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.

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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

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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

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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.

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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

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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

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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.

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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.

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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.

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Section 2
SAFETY AND INSTRUCTIONAL DECALS2.6
WARNING
DO NOT OPERATE WITHOUT DISCHARGE CHUTE, MULCHING
KIT, OR ENTIRE GRASS CATCHER INSTALLED 483405
483442
WARNING
READ OPERATOR'S MANUAL 483402
INSTALL BELT COVER
BEFORE OPERATING MACHINE
WARNING
* Keep hands, feet & clothing clear
* Keep all guards in place
* Shut off engine & disengage blade
clutch before servicing
* Use caution in directing discharge
* Read instruction manual before operating
ROTATING BLADES AND BELTS
DO NOT OPERATE UNLESS GRASS
CATCHER, MULCHING KIT OR
DISCHARGE CHUTE IS INSTALLED 483406
SPINNING BLADES
KEEP CLEAR
BLADE CONTACT & THROWN
OBJECTS CAN INJURE 483407
483406
483442
BEFORE OPERATING
Read operator's manual
Solicite etiquetas en espanol
a un distribuidor Scag
Make sure guards, shields
& safety devices are in place
& working
Clear area of children,
bystanders & debris
Mow across face of slopes
Trained operators only
WARNING
483405 483402
483407

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Section 3
SPECIFICATIONS
ENGINE3.1
General Type ................................................................................................Heavy Duty Industrial/Commercial Gasoline
Brand..............................................................................................................Kohler 23 Hp Pro Series (Spec PS-75523)
Horsepower.........................................................................................................................................23hp @ 3600 Rpm
Type..........................................................................................................4 Cycle Gasoline, Twin Cylinder, Vertical Shaft
Cylinders..................................................................................................................................... 2 with Cast Iron Sleeves
Displacement.......................................................................................................................................................... 674 cc
Valve...............................................................................................................................Hydraulic Valve Lifters Standard
Governor.........................................................................Mechanical Type with Variable Speed Control Set At 3600 rpm
Idle Speed ..........................................................................................................................................................1400 rpm
Fuel Pump.................................................................................................. Mechanical Fuel Pump with Inline Fuel Filter
Carburation....................................................... Fixed Jet Carburetor with Smart-Choke™ and Fuel Shutdown Solenoid
Fuel.....................................................................................Non-Leaded Gasoline with A Minimum Octane Rating Of 87
Air Intake Group ..................................................................Large Capacity Dual Element, Chopper-Type Grass Screen
Exhaust Group.................................................................................................................Single Exhaust Canister Muffler
Oil Pump........................................................................................................................Positive Displacement Gerotor™
Oil Capacity..............................................................................................................................2.0 U.S. Quarts with Filter
Ignition......................................................... Solid State Ignition with Smart-Spark™ Automatic Spark Advance System
Starter............................................................................................................Electric Starting with Solenoid Shift Starter
ELECTRICAL3.2
Battery...........................................................................................12 Volt "Maintenance Free" Sealed Battery (300 cca)
Charging System............................................................................................................................................... Alternator
Charging Output.......................................................................................................................................12 Volt, 15 Amp
System Polarity.......................................................................................................................................Negative Ground
Starter.................................................................................12 Volt Electric Ring Gear Type, Key and Solenoid Operated
Interlock Switches........................................... Foot Actuated Engine Kill, Brake Interlock, Blade/Clutch Interlock Switch
Instrument Panel .......... Ammeter, Hour Meter, Key Switch, Throttle, Fuses, Manual Choke, Blade Brake Clutch Switch
Wire Harness.............................................................................................................................................14 Gauge Wire
Fuses........................................................................................................................................................Two (2) 20 Amp
POWER HEAD3.3
Frame ................................................................................................... Hybrid Tractor Trailer Frame with Stabilized Pivot
Engine Deck...............................................................................................................................................7 Gauge Steel
Drive System.................Hydraulic Drive with One Variable Displacement Pump and Two Cast-Iron High Torque Motors
Hydrostatic Pump................................................#15 Cast-Iron Variable Displacement Pump with Remote Dump Valve
Dump Valve .........................................................................Single Lever Allows For Movement without Engine Running
Drive Wheel Motors...........................................12 Cu. Inch Cast-Iron High Torque Motors 1-1/4" Tapered Motor Shafts
Drive Belts....................................................................................................Kevlar Cord. Self-Adjusting, Self-Tightening
Steering...........................................................................Aircraft-TypeYoke Steering Handle with Stainless Steel Cable
Travel Control..........................Hydro Drive with Single Foot Pedal For Forward and Reverse, InfinitelyVariable Speeds
Brakes ........................................................................................................................Integral Braking with Drive System
Parking Brake.................................................................................................................................................. Drum-Type
Drive Wheels/Tires ............................................................... 20 X 10.0 - 10 Four-Ply Pneumatic Tubeless, Radius Edge
Steering Wheel/Tire............................16 X 6.5 - 8 Four-Ply Pneumatic Tubeless Turf Tread, Split Rims, Roller Bearings
Tire Pressure:
Steering Tire...................................................................................................................... 15 - 28 psi, 20 psi Nominal
Drive Tires.......................................................................................................................................................... 12 psi
Fuel Tank.................................................5 Gallon (19.0 Liters) Seamless Polyethylene Tank with Fuel Gauge Gas Cap
Seat......................................................... Foam Padded, Lever Adjustment Forward and Back, with Padded Arm Rests

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Section 3
Travel Speed:
Forward ........................................................................................................................................................0-6.8 mph
Reverse........................................................................................................................................................0-5.4 mph
-Note- The machine will travel at 6.8 mph for transport purposes. For best cutting performance the forward travel
speed should be adjusted depending upon the cutting conditions.
CUTTER DECK3.4
Type...................................Out-Front Design with Anti-Scalp Roller and Pneumatic Shock Absorber For Deck Flotation
Construction ........................................................10-Gauge Steel with 7-Gauge (3/16") Steel Skirt.Trim-Side Wear Pad
Cutting Width:
SM61V.....................................................................................................................................61.0 Inches (155.0 cm)
SM72A.....................................................................................................................................71.5 Inches (181.6 cm)
Cutter Deck Baffles................Custom Cut Baffle Allows Adjustment To Individual Cutting Conditions (up to 7 Positions)
Cutting Height Adjustment............................................................... Adjustable From 1-3/4" To 4-1/2" In 1/4" Increments
Cutter Blades............................... 0.197 In.Thick, Milled Edge, Wear Resistant High Strength Marbain™ Cutter Blades
SM61V.....................................................................................................................................................Three (3) 21"
SM72A.....................................................................................................................................................Three (3) 24"
Blade Engagement................................................................. Electric Blade Brake Clutch with Instrument Panel Switch
Clutch Type.............................................................................................................Ogura Heavy Duty PTO Clutch Brake
Lift System.................................................Patented Manual Winch with Automatic Brake/Clutch, Stainless Steel Cable
Discharge Opening.......................................................Extra Wide with Spring-Loaded Polypropylene Discharge Chute
SM61V..................................................................................................................................18.5" Discharge Opening
SM72A................................................................................................................................14.75" Discharge Opening
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
Spindle Pulleys................................................................................ Split Steel Design with Easily Removed Taper Hubs
Idler Arm......................................................................................................Heavy-Duty Idler Arm Of 1/4" Channel Steel
Cutter Deck Belts.................................................................................................................... B-Section with Kevlar Cord
Caster Wheels.............................9 X 3.5 Smooth Tread Flotation, Split Rims, Roller Bearings, with Quick Pin Removal
Flat-Free Caster Tires.......................................Semi-Pneumatic Caster Tires Minimize Downtime Resulting From Flats
HYDRAULIC SYSTEM3.5
Hydro Fluid Cooling.............................................................................................................Heavy-Duty Cooling Radiator
Hydraulic Oil Filter........................................................................................................ 10 Micron Spin-On ElementType
Hydraulic Reservoir............................................................ Nylon Cooling Reservoir, 13 Qt. Capacity SAE 10W30 Fluid
WEIGHTS AND DIMENSIONS SM61V SM72A3.6
Length..............................................................................................................................110.0".............................115.0"
Length with Grass Catcher..............................................................................................137.0".............................142.0"
Tracking Width..................................................................................................................50.0"................................50.0"
Width ................................................................................................................................72.0"................................83.0"
Width (with Discharge Chute Up).....................................................................................62.0"................................73.0"
Height...............................................................................................................................43.0"................................43.0"
Weight ..............................................................................................................................950#..............................1000#
PRODUCTIVITY SM61V SM72A3.7
Cutting Width..................................................................................................................... 61" .................................71.5"
Acres Per Day................................................................................................................... 23.7.....................................28
The preceding 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 6 mph with a 20% allowance for overlap and turns.

10
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Section 4
CAUTION
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.
CONTROLS AND INSTRUMENT4.1
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.
Ignition Switch (Figure 4-1).1. The ignition switch
is used to start the engine and has three positions;
OFF, ON, and START.
Mower Deck Switch (Figure 4-1).2. 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.
Fuse Holders (Figure 4-1).3. Two 20-amp fuses
protect the mower’s electrical system.To replace
fuses, pull fuse out of the socket and install a new
fuse.
Hourmeter (Figure 4-1).4. 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.
Ammeter (Figure 4-1).5. Indicates the current flow of
the charging system.
Parking Brake Control (Figure 4-1).6. 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.
EngineThrottle Control (Figure 4-1).7. 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.
OPERATING INSTRUCTIONS
Engine Choke Control (Figure 4-1).8. Used to start
a cold engine.
Fuel ShutoffValve (Figure 4-1).9. Located on the
bottom of the fuel tank. Used to shut off fuel supply
to the engine.Rotate the valve clockwise to supply
fuel from the tank.
LiftWinch (Figure 4-1).10. Used to raise and lower
the cutter deck.
DumpValve Control Levers (Figure 4-1).11. Located
on the control panel pedestal, used to “free-wheel”
the mower. Rotating the lever clockwise until it stops
(closed) allows the unit to move under hydraulic
power.The levers must be in this position and
torqued to 10 lb-ft during operation of the mower.
Rotating the lever counter-clockwise (open) allows
the mower to be moved by hand (free-wheeling).
STHM_CII
BEFORE OPERATING
Readoperator's manual
Soliciteetiquetas en espanol
aun distribuidor Scag
Makesure guards, shields
&safety devices are in
place& working
Cleararea of children,
bystanders& debris
Mowacross face of slopes
Trainedoperators only
WARNING
2
6
1
5
7
11
4
8
9
Under
Fuel
Tank
3
Behind Panel
10
Under
Seat
Control and Instrument LocationFigure 4-1.

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Section 4
SAFETY INTERLOCK SYSTEM4.2
WARNING
Never operate the mower with the interlock
system disconnected or malfunctioning. Do not
disengage orbypassanyswitch;injurytoyourself
and others or property damage could result.
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 drive pedal
is in the neutral position, and the operator presents pedal
is pressed.The interlock system shuts off the engine if
the operator leaves the seat with the drive pedal not in the
neutral position and/or the cutter blades engaged and the
parking brake not engaged.
INITIAL RUN-IN PROCEDURES4.3
FIRST DAY OF USE OR APPROXIMATELY 10 HOURS
Check all belts for proper alignment and wear at 2, 41. and 8 hours.
Change the engine oil and oil filter after the first 202. hours of operation.(See Section 7.4.)
Check hydraulic oil level in reservoir. (See Section3. 7.3.)
Check for loose hardware.Tighten as needed.4.
Check interlock system for proper operation.(See5. Section 4.2.).
Check the neutral adjustment. (See Adjustments,
6. page 9)
Check tire pressure. Adjust pressure if necessary.7. (See Section 7.10).
STARTINGTHE ENGINE4.4
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.
Be sure the fuel shutoff valve, located under the fuel1. tank, is completely open.
Sit in the operator’s seat, depress the left foot2. (operators presents) pedal, and place the right foot
(drive) pedal in the neutral position.
Engage the parking brake.3.
Place the PTO switch in the disengaged position.4.
If the engine is cold, choke the engine as needed.5.
Move the engine throttle control to about half engine6. speed.
Turn the ignition key to the START position and7. 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.
Allow engine to warm before operating the mower.8.

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Section 4
GROUNDTRAVEL4.5
- IMPORTANT -
If you are not familiar with the operation of this
machine,thesteeringandgroundspeedoperations
should be learned and practiced in an open area,
away from buildings, fences, or obstructions.
Learntheoperationonflatgroundbeforeoperating
on slopes.
Start practicingwithaslowenginespeedandslow
forward travel.
Learn to feather the foot control and the steering
control to obtain a smooth operating action.
Practice operating the mower until you are
comfortable with the controls before proceeding
to mow.
FORWARDTRAVEL
- NOTE -
The left side operator presence pedal must be
depressed for operation.
To travel forward with the mower, disengage the parking
brake, slowly depress the toe end of the drive pedal
(right). The further the drive pedal is depressed the
greater the forward speed will be.To increase the speed,
depress the drive pedal further forward and to decrease
the speed, allow the drive pedal to return toward the
neutral position.
sgb002
Forward OperationFigure 4-2.
DepressToe End of Pedal
To stop the forward travel, release the drive pedal to the
neutral position.
- IMPORTANT -
When driving over curbs, disengage the cutter
blades and raise the cutter deck to clear the curb.
Drive forward over the curb.After the curb is clear,
lower the cutter deck back to normal operating
position. Be sure to leave slack in the cable after
lowering the cutter deck.
REVERSETRAVEL
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.
CAUTION
Before backing up, observe the rear for persons
and obstructions. Clear the area before backing
up. Possible injury or property damage could
occur.
- NOTE -
The left side operator presence pedal must be
depressed for operation.
To travel in reverse with the mower, disengage the
parking brake, slowly depress the heel end of the drive
pedal (right).The further the drive pedal is depressed the
greater the reverse speed will be.To increase the speed,
depress the drive pedal further rearward and to decrease
the speed, allow the drive pedal to return toward the
neutral position.

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Section 4
SGB003
Reverse OperationFigure 4-3.
Depress Heel End of Pedal
To stop the reverse travel, release the drive pedal to the
neutral position.
- NOTE -
The mower may not travel straight in reverse.
Slight adjustments may need to be made using
the steering control.
ENGAGINGTHE DECK DRIVE (CUTTER4.6
BLADES)
Set the throttle at about 3/4 speed. Do not attempt to1. engage the deck drive at high speed as this shortens
the electric clutch life — use only moderate engine
speed when engaging the deck drive.
Engage the deck drive by pulling out on the yellow2. switch, located on the instrument panel, to the
engage position. See Figure 4-4.
390S0138
PULL UP TO ENGAGE
PUSH DOWN TO DISENGAGE
Cutter Engage SwitchFigure 4-4.
- NOTE -
A squealing noise may be heard when engaging
or disengaging the deck drive.It is caused by the
electricclutchplatesmeshingasthemowercomes
up to speed.This is normal.
To disengage the deck drive, push the switch in to
3. the disengage position.
Always operate the engine at full throttle to properly4. maintain cutting speed. If the engine starts to lug
down, reduce the forward speed and allow the
engine to operate at maximum RPM.
HILLSIDE OPERATION4.7
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.
This mower has been designed for good traction and
1. 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.
To prevent tipping or loss of control, do not start or2. stop suddenly, avoid unnecessary turns and travel
at reduced speed. If tires loose traction, disengage
blades and proceed slowly off the slope.
Loss of traction may occur when traveling on a hill3. or slope.Weight transfer on the machine may cause
the drive wheels to slip causing loss of braking or
steering.
Keep tires properly inflated.
4.

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Section 4
PARKINGTHE MOWER4.8
Park the machine on a flat, level surface only. Do not1. park the machine on an incline.
Place the drive pedal 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 remove6. the key.
AFTER OPERATION4.9
Wash the entire mower after each use.Do not1. 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.
Keep the entire mower clean to inhibit serious heat
2. damage to the engine or hydraulic oil circuit.
Check the drive belts for proper alignment and any3. signs of wear. Correct and adjust if necessary.
DANGER
To avoid injury from burns, allow the mower
to cool before removing the fuel tank cap and
refueling.
After the mower has cooled down, fill the fuel tank4. with fresh, clean fuel at the end of every day of
operation.See Engine Owner's Manual for proper
octane requirements.
Check the tire pressure. Adjust pressure if5. necessary. See Section 7.10 Tires.
REMOVING CLOGGED MATERIAL4.10
DANGER
ROTATING BLADES
NEVERPUTYOURHANDS INTOTHEDISCHARGE
CHUTE FOR ANY REASON!
Shut off the engine and remove the key and
only then use a stick or similar object to remove
material if clogging has occurred.
If the discharge chute becomes clogged, shut off
1. the engine and remove the ignition key. Using a stick
or similar item, dislodge the clogged material.Then
resume normal mowing.
MOVING MOWER WITH ENGINE4.11
STOPPED
To "freewheel" or move the machine around without the
engine running, rotate the dump valve lever located on
the left rear of the engine deck to the freewheel position.
See Figure 4-5. Disengage the parking brake and move
the mower by hand.When the machine is in the desired
position, engage the parking brake and rotate the lever to
the drive position.The dump valve lever must be returned
to the DRIVE position to drive the mower.
DUMP VALVE
FREE
WHEEL DRIVE
SGB006
DumpValve LocationFigure 4-5.

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Section 4
- NOTE -
To prevent damage to the hydraulic system, do
not exceed 1MPH when moving the machine in
the freewheel position.
RECOMMENDATIONS FOR MOWING4.12
Do not mow with dull blades. A dull blade will tear1. grass, resulting in poor lawn appearance and
reduced mowing power.
WARNING
DO NOT operate without Discharge Chute,
Mulching Kit, or entire Grass Catcher properly
installed.
The discharge chute must not be removed and2. must be kept in the lowest position to deflect grass
clippings and thrown objects downward.Direct the
side discharge away from sidewalks or streets to
minimize cleanup of clippings.When mowing close
to obstacles, direct the discharge away from the
obstacles to reduce the chance of property damage
by thrown objects.
Cut grass when it is dry and not too tall. Do not cut3. grass too short (cut off 1/3 or less of existing grass
for best appearance).Mow frequently.
Keep mower and discharge chute clean.4.
When mowing wet or tall grass, mow the grass twice.5. Raise the mower to the highest setting for the first
pass and then make a second pass to the desired
height.
Use a slow travel speed for trimming purposes.6.
Operate the engine at full throttle for best cutting.7. Mowing with a lower RPM causes the mower to tear
the grass.The engine is designed to be operated at
full speed.
Use the alternate stripe pattern for best lawn8. appearance.Vary the direction of the stripe each
time the grass is mowed to avoid wear patterns in
the grass.
TOWING (OPTIONAL HITCH4.13
ACCESSORY)
NEVER allow children or others in or on towed1. equipment.
Tow only with a machine that has a hitch designed
2. for towing.Do not attach towed equipment except at
the hitch point.
Follow manufacturer's recommendations for weight3. limit for towed equipment.250 lbs. maximum towing
weight.
NEVER tow on slopes.The weight of the towed
4. equipment may cause loss of traction and loss of
control.
Travel slowly and allow extra distance to stop.5.
Sharp turns with a trailer attached could cause6. damage to the trailer or mower.

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Section 5
CONDITION CAUSE CURE
STRINGERS - OCCASIONAL
BLADES OF UNCUT GRASS
Width of Deck
SGB020
Low engine RPM Run engine at full RPM
Ground speed too fast Slow speed to adjust for conditions
Wet grass Cut grass after it has dried out
Dull blades, incorrect sharpening Sharpen blades
Deck plugged, grass accumulation Clean underside of deck
Belts slipping Adjust belt tension
STREAKING - STRIPS OF
UNCUT GRASS IN CUTTING
PATH
Width of Deck
SGB018
Dull, worn blades Sharpen blades
Incorrect blade sharpening Sharpen blades
Low engine RPM Run engine at full RPM
Belt slipping Adjust belt tension
Deck plugged, grass accumulation Clean underside of deck
Ground speed too fast Slow speed to adjust for conditions
Wet grass Cut grass after it has dried out
Bent blades Replace blades
STREAKING - STRIPS OF
UNCUT GRASS BETWEEN
CUTTING PATHS
Width
of
Deck
Width
of
Deck
SGB019
Not enough overlapping between rows Increase the overlap of each pass
TROUBLESHOOTING CUTTING CONDITIONS