers back.

15
Section 4
To stop the forward travel, pull the steering control levers
back to the neutral position.
To steer the mower left while traveling forward, pull the
left steering lever back. The further the lever is pulled
back, the quicker the mower will turn left.
To steer the mower right while traveling forward, pull the
right steering control lever back. The further the lever is
pulled back, the quicker the mower will turn right.
-NOTE-
Smooth operation of the steering levers will
produce smooth mower operation. While
learning the operation of the steering controls,
keep the travel speed low.
-IMPORTANT-
Do not travel forward over a curb. The mower
will hang up on the curb. Raise the deck and
travel backwards over the curb at a 45 degree
angle. (see section 4.13 on Page 16 for cutter
deck raising instructions)
Disengage power to the mower before backing up.
Donotmowinreverseunlessabsolutelynecessary
and then only after observation of the entire area
behind the mower.
To travel in reverse, pull both handles back. Keep the
travel speed low while traveling in reverse.
-NOTE-
The mower may not travel straight in reverse.
Slight adjustments may need to be made using
the steering controls.
To steer left while traveling in reverse, allow the left
steering control lever to move forward. The further the
control is allowed to move forward, the quicker the
mower will turn left.
To steer right while traveling in reverse, allow the right
steering control lever to move forward. The further the
control is allowed to move forward, the quicker the
mower will turn right.
To stop the reverse travel, allow the steering control
levers to return to the neutral position. If the mower is to
be parked, engage the parking brake.
4.6 ENGAGING THE DECK DRIVE (CUTTER
BLADES)
1. Set the throttle at about 3/4 speed. Do not attempt to
engage the deck drive at high speed as this shortens
the electric clutch life — use only moderate engine
speed when engaging the deck drive.
2. Engage the deck drive by pulling out on the yellow
switch, located on the instrument panel, (Figure 4-3)
to the engage position.
-NOTE-
A squealing noise may be heard when
engaging or disengaging the deck drive. It is
caused by the electric clutch plates meshing
as the mower comes up to speed.
CAUTION:
Reverse Travel
Beforebacking up, observe therearforpersons and
obstructions. Clear the area before backing up.
Possible injury or property damage could occur.
CAUTION:
Figure 4-3 Cutter Engage Switch
STT99CES
PULL UP TO ENGAGE
PUSH DOWN TO DISENGAGE

16
Section 4
3. To disengage the deck drive, push the switch in to
the disengage position.
4. Always operate the engine at full throttle to properly
maintain cutting speed. If the engine starts to lug
down, reduce the forward speed and allow the
engine to operate at maximum RPM.
5. To properly burnish the electric PTO clutch brake,
followthefollowingsteps.
A. Start and run the engine at approximately 3/4
throttle.
B. Engage and disengage the PTO
approximately 25 times, waiting for 10
seconds between each on/off cycle.
-NOTE-
Burnishing the electric clutch improves
longevity and performance and should be done
on every new machine and after a clutch
replacement. The burnishing procedure should
not be performed while cutting grass.
4.7 HILLSIDE OPERATION
DO NOT operate on steep slopes. To check a slope,
attempt to back up it (with the cutter deck down).
If the machine can back up the slope without the
wheels slipping, reduce speed and use extreme
caution. ALWAYS FOLLOW OSHA APPROVED
OPERATION.
1. The mower has been designed for good traction and
stability under normal mowing conditions. However,
caution must be used when traveling on slopes,
especially when the grass is wet. Wet grass reduces
traction and steering control. The Roll Over
Protection System is standard equipment for this
machine. See section 2.5, page 6 of this manual for
further details.
2. To prevent tipping or loss of control, start and stop
smoothly, avoid unnecessary turns and travel at
reduced speed.
WARNING:
3. Keep tires properly inflated.
4.8 PARKINGTHE MOWER
1. Stop on level ground and place the steering control
levers in the neutral position.
2. Disengage the cutter blades
3. Slow the engine to idle speed.
4. Engage the parking brake.
5. Turn the ignition key to the OFF position and remove
the key.
4.9 AFTER OPERATION
1. Wash the entire mower after each use. Do not use
high pressure spray or direct the spray onto electrical
components.
-IMPORTANT-
Do not wash a hot or running engine. Cold
water will damage the engine. Use compressed
air to clean the engine if it is hot.
2. Keep the entire mower clean to inhibit serious heat
damage to the engine or hydraulic oil circuit.
3. Check the drive belts for proper alignment and any
signs of wear. Correct and adjust if necessary.
4. After the mower has cooled down, fill the fuel tank
with fresh, clean fuel with a minimum cetane rating
of 40 at the end of every day of operation.
5. Check the tire pressure. Adjust pressure if
necessary.
To avoid injury from burns,allow the mower to cool
before removing the fuel tank cap and refueling.