Scag Power Equipment STHM-23GV User manual

PART NO. 03223 Rev. 1
PRINTED 3/2008
PRINTED IN USA
© 2008
Scag Power Equipment
Division of Metalcraft of Mayville, Inc.
Congratulations on owning a Scag mower! This manual contains the operating
instructions and safety information for your Scag mower. Reading this manual
can provide you with assistance in maintenance and adjustment procedures to
keep your mower performing to maximum efciency. The specic models that
this book covers are listed on the inside cover. Before operating your machine,
please read all the information enclosed.
OPERATOR’S
MANUAL
STHM
Model: STHM-23CV

WARNING
FAILURETO FOLLOW SAFE OPERATING PRACTICES MAY RESULT
IN SERIOUS INJURY OR DEATH.
Read this manual completely as well as other manuals that came with your mower.•
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.
DO NOT mow on wet grass.Wet grass reduces traction and steering control.•
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.•
Keep others off the mower (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 OFTHE EQUIPMENT.
This manual covers the operating instructions and illustrated parts list for:
STHM-23CV with a serial number of D6300001 to D6399999
SM-61V with a serial number of D8900001 to D8999999
SM-72A with a serial number of D9000001 to D9099999
Always use the entire serial number listed on the serial number tag when referring to this product.

I
R
Table of Contents
TABLE OF CONTENTS
GENERAL INFORMATIONSECTION 1 - ...................................................................................1
1.1 INTRODUCTION...........................................................................................................................................1
1.2 DIRECTION REFERENCE...........................................................................................................................1
1.3 SERVICINGTHE ENGINE AND DRIVETRAIN COMPONENTS.................................................................1
1.4 SYMBOLS ....................................................................................................................................................2
SAFETY INFORMATIONSECTION 2 - ......................................................................................3
2.1 INTRODUCTION...........................................................................................................................................3
2.2 SIGNALWORDS..........................................................................................................................................3
2.3 BEFORE OPERATION CONSIDERATIONS................................................................................................3
2.4 OPERATION CONSIDERATIONS................................................................................................................4
2.5 MAINTENANCE CONSIDERATIONS & STORAGE....................................................................................6
2.6 SAFETY AND INSTRUCTIONAL DECALS.................................................................................................7
SPECIFICATIONSSECTION 3 - ................................................................................................8
3.1 ENGINE ........................................................................................................................................................8
3.2 ELECTRICAL ...............................................................................................................................................8
3.3 POWER HEAD .............................................................................................................................................8
3.4 CUTTER DECK ............................................................................................................................................9
3.5 HYDRAULIC SYSTEM .................................................................................................................................9
3.6WEIGHTS AND DIMENSIONS.....................................................................................................................9
3.7 PRODUCTIVITY ...........................................................................................................................................9
OPERATING INSTRUCTIONSSECTION 4 - ...........................................................................10
4.1 CONTROLS AND INSTRUMENT IDENTIFICATION.................................................................................10
4.2 SAFETY INTERLOCK SYSTEM................................................................................................................11
4.3 INITIAL RUN-IN PROCEDURES................................................................................................................11
4.4 STARTINGTHE ENGINE ...........................................................................................................................11
4.5 GROUNDTRAVEL .....................................................................................................................................12
4.6 ENGAGINGTHE DECK DRIVE (CUTTER BLADES)................................................................................13
4.7 HILLSIDE OPERATION..............................................................................................................................13
4.8 PARKINGTHE MOWER.............................................................................................................................14
4.9 AFTER OPERATION..................................................................................................................................14
4.10 REMOVING CLOGGED MATERIAL........................................................................................................14
4.11 MOVING MOWER WITH ENGINE STOPPED..........................................................................................14
4.12 RECOMMENDATIONS FOR MOWING....................................................................................................15
4.13TOWING (OPTIONAL HITCH ACCESSORY)...........................................................................................15
TROUBLESHOOTING CUTTING CONDITIONSSECTION 5 - ...............................................16

II
R
Table of Contents
ADJUSTMENTSSECTION 6 - .................................................................................................19
6.1 PARKING BRAKE ADJUSTMENT ............................................................................................................19
6.2 NEUTRAL ADJUSTMENT .........................................................................................................................19
6.3THROTTLE CONTROL AND CHOKE ADJUSTMENTS............................................................................20
6.4 BELT ADJUSTMENT .................................................................................................................................20
6.5 BELT ALIGNMENT.....................................................................................................................................21
6.6 CUTTER DECK ADJUSTMENTS ..............................................................................................................21
6.7 CUSTOM-CUT BAFFLE ADJUSTMENT ...................................................................................................23
MAINTENANCESECTION 7 - ..................................................................................................25
7.1 MAINTENANCE CHART - RECOMMENDED SERVICE INTERVALS ......................................................25
7.2 LUBRICATION............................................................................................................................................26
7.3 HYDRAULIC SYSTEM ...............................................................................................................................27
7.4 ENGINE OIL ...............................................................................................................................................28
7.5 ENGINE FUEL SYSTEM............................................................................................................................28
7.6 ENGINE AIR CLEANER.............................................................................................................................29
7.7 DRIVE BELT...............................................................................................................................................29
7.8 BATTERY....................................................................................................................................................30
7.9 CUTTER BLADES......................................................................................................................................31
7.10TIRES........................................................................................................................................................32
7.11 BODY, DECK, AND UPHOLSTERY .........................................................................................................32
ILLUSTRATED PARTS LISTSECTION 8 - ..............................................................................33
8.1 SCAG APPROVED ATTACHMENTS AND ACCESSORIES......................................................................33
SM-61V & SM-72A CUTTER DECK.................................................................................................................34
ENGINE DECK.................................................................................................................................................36
UPPER HYDRAULICS .....................................................................................................................................38
LOWER HYDRAULICS ....................................................................................................................................40
CONTROL LINKAGE .......................................................................................................................................42
INSTRUMENT PANEL AND ELECTRICAL COMPONENTS ..........................................................................44
RIDER FRAME ASSEMBLY.............................................................................................................................46
BRAKE LINKAGE ............................................................................................................................................48
WINCH LIFT SYSTEM .....................................................................................................................................50
REPLACEMENT DECALS AND INFORMATION PLATES .............................................................................52
ELECTRICALWIRING HARNESS...................................................................................................................54
LIMITEDWARRANTY - COMMERCIAL EQUIPMENT .................................Inside Back Cover

1
R
Section 1
INTRODUCTION1.1
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.
- IMPORTANT -
The replacement of any part on this product
by other than the manufacturer's authorized
replacement part may adversely affect the
performance, durability or safety of this
product.
Use of other than original Scag replacement
parts will void the warranty.
When ordering parts, always give the model and serial
number of your mower.The serial number plate is located
on the top of the engine deck to the right side of the
control pedestal.
GENERAL INFORMATION
USE ONLY SCAG APPROVED ATTACHMENTS AND
ACCESSORIES.
Attachments and accessories manufactured by companies
other than Scag Power Equipment are not approved for
use on this machine.See Section 8-1.
WARNING
Forpictorialclarity,someillustrationsandfigures
inthismanualmayshow shields,guardsor plates
open orremoved.Undernocircumstancesshould
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.
DIRECTION REFERENCE1.2
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.
SERVICINGTHE ENGINE AND DRIVE1.3
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.

2
R
Section 1
SYMBOLS1.4
SYMBOL DESCRIPTION SYMBOL DESCRIPTION
Choke Transmission
Parking Brake
48071S
Spinning Blade
On/Start Spring Tension on Idler
Off/Stop Oil
Falling Hazard Thrown Object Hazard
Fast Slow
Continuously Variable - Linear Cutting Element - Basic Symbol
481039S
Pinch Point Cutting Element - Engage
Hour meter/Elapsed Operating Hours Cutting Element - Disengage
STT MODELS
Seat must be installed under the seat
hold down bracket during installation.
Failure to secure the seat under the hold
down bracket could result in serious
injury or death in a roll over.
CE Mark
Thrown Object Hazard
Keep Bystanders Away
Read Operator's Manual

3
R
Section 2
INTRODUCTION2.1
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 occurring to themselves, other
people or property.
READ THIS OPERATOR’S MANUAL BEFORE
ATTEMPTING TO STARTYOUR 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.
SIGNALWORDS2.2
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.
SIGNALWORD:
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.
DANGER
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 irreparable
injury if proper precautions are not taken.
WARNING
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.
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.
BEFORE OPERATION2.3
CONSIDERATIONS
NEVER allow children to operate this riding mower.1. Do not allow adults to operate this machine without
proper instructions.
Do not mow when children and/or others are2. 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.
DO NOT allow children to ride or play on the3. machine, it is not a toy.
Clear the area to be mowed of objects that could be4. picked up and thrown by the cutter blades.
DO NOT carry passengers.5.
DO NOT operate the machine under the influence of6. alcohol or drugs.
SAFETY INFORMATION

4
R
Section 2
If the operator(s) or mechanic(s) cannot read English7. or Spanish, it is the owner's responsibility to explain
this material to them.
DO NOT wear loose fitting clothing. Loose clothing,
8. 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.
WARNING
Always wear hearing protection. Operating this
machine over prolonged periods of time can
cause loss of hearing.
Keep the machine and attachments in good9. 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.
WARNING
Thismachineisequippedwithaninterlocksystem
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
engineiftheoperator leavesthe seatwiththedeck
drive engaged and/or the steering control levers
are not in the neutral position and the parking
brake is not engaged. Never operate equipment
with the interlock system disconnected or
malfunctioning.
Be sure the interlock switches are functioning10. correctly.
Fuel is flammable;handle it with care.Fill the fuel11. tank outdoors. Never fill it indoors. Use a funnel or
spout to prevent spillage.Clean up any spillage
before starting the engine.
DO NOT add fuel to a running or hot engine.Allow
12. the engine to cool for several minutes before adding
fuel. Never fuel indoors or inside enclosed trailers.
Keep flammable objects (cigarettes, matches, etc.),13. open flames and sparks away from the fuel tank and
fuel container. Use only approved containers.
Equipment must comply with the latest requirements14. per SAE J137 and/or ANSI/ASAE S279 when driven
on public roads.
- NOTE -
If the mower is driven on public roads, it must
comply with state and local ordinances as well as
SAE J137and/or ANSI/ASAE S279requirements.
Contact your local authorities for regulations and
equipment requirements.
Do not operate without the side discharge chute15. installed and in the down position or without an
optional grass catcher or mulch plate completely
installed.
Check the blade mounting bolts at frequent intervals16. for proper tightness.
Make sure all hydraulic fluid connections are tight17. and all hydraulic hoses and lines are in good
condition before starting the machine.
OPERATION CONSIDERATIONS2.4
Know the function of all controls and how to stop1. quickly.
WARNING
DONOToperate onsteep slopes.To checkaslope,
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.
Reduce speed and exercise extreme caution on2. slopes and in sharp turns to prevent tipping or loss
of control. Be especially cautious when changing
directions on slopes.

5
R
Section 2
To prevent tipping or loss of control, start and stop3. smoothly, avoid unnecessary turns and travel at
reduced speed.
When using any attachment, never direct the4. discharge of material toward bystanders or allow
anyone near the machine while in operation.
Before attempting to start the engine, with the5. operator in the seat, disengage power to the cutter
deck, place the right foot pedal in the neutral position
and engage the parking brake.
If the mower discharge ever plugs, shut off the6. engine, remove the ignition key, and wait for all
movement to stop before removing the obstruction.
WARNING
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.
Be alert for holes, rocks, roots and other hidden7. hazards in the terrain.Keep away from any drop-
offs.Beware of overhead obstructions (low limbs,
etc.), underground obstacles (sprinklers, pipes, tree
roots, etc.).Cautiously enter a new area. Be alert for
hidden hazards.
Disengage power to cutter deck before backing up.8. Do not mow in reverse unless absolutely necessary
and then only after observation of the entire area
behind the mower. If you must mow in reverse,
maintain a constant lookout to the rear of the
machine and mow slowly.
DO NOT turn sharply. Use care when backing up.9.
Disengage power to cutter deck before crossing10. roads, walks or gravel drives.
Mow only in daylight or good artificial light.11.
NEVER raise the deck with the blades engaged.12.
Take all possible precautions when leaving the13. machine unattended, such as disengaging the
mower, lowering the attachments, setting the parking
brake, stopping the engine, and removing the key.
Disengage power to the attachments when14. transporting or when not in use.
The machine and attachments should be stopped15. and inspected for damage after striking a foreign
object, and damage should be repaired before
restarting and operating the machine.
CAUTION
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.
DANGER
DO NOT run the engine inside a building or
a confined area without proper ventilation.
Exhaust fumes are hazardous and contain
carbon monoxide which can cause brain injury
and death.
Keep hands and feet away from cutter blades and16. moving parts. Contact can injure.
Transport the mower using a heavy duty trailer17. or truck.Insure the trailer or truck has all of the
necessary lighting and markings as required by
laws, codes, and ordinances.Secure a trailer with a
safety chain.
Be cautious when loading and unloading onto18. trailers or trucks. Use only a full width ramp. Ramp
angle should be no more than 15 degrees. Back up
the ramp and drive down forward.
When transporting the mower, make sure the park19. brake is engaged, the steering control levers are in
the neutral position, the engine is off with the key
removed, and the wheels have been blocked.
Tie the mower down securely using straps, chains,20. cable, or ropes. Both front and rear straps must be
directed down and outward from machine.
Use care when approaching blind corners, shrubs,21. trees, or other objects that may obscure vision.
NEVER leave the machine running unattended.22.

6
R
Section 2
WARNING
Hydraulicfluidisunderhighpressure.Keepbody
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.
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,18. away from spark and flames. Unplug charger before
connecting or disconnecting from battery.Wear
protective clothing and use insulated tools.
MAINTENANCE CONSIDERATIONS &2.5
STORAGE
Never make adjustments to the machine with the1. engine running unless specifically instructed to do
so. If the engine is running, keep hands, feet, and
clothing away from moving parts.
Disengage drives, lower implement, set parking
2. 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.
Disconnect battery or remove spark plug wire before3. making any repairs. Disconnect the negative terminal
first and the positive last.Reconnect the positive first
and the negative last.
Keep all nuts, bolts and screws tight, to ensure the4. machine is in safe working condition. Check blade
mounting bolts frequently to be sure they are tight.
Do not change the engine governor settings or5. overspeed the engine. See the engine operator's
manual for information on engine settings.
To reduce fire hazard, keep the cutting units, drives,6. muffler and engine free of grass, leaves, excessive
grease, oil and dirt.
Park the machine on level ground and engage the7. parking brake.
NEVER allow untrained personnel to service the8. machine.
Use care when checking blades. Use a Blade Buddy,9. wrap the blade(s) or wear gloves and USE CAUTION
when servicing blades. Only replace blades. NEVER
straighten or weld blades.
Keep all parts in good working condition. Replace all10. worn or damaged decals.
Use jack stands to support components when11. required.
If the mower must be tipped to perform maintenance12. or adjustment, remove the battery, drain the gasoline
from the fuel tank and the oil from the crankcase.
Carefully release pressure from components with13. stored energy.