Scag Power Equipment SFC-21-4GX User manual

PART NO. 03539
PRINTED 01/23
PRINTED IN USA
© 2023
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
Models: SFC-21-4GX
SFC-21-5CV
SFC-21-7CV

WARNING
FAILURE TO 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.
• ALWAYS follow all safety instructions on this product and in the manual to avoid
personal injury or death.
• ALWAYS FOLLOW OSHA APPROVED OPERATION.
• This product is capable of amputating hands and feet and throwing objects.
• Keep hands, feet and clothing away from power-driven parts.
• DO NOT operate on steep slopes.
• Always travel across slopes.
• 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.
• If a mechanism becomes clogged, stop the engine before cleaning.
• Keep others o󰀨 the mower (only one person at a time)
REMEMBER - YOUR MOWER IS ONLY AS SAFE AS THE OPERATOR!
HAZARD CONTROL AND ACCIDENT PREVENTION ARE DEPENDENT UPON THE AWARENESS,
CONCERN, PRUDENCE, AND PROPER TRAINING OF THE PERSONNEL INVOLVED IN THE
OPERATION, TRANSPORT, MAINTENANCE, AND STORAGE OF THE EQUIPMENT.
This manual covers the operating instructions and illustrated parts list for:
SFC-21-4GX with a serial number of W5000001 to W5099999
SFC-21-5CV with a serial number of W5100001 to W5199999
SFC-21-7CV with a serial number of W5200001 to W5299999
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
SECTION 1 - GENERAL INFORMATION...................................................................................1
1.1 INTRODUCTION.........................................................................................................................................1
1.2 DIRECTION REFERENCE.........................................................................................................................1
1.3 SERVICING THE ENGINE AND DRIVE TRAIN COMPONENTS...........................................................1
1.4 ASSEMBLY INSTRUCTIONS ....................................................................................................................2
1.5 SYMBOLS ...................................................................................................................................................3
SECTION 2 - SAFETY INFORMATION ......................................................................................4
2.1 INTRODUCTION.........................................................................................................................................4
2.2 SIGNAL WORDS ........................................................................................................................................4
2.3 BEFORE OPERATION CONSIDERATIONS ............................................................................................ 4
2.4 TESTING THE BLADE STOP SYSTEM ...................................................................................................5
2.5 OPERATION CONSIDERATIONS.............................................................................................................6
2.6 MAINTENANCE CONSIDERATIONS AND STORAGE ......................................................................7
2.7 USING A SPARK ARRESTOR...................................................................................................................8
2.8 SPARK IGNITION SYSTEM.......................................................................................................................8
2.9 SAFETY AND INSTRUCTIONAL DECALS..............................................................................................9
SECTION 3 - SPECIFICATIONS ..............................................................................................10
3.1 ENGINE .....................................................................................................................................................10
3.2 CONTROLS...............................................................................................................................................10
3.3 MOWER .....................................................................................................................................................10
3.4 CUTTER DECK.........................................................................................................................................10
3.5 WEIGHTS AND DIMENSIONS ................................................................................................................ 11
3.6 PRODUCTIVITY........................................................................................................................................ 11
SECTION 4 - OPERATING INSTRUCTIONS ...........................................................................12
4.1 CONTROLS AND INSTRUMENT IDENTIFICATION ............................................................................ 12
4.2 TESTING THE BLADE STOP SYSTEM .................................................................................................13
4.3 INITIAL RUN-IN PROCEDURES.............................................................................................................14
4.4 STARTING THE ENGINE.........................................................................................................................14
4.5 GROUND TRAVEL ...................................................................................................................................15
4.6 ENGAGING THE CUTTER BLADES ......................................................................................................15
4.7 SLOPE OPERATION................................................................................................................................16
4.8 PARKING THE MOWER ..........................................................................................................................16
4.9 AFTER OPERATION ................................................................................................................................16
4.10 REMOVING CLOGGED MATERIAL .....................................................................................................17
4.11 MOVING MOWER WITH ENGINE STOPPED......................................................................................17
4.12 RECOMMENDATIONS FOR MOWING ................................................................................................17
4.13 ADJUSTING CUTTING HEIGHT ...........................................................................................................18

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Table of Contents
SECTION 5 - TROUBLESHOOTING CUTTING CONDITIONS ...............................................19
SECTION 6 - ADJUSTMENTS .................................................................................................22
6.1 SELF-PROPEL DRIVE ADJUSTMENTS................................................................................................22
6.2 THROTTLE CONTROL AND CHOKE ADJUSTMENTS ....................................................................... 24
6.3 TRANSMISSION DRIVE BELT................................................................................................................24
6.4 BLADE CONTROL BAR CABLE ADJUSTMENT .................................................................................24
6.5 CUTTER DECK ADJUSTMENTS............................................................................................................25
SECTION 7 - MAINTENANCE..................................................................................................26
7.6 MAINTENANCE CHART - RECOMMENDED SERVICE INTERVALS ................................................26
7.7 ENGINE OIL ..............................................................................................................................................27
7.8 ENGINE FUEL SYSTEM ..........................................................................................................................27
7.9 ENGINE AIR CLEANER...........................................................................................................................29
7.10 DRIVE BELT............................................................................................................................................29
7.11 CUTTER BLADE.....................................................................................................................................30
7.12 WHEELS..................................................................................................................................................31
7.13 BODY AND DECK ..................................................................................................................................31
SECTION 8 - ILLUSTRATED PARTS LIST..............................................................................32
8.1 SCAG APPROVED ATTACHMENTS AND ACCESSORIES ................................................................32
CUTTER DECK...............................................................................................................................................34
SHEET METAL COMPONENTS....................................................................................................................36
BAG ASSEMBLY ............................................................................................................................................38
HANDLE BAR COMPONENTS .....................................................................................................................40
REAR DRIVE SYSTEM COMPONENTS ......................................................................................................42
FUEL SYSTEM (MACHINES WITH 7CV ENGINE)......................................................................................44
REPLACEMENT DECALS AND INFORMATION PLATES ........................................................................46
LIMITED WARRANTY - ..........................................................................INSIDE BACK COVER

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Section 1
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. Be aware that using
attachments with the mower may affect stability. Be sure to
follow the directions found in the operator's manual. See
Section 8, Paragraph 8-1.
WARNING
For pictorial clarity, some illustrations and gures
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 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, transmissions
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 Authorized Scag
Power Equipment 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.
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
Authorized Scag Power Equipment Dealer.
We encourage you to contact your Authorized Scag Power
Equipment 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.
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 right side on the frame. See Figure 1-1.
LOT
ABCD
1234
Division of Metalcraft of Mayville
Assembled in West Bend, WI
www.scag.com/patents
Meets CPSC
blade safety
requirements
Figure 1-1. Mower Serial Number Plate Location

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Section 1
1.4 ASSEMBLY INSTRUCTIONS
1. In an open area, remove the grass bag, hardware
bag and mower from the packaging.
2. With help from an assistant, loosen the two (2) 3/8-
16 elastic flange nuts identified and raise the handle
bar assembly. See Figure 1-2.
2
1
1
Figure 1-2. Lift the Handle Bar Assembly
3. While holding the handle bar assembly in place,
secure using four (4) 3/8-16 x 3/4" carriage bolts
and four (4) 3/8-16 elastic flange nuts provided as
shown tighten mounting hardware and pivot bolts
See Figure 1-3.
2
4
1
3
Figure 1-3. Secure the Handle Bar Assembly
4. The engine installed on this mower is shipped
"dry" from the factory. Add the recommended
amount of oil to the engine per the engine operator's
manual supplied with this mower.
5. Install the fabric grass collection bag over the bag
frame weldment. See Figure 1-4.
Figure 1-4. Install the Fabric Grass Collection Bag
6. Secure the fabric grass collection bag to the frame
weldment using the eight (8) hooks located on the
each side. See Figure 1-5.
Figure 1-5. Install the Grass Collection Bag
7. Install the grass collection bag onto the back of the
mower.
8. Assembly is now complete on the mower.

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Section 1
1.5 SYMBOLS
SYMBOL DESCRIPTION SYMBOL DESCRIPTION
Choke Transmission
Parking Brake
48071S
Spinning Blade
On/Start Spring Tension on Idler
O󰀨/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
Keep Bystanders Away Read Operator's Manual

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Section 2
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 occurring to themselves, other people or property.
This product is capable of amputating hands and feet and
throwing objects. Always follow all safety instructions on this
product and in the manual to avoid personal injury or death.
READ THIS OPERATOR’S MANUAL BEFORE
ATTEMPTING TO START YOUR MOWER. MAKE
SURE THAT EVERYONE KNOWS WHERE THE
MANUAL IS LOCATED AND KEEP A RECORD OF
EACH EMPLOYEE THAT HAS READ THE MANUAL.
A replacement manual is available from your Authorized
Scag Power Equipment 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.
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.
2.3 BEFORE OPERATION
CONSIDERATIONS
1. NEVER allow children to operate this 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.
SAFETY INFORMATION

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Section 2
4. Clear the area to be mowed of objects that could be
picked up and thrown by the cutter blades.
5. DO NOT carry passengers.
6. DO NOT operate the machine under the influence of
alcohol or drugs.
7. If the operator(s) or mechanic(s) cannot read
English, it is the owner's responsibility to explain this
material to them. A Spanish decal kit is available for
this model. See your local Authorized Scag Power
Equipment Dealer.
8. DO NOT wear loose fitting clothing. Loose clothing,
jewelry or long hair could get tangled in moving
parts. Do not operate the machine wearing shorts;
always wear adequate protective clothing including
long pants and substantial slip-resistant footwear.
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.
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.
10. 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.
11. 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 inside enclosed trailers.
12. DO NOT start the engine until any spilled fuel has
been cleaned up or has evaporated.
13. Keep flammable objects (cigarettes, matches, etc.),
open flames and sparks away from the fuel tank and
fuel container. Use only approved containers.
14. See Section 7.3 ENGINE FUEL SYSTEM for fueling
procedure.
15. Equipment must comply with the latest requirements
per SAE J137 and/or ANSI/ASAE S279 when driven
on public roads.
16. Do not operate without the discharge plug installed
or with the grass catcher installed.
17. Check the blade mounting bolts at frequent intervals
for proper tightness.
2.4 TESTING THE BLADE STOP SYSTEM
The blade stop system should be tested each time before
using the machine. Check that the blade stops within 3
seconds of releasing the control bar as described below.
-IMPORTANT-
If the blade does not stop within 3 seconds of
releasing the control bar, contact your local
Authorized Scag Power Equipment Dealer
immediately to have the blade stop system
repaired.
TEST USING THE GRASS BAG
1. Remove the rear discharge plug.
2. Install the empty grass bag onto the rear of the
machine.
3. Start the engine. Allow the engine to warm up before
engaging the blade.
4. Engage the blade.
-NOTE-
The bag should begin to inflate, indicating that the
blade is rotating.
5. Watch the bag and release the control bar.
6. Immediately start counting out 3 seconds and watch
for the bag to deflate.
-NOTE-
If the bag does not deflate within 3 seconds of
releasing the control bar, the blade stop system
could be deteriorating or out of adjustment. Contact
your local Authorized Scag Power Equipment
Dealer immediately to have the blade stop system
repaired.
7. Shut the engine off and wait for all moving parts to
stop.

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Section 2
TEST NOT USING THE GRASS BAG
1. Remove the grass bag.
2. Install the rear discharge plug.
3. Move the machine onto a paved surface such as
a driveway, sidewalk, parking lot or patio next to a
section of grass.
4. Position the machine next to a patch of grass and
approximately 3" away. See Figure 2-1.
5. Start the engine. Allow the engine to warm up before
engaging the blade.
6. Engage the blade.
-NOTE-
The grass next to the the machine should start to
move from the air flow, indicating that the blade
is rotating.
3”
3”
Figure 2-1. Blade Stop
7. Watch the grass and release the control bar.
8. Immediately start counting out 3 seconds and watch
for the grass to stop moving.
-NOTE-
If the grass does not stop moving within 3 seconds
of releasing the control bar, the blade stop system
could be deteriorating or out of adjustment. Contact
your local Authorized Scag Power Equipment
Dealer immediately to have the blade stop system
repaired.
9. Shut the engine off and wait for all moving parts to
stop.
2.5 OPERATION CONSIDERATIONS
1. Know the function of all controls and how to stop
quickly.
WARNING
DO NOT operate on steep slopes. ALWAYS
FOLLOW OSHA APPROVED OPERATION.
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. Do not mow or operate on excessively steep slopes.
Poor footing could cause a slip and fall accident.
4. To prevent tipping or loss of control, start and stop
smoothly, avoid unnecessary turns and travel at
reduced speed.
5. Immediately stop the machine if you lose drive
control while operating. Inspect the machine and
correct the problem before continuing to operate.
6. When using any attachment, never direct the
discharge of material toward bystanders or allow
anyone near the machine while in operation.
7. Start the engine when the blade control bar is in
the neutral lock position, and the drive control bar is
disengaged.
8. If the mower discharge ever plugs, shut off the
engine, remove the spark plug wire, and wait for all
movement to stop before removing the obstruction.