Scag Power Equipment STT User manual

MODEL STT
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. 03197
PRINTED 7/06
PRINTED IN USA
©2006
SCAGPOWEREQUIPMENT
DIVISION OF METALCRAFT OF MAYVILLE, INC.

FAILURE TO FOLLOW SAFE OPERATING PRACTICES
MAY RESULT IN SERIOUS INJURY.
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.
WARNING:
Alwaysusetheentireserial number listed on the serialnumber
tag when referring to this product.
Thismanualcoverstheoperatinginstructions
and illustrated parts list for:
STT52V-27CH with a serial number of C7300001 to C7399999
STT61V-27CH with a serial number of C7400001 to C7499999
STT61V-27CH-SS with a serial number of C7600001 to C7699999
STT61V-27KA with a serial number of C7700001 to C7799999
STT61V-27KA-SS with a serial number of C7800001 to C7899999
STT61V-29DFI-SS with a serial number of C7900001 to C7999999
STT61V-35BVAC-SS with a serial number of C8300001 to C8309999
STT61V-35BV-SS with a serial number of C8000001 to C8099999
STT-29DFI-SS with a serial number of C8100001 to C8199999
STT-35BVAC-SS with a serial number of C8400001 to C8499999
STT-35BV-SS with a serial number of C8200001 to C8299999
SMT-52V with a serial number of C8500001 to C8599999
SMT-61V with a serial number of C8600001 to C8699999
SMT-61V (BVAC, BV) with a serial number of C8700001 to C8799999
SMST-72A with a serial number of C9000001 to C9099999
* Keep all shields in place, especially the grass discharge chute.
* Before performing any maintenance or service, stop the machine and
remove the spark plug wire and ignition key.
* If a mechanism becomes clogged, stop the engine before cleaning.
* Keep hands, feet and clothing away from power-driven parts.
* Read this manual completely as well as other manuals that came
with your mower.
* Keep others off the tractor (only one person at a time)
* 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.
Under no circumstances should the machine be operated on slopes
greater than 15 degrees. ALWAYS FOLLOW OSHAAPPROVED
OPERATION.
* DO NOT mow on wet grass. Wet grass reduces traction and steering
control.

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
1.3 Symbols ............................................................................................................................... 2-3
Section 2 - Safety Information
2.1 Introduction .............................................................................................................................4
2.2 SignalWords ...........................................................................................................................4
2.3 Considerations Before Operation ...........................................................................................4
2.4 OperationConsiderations ........................................................................................................5
2.5 Roll Over Protection System ..................................................................................................7
2.6 Maintenance Considerations ...................................................................................................9
2.7 Safety and Instructional Decals ............................................................................................10
Section 3 - Specifications ....................................................................................................11-12
Section 4 - Operating Instructions
4.1 Controls and Instrument Identification ..................................................................................13
4.2 Safety Interlock System........................................................................................................14
4.3 Initial Run-In Procedures ......................................................................................................15
4.4 Starting the Engine................................................................................................................15
4.5 Ground Travel and Steering ..................................................................................................15
4.6 Engaging the Deck Drive .....................................................................................................16
4.7 HillsideOperation .................................................................................................................17
4.8 Parking the Mower ...............................................................................................................17
4.9 After Operation ....................................................................................................................17
4.10 Removing Clogged Material .................................................................................................17
4.11 Moving Mower with Engine Stopped ...................................................................................18
4.12 Recommendations for Mowing .............................................................................................18
4.13 Adjusting Cutting Height .......................................................................................................18
4.14 Towing ..................................................................................................................................19
4.15 Adjusting the Steering Levers...............................................................................................19
4.16 Adjusting the HeightAdjust Pedal ........................................................................................19
Section 5 - Troubleshooting Cutting Conditions............................................................. 20-22

II
TABLE OF CONTENTS (CONT'D)
SUBJECT PAGE
Section 6 - Adjustments
6.1 Parking Brake Adjustment ....................................................................................................23
6.2 TravelAdjustments ...............................................................................................................23
6.3 Throttle Control and ChokeAdjustments ..............................................................................25
6.4 BeltAdjustment ....................................................................................................................25
6.5 BeltAlignment ......................................................................................................................25
6.6 Cutter Deck Adjustments .....................................................................................................26
Section 7 - Maintenance
7.1 Maintenance Chart ...............................................................................................................29
7.2 LubricationFittingPoints ......................................................................................................30
7.3 Hydraulic System ..................................................................................................................32
7.4 EngineOil .............................................................................................................................33
7.5 Engine Fuel System ..............................................................................................................33
7.6 EngineAir Cleaner................................................................................................................34
7.7 Battery ..................................................................................................................................35
7.8 Drive Belts ............................................................................................................................36
7.9 Cutter Blades ........................................................................................................................36
7.10 Tires ......................................................................................................................................37
7.11 Cutter Deck Gearbox ...........................................................................................................37
7.12 Kawasaki Cooling System ....................................................................................................38
7.13 Body, Deck, Hopper and Upholstery ....................................................................................39
Section 8 - Replacement Parts
STT52V, STT61V Cutter Deck ................................................................................................ 40-41
STT72A Cutter Deck ................................................................................................................ 42-43
Cutter Deck Controls ................................................................................................................ 44-45
Sheet Metal Components .......................................................................................................... 46-47
STT Roll Over Protection System without Suspension Seat..................................................... 48-49
STT Roll Over Protection System with Suspension Seat.......................................................... 50-51
Deck Drive Components ........................................................................................................... 52-53
Engine andAttaching Parts (Kohler) ......................................................................................... 54-55
Engine andAttaching Parts (Kawasaki & Briggs & Stratton) .................................................... 56-57
Brake and Steering Components ............................................................................................... 58-59
Fuel and Hydraulic System ....................................................................................................... 60-61
Fuel and Hydraulic System (Kawasaki 29DFI) ......................................................................... 62-63
Hydraulic Pump (BDP-16A) ..................................................................................................... 64-65
Hydraulic Pump with Cooling Fan (BDP-16A) ......................................................................... 66-67
Electrical System (Kohler & Briggs & Stratton 35hpAir Cooled) ............................................. 68-69
Electrical System (Kawasaki 27HP, Briggs & Stratton 35hp Liquid Cooled) ............................ 70-71
ElectricalSystem (Kawasaki 29DFI)......................................................................................... 72-73
ReplacementDecals .................................................................................................................. 74-75
ElectricalSchematic(Kohler) ......................................................................................................... 76
ElectricalSchematic (Kawasaki 27HP) .......................................................................................... 77
ElectricalSchematic (Kawasaki 29DFI) ......................................................................................... 78
ElectricalSchematic(Briggs & Stratton35BVAC) ......................................................................... 79
Electrical Schematic(Briggs& Stratton35BV) .............................................................................. 80
Warranty Statement............................................................................................... following section 8

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.
THEREPLACEMENTOFANYPARTONTHIS
PRODUCTBYOTHERTHANTHE
MANUFACTURER'SAUTHORIZED
REPLACEMENTPARTMAYADVERSELY
AFFECTTHEPERFORMANCE,DURABILITYOR
SAFETYOFTHISPRODUCT.
USEOFOTHERTHANORIGINALSCAG
REPLACEMENTPARTSWILLVOIDTHE
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
Divisionof Metalcraft of Mayville, Inc.
Mayville, Wisconsin 53050
Patents Issued and Pending
MANUFACTURED UNDER ONE OR MORE
OF THE FOLLOWING PATENTS:
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/n9059, 9060,9039)
GC-STT-CS(p/n9063,9064, 9041)
Mulch Plate (p/n 9287, 9288, 9262)
Hurricane Mulch (p/n 9284, 9285, 9267)
STT Hitch (p/n 9242)
STT Bumper (p/n 9256)
Suspension Seat w/Seat Belt (p/n 9292)
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
Symbols
SpinningBlade
48071S
Parking Brake
WARNING
FALLING HAZARD
USE ONLY SCAG APPROVED
RIDING ATTACHMENTS
SEE OPERATOR'S MANUAL
481109
FallingHazard Thown Object Hazard
Seat must be installed under the seat
hold down bracket during installation.
Failuretosecurethe seat underthehold
down bracket could result in serious
injury or death in a roll over.

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 contact us via the Internet at
www.scag.com. The manual for this 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. DO NOT allow children to ride or play on the
machine, it is not a toy.
4. Clear the area to be mowed of objects that could be
picked up and thrown by the cutter blades.
5. DONOT carry passengers.
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/orthesteeringcontrolleversare
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. Never fuel indoors or enclosed trailers.
13. Keep flammable objects (cigarettes, matches, etc.),
open flames and sparks away from the fuel tank and
fuel container. Use only approved containers.
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. DONOT 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.
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. Under no circumstances should the
machine be operated on slopes greater than 15
degrees. ALWAYS FOLLOW OSHA APPROVED
OPERATION.
7. If the operator(s) or mechanic(s) cannot read
English or Spanish, it is the owner's responsibility to
explain this material to them.
8. DONOT 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
somelocal ordinances and insurance regulations.
Always wear hearing protection. Operating this
machine over prolonged periods of time can
cause loss of hearing.
6. DO NOT operate the machine under the influence of
alcohol or drugs.
Section 2
WARNING:
-NOTE-
WARNING:
WARNING:

6
Section 2
2.4 OPERATION CONSIDERATIONS
(CONT'D)
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.
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 after the engine has
stopped running and the blades have stopped
turning.
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. If you must mow in reverse, maintain a
constant lookout to the rear of the machine and mow
slowly.
9. DO NOT turn sharply. Use care when backing up.
10. Disengage power to cutter deck before crossing roads,
walks or gravel drives.
11. Mow only in daylight or good artificial light.
12. NEVERraise 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. Disengagepowertotheattachments 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
fumesarehazardous and containcarbonmonoxide
which can cause brain injury and 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.
19.NEVERleave the machine running unattended.
WARNING:
CAUTION:

7
Section 2
2.5 ROLL-OVER PROTECTION SYSTEM
WARNING:
Keep the roll bar in the raised and locked
position and the seat belt securely fastened
during operation. Failure to do so could
cause serious injury or loss of life.
This 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. Do not mow on wet grass. Wet
grass reduces traction and steering control.
Any or all partsof the Roll-Over Protection System MUST
NOTbe removed. Failure to adheretothisguidelinecould
result in injury or death.
Lower the roll bar only when absolutely necessary.
1. To lower the roll bar, loosen the tension knob on both
the left hand and right hand bar. See Figure 2-1.
2. Remove the hairpin cotter pins and remove the (2) two
lock pins. See Figure 2-2.
3. Lower the roll bar to the down position.
4. To raise the roll bar, lift the bar to the upright position.
5. Install the (2) two lock pins through the hole, secure
with the (2) two hairpin cotter pins and tighten the
tension knobs. See Figure 2-2. Remove the seat belt
from the retainer brackets.
There is no roll-over protection when the roll bar is
in the down position.
Lower the roll bar only when absolutely
necessary.
Raise the roll bar as soon as clearance permits.
DO NOT wear the seat belt when the roll bar is
in the down position.
ALWAYS wear seat belt when roll bar is in the
upposition.
Operate the machine smoothly, no sudden turns,
starts or stops.
Check the area carefully before mowing for proper
overhead clearance (i.e. branches, doorways, etc.).
DO NOT contact any overhead object with the roll
bar.
WARNING:
Figure 2-1 Foldable Roll-Over Protection System
UPRIGHT AND
LOCKED POSITION
TENSION
KNOBS
Figure 2-2 ROPS Hinge
TENSION
KNOB
HAIR PIN
LOCK PIN

8
Figure 2-3 Seat Belt Inspection
The potential exposure of the 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
discolorationduetoUVexposure, dirtor 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 2-3.
2. Check the seat belt webbing in areas exposed to ultra
violet rays from the sun or extreme dust or dirt. If the
originalcolorofthewebbingin these areas is extremely
faded and/or is packed with dirt, the physical strength
ofthiswebbingmayhave deteriorated. If this condition
exists, replace the seat belt system.
WARNING:
Failure to properly inspect and maintain the
seat belt can cause serious injury or loss of
life.
3. Check the buckle and latch for proper operation and
determine if the latch plate is excessively worn,
deformed, or if the buckle is damaged or cracked. See
Figure2-3.
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, attempt 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. Under no circumstances
should the machine be operated on slopes greater
than 15 degrees.
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:
Section 2
INSPECT WEBBING
INSPECT BUCKLE
& LATCH

9
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.
Section 2
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.
WARNING:
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. Use a Blade
Buddy, 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.
6. To reduce fire hazard, keep the cutting units, drives,
muffler and engine free of grass, leaves, excessive
grease, oil and dirt.

10
Section 2
2.7 SAFETY AND INSTRUCTIONAL DECALS
WARNING
INSTALL BELT COVER BEFORE
OPERATING MACHINE
READ OPERATOR'S MANUAL 483402
390S0150G
481568
FORWARD
REVERSE
FR
482710
483397
483406
483407
483402
483398
483407
483397
483411
483425
483429
483300

11
SPECIFICATIONS
Section 3
3.1 ENGINE
GeneralType .............................................................................. Heavy Duty Industrial/CommercialGasoline
Brand ......................................................................................... Kohler25HP(Spec.#PS-CH730-0066)
................................................................................................... Kohler27HP(Spec.#PS-CH740-0021)
Kawasaki,27HP(Spec. #FD750D-AS04)
Kawasaki,29HP(Spec. #FD791D-AS03)
Briggs & Stratton, 35HP Air Cooled (613477-0132-E1)
Briggs& Stratton,35HPLiquid Cooled(61317711454-E1)
Model......................................................................................... KohlerCommand, Kaw. FD671D,Kaw. FD750D,Kaw. FD791D
Horsepower................................................................................ 25HPat3800RPM(ModelSTT52V-25CH,STT61V-25CH)
27HPat3800RPM (ModelSTT61V-27KA,STT61V-27CH)
29HPat 3800RPM(ModelSTT61V-29DFI-SS,STT72A-29DFI-SS)
35HPat 3800RPM(ModelSTT61V-35BVAC-SS,STT72A-35BVAC-SS)
35HPat 3800RPM(ModelSTT61V-35BV-SS,STT72A-35BV)
Type ........................................................................................... 4 Cycle Gasoline,Twin Cylinder, HorizontalShaft
Displacement............................................................................ 25HP Kohler 725cc., 27hp Kohler 725cc.
.................................................................................................. 27HP Kaw. 745cc., 29HP Kaw. 745cc.
.................................................................................................. 35BVBriggs &Stratton 993cc.
Cylinders.................................................................................... 2 with Cast Iron Sleeves
Governor .................................................................................... MechanicalType with Variable Speed Control SetAt 3800 RPM
Idle Speed .................................................................................. 1400 RPM Kohler& Kawasaki,1750 RPMBriggs & Stratton
KohlerFuel Pump Group............................................................ MechanicalTypeFuelPump withIn-Line Fuel Filter, Fixed Jet
Carburetor with Smart-Choke™ and Fuel Shutdown Solenoid
KawasakiFuel Pump Group ....................................................... ElectricFuel Pumpwith In-LineFuel Filter,FixedJet Downdraft
Carburetor
Briggs & Stratton Fuel Pump Group..........................................Mechanical Type Fuel Pump with In-Line Fuel Filter, Fixed Jet
Sidedraft Carburetor
Fuel ............................................................................................ Non-Leaded Gasoline with a Minimum Octane Rating of 87
OilPumpGroup .......................................................................... Positive Displacement Gerotor™Oil Pumpwith RemoteOil
Filter
Starter......................................................................................... Electric Starting with Solenoid Shift Starter
Belts: .......................................................................................... Kevlar cord. Self-adjusting, Self-tightening
Deck Drive Belt....................................................................... ScagPartNumber -481460
Pump Drive Belt...................................................................... Scag PartNumber -482641
Pump Drive Belt (29HP & Higher) ....................................... Scag Part Number - 483086
3.2 ELECTRICAL
Battery ....................................................................................... 12Volt
Charging System ........................................................................ Alternator
Charging Output ........................................................................ 12Volt,15AmpKohler &Kawasaki, 20Amp Briggs &Stratton
System Polarity .......................................................................... Negative Ground
Starter......................................................................................... 12Volt Electric Ring Gear Type, Key and Solenoid Operated Interlock
Switches..................................................................................... Seat,Neutral Control,Mower Engagement(BBC), Parking Brake
Instrument Panel ....................................................................... Ammeter, Key Switch, Throttle Lever, Manual Choke, BBC Switch,
................................................................................................... Fuses and Safety Start module, Temp. gauge (KA), Check Engine
................................................................................................... Indicator (DFI)
Fuses.......................................................................................... Two (2) 20 Amp
3.3TRACTOR
Drive System ............................................................................. Hydraulic Drive with Two Variable Displacement Pumps and Two
................................................................................................... Cast-iron High Torque Motors
Hydrostatic Pumps .................................................................... Two Hydro-Gear™ BDP 16A Pumps with Dump Valves for
movement without running the engine and pressure relief valves
Drive Wheel Motors .................................................................. Two Hydro-Gear™ 15E Cast-iron High Torque Motors
................................................................................................... Two Ross Model TG 15 cu. inch Cast-iron High Torque Motors
Steering/Travel Control.............................................................. Twin Lever Fingertip Steering Control with Individual Control to
Each Wheel with Gas Spring Dampers
ParkingBrake ............................................................................. LeverActuated Linkage to Brakes on Both Drive WheelAxles
Wheels:
(2) Front Caster...................................................................... 13X5.00 Four-Ply,52". 13 X6.00 FourPly, 61"& 72"
(2) Drive ................................................................................. 23 X 10.5 X 12 Four-Ply Pneumatic Tubeless, Radius Edge, 52"
................................................................................................... 24X12.0X12Four-Ply Pneumatic Tubeless,Radius Edge,61" & 72"

12
FuelTank ................................................................................... 10-Gallon Seamless Polyethylene Tank with Large opening and
................................................................................................... Fuel Gauge Fill Cap
Tire Pressure:
Front Caster ........................................................................... 25PSI
Drive ...................................................................................... 12PSI
Seat ............................................................................................ Padded, Thick Cushion with tall back rest
Travel Speed:
Forward ................................................................................. 0-10MPH,0-12MPHfor29DFI,35BVAC,35BVOnly
Reverse.................................................................................. 0-5 MPH,0-6 MPHfor 29DFI,35BVAC,35BVOnly
3.4 CUTTER DECK
Type:.......................................................................................... Floating, Adjustable, Anti-scalping, Hybrid Design Combines
Out-front and Belly-mount Designs
Construction: ............................................................................. 10-gaugesteel reinforcedwith 7-gauge(3/16") Support Plate.
7-gauge(3/16")deckskirt.
True Cutting Width:................................................................... 52"(132.0cm),61"(155.0cm),71.5"(181.6cm)
Cutting Height Adjustment:....................................................... Foot Operated Lever Adjustment from Operator's Seat, 1.00" to
6.00"in1/4"increments
CutterBlades:............................................................................. .197or.250Thick,MilledEdge,WearResistantMarbain™
SMT52V: Three(3)18"blades
SMT61V: Three(3)21"blades
SMT72A: Three(3)24-1/2"blades
BladeEngagement: ................................................................... ElectricBladeEngagementClutchwithControlPanelSwitch
Connected to the Cutter Deck Gearbox through a Drive Shaft.
DischargeOpening: ................................................................... Extra Wide11.5" DischargeOpeningwith SpringLoaded
Discharge Chute
DischargeChute..................................................................................Black,Polypropylene(Plastic),Flexible
Caster Wheels: ........................................................................... 13x5.00 Four-Ply(52"),13X6.00Four-Ply(61"&72")
Spindles: .................................................................................... Heavy-duty 1-1/8" Top Dimension Spindle Shaft, Cast Housing,
Taper Roller Bearing, Low Maintenance with Top Access Grease
FittingandGreaseOverfillReliefPoppet
SpindlePulleys:.......................................................................... Split Steel withEasilyRemoved TaperHubs
CutterDeckBelts: ...................................................................... B-sectionwithKevlarCord.Self-adjusting,Self-tightening
SMT52 ................................................................................... ScagPartNumber-482281
SMT61 ................................................................................... ScagPartNumber-481558
SMST72 ................................................................................. ScagPartNumber-481980
Electric Clutch Type ................................................................... OguraElectric Clutch
Drive Shaft ................................................................................. ClampYoke Shaft With Two High Speed U-Joints
3.6 HYDRAULIC SYSTEM
HydraulicOil Filter ..................................................................... 10 Micron Spin-on Element Type
Hydraulic Reservoir ................................................................... Nylon; 3 Quart Capacity
3.7 WEIGHTS AND DIMENSIONS SMT52V SMT61V SMT72A
Length 82.5" 87.5" 90"
Tracking Width 52" 55" 55"
OverallWidth 62" 72" 83.5"
OverallHeight 46" 46" 46"
Operating Weight 1200# 1298# 1348#
Section 3
3.8 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.
CuttingWidth: 52" 61" 72"
AcresPerDay: 23 27 32
3.3TRACTOR (CONT'D)
-NOTE-
The machine will travel at 10-12mph for transport purposes.
For best cutting performance the forward travel speed should
be adjusted depending upon the cutting conditions.

13
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.
CAUTION:
1. Ignition Switch (Figure 4-1). The ignition switch
is used to start the engine and has three positions;
OFF, ON, and START.
2. 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.
3. Engine Choke Control (Figure 4-1). Used to
start a cold engine. Not used on the 29DFI.
4. 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 Hour Meter Instruments
CHOKE
481348
F
LEFT STEERING
CONTROL
MOWER DECK
IGNITION SWITCH
FUEL GAUGE
DUMP VALVE
DUMP VALVE
FUSES
ENGINE
CHOKE
CONTROL
ENGINE THROTTLE
CONTROL
RIGHT STEERING
CONTROL
DECK LIFT
DECK RELEASE
2006 STTCHMI
PARKING BRAKE
CONTROL
CUTTING HEIGHT
ADJUSTMENT
KAWASAKI DFI ONLY
AMMETER
SWITCH
WATER TEMPERATURE
CHECK
ENGINE
LIGHT
CHECK
ENGINE LIGHT
482796
SLOW
FAS T
HOUR METER
SEAT BELT

14
Section 4
5. Ammeter (Figure 4-1). Indicates the condition of
the charging system. When the engine is running the
needle should be toward the positive end of the
meter. If the needle is toward the negative end of
the meter, this indicates a discharge condition and
the machine should be taken in for service.
6. Hourmeter (Figure 4-1). Indicates the number of
hours the engine has been operated. It operates
whenever the ignition key switch is in the ON
position. Has preset maintenance reminders for
engine and hydraulic system oil changes. Will start
flashing scheduled maintenance 2 hours before
preset time and continue flashing until 2 hours after.
Automatically resets.
7. Fuse Holders (Figure 4-1). Two 20-amp fuses
protect the mower’s electrical system. To replace
fuses, pull fuse out of the socket and install a new
fuse.
8. Left Steering Control (Figure 4-1). Used to
control the mower's left wheel when traveling
forward or reverse.
9. Right Steering Control (Figure 4-1). Used to
control the mower's right wheel when traveling
forward or reverse.
10. 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.
11. Fuel Tank Gauge (Figure 4-1). Indicates the
amount of fuel in the fuel tank.
12. Dump Valve Control Levers (Figure 4-2).
Located on the hydraulic pumps, used to “free-
wheel” the mower. Rotating the valves clockwise
until they stop allows the unit to move under
hydraulic power. The valves must be in this position
and torqued to 10ft/lbs during operation of the
mower. Rotating the valves counter-clockwise
allows the mower to be moved by hand (free-
wheeling).
13. Deck Lift Foot Lever (Figure 4-1). Used to raise
and lower the cutter deck.
14. Cutting Height Adjustment (Figure 4-1). Used
to set the cutter deck at the desired cutting height.
Figure 4-2 DumpValve Control
15. 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.
16. Temperature Gauge (Figure 4-1). Indicates the
operating temperature of the engine. Used on
mowers with the Kawasaki liquid cooled engine
only.
17. Check Engine Light (Figure 4-1). Indicates the
operation of the engine sensors on the Kawasaki
Digital Fuel Injection (DFI). Light will flash once at
initial start up. If a problem occurs with a sensor on
the engine, the light will flash a code. See your
authorized Scag Dealer for diagnosis and repair.
18. Seat Belt (Figure 4-1). Used to secure the
operator. Seat belt must be worn only when the roll
bar is in the upright and locked position.
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/or the parking brake not engaged.
390S141-1
DUMP VALVE
CONTROL
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.

15
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 20
hours of operation. (See Section 7.4.)
3. Check oil level in the hydraulic system reservoir.
(See Section 7.3.)
4. Check for loose hardware. Tighten as needed.
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
1. Be sure the fuel shutoff valve, located behind the
operator's seat, is completely open. (See Section 7.5.)
2. Sit in the operator’s seat, fasten seat belt and place
the steering control levers in the neutral position.
3. Engage the parking brake.
4. If the engine is cold, choke the engine as needed.
5. Move the engine throttle control to about half engine
speed.
6. 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.
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.
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.
CAUTION:
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.
7. Allow engine to warm before operating the mower.

16
Section 4
-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 for cutter deck raising
instructions)
Reverse Travel
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. This is normal.
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.
Figure 4-3 Cutter Engage Switch
STT99CES
PULL UP TO ENGAGE
PUSH DOWN TO DISENGAGE
Before backing up, observe behind the mower for
persons and obstructions. Clear the area before
backing up. Possible injury or property damage
could occur.
CAUTION:
CAUTION:
Disengage power to the mower before backing
up. Do not mow in reverse unless absolutely
necessary and then only after observation of the
entire area behind the mower.