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OPERATOR'S MANUAL

MODELS Z122E
Z121S
Z125E
Z125S

Z
1
2
2
E
·
Z
1
2
1
S
·
Z
1
2
5
E
·
Z
1
2 1BDABDYAP0010
English 5
AS . E . 2 - 2 . - . AK Code No. K3011-7123-2 S

READ AND SAVE THIS MANUAL

PRINTED IN U.S.A. © KUBOTA Corporation 2013
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ABBREVIATION LIST
Abbreviations Definitions

API American Petroleum Institute

PTO Power Take Off
RH/LH Right-hand and left-hand sides are determined by facing in
the direction of forward travel
ROPS Roll-Over Protective Structures
rpm Revolutions Per Minute KUBOTA Corporation is ···
SAE Society of Automotive Engineers Since its inception in 1890, KUBOTA Corporation has grown to
rank as one of the major firms in Japan.

To achieve this status, the company has through the years

UNIVERSAL SYMBOLS diversified the range of its products and services to a remarkable
extent, until today, 19 plants and 16,000 employees produce over
1,000 different items, large and small.
As a guide to the operation of your machine, various universal symbols have been utilized on the instruments and
controls. The symbols are shown below with an indication of their meaning. All these products and all the services which accompany them,
however, are unified by one central commitment. KUBOTA makes
products which, taken on a national scale, are basic necessities.
Safety Alert Symbol Power Take-Off Switch Control-Off Position Products which are indispensable, products intended to help
(Disengaged) individuals and nations fulfill the potential inherent in their
Read Operator's Manual environment. For KUBOTA is the Basic Necessities Giant.
Power Take-Off Switch Control-On Position
Gasoline Fuel (Engaged) This potential includes water supply, food from the soil and from
the sea, industrial development, architecture and construction,
Fuel-Level Hours transportation.

Parking Brake-Engaged position Cutting Height Thousands of people depend on KUBOTA's know-how, technology,
experience and customer service. You too can depend on
Parking Brake-Disengaged position Fast
KUBOTA.
Engine-Stop Slow

Engine-Run Engine Speed Control

Starter Control Choke

California Proposition 65

WARNING
Engine exhaust, some of its constituents,
certain vehicle components and fluids,
contain or emit chemicals known to the
State of California to cause cancer and birth
defects or other reproductive harm.

This spark ignition system complies with Canadian ICES-002.

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FOREWORD
You are now the proud owner of a KUBOTA ZERO TURN MOWER. This machine
is a product of KUBOTA's quality engineering and manufacturing. It is made of
excellent materials and under a rigid quality control system. It will give you long,
satisfactory service. To obtain the best use of your machine, please read this
manual carefully. It will help you become familiar with the operation of the machine
and contains many helpful hints about machine maintenance. It is KUBOTA's policy
to utilize, as quickly as possible, every advance in our research. The immediate use
of new techniques in the manufacturing of products may cause some small parts of
this manual to become outdated. KUBOTA distributors and dealers will have the
most up-to-date information. Please do not hesitate to consult them.

3 SAFETY FIRST
This symbol, the industry's ''Safety Alert Symbol'', is used throughout this manual
and on labels on the machine itself to warn of the possibility of personal injury.
Read these instructions carefully. It is essential that you read the instructions and
safety regulations before you attempt to assemble or use this unit.

3 DANGER : Indicates an imminently hazardous situation which, if not

avoided, will result in death or serious injury.

3 WARNING : Indicates a potentially hazardous situation which, if not

avoided, could result in death or serious injury.

3 CAUTION : Indicates a potentially hazardous situation which, if not

avoided, could result in minor or moderate injury.

IMPORTANT : Indicates that equipment or property damage could result if

instructions are not followed.

NOTE : Gives helpful information.

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CONTENTS
SAFE OPERATION ............................................................................................ -1
SERVICING OF MACHINE ......................................................................................... 1
SPECIFICATIONS....................................................................................................... 3
IMPLEMENT LIMITATIONS ........................................................................................ 5
INSTRUMENT PANEL AND CONTROLS................................................................... 6
MOWER MOUNTING .................................................................................................. 8
MOUNTING THE MOWER DECK ........................................................................... 8
ADJUSTING THE MOWER ..................................................................................... 8
DISMOUNTING THE MOWER DECK ..................................................................... 8
OPERATING THE ENGINE......................................................................................... 9
MOUNT AND DISMOUNT MACHINE SAFELY....................................................... 9
STARTING THE ENGINE ........................................................................................ 9
Throttle Lever.................................................................................................................. 11
Key Switch ...................................................................................................................... 11
CHECK DURING OPERATING ............................................................................. 12
Immediately Stop the Engine if: ...................................................................................... 12
Fuel Gauge .....................................................................................................................12
Hour Meter...................................................................................................................... 12
COLD WEATHER STARTING ............................................................................... 12
WARMING UP ....................................................................................................... 13
Warm-up and Transmission Oil in the Low Temperature Range.................................... 13
JUMP STARTING .................................................................................................. 13
STOPPING THE ENGINE...................................................................................... 14
OPERATING THE MACHINE.................................................................................... 15
OPERATING NEW MACHINE ............................................................................... 15
Changing Lubricating Oil for New Machines................................................................... 15
Engine Break-in .............................................................................................................. 15
Machine Break-in............................................................................................................ 15
STARTING ............................................................................................................. 16
Operator's Seat............................................................................................................... 16
Seat Belt ......................................................................................................................... 16
Light Switch .................................................................................................................... 16
Mower Lift Pedal ............................................................................................................. 17
Throttle Lever.................................................................................................................. 17
Parking Brake Lever ....................................................................................................... 17
Motion Control Lever ...................................................................................................... 18
STOPPING............................................................................................................. 20
PARKING ............................................................................................................... 20
TRANSPORTING................................................................................................... 21
Hydrostatic Transaxle Bypass Rods............................................................................... 21
OPERATING THE MOWER ...................................................................................... 22
MAKING THE MOST OF YOUR MOWER............................................................. 22
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CONTENTS

ADJUSTING CUTTING HEIGHT ........................................................................... 22

OPERATING MOWER........................................................................................... 23
PTO Switch.....................................................................................................................23
Starting ........................................................................................................................... 24
TIRES AND WHEELS ............................................................................................... 25
TIRES..................................................................................................................... 25
Inflation Pressure............................................................................................................ 25
WHEELS ................................................................................................................ 25
Remove and Install Front Caster Wheels ....................................................................... 26
MAINTENANCE......................................................................................................... 27
SERVICE INTERVALS .......................................................................................... 27
LUBRICANTS AND FUEL...................................................................................... 30
PERIODIC SERVICE................................................................................................. 31
HOW TO RAISE THE OPERATOR'S SEAT.......................................................... 31
DAILY CHECK ....................................................................................................... 32
Checking Engine Oil Level.............................................................................................. 32
Checking Amount of Fuel and Refueling ........................................................................ 33
Checking and Cleaning Air Intake Screen ...................................................................... 34
Checking Tire Pressure .................................................................................................. 34
Inflation Pressure............................................................................................................ 34
Checking Transaxle Fluid Level...................................................................................... 35
Checking Movable Parts................................................................................................. 35
EVERY 25 HOURS ................................................................................................ 36
Cleaning Precleaner Element (Except Z125E) ............................................................... 36
Cleaning Air Cleaner Element (Z122E, Z125E).............................................................. 37
EVERY 50 HOURS ................................................................................................ 39
Checking Engine Start System ....................................................................................... 39
Checking OPC System ................................................................................................... 40
Checking Carbon Canister Air Filter ............................................................................... 40
Changing Engine Oil (Z122E, Z125E) ............................................................................ 41
Replacing Engine Oil Filter (Z122E, Z125E)................................................................... 42
Checking Muffler and Spark Arrester (if equipped)......................................................... 43
EVERY 100 HOURS .............................................................................................. 43
Changing Engine Oil (Z121S, Z125S) ............................................................................ 43
Replacing Precleaner Element (Except Z125E) ............................................................. 44
Replacing Air Cleaner Element (Z122E, Z125E) ............................................................ 44
Replacing Air Cleaner Element (Z121S, Z125S) ............................................................ 44
Cleaning Engine Shroud................................................................................................. 45
Checking Spark Plug ...................................................................................................... 46
Checking Fuel Lines ....................................................................................................... 47
Battery Condition ............................................................................................................ 48
Adjusting Throttle Cable ................................................................................................. 50
Replacing Engine Oil Filter (Z121S, Z125S)................................................................... 51
EVERY 200 HOURS .............................................................................................. 52
Checking Hydraulic Hose ............................................................................................... 52
EVERY 400 HOURS .............................................................................................. 53
Replacing Transaxle Oil Filter Cartridge......................................................................... 53
Changing Transaxle Fluid............................................................................................... 54
EVERY 500 HOURS .............................................................................................. 54
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CONTENTS

Electric Clutch Adjustment.............................................................................................. 54

Checking Engine Valve Clearance (Z121S, Z125S)....................................................... 55
EVERY AFTER 500 HOURS ................................................................................. 55
Cleaning Combustion Chamber...................................................................................... 55
EVERY 1 YEAR ..................................................................................................... 55
Replacing Precleaner Element (Except Z125E) ............................................................. 55
Replacing Air Cleaner Element (Z122E, Z125E) ............................................................ 55
Replacing Air Cleaner Element (Z121S, Z125S) ............................................................ 55
Changing Engine Oil (Z122E, Z125E) ............................................................................ 55
Replacing Engine Oil Filter (Z122E, Z125E)................................................................... 55
Replacing Fuel Filter (Z122E, Z125E) ............................................................................ 55
Checking Muffler and Spark Arrester (if equipped)......................................................... 55
Replacing Spark Plug ..................................................................................................... 55
Checking Engine Valve Clearance (Z122E, Z125E)....................................................... 55
EVERY 2 YEARS................................................................................................... 56
Replacing Hydraulic Hose .............................................................................................. 56
Replacing Fuel Lines ...................................................................................................... 56
Replacing Engine Breather Hose ................................................................................... 56
Replacing Carbon Canister Air Filter .............................................................................. 56
SERVICE AS REQUIRED...................................................................................... 56
Replacing Fuses ............................................................................................................. 56
Checking and Replacing Blade....................................................................................... 57
Mower Belt Replacement................................................................................................ 58
ADJUSTMENT........................................................................................................... 59
MOTION CONTROL LEVER ................................................................................. 59
HST NEUTRAL............................................................................................................... 59
MAXIMUM SPEED (FORWARD) ................................................................................... 60
MOTION CONTROL LEVER ALIGNMENT .................................................................... 60
MOWER DECK LEVEL.......................................................................................... 61
ANTI-SCALP ROLLERS................................................................................................. 61
LEVEL MOWER DECK (Side-to-Side) ........................................................................... 62
LEVEL MOWER DECK (Front-to-Rear) ......................................................................... 63
GENERAL TORQUE SPECIFICATION ................................................................. 64
TIGHTENING TORQUE CHART ........................................................................... 65
STORAGE ................................................................................................................. 66
TROUBLESHOOTING............................................................................................... 67
ENGINE TROUBLESHOOTING ............................................................................ 67
BATTERY TROUBLESHOOTING ......................................................................... 69
MACHINE TROUBLESHOOTING ......................................................................... 69
MOWER TROUBLESHOOTING............................................................................ 70
INDEX........................................................................................................................ 72
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SAFE OPERATION -1

SAFE OPERATION
Careful operation is your best insurance against an
accident. Read and understand this manual carefully
before operating the machine. All operators, no matter
how much experience they may have had, should read
this and other related manuals before operating the
machine or any implement attached to it. It is the owner's
obligation to instruct all operators in safe operation.
This mowing machine is capable of amputating hands and
feet and throwing objects. Failure to observe the following
safety instructions could result in serious injury or death.

1. BEFORE OPERATING
1. The ZERO TURN MOWING MACHINE has different (1) ROPS
steering characteristics than other machines with a (2) Seat belt
steering wheel and does not have a service brake
pedal (but, has a parking brake lever. Normal slowing 5. Always use the seat belt if the machine has the ROPS.
down and stopping is done with the motion control Check the seat belt regularly and replace if frayed or
levers.). Read and understand the operators manual damaged.
before operating the machine. Practice operating 6. Do not allow any bystanders around or near machine
machine at low engine speed without mower engaged during operation.
in an unobstructed area. 7. Do not allow passengers, children or non-qualified
2. Know your equipment and its limitations. Read all operators on the machine at any time. The operator
instructions in this manual and machine safety labels must remain in the machine seat throughout
before attempting to start and operate the machine. operation.
3. Pay special attention to the safety labels on the 8. Do not operate the machine or any attachments while
machine itself. under the influence of alcohol, medication, controlled
4. KUBOTA recommends the use of a Roll Over substances or when fatigued.
Protective Structures (ROPS) and seat belt in almost 9. Do not wear loose, torn, or bulky clothing around
all applications. This combination will reduce the risk machine. The clothing may catch on moving parts or
of serious injury or death, should the machine be controls, leading to the risk of accident. Wear and use
upset. any additional safety items such as hard hat, safety
If the ROPS is loosened or removed for any reason, boots or shoes, eye and hearing protection, gloves,
make sure that all parts are reinstalled correctly before etc. as appropriate or required.
operating the machine. 10. Do not wear radio or music headphones while
Never modify or repair a ROPS because welding, operating the machine.
bending, drilling, grinding, or cutting may weaken the Safe operation requires your full attention.
structure. 11. Carefully check the vicinity before operating machine
If any structural member of the ROPS is damaged, or any implement attached to it. Clear the work area of
replace the entire structure at your local KUBOTA objects (wires, rocks, etc.) that might be picked up and
Dealer. thrown. Check for overhead clearance which may
interfere with a grass catcher or ROPS.
12. Check brakes and other mechanical parts for correct
adjustment and wear. Replace worn or damaged parts
promptly. Check the tightness of all nuts and bolts
regularly. (For further details, see "PERIODIC
SERVICE" and "ADJUSTMENT" section.)
13. Keep all shields and guards in place. Replace any that
are damaged or missing.
14. Before allowing other people to use your machine,
explain how to operate and have them read this
manual before operation.
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-2 SAFE OPERATION

15. In addition to the design and configuration of 5. Watch where you are going at all times. Watch for and
equipment, hazard control and accident prevention avoid obstacles. Be alert at curbs, near trees, and
are dependent upon the awareness, concern and other obstructions and hidden hazards.
prudence of personnel involved in the operation, 6. Know what is behind you before backing up. Look to
transport and maintenance of the equipment. the rear before and when backing. Do not mow while
16. Keep the machine and attachments in good operating in reverse unless absolutely necessary and make sure
condition and keep safety devices in place and in the area immediately behind you is clear of
proper working condition. obstructions or holes and small children. Use extra
17. Do not modify the machine. Unauthorized modification caution when machine is equipped with Grass
may affect the function of the machine, which may Catcher. Your view to the rear is restricted.
result in personal injury. 7. When working in groups, always let others know what
18. Use only implements approved by KUBOTA. Use you are doing ahead of time.
proper ballast to front or rear of machine to reduce the 8. Do not drive machine on streets or highways. Watch
risk of upsets. Follow the "Safe Operation" for traffic when you cross roads or operate near roads.
procedures, specified in the manuals with equipment. 9. Be aware of the mower discharge direction and do not
19. Keep your machine clean. Accumulations of dirt, point it at anyone.
grease, and trash can contribute to fires and lead to 10. When using any attachments, never direct discharge
personal injury. material toward bystanders. Do not allow anyone near
20. The exhaust gas from the muffler is very hot. To the attachments while in operation.
prevent fire, do not expose dry grass, mowed grass, oil Do not mow when bystanders are present in the
and any other combustible materials to exhaust gas. mowing area.
Use a spark arrester where required. Also keep the 11. To reduce fire hazards, keep the engine exhaust area
engine and muffler clean all the time. free of grass or leaves.
12. Be sure rotating blades and engine are stopped and
the key is removed before placing hands or feet near
blades and cleaning blockages or unclogging chute.
2. OPERATING 13. Shut the engine off and wait for all movement to stop
before removing grass catcher or unclogging chute.
C Starting 14. Maintain all screens to avoid overheating conditions.
1. Always sit in the operator's seat when starting engine 15. Always inspect the mower for damage after striking a
or operating levers or controls. foreign object. Repair or replace any damaged parts
2. Before starting the engine make sure that the motion before restarting.
control levers are in neutral lock, the parking brake is 16. Operate during daylight or in bright artificial light.
applied, and Power Take Off (PTO) is disengaged
(OFF). C Children
3. Do not start engine by shorting across starter Tragic accidents can occur if the operator is not alert to
terminals. The machine may start in gear and move if the presence of children. Children are attracted to the
normal starting circuitry is bypassed. machine and mowing activity.
4. Do not operate or idle engine in a non-ventilated area. Never assume that children will remain where you last
Carbon monoxide gas is colorless, odorless, and saw them.
deadly. 1. Keep children out of the mowing area and under the
5. Do not start engine while tilting deck. watchful care of another responsible adult.
6. Check before each use that operator presence 2. Be alert and turn machine off if children enter the area.
controls are functioning correctly. Test safety systems. 3. Before and when backing, look behind and down for
(See "Checking Engine Start System" and "Checking small children.
OPC System" in "EVERY 50 HOURS" in "PERIODIC 4. Never carry children. There is no safe place for them
SERVICE" section.) to ride. They may fall off and be seriously injured or
Do not operate unless they are functioning correctly. interfere with safe machine operation.
5. Never allow children to operate the machine, even
C Working under adult supervision.
1. Do not turn sharply when driving at high speed. 6. Use extra care when approaching blind corners,
2. To avoid tip over, slow down when turning on uneven shrubs, trees, or other obstructions that might hide
terrain or before stopping. children from sight.
3. Do not operate near ditches, holes, embankments, or 7. Do not mow in reverse unless it is absolutely
other terrain, which may collapse under the machine necessary and make sure area to the rear is clear of
weight. The risk of machine tip over increases when children before doing so.
the ground is loose or wet.
4. Park the machine on a firm and level surface.
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SAFE OPERATION -3

C Operators, age 60 years and above C Stopping

Data indicates that operators, age 60 years and above, 1. Park the machine on level ground.
are involved in a large percentage of machine-related 2. Make sure that the machine and all attachments have
injuries. These operators should evaluate their ability to come to a complete stop before dismounting.
operate the machine safely enough to protect themselves 3. Before dismounting, apply parking brake, place the
and others from serious injury. motion control levers in their neutral lock positions,
disengage the PTO, lower all attachments to the
C Operation on slopes ground, turn off the engine, and remove the key.
Slopes are a major factor related to loss-of-control and tip- 4. Do not park the machine on dry grass or leaves.
over accidents, which can result in severe injury or death.
All slopes require extra caution.
3. TRANSPORTING
If you cannot back up the slope or if you feel uneasy on it,
do not mow it. 1. Disengage power to attachment(s) when transporting
If the engine stops when operating on a slope apply the or not in use.
parking brake immediately to prevent machine run away. 2. Do not tow this machine. Use a suitable truck or trailer
when transporting on public roads.
DO 3. Use extra care when loading or unloading the machine
1. To avoid tip over, operate across the slopes not up and into a trailer or truck.
down. Stay off hills and slopes too steep for safe 4. This machine is not allowed to be used on public
operation. roads.
2. Remove obstacles such as rocks, tree limbs, etc.
3. Stay alert for holes in the terrain and other hidden
hazards. Keep away from drop-offs. Uneven terrain
could overturn the machine. Tall grass can hide
4. SERVICING AND STORAGE
obstacles. C Servicing
4. Follow the manufacturer's recommendations for wheel 1. Before servicing, park the machine on a firm, level
weight or counterweights to improve stability. surface and apply the parking brake. Remove the key
5. Keep all movement on the slopes slow and gradual. to prevent accidental start-up.
Do not make sudden changes in speed or direction. 2. Allow the machine time to cool before touching the
6. Avoid starting or stopping on a slope. If tires lose engine, muffler, etc.
traction, disengage PTO and proceed slowly straight 3. Always stop the engine before refueling. Avoid spills
down the slope. and overfilling. Wipe up spilled fuel immediately.
7. Reduce speed and exercise extreme caution on
slopes and in sharp turns to prevent tip-over or loss of
control.
8. Use special caution when changing direction on
slopes. Slow down, and use extra caution when
changing direction on a slope.

DO NOT
1. Do not turn on slopes unless necessary. If necessary,
turn uphill slowly and gradually.
2. Do not mow near drop-offs, ditches, or embankments.
The mower could suddenly turn over if a wheel is over
the edge of cliff or ditch, or if an edge caves in.
3. Do not mow on wet grass. Reduced traction could
cause sliding and loss of control.
4. Do not try to stabilize the machine by putting your foot
on the ground. (1) Fuel tank cap
5. Do not use grass catcher on steep slopes. 4. Use extra care in handling gasoline fuels. They are
6. Do not start or stop suddenly when going uphill or flammable.
downhill. Avoid sudden start and stops on slopes. (1) Use only an approved container.
7. Never "freewheel". Do not let the machine travel (2) Do not remove fuel cap or refuel with the engine
downhill with motion control levers at neutral lock running. Allow engine to cool before refueling. Do
position or in neutral. not smoke while refueling or when standing near
8. Do not operate machine without the mower deck fuel.
installed. (3) Do not refuel the machine indoors and always
clean up spilled fuel or oil.
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-4 SAFE OPERATION

(4) Do not store the machine or fuel container inside 20. Never tamper with safety devices. Check their
where there is an open flame, such as in a water operation for proper function regularly.
heater. 21. Waste products such as used oil, fuel, coolant, brake
5. Do not smoke when working around battery or when fluid, and batteries, can harm the environment, people,
refueling. Keep all sparks and flames away from pets and wildlife. Please dispose of properly.
battery and fuel tank. 22. Do not use beverage containers for waste fluids or
A battery, especially when charging, will give off other products. Someone, particularly children, may
hydrogen and oxygen gases, which can explode and drink them by mistake.
cause serious personal injury. 23. Securely support machine or any machine elements
6. Before "jump starting" a dead battery, read and follow with stands or suitable blocking before working
all the instructions. underneath. For your safety do not rely on
7. Disconnect the battery's ground cable before working hydraulically supported devices, they may leak down,
on or near electric components. suddenly drop or be accidently lowered.
8. Do not use or charge the refillable type battery if the 24. See your local Recycling Center or KUBOTA Dealer to
fluid level is below the LOWER (lower limit level) mark. learn how to recycle or get rid of waste products.
Otherwise, the battery component parts may A A Material Safety Data Sheet (MSDS) provides
prematurely deteriorate, which may shorten the specific details on chemical products; physical and
battery's service life or cause an explosion. Check the health hazards, safety procedures, and emergency
fluid level regularly and add distilled water as required response techniques. The seller of the chemical
so that the fluid level is between the UPPER and products used with your machine is responsible for
LOWER levels. providing the MSDS for that product upon request.
9. Keep first aid kit and fire extinguisher handy at all
times. C Storage
10. Do not attempt to mount a tire on a rim unless qualified 1. Keep the machine and supply of fuel in locked storage
to do so and all proper safety precautions are followed. and remove the ignition key to prevent children or
11. Always maintain the correct tire inflation pressure. Do others from playing or tampering with them.
not inflate tires above the recommended pressure 2. To avoid sparks from an accidental short circuit,
shown in the Operator's Manual. always disconnect the battery's ground cable (-) first
and reconnect it last.

12. Provide adequate support when changing wheels. (1) Battery (+): Positive terminal
13. Make sure that wheel nuts and bolts have been (2) Ground cable (-): Negative terminal
tightened to the specified torque.
14. Do not make adjustments or repairs with the engine 3. To avoid the danger of exhaust fume poisoning, do not
running. operate the engine in a closed building without
15. Keep machine free of grass, leaves, or other debris adequate ventilation.
build-up. 4. To reduce fire hazards, clean the machine thoroughly
16. Do not change the engine governor setting or before storage. Dry grass and leaves around the
overspeed the engine. engine and muffler may ignite.
17. Do not run a machine inside a closed area.
18. Mower blades are sharp and can cut your hands. Wrap
the blade(s) or wear gloves, and use extra caution
when servicing them.
19. Keep nuts and bolts, especially blade attachment
bolts, tight and keep equipment in good condition.
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SAFE OPERATION -5

5. DANGER, WARNING AND CAUTION LABELS

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-6 SAFE OPERATION
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SAFE OPERATION -7
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-8 SAFE OPERATION

6. CARE OF DANGER, WARNING, AND CAUTION LABELS

1. Keep danger, warning and caution labels clean and free from obstructing material.
2. Clean danger, warning and caution labels with soap and water, and dry with a soft cloth.
3. Replace damaged or missing danger, warning and caution labels with new labels from your local KUBOTA Dealer.
4. If a component with danger, warning and caution label(s) affixed is replaced with new part, make sure new label(s) is
(are) attached in the same location(s) as the replaced component.
5. Mount new danger, warning and caution labels by applying on a clean dry surface and pressing any bubbles to outside
edge.
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SERVICING OF MACHINE 1

SERVICING OF MACHINE
After reading this manual thoroughly, you will find that you
can do some of the regular maintenance yourself. Your
dealer is interested in helping you get the best
performance from your new machine and wants to help
you get the most value from it. When in need of parts or
major service, be sure to see your KUBOTA Dealer. When
in need of parts, be prepared to give your dealer the serial
number of the machine, ROPS, engine and mower.

Locate the serial numbers now and record them in the

space provided.

Type Serial No.

Machine (1) Machine identification plate
ROPS (2) Machine serial No.

Engine
[Z122E]
Mower
Date of Purchase
Name of Dealer
(To be filled in by purchaser)

C Warranty
This machine is warranted under the Kubota Limited
Express warranty, a copy of which may be obtained from
your selling dealer. No warranty shall, however, apply if
the machine has not been handled according to the
instruction given in the Operator's Manual even it is within
the warranty period.
(1) Engine serial No.
C Scrapping the machine and its procedure
To put the machine out of service, correctly follow the [Z125E]
local rules and regulations of the country or territory where
you scrap it. If you have questions, consult your local
KUBOTA Dealer.

(1) Engine serial No.

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2 SERVICING OF MACHINE

[Z121S, Z125S]

(1) Engine serial No.

(1) Mower identification plate

(2) Mower serial No.

(1) ROPS serial No.

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SPECIFICATIONS 3

SPECIFICATIONS
Model Z122E Z121S Z125E Z125S
Model GH731V-1 GH736V GH733V-1 GH750V
Max. engine power
kW (HP) 16.4 (22) *1*2 15.7 (21) *1*3 18.6 (25) *1*2 18.6 (25) *1*3
(Gross)
Type Air-cooled gasoline engine
Number of cylinders 2 (V-Twin)
79 x 73 83 x 67 79 x 73 83 x 69
Bore and stroke mm (in.)
(3.11 x 2.87) (3.27 x 2.64) (3.11 x 2.87) (3.27 x 2.72)
Engine Total displacement cm (cu. in.) 724 (44) 725 (44) 724 (44) 747 (46)
Rated revolution rpm 3600
Fuel Unleaded gasoline
Starter Electric
Lubrication Full pressure lubrication
Cooling Air cooled
Battery U1 (12 V, RC: 45 min, CCA: 300, CA: 410)
Fuel tank L (U.S.gals.) 16 (4.2)
Engine crankcase
L (U.S.qts.) 1.8 (1.9)
(with filter)
Capacities
Transmission case
including Rear axle gear L (U.S.qts.) 4.8 (5.1) (*4)
case
Overall length mm (in.) 1940 (76.4)
Overall width
mm (in.) 1207 (47.5)
w/o mower deck
Overall
With ROPS mm (in.) 1652 (65.0)
height
Dimensions
Wheelbase mm (in.) 1155 (45.5)
123 (4.84) 123 (4.84)
Min. ground clearance mm (in.)
W/48" W/54"
Front mm (in.) 796 (31.3)
Tread
Rear mm (in.) 954 (37.6)
Weight (W/MOWER DECK) kg (lbs.) 330 (728) with 48" 340 (750) with 48" 340 (750) with 54" 350 (772) with 54"
Front 11 x 4 - 5 (4PR) Smooth
Tires
Rear 22 x 10 - 14 (4PR) Turf

Traveling Forward mph (km/h) 0 to 8.0 (0 to 12.9)

speeds Reverse mph (km/h) 0 to 4.0 (0 to 6.4)
Traveling
system Steering 2 - Hand levers
Transmission 2 - HST w / Gear
Parking brake Hand lever applied, released
Min. turning radius mm (in.) 0 (0)
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4 SPECIFICATIONS

Model Z122E Z121S Z125E Z125S

Drive system Belt
PTO
Clutch type Electric

(Specifications and design subject to change without notice)

NOTE:
*1: Manufacturer's estimate
*2: The gross power rating for individual gas engine models is labeled in accordance with SAE (Society of
Automotive Engineers) code J1940 (Small Engine Power & Torque Rating Procedure), and rating performance has
been obtained and corrected in accordance with SAE J1995 (Revision 2002-05). Torque values are derived at 3060
RPM; horsepower values are derived at 3600 RPM. Actual gross engine power will be lower and is affected by,
among other things, ambient operating conditions and engine-to-engine variability. Given both the wide array of
products on which engines are placed and the variety of environmental issues applicable to operating the equipment,
the gas engine will not develop the rated gross power when used in a given piece of power equipment (actual "on-
site" or net power). This difference is due to a variety of factors including, but not limited to, accessories (air cleaner,
exhaust, charging, cooling, carburetor, fuel pump, etc.), application limitations, ambient operating conditions
(temperature, humidity, altitude), and engine-to-engine variability. Due to manufacturing and capacity limitations,
Briggs & Stratton may substitute an engine of higher rated power for this Series engine.
*3: Horsepower ratings exceed Society of Automotive Engineers Small Engine Test Code J1940. Actual engine
horsepower is lower and affected by, but not limited to, accessories (air cleaner, exhaust, charging, cooling, fuel
pump, etc.), application, engine speed and ambient operating conditions (temperature, humidity, and altitude).
Kohler reserves the right to change product specifications, design, and standard equipment without notice and without
incurring obligation.
*4: Oil amount when the oil level is at the upper level.

Model RCK48P-124Z RCK54P-127ZA

Suitable machine Z122E, Z121S Z125E, Z125S
Mounting method Parallel linkage
Adjustment of cutting height Dial gauge
Cutting width mm (in.) 1225 (48) 1375 (54)
Cutting height mm (in.) 38 to 114 (1.5 to 4.5)
PRO
Weight (Approx.) kg (lbs.) 60 (132) 68 (150)
Commercial
Deck Blade spindle speed r/s (rpm) 69.1 (4140) *1 61.7 (3700) *1
(Fabricated
Blade tip velocity m/s (fpm) 92.0 (18100) *1 92.0 (18100) *1
deck)
Blade length mm (in.) 424 (16.7) 475 (18.7)
Number of blades 3
Total length mm (in.) 880 (34.6) 925 (36.4)
Dimensions Total width mm (in.) 1552 (61.1) 1710 (67.3)
Total height mm (in.) 340 (13.3)

*1: Engine Max rpm

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IMPLEMENT LIMITATIONS 5

IMPLEMENT LIMITATIONS
The KUBOTA Machine has been thoroughly tested for proper performance with implements sold or approved by KUBOTA.
Use with implements which are not sold or approved by KUBOTA and which exceed the maximum specifications listed
below, or which are otherwise unfit for use with the KUBOTA Machine may result in malfunctions or failures of the machine,
damage to other property and injury to the operator or others. [Any malfunctions or failures of the machine resulting from
use with improper implements are not covered by the warranty.]

Maximum loading weight

Maximum total Tongue weight Towing capacity
Front axle Rear axle weight W W
Wf Wr
Z122E, Z121S,
98 kg (217 lbs.) 380 kg (837 lbs.) 478 kg (1054 lbs.) 34 kg (75 lbs.) 113 kg (250 lbs.)
Z125E, Z125S

A Do not operate with trailer on incline greater than 10 .

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6 INSTRUMENT PANEL AND CONTROLS

INSTRUMENT PANEL AND CONTROLS

ILLUSTRATED CONTENTS ILLUSTRATED CONTENTS

(1) Parking brake lever.............................. 9, 17 (8) Cutting height control dial..................... 22
(2) Motion control lever.............................. 9, 18 (9) Key switch............................................ 11
(3) Seat belt............................................... 16 (10) Hour meter........................................... 12
(4) Cup holder............................................ - (11) PTO switch........................................... 23
(5) Operator's seat..................................... 16 (12) Throttle lever........................................ 17
(6) ROPS................................................... - (13) Light switch (Z121S, Z125S)................ 16
(7) Mower lift pedal.................................... 17
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INSTRUMENT PANEL AND CONTROLS 7

ILLUSTRATED CONTENTS
(1) Anti-scalp roller (Front, bolt shift type)....... 22
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8 MOWER MOUNTING

MOWER MOUNTING
MOUNTING THE MOWER DECK 7. Attach the PTO belt to the engine pulley. Refer the belt
routing.

To avoid serious injury:

A Park the machine on a firm and level surface.
A Apply the parking brake.
A Stop the engine and remove the key.

1. Before mounting the mower deck, raise the lift links to

the full up position.
2. Adjust the cutting height control dial to 1.5 in. position.
3. Change the direction of the front tires as shown in the
figure.
4. Place the mower deck at the right side of the machine.

5. Slide the mower deck under the machine, then lower

mower lift links. (1) PTO belt
6. Attach the lift links to the mower deck with attaching (2) Engine pulley
hardware.
8. After mounting the mower, check the mower level. If
necessary, adjust the mower level and anti-scalp
rollers.

ADJUSTING THE MOWER

See "OPERATING THE MOWER" section.

DISMOUNTING THE MOWER DECK

For dismounting the mower deck, reverse the above
procedures.

(1) Lift link

(2) Clevis pin, snap pin
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OPERATING THE ENGINE 9

OPERATING THE ENGINE

STARTING THE ENGINE
To avoid serious injury:
A Read and understand "SAFE OPERATION" in 1. Sit on the operator's seat.
the front of this manual.
A Read and understand the danger, warning and 2. Apply the parking brake.
caution labels located on the machine.
A To avoid danger of exhaust fume poisoning, do To apply the parking brake:
not operate the engine in a closed building Place the parking brake lever in the "ENGAGED"
without proper ventilation. position.
A Never start the engine while standing on the
ground. Start the engine only from operator's
seat.

MOUNT AND DISMOUNT MACHINE

SAFELY
DO NOT step on either side of the mower deck when
mounting and dismounting the machine. When mounting
the machine from either side, step over the mower deck.

(1) Parking brake lever "ENGAGED"

"DISENGAGED"

To release the parking brake:

Place the parking brake lever in the "DISENGAGED"
position.
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10 OPERATING THE ENGINE

3. Make sure that the PTO switch is in the 5. Set the throttle lever as follows.
"DISENGAGED" (OFF) position. A If the engine is cold:
Place the throttle lever to the "CHOKE" position.
A If the engine is warm:
Place the throttle lever midway between the "SLOW"
and the "FAST" positions.

(1) PTO switch "ENGAGED" (ON)

"DISENGAGED" (OFF)

4. Place the motion control levers in the

(1) Throttle lever "FAST"
"NEUTRAL LOCK" position. "SLOW"
"CHOKE"

(1) Motion control lever (LH) (A) "NEUTRAL LOCK"

(2) Motion control lever (RH) Position
(B) "NEUTRAL" Position
(held by hands)
(C) "FORWARD"
(D) "REVERSE"
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OPERATING THE ENGINE 11

6. Insert the key into the key switch. Turn

the key switch to the "START" position
and release the key to the "ON" position
when the engine starts.

A Because of the start interlocks, the engine can not be

started except when the PTO switch is disengaged
(OFF), the parking brake lever is applied, motion
control levers are in "NEUTRAL LOCK" position and
the operator is sitting on the seat.

: "OFF" : "START"
BThrottle Lever : "ON"
Pulling the throttle lever backward decreases the engine
speed and pushing it forward increases the engine speed. A Do not use starting fluid or ether.
When the lever is pushed beyond the "FAST" position, the A To protect the battery and the starter, make sure that
choke is engaged. the starter is not continuously turned for more than 10
seconds at a time.
[For a Cold Engine] If the engine does not start, allow 60 seconds cool
Always place the throttle lever to the "CHOKE" position to down period between starting attempts.
start the engine in cold conditions. A If the starter does not turn the engine over, shut off the
starter immediately. Do not make further attempts to
Gradually return the throttle lever to the usual position start the engine until the condition is corrected. Do not
after the engine starts and warms up. jump start using another battery.
Consult your local KUBOTA dealer.
The engine/equipment may be operated during the warm- A Do not turn the key switch to the "START" position
up period, but it may be necessary to leave the choke while the engine is running.
partially on until the engine warms up. A When the temperature is below 0 (32 ), run the
engine at medium speed to warm up the lubricant of
[For a Warm Engine] the engine and the transmission for at least 10
Always place the throttle lever to the usual position after minutes. If the machine is operated before the
the engine starts. lubricant is warm enough, the machine life will be
shortened.
A Do not operate the machine under full load until it is
BKey Switch sufficiently warmed up 2 or 3 minutes for temperature
above 0 (32 ).
OFF............ The position where the key can be A When the ambient temperature is less than -15
inserted into or removed from the (5 ), remove the battery from the machine and store
key switch. [When the key is turned it somewhere warm until the next operation.
to this position, the engine shuts off.]
7. Warm the engine by running at medium
ON.............. The engine keeps running. speed.
START........ Apply the parking brake and turn the
key switch to this position to start the
engine.
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12 OPERATING THE ENGINE

CHECK DURING OPERATING

While operating, make the following checks to see that all BHour Meter
the parts are functioning normally. This meter gives readings for the number of hours the
engine has been running.
BImmediately Stop the Engine if:
A The engine suddenly slows down or accelerates.
A Unusual noises suddenly occur.
A Exhaust fumes suddenly become discolored.

BFuel Gauge
The fuel gauge indicates the fuel level.

(1) Hour meter

COLD WEATHER STARTING

If the ambient temperature is below 0 (32 ) and the
engine is very cold, start it in the following manner:
1. Place the throttle lever to the "CHOKE" position.
2. Turn the key switch to the START (" ") position.
(1) Fuel gauge (E) "EMPTY" A Operate the starter 5 seconds.
(F) "FULL" A If the engine does not start, wait 10 seconds.
A Repeat this procedure until the engine starts.
A Do not refuel over "F". Fill the tank only to the bottom 3. When the engine starts, release the key to the "ON"
of the filler neck in the fuel tank. (" ") position.
A Fill the fuel on a level ground. 4. Place the throttle lever midway between the "SLOW"
and the "FAST" positions.
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OPERATING THE ENGINE 13

WARMING UP JUMP STARTING

To avoid serious injury: To avoid serious injury:

A Be sure to apply the parking brake during A Keep cigarettes, sparks, and flames away from
warm-up. battery.
A If the machine battery is frozen, do not jump
For 5 minutes after engine start-up, allow the engine to start the engine.
warm up without applying any load. This is to allow oil to A Do not connect the other end of negative
reach every part of the engine. If load should be applied jumper cable to the negative terminal of the
to the engine without this warm-up period, problems may machine battery.
develop such as seizure, breakage or premature wear
When jump starting the engine, follow the instructions
may develop.
below to start the engine safely.
1. Bring a helper vehicle with a battery of the same
BWarm-up and Transmission Oil in the Low voltage as the disabled machine within easy cable
Temperature Range reach. "THE VEHICLES MUST NOT TOUCH".
Hydraulic oil serves as transmission oil. In cold weather, 2. Apply the parking brakes of both vehicles and put the
the oil may be cold with increased viscosity. This can shift levers in neutral. Shut the engine off.
cause delayed oil circulation or abnormally low hydraulic 3. Put on safety goggles and rubber gloves.
pressure for some time after engine start-up. This in turn 4. Ensure vent caps are securely in place (if equipped).
can create problems with the hydraulic system. 5. Attach the red clamp to the positive (red, (+) or pos.)
To prevent the above, observe the following instructions: terminal of the dead battery and clamp the other end
of the same cable to the positive (red, (+) or pos.)
Warm up the engine at about 50% of rated rpm according
terminal of the helper battery.
to the table below:
6. Clamp the other cable to the negative (black, (-) or
Ambient temperature Warm-up time requirement neg.) terminal of the helper battery.
7. Clamp the other end to the engine block or the frame
Higher than 0 (32 ) Approx. 5 minutes
of the disabled machine as far from the dead battery
-10 to 0 (14 to 32 ) 5 to 10 minutes as possible.
8. Start the helper vehicle and let its engine run for a few
-20 to -10 (-4 to 14 ) 10 to 15 minutes
moments. Start the disabled machine.
Below -20 (-4 ) More than 15 minutes 9. Disconnect the jumper cables in the exact reverse
order of attachment. (Steps 7, 6 and 5)

A Do not operate unless the engine is well warmed up. If

operation is attempted while the engine is still cold, the
hydraulic mechanism will not function properly and its
service life will be shortened.
A If noises are heard after the hydraulic control lever has
been activated and the implement is lifting, the
hydraulic mechanism is not adjusted properly. Unless
corrected, the unit will be damaged. Contact your local
KUBOTA Dealer for adjustment.

(1) Dead battery Connect cables in numerical order.

(2) Jumper cables Disconnect in reverse order after
(3) Engine block or frame use.
(4) Helper battery

A This machine has a 12 volt negative (-) ground starting

system.
A Use only same voltage for jump starting.
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14 OPERATING THE ENGINE

A Use of a higher voltage source on a machine could

result in severe damage to the machine electrical
STOPPING THE ENGINE
1. After slowing the engine to half speed, turn the key
system.
switch to the "OFF" position.
Use only matching voltage source when "jump-
2. Remove the key.
starting" a low or dead battery condition.
3. Do not leave the key switch "ON" (key in the "ON"
position) as the battery will discharge when the engine
is not running.
4. Apply the parking brake.
5. Turn the carburetor fuel valve to "STOP" (OFF)
position.

(1) Carburetor fuel valve (A) "STOP" (OFF)

(B) "RUN"

A Do not stop the engine when the machine is on an

incline for a long time. The engine oil may go into the
carburetor and the muffler through the valve system.
A Place the throttle control lever in the half speed
position to help prevent the engine from backfiring
before stopping the engine.
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OPERATING THE MACHINE 15

OPERATING THE MACHINE

OPERATING NEW MACHINE
How a new machine is operated and maintained will
determine the life of the machine. To avoid serious injury or death:
A new machine just off the factory production line has A The machine relies upon the engine driven
been tested, but the various parts are not accustomed to transmission for speed, direction, and motion
each other, so care should be taken to operate the control. If the engine is not running, the
machine cannot be driven or controlled.
machine for the first 50 hours at a slower speed and avoid
If the engine stops when operating on a slope,
excessive work or operation until the various parts
apply the parking brake immediately to prevent
become "broken-in." The manner in which the machine is
machine runaway.
handled during the "breaking-in" period greatly affects the
A Do not allow any person other than the driver to
life of your machine. Therefore, to obtain the maximum
ride on the machine.
performance and the longest life of the machine, it is very A Do not drive the machine close to the edges of
important to properly break-in your machine. In handling a ditches or banks which may collapse under the
new machine, the following precautions should be weight of the machine, especially when the
observed. ground is loose or wet.
A When turning the machine, be sure to reduce
BChanging Lubricating Oil for New the travel speed and operate motion control
levers carefully.
Machines
A To avoid tip over, operate across slopes, not up
The lubricating oil is especially important in the case of a
and down. Avoid sudden starts and stops on
new machine. The various parts are not "broken-in" and slopes. Slow down, and use extra caution when
are not accustomed to each other; small metal grit may changing direction on a slope.
develop during the operation of the machine; and this may Park the machine on a firm and level surface.
wear out or damage the parts. Therefore, care should be A Watch where you are going at all times. Watch
taken to change the lubricating oil a little earlier than for and avoid obstacles. Be alert at curbs, near
would ordinarily be required. trees, and other obstructions and hidden
For further details of change interval hours. hazards.
(See "SERVICE INTERVALS" in "MAINTENANCE" A Do not mow near drop-offs, ditches or
section.) embankments. The mower could turn over if a
wheel is over the edge of a cliff or ditch, or if an
edge caves in.
BEngine Break-in A Do not drive machine on streets or highways.
After the first 100 hours of operation, change the engine Watch for traffic when you cross roads or
oil and filter. (See "EVERY 100 HOURS" in "PERIODIC operate near roads.
SERVICE" section.) A Look to the rear before and when backing.
Make sure the area immediately behind you is
BMachine Break-in clear of obstructions, holes and small children.
Use extra caution when machine is equipped
After the first 100 hours of operation, change the transaxle
with Grass Catcher.
fluid and oil filter cartridge. (See "EVERY 100 HOURS" in
A Keep bystanders especially children and
"PERIODIC SERVICE" section.) animals away from the mowing area.

To avoid serious injury or death: To avoid serious injury:

A Do not operate the mower without the deflector A Clear the work area of objects which might be
shield in the down position. picked up and thrown by blades.
A Do not direct the opening of the chute at
bystanders or animals. Ejected objects may
cause injury. Plan your mowing carefully
before starting operation.
A Be sure to disengage the PTO and sit on the
operator's seat before starting the engine.
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16 OPERATING THE MACHINE

STARTING
BSeat Belt

1. Adjust the operator's position and

apply the seat belt. To avoid serious injury or death:
A Always use the seat belt when the ROPS is
BOperator's Seat installed.
A Do not use the seat belt if a foldable ROPS is
down or there is no ROPS.
To avoid serious injury: Adjust the seat belt for proper fit and connect to the
A Make adjustments to the seat only while the buckle. The seat belt is an auto-locking retractable type.
machine is stopped.
A Make sure that the seat is completely secured
after each adjustment.
A Do not allow any person other than the driver to
ride on the machine.

(1) Seat belt

2. Select Light Switch Positions.

(if equipped)
(1) Armrest
(2) Fore-aft adjusting handle
(3) Suspension adjust knob (if equipped) BLight Switch
Pushing the light switch forward illuminates the headlights
C How to adjust the operator's seat and pushing it rearward turns the lights off.
A Fore-aft adjustment
Pull the seat adjusting lever and slide the seat.

C Suspension adjustment (if equipped)

Pull the suspension adjust knob and turn it to achieve the
optimum suspension setting. After setting, keep the knob
oriented horizontally and push the knob back.

C Arm rest
Arm rest may be set at upright position if desired.

A After adjusting the operator's seat, be sure to check

and see that the seat is securely locked.

(1) Light switch

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OPERATING THE MACHINE 17

3. Start the engine. 5. Accelerate the engine.

See "OPERATING THE ENGINE"
section. BThrottle Lever
Moving the throttle lever backward decreases the engine
speed and moving it forward increases the engine speed.
4. Raise the implement.

BMower Lift Pedal

The mower lift pedal is used to raise and lower the mower
deck. To raise and lock the mower deck at carry position,
push the pedal to the end of the pedal stroke. To lower the
mower deck, push the pedal all the way then release the
pedal to the desired mower deck cutting height.

(1) Throttle lever "INCREASE"

"DECREASE"
"CHOKE"

6. Unlock the parking brake.

BParking Brake Lever

(1) Mower lift pedal (A) "RAISE and LOCK" position To release the parking brake:
(B) "LOWER" position Place the parking brake lever in the "DISENGAGED"
position.

(1) Parking brake lever "ENGAGED"

"DISENGAGED"
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18 OPERATING THE MACHINE

Operating position
7. Operate the machine. Machine speed and steering is controlled by the motion
control levers, when the engine is running and the parking
BMotion Control Lever brake is released.

To avoid serious injury: To avoid serious injury:

A Understand how to use the motion control A No control is provided by the motion control
levers and practice in an unrestricted area at a levers when the engine is off.
little more than an idle speed without the
mower engaged until becoming proficient in C Neutral position
the operation of the machine. A Grasp the motion control levers and move them
A Do not move motion control levers from inward from the "NEUTRAL LOCK" position so that
forward to reverse or reverse to forward the machine is in "NEUTRAL". (Engine cannot be
position rapidly. restarted.)
Sudden direction changes could cause loss of
control or damage to the machine or property. C Forward and Reverse Motion:
A Do not make sharp turns at high speeds. 1. Move throttle lever to the "FAST" position.
Fast and sharp turns could cause loss of 2. Release the parking brake.
control. 3. Move both motion control levers from the "NEUTRAL
A Motion control levers must be in "NEUTRAL LOCK" position inward to the "NEUTRAL" position.
LOCK" position to safely enter and exit the 4. Push the control levers slowly forward to begin forward
operator's seat or to carry out maintenance and motion.
safety checks. To move reverse:
A This machine can make sharp turns. Always Pull both control levers slowly rearward at the same
make sure your intended path is clear of time to begin reverse motion.
obstructions or persons. To stop:
Move and hold both motion control levers to the
"NEUTRAL" position until the machine comes to a
Stop position
stop.
C Neutral lock position
A Forward and reverse movement of the motion control
levers are prevented when levers are in "NEUTRAL To avoid serious injury:
LOCK" position. (Engine can only be started with A The motion control lever adjustment is
levers in this position.) important to ensure the machine operates
properly.

A The motion control linkages are adjustable.

If adjustment is required, see "ADJUSTMENT"
section. We recommend you to contact your local
KUBOTA Dealer.

(1) Motion control levers (A) "NEUTRAL LOCK" position

(B) "NEUTRAL" position
(held by hand)
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OPERATING THE MACHINE 19

FORWARD: GENERAL RIGHT TURN:

A Push both motion control levers forward equally at the A Push left motion control lever further forward than the
same time. For forward travel in a straight line. right motion control lever. For forward travel to the
right.

REVERSE:
A Pull both motion control levers past center rearward SHARP (ZERO) LEFT TURN:
equally at the same time. For rearward travel in a A Push right motion control lever forward and pull left
straight line. motion control lever rearward at the same time.

GENERAL LEFT TURN: SHARP (ZERO) RIGHT TURN:

A Push right motion control lever further forward than the A Push left motion control lever forward and pull right
left motion control lever. For forward travel to the left. motion control lever rearward at the same time.
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20 OPERATING THE MACHINE

STOPPING PARKING
TO LOCK:
Place the parking brake lever in the "ENGAGED"
To avoid serious injury: position.
A Park the machine on level ground. TO UNLOCK:
If necessary to park on an incline, Place the parking brake lever in the "DISENGAGED"
(1) Stop the machine, position.
(2) Apply the parking brake, then
(3) Stop the engine.
A If you stop the engine on an incline without
applying the parking brake, the machine could To avoid serious injury:
move and run away. Before leaving the operator's position,
A Apply parking brake.
A Lower all implements to the ground.
A The parking brake lever is for parking use only. If the A Shut off the engine.
parking brake is applied when the motion control A Remove the key.
levers are not in "NEUTRAL LOCK" position, the A Place the motion control levers in the
engine will stop. This feature is to prevent brake and "NEUTRAL LOCK" position.
transmission damage during operation.
If necessary to park on an incline, be sure to chock the
1. Move both motion control levers to the "NEUTRAL" wheels on the downhill side to prevent accidental rolling of
position to stop the machine.
the machine.
2. Move both motion control levers to "NEUTRAL LOCK"
position.
3. Apply parking brake.
4. Move the throttle lever to the half speed position and
push PTO switch to the "DISENGAGE" (OFF)
position.
5. Lower all implements to the ground.
6. Turn off the engine and remove the key.

A Do not stop the engine when the machine is on an

incline for a long time. The engine oil may go into the
carburetor and the muffler through the valve system.
A Place the throttle control lever in the half speed
position to help prevent the engine from backfiring
before stopping the engine.
(1) Chocks
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OPERATING THE MACHINE 21

TRANSPORTING
1. Transport the machine on a trailer.
A Turn the carburetor fuel valve to the "OFF"
position.
A Fasten the machine to the trailer.
2. Do not attempt to tow this machine, or damage to the
transmission may result.
3. When transporting the machine over a long distance:
A Make sure to lift the mower by the mower lift pedal.

BHydrostatic Transaxle Bypass Rods

(1) Right side HST bypass rod (A) Operating position

To avoid serious injury: (B) Bypass position
A Do not touch muffler or exhaust pipes while (H) "HOLD"
they are hot; severe burns could result.
3. After moving, place both the right side and left side
HST bypass rod back into the "OPERATING
A Do not push the machine without pulling the bypass POSITION" hole.
rods, or transmission damage may occur.
A Never pull the rods with the engine running.

1. While facing the machine from the rear, pull the left
side HST bypass rod out of the "OPERATING
POSITION" hole and place it into the "BYPASS
POSITION" hole.
See the figure below.

(1) Left side HST bypass rod (A) Operating position

(B) Bypass position

2. Pull the right side HST bypass rod out of the

"OPERATING POSITION" hole and pull to the
"BYPASS POSITION". Continue to hold the right side
HST bypass rod in the "BYPASS POSITION" in order
to move the machine.
See the figure below.
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22 OPERATING THE MOWER

OPERATING THE MOWER

MAKING THE MOST OF YOUR MOWER ADJUSTING CUTTING HEIGHT
1. When using your mower for the first time, choose a
smooth level area and cut in straight and slightly
overlapping strips.
To avoid serious injury or death:
2. The size and type of the area to be mowed will
A Do not engage the mower in the transport
determine the proper mowing pattern. Take into
position.
account obstructions, such as trees, fences and
buildings. To keep grass clippings off fences, 1. Before adjusting cutting height, check that all tire
sidewalks, etc., it is advisable to go over the outside of pressures are correct. If necessary adjust to the
the area to be mowed several times in a clockwise correct tire pressure.
direction. To mow the area remaining, work in a 2. To set the cutting height, push the mower lift pedal to
counterclockwise direction so that the clippings are raise mower deck to the top position. Then adjust the
dispersed onto the previously cut area. cutting height control dial to desired height.
3. Always keep the left side of the mower toward trees,
posts or other obstacles on the first trip around the
obstacle.
4. Most lawns should be mowed to keep the grass
approximately 50 to 80 mm (2 to 3 in.) high. Best
results are obtained by cutting often and not too short.
To keep a green lawn, never mow more than 1/3 of the
height of the grass or a maximum of 25 mm (1 in.) in 1
mowing.
For extremely tall grass, set the cutting height at
maximum cutting height for the first mowing, then
reset to the desired height and mow again. Allow the
grass to grow to 80 mm (3 in.), then cut off only the top
inch.
5. For best appearance, grass should be cut in the
afternoon or evening when it is free of moisture. (1) Mower lift pedal (A) "RAISE and LOCK" position
(B) "LOWER" position

3. Use the higher settings for mowing in a rough area or

when mowing tall grass. Lower settings should be
used only for smooth lawns where short grass is
desired.

(1) Cutting height control dial

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OPERATING THE MOWER 23

4. Lower the mower deck by pushing the mower lift pedal

again. This lowers the mower deck from the
OPERATING MOWER
"TRANSPORT" position to the "OPERATING"
position.
5. Adjust the anti-scalp rollers' height as recommended To avoid serious injury or death:
below for normal operating condition. A Do not operate the mower without the
discharge deflector being in place properly.

A Never allow roller to contact the ground continuously

as premature roller wear may develop if set
incorrectly. To avoid serious injury:
A Anti-scalp rollers must maintain a minimum clearance A Clear the work area of objects which might be
of 6 mm (1/4 in.) to the ground. picked up and thrown.
A Do not direct the opening of the deflector at
[BOLT] bystanders especially children or animals.
Ejected objects may cause injury. Plan your
mowing carefully before starting operations.
A Keep bystanders and animals away from the
mowing area.
A Be sure to disengage the PTO clutch of the
mower before attempting to start the engine.

BPTO Switch
To engage the PTO, pull the PTO switch to the
"ENGAGED" (ON) position.

(1) PTO switch "ENGAGED" (ON)

"DISENGAGED" (OFF)

1. If you get off the seat while the PTO is running, the
engine will stop automatically. (Operator presence
control)
2. Before starting the engine, push the PTO switch to the
"DISENGAGED" (OFF) position. If it is at the
"ENGAGED" (ON) position, the engine will not start.
(1) Anti-scalp roller (Front, bolt shift type)

A These interlock features are built-in.

A Operation of the mower deck in "TRANSPORT"
position is allowed in order to achieve a cutting height
of 4.5".
Downloaded from https://www.rsmanuals.com
24 OPERATING THE MOWER

BStarting

To avoid serious injury:

A Engine components can get extremely hot from
operation. To prevent severe burns, do not
touch these areas while the engine is running,
or immediately after it is turned off.
Never operate the engine without heat shields
or guards.

1. Sit on the operator's seat.

2. Start the engine.
3. Engage the PTO switch.
4. Disengage the parking brake.
5. Speed up the engine by moving the throttle lever
forward.
6. Push or pull the motion control levers to move forward
or backward.

A Never attempt to move the machine with the parking

brake "ON".

A Keep the engine running at full throttle for best results.

Control the travel speed with the motion control levers.
A During heavy duty use, operate the machine at a
slower ground speed or go over the area twice.
A Keep the mower deck in the raised position when the
mower is disengaged.
A The mower will not cut cleanly if the ground speed is
too high or if the blade speed drops due to an
overload.
A If debris builds up on the grass screen or other cooling
air intake areas, stop the engine and clean them.
Operating the engine with blocked or dirty air intake
and cooling areas causes damage due to overheating.
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TIRES AND WHEELS 25

TIRES AND WHEELS

TIRES WHEELS
A When re-fitting a wheel, tighten the wheel bolt to the
following torques then recheck after traveling 200 m
To avoid serious injury: (200 yards) changing directions several times.
A Do not attempt to mount a tire. This should be
done by a qualified person with the proper
equipment.
A Always maintain the correct tire pressure.
Do not inflate tires above the recommended
pressure shown in the Operator's Manual.
A Inflation pressure in front tires rises quickly
when using compressed air.

To avoid serious injury:

Never operate machine with a loose rim, wheel, or
axle.
A Whenever bolts are loosened, retighten to
specified torque.
A Check all bolts frequently and keep them
Wheels with beveled or tapered holes:
tightened.
Use the tapered wheel nut.
BInflation Pressure
Though the inflation pressure is factory-set to the
prescribed level, it naturally drops slowly in the course of
time. Thus, check it everyday and inflate as necessary.
Recommended Inflation
Tire sizes
Max. Pressure
11 x 4 - 5, 170 kPa
Front
4PR Smooth (1.7 kgf/cm , 25 psi)
22 x 10 - 14, 110 kPa
Rear
4PR Turf (1.1 kgf/cm , 16 psi)

(1) Ground (A) "INSUFFICIENT"

(B) "NORMAL"
(C) "EXCESSIVE"
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26 TIRES AND WHEELS

BRemove and Install Front Caster Wheels

C Removing
1. Park the machine on a firm and level surface.
2. Stop the engine and apply parking brake.
3. Lift the front of machine with a safe lifting device.
4. Remove the nut and the wheel bolt.
5. Remove the wheel from assembly yoke.

C Installing
1. Install the replacement wheel.
2. Install the wheel bolt and the nut.
3. Tighten the nut.

Reference

48 to 56 N-m
Tightening torque (36 to 41 lbf-ft)
(4.9 to 5.7 kgf-m)

4. Lower machine.

(1) Nut
(2) Wheel bolt
(3) Yoke
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MAINTENANCE 27

MAINTENANCE
SERVICE INTERVALS
The following servicing tasks should be carried out on the machine at the stated running-time intervals.

[Z122E, Z125E]
Indication hour meter (Hr) Ref.
No. Items
5 25 50 100 150 200 250 300 350 400 450 500 550 600 After since Page

every 50Hr
41
1 Engine oil Change or every *1
55
1 year

every 50Hr
42
2 Engine oil filter Replace or every *1
55
1 year

every
3 Transaxle oil filter Replace 53
400Hr

every
4 Transaxle fluid Change 54
400Hr

5 Engine start system Check every 50Hr 39

6 OPC system Check every 50Hr 40

every 25Hr
Clean or every 36 *2
Precleaner 1 year
element
(only every
Z122E) 100Hr 44
Replace
or every 55
Air 1 year
7
cleaner every 25Hr
Clean or every 37 *2
1 year
Air cleaner
element every
100Hr 44
Replace
or every 55
1 year

Check every 50Hr 40

Carbon canister air
8 *3
filter every 2
Replace 56
years

Check every 47
100Hr

9 Fuel filter every

100Hr
Replace 47 *3
or every
1 year

Check every 47
100Hr
10 Fuel line
every 2
Replace 56 *3
years

11 Battery condition Check every 48

100Hr

12 Throttle cable Adjust every 50

100Hr
every 50Hr
Muffler and Spark 43
13 Check or every
Arrester (if equipped) 55
1 year
Downloaded from https://www.rsmanuals.com
28 MAINTENANCE

Indication hour meter (Hr) Ref.

No. Items
5 25 50 100 150 200 250 300 350 400 450 500 550 600 After since Page

every
Check 46
100Hr
14 Spark plug
every
Replace 55
1 year

Check every 52
200Hr
15 Hydraulic hose
every
Replace 56 *3
2 years

every
16 Engine breather hose Replace 56 *4
2 years

every
100Hr
17 Engine shroud Clean 45
or every
1 year

every
18 Electric clutch Adjust 54
500Hr

19 Combustion chamber Clean *5 55

20 Fuse Replace 56
Service as
21 Blade Replace required 57
22 Mower belt Replace 58
Engine valve every *4
23 Check 55
clearance 1 year *6

A The jobs indicated by must be done initially.

*1 This maintenance should be done every 50 hours or every 1 year if using a standard oil filter.
If using a high-efficiency oil filter, it may be extended to every 100 hours or every 1 year.
A genuine KUBOTA oil filter is a high-efficiency oil filter.
*2 This maintenance should be done daily or more often in dusty condition than in normal conditions.
Suggested cleaning interval is every 25 hours or every 1 year in normal conditions.
*3 These items should be serviced by an authorized KUBOTA Dealer, unless the owner has the proper tools
and is mechanically proficient.
*4 Consult your local KUBOTA Dealer for this service.
*5 On every after 500 Hr, clean it if necessary.
*6 Not required unless engine performance problems are noted.
Downloaded from https://www.rsmanuals.com
MAINTENANCE 29

[Z121S, Z125S]
Indication hour meter (Hr) Ref.
No. Items
25 50 100 150 200 250 300 350 400 450 500 550 600 After since Page

1 Engine oil Change every 100Hr 43 *1

2 Engine oil filter Replace every 100Hr 51 *1

3 Transaxle oil filter Replace every 400Hr 53

4 Transaxle fluid Change every 400Hr 54

5 Engine start system Check every 50Hr 39

6 OPC system Check every 50Hr 40

Clean every 25Hr 36 *1

Precleaner
Air element every 100Hr or 44
7 Replace *1
cleaner every 1 year 55
Air cleaner Replace every 100Hr or 44 *1
element every 1 year 55

Carbon canister air Check every 50Hr 40

8 *2
filter Replace every 2 years 56

Check every 100Hr 47

9 Fuel filter
Replace every 100Hr 47 *2

Check every 100Hr 47

10 Fuel line
Replace every 2 years 56 *2

11 Battery condition Check every 100Hr 48

12 Throttle cable Adjust every 100Hr 50

13 Muffler and Spark Check every 50Hr or 43

Arrester (if equipped) every 1 year 55
Check every 100Hr 46
14 Spark plug
Replace every 1 year 55

Check every 200Hr 52

15 Hydraulic hose
Replace every 2 years 56 *2

16 Engine breather hose Replace every 2 years 56 *3

17 Engine shroud Clean every 100Hr 45

18 Electric clutch Adjust every 500Hr 54

19 Combustion chamber Clean *4 55

20 Fuse Replace 56
Service as
21 Blade Replace required 57
22 Mower belt Replace 58
23 Engine valve clearance Check every 500Hr 55 *3

A The jobs indicated by must be done initially.

*1 This maintenance should be done daily or more often in dusty condition than in normal conditions.
*2 These items should be serviced by an authorized KUBOTA Dealer, unless the owner has the proper tools
and is mechanically proficient.
*3 Consult your local KUBOTA Dealer for this service.
*4 On every after 500 Hr, clean it if necessary.
Downloaded from https://www.rsmanuals.com
30 MAINTENANCE

A GASOLINE ENGINE EMISSION RELATED MAINTENANCE INSTRUCTIONS:

1. Non-warranty maintenance, repair, or replacement of the emission control devices and systems should be
performed by a qualified repair establishment or individual which has the experience and equipment to perform
such work.
See the Emissions Warranty Statement.
2. To ensure the best quality and reliability, use new KUBOTA Genuine parts or their equivalents for repair and
replacement, whenever you have maintenance done.

LUBRICANTS AND FUEL

Capacities
Place Lubricants
Z122E Z121S Z125E Z125S
Automobile unleaded or regular gasoline
Fuel 16 L (4.2 U.S. gals.)
Unleaded gasoline 87 octane or higher
Engine oil: API service
Classification SG, SH, SJ or higher
Engine crankcase 1.8 L (1.9 U.S.qts.)*1 Above 10 (50 )...SAE30
Between -18 (0 ) to 38 (100 )...SAE10W-30
Below 0 (32 )...SAE5W-30
Transmission case Engine oil: API service
with filter, hose and 4.8 L (5.1 U.S.qts.) Classification SL
tank (RH & LH) SAE20W-50

Note *1 Oil amount when the oil level is at the upper level of the oil level gauge.

C Engine Oil:
A Oil used in the engine should have an American Petroleum Institute (API) service classification and proper SAE
Engine Oil according to the ambient temperatures as shown above.
A Synthetic oil meeting the listed classifications may be used after 50 hours of run time.

C Fuel:
A Clean, fresh, unleaded gasoline.
A A minimum of 87 octane / 87AKI (90 RON).
A Gasoline with up to 10% ethanol (gasohol) or up to 15% MTBE (methyl tertiary butyl ether) is acceptable.
A Do not use unapproved gasoline, such as E85. Do not mix oil in gasoline or modify the engine to run on alternate
fuels. This will damage the engine components and void the engine warranty.
A This engine is certified to operate on gasoline. The emissions control system for this engine is EM (Engine
Modifications).
A High Altitude:
At altitudes over 5,000 feet (1524 meters), a minimum 85 octane / 85 AKI (89 RON) gasoline is acceptable. To
remain emissions compliant, high altitude adjustment is required. Operation without this adjustment will cause
decreased performance, increased fuel consumption, and increased emissions.
Operation of the engine at altitudes below 2,500 feet (762 meters) with the high altitude kit is not recommended.
A Indicated capacity of fuel is manufacture's estimate.
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PERIODIC SERVICE 31

PERIODIC SERVICE
HOW TO RAISE THE OPERATOR'S SEAT 2. Raise the operator's seat to the resting position.

C Raise

To avoid serious injury:

A Fully raise the operator's seat.
(To the resting position)
Do not keep the seat halfway.

1. Pull the latch lever on the seat panel rearward.

(1) Operator's seat

C Lower

To avoid serious injury:

A Do not drop the seat to close it.
A Watch your hands. Do not place your hands
under the seat, when closing.

(1) Latch lever (A) "PULL" 1. Lower the seat slowly to lock.
Downloaded from https://www.rsmanuals.com
32 PERIODIC SERVICE

DAILY CHECK BChecking Engine Oil Level

To prevent trouble from occurring, it is important to know
the condition of the machine. Check it before starting.
To avoid serious injury:
A Always stop the engine and remove the key
before checking oil.
To avoid serious injury:
A Be sure to check and service the machine on a 1. Check engine oil before starting and 5 minutes or more
level surface with the engine shut off, the key after the engine has stopped.
removed and the parking brake securely set or 2. Wipe dipstick area clean.
chock the rear wheels. 3. To check the oil level, remove the dipstick, wipe it
clean, replace it, and draw it out again. Check to see
that the oil level is between the 2 notches.
4. Add new oil to the prescribed level at the oil port if
Ref.
No. Check item necessary.
Page

Walking 1 Damage of machine body, tightness - [Z122E, Z125E]

around the of all bolts, nuts and pins, etc.
machine 2 Fuel and oil leak -

3 Tire pressure, wear and damage 25

34
4 Engine oil level 32

5 Fuel level 33

6 Air intake screen 34

7 Transaxle fluid level 35

8 Air cleaner (precleaner element) 36

9 Machine body cleaning -

Clean area around muffler and

10 -
engine controls.

Mower 1 Check all hardware. - (1) Engine oil port (A) "UPPER LEVEL"
(2) Oil level dipstick (B) "LOWER LEVEL"
2 Make sure all pins are in place -

3 Mower deck cleaning - [Z121S, Z125S]

4 Make sure blade bolts are tight 57

5 Blades and belt wear or damage 57

While sitting in 1 Motion control lever -

the operator's
seat 2 Parking brake -

3 Other movable parts 35

Turning the
key switch 1 Headlight (if equipped) 16
"ON"
Starting the 1 Color of the exhaust fumes -
engine
2 Check for abnormal noise and -
vibration.
Safety systems.
If either of these do not operate 39 (1) Engine oil port (A) "UPPER LEVEL"
3
properly, contact your local KUBOTA 40 (2) Oil level dipstick (B) "LOWER LEVEL"
Dealer immediately.

Others 1 Check the areas where previous - 5. When using a different brand or viscosity oil from the
trouble was experienced. previous one, remove all of the old oil and oil filter.
Never mix 2 different types of oil.
6. Use the proper Engine Oil SAE according to the
ambient temperatures. (See "LUBRICANTS AND
FUEL" in "MAINTENANCE" section.)
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PERIODIC SERVICE 33

A Infrequent use of the engine during a season can

make fuel stale in the fuel tank of the machine. Stale
BChecking Amount of Fuel and Refueling fuel condition can cause engine performance troubles
by varnish and plugged carburetor components.
A Seal the fuel storage container tightly and store it out
of sunlight and heat to prevent fuel degradation.
To avoid serious injury: A Condensation in the fuel tank may occur because of
A Handle fuel carefully. If the engine is running, various operating or environmental conditions. To
do not fill the fuel tank. If engine is hot, let reduce condensation and avoid affecting machine
engine cool several minutes before adding fuel. operation, fill the fuel tank at the end of daily
Do not smoke while filling the fuel tank or operations.
servicing the fuel system. Fill fuel tank only to
bottom of filler neck. Do not fill completely full.
The empty space in the tank allows gasoline to A Do not use old fuel.
expand, when it heats up. Never remove the
fuel tank cap or add fuel when the fuel tank is [Use of alcohol mixed gasoline (Gasohol)]
hot. Use "gasohol" only when the ethanol additive is less than
10% of the fuel. The use of methanol additive is not
recommended. For the best results, use unleaded fuel
with a minimum of 87 octane.

Check the fuel level. Take care that the fuel tank does not
become empty.
Fuel tank capacity 16 L (4.2 U.S.gals.)

A Do not mix oil with gasoline.

A Tighten the fuel cap until it clicks.
A Do not use the fuel cap other than KUBOTA approved
one.
A Do not permit dirt or trash or water to get into the fuel
system.
A Be careful not to spill fuel during refueling. If a spill
should occur, wipe it off at once, or it may cause a fire.

Use only unleaded gasoline with an octane rating index of

87 or higher may be used.
(1) Fuel tank cap (C) Clearance
A Use fuel within approximately 30 days after purchase (2) Fuel tank filler neck (Fuel level is under the filler neck.)
to avoid deterioration in fuel quality, or add fuel (3) Empty space
stabilizer to keep fuel fresh and stabilized. (4) Max. fuel level
A Fuel blend differs from season to season for the best
seasonal engine performance. To prevent engine
performance troubles such as vapor lock or hard
starting, use fuel within the season in which the fuel is
purchased.
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34 PERIODIC SERVICE

BChecking and Cleaning Air Intake Screen BChecking Tire Pressure

To avoid serious injury: To avoid serious injury:

A Be sure to stop the engine and remove the key A Do not attempt to mount a tire on a rim. This
before cleaning. should be done by a qualified person with the
A Make sure that the engine is cool to the touch proper equipment.
before cleaning. A Always maintain the correct tire pressure.
Inflation pressure in front tires rises quickly
when using compressed air.
A The air intake screen and air intake area must be clear Do not inflate tires above the recommended
of debris to prevent the engine from overheating. pressure shown in the Operator's Manual.

Daily or after every 5 hours of operation, check to be sure

A Do not use tires larger than specified.
the air intake screen and the air intake area are clean.
Dirt or chaff around the air intake screen and air intake
area or the engine cooling area decrease cooling BInflation Pressure
performance. Though the inflation pressure is factory-set to the
1. Check that the air intake screens are clear of grass prescribed level, it naturally drops slowly in the course of
clippings and debris.
time. Thus, check it and inflate as necessary.
2. If screens are dirty, clean screens with a brush or
cloth.
3. Remove the dust and all foreign material from the
engine plate. Recommended Inflation
Tire sizes
Max. Pressure
11 x 4 - 5, 170 kPa
Front
4PR Smooth (1.7 kgf/cm , 25 psi)
22 x 10 - 14, 110 kPa
Rear
4PR Turf (1.1 kgf/cm , 16 psi)

(1) Air intake screen

(2) Engine plate

(1) Ground (A) "INSUFFICIENT"

(B) "NORMAL"
(C) "EXCESSIVE"
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PERIODIC SERVICE 35

BChecking Transaxle Fluid Level BChecking Movable Parts

1. Park the machine on a flat surface, lower the If any of the movable parts, such as levers and pedals, is
implement to the ground and shut off the engine and not smoothly moved because of rust or anything sticky, do
remove the key. not attempt to force it into motion.
2. Check to see that the oil level lies at the "FULL COLD" In the above case, remove the rust or the sticky object,
line while the machine is at ambient temperature. and apply oil or grease on the relevant spot.
If the level is too low, add the new oil to the prescribed
Otherwise, the machine may get damaged.
level into the tank.
(See "LUBRICANTS AND FUEL" in "MAINTENANCE"
section.)

(1) Transaxle fluid tank (A) Oil level is acceptable

at this line.

A If oil level is low, do not run engine.

Add the new oil to the prescribed level into the tank.
A Do not overfill the tank.
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36 PERIODIC SERVICE

C Clean precleaner
EVERY 25 HOURS [Z122E]
BCleaning Precleaner Element (Except Wash the precleaner every 25 hours of operation.
Z125E) (more often under extremely dusty or dirty conditions.)
Check the air cleaner daily or before starting the 1. Loosen the air cleaner cover knobs and remove the air
engine. Check for a buildup of dirt and debris around the cleaner cover.
air cleaner system. Keep this area clean. Also check for
loose or damaged components. Replace all bent or
damaged air cleaner components.

A Operating the engine with loose or damaged air

cleaner components could allow unfiltered air into the
engine causing premature wear and failure.

(1) Air cleaner cover

(2) Air cleaner cover knob

2. Remove the air cleaner element with the precleaner

and remove the precleaner from it. Make sure the base
and the sealing area is clean before reassembly is
performed.

(1) Air cleaner element (A) Air intake

(2) Precleaner (B) Base

3. Wash the precleaner in warm water with detergent.

Rinse the precleaner thoroughly until all traces of
detergent are eliminated. Squeeze out excess water.
(do not wring.) Allow the precleaner to air dry.
Do not oil the precleaner.
4. Reinstall the precleaner over the paper element and
reinstall them to air intake.
5. Reinstall the air cleaner cover and secure with the 2
knobs.
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PERIODIC SERVICE 37

[Z121S, Z125S]
Wash and reoil the precleaner every 25 hours of BCleaning Air Cleaner Element (Z122E,
operation. (more often under extremely dusty or dirty Z125E)
conditions.) Every 100 hours of operation or annually replace the
1. Unlatch the cover and remove the air cleaner cover. paper element. Check every 25 hours of operation.
2. Remove the precleaner from the air cleaner element,
(More often under extremely dusty or dirty conditions.)
or remove as an assembly for servicing. Make sure the
base and the sealing area is clean before reassembly [Z122E]
is performed. 1. Loosen the air cleaner cover knobs and remove the air
cleaner cover.

(1) Air cleaner cover (A) "UNLATCH"

(B) "REMOVE"
(1) Air cleaner cover
(2) Air cleaner cover knob

2. Remove air cleaner element with precleaner.

(1) Air cleaner cover (A) Air intake

(2) Air cleaner element
(3) Precleaner
(1) Air cleaner element (A) Air intake
3. Wash the precleaner in warm water with detergent.
(2) Precleaner (B) Base
Rinse the precleaner thoroughly until all traces of
detergent are eliminated. Squeeze out excess water. 3. Remove the precleaner from the paper element.
(do not wring.) Allow the precleaner to air dry. 4. Gently tap the paper element to dislodge dirt. Do not
4. Saturate the precleaner with new engine oil. wash the paper element or use pressurized air, as
Squeeze out all excess oil. this will damage the element. Replace a dirty, bent, or
5. Reinstall the precleaner over the paper element and damaged element with a genuine part. Handle the new
install in air intake. element carefully; do not use if the sealing surfaces
6. Reinstall the air cleaner cover and secure with the 2 are bent or damaged.
latches. 5. Clean the air cleaner base as required and check
condition.
6. Reinstall the precleaner over the paper air cleaner
element and install it on the base.
Downloaded from https://www.rsmanuals.com
38 PERIODIC SERVICE

7. Reinstall the air cleaner cover and secure it with 2 6. Reinstall the air cleaner cover and secure it with 2
knobs. knobs.

A Operating the engine with loose or damaged air A Operating the engine with loose or damaged air
cleaner components could allow unfiltered air into the cleaner components could allow unfiltered air into the
engine causing premature wear and failure. engine causing premature wear and failure.

[Z125E]
1. Loosen the air cleaner cover knobs and remove the air
cleaner cover.

(1) Air cleaner cover

(2) Air cleaner cover knob

2. Open the latch and remove the air cleaner element.

(1) Air cleaner cover

(2) Air cleaner cover knob
(3) Latch
(4) Air cleaner element

3. Gently tap the paper element to dislodge dirt. Do not

wash the paper element or use pressurized air, as
this will damage the element. Replace a dirty, bent, or
damaged element with a genuine part. Handle the new
element carefully; do not use if the sealing surfaces
are bent or damaged.
4. Clean the air cleaner base as required and check
condition.
5. Reinstall the air cleaner element and close the latch.
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PERIODIC SERVICE 39

EVERY 50 HOURS Test 3 (OPERATOR ON THE SEAT)

BChecking Engine Start System 1. Securely set the parking brake.
2. Set the PTO switch to "DISENGAGE" (OFF) position.
The Engine Start System in your machine are designed to
3. Grasp the motion control levers and move them
protect you while operating. Please check these Engine
inward from the "NEUTRAL LOCK" position to the
Start System periodically - daily is best - to test function of "NEUTRAL" position and then release the levers.
the Engine Start System before operation. 4. Turn the key switch to "START" position.
5. The engine must not crank.

Test 4 (OPERATOR ON THE SEAT)

To avoid serious injury: 1. Securely set the parking brake.
A Do not allow anyone near the machine while 2. Set the PTO switch to "ENGAGE" (ON) position.
testing. 3. Set the motion control levers to the "NEUTRAL LOCK"
A If the machine does not pass one of the position.
following tests, do not operate the machine. 4. Turn the key switch to "START" position.
See your local KUBOTA Dealer. 5. The engine must not crank.
A Sit on operator's seat for all tests except for
Test 1.
A If the engine cranks in Test 1 through 4, consult your
local KUBOTA Dealer to have the unit checked before
A Check the following tests before operating the operation.
machine.
Test 5 (OPERATOR ON THE SEAT)
1. Start the engine.
2. Keep the parking brake securely set.
3. Set the PTO switch to "DISENGAGE" (OFF) position.
4. Grasp the motion control levers and move them
inward from "NEUTRAL LOCK" position to
"NEUTRAL" position and then release the levers.
5. The engine must shut off.

A If the engine remains running in Test 5, consult your

local KUBOTA Dealer to have the unit checked before
operation.

(1) Parking brake lever

(2) Motion control lever
(3) Key switch
(4) PTO switch
(5) Seat switch

Test 1 (OPERATOR NOT ON THE SEAT)

1. Securely set the parking brake.
2. Set the PTO switch to "DISENGAGE" (OFF) position.
3. Set the motion control levers to the "NEUTRAL LOCK"
position.
4. Turn the key switch to "START" position.
5. The engine must not crank.

Test 2 (OPERATOR ON THE SEAT)

1. Do not set the parking brake. (release it from test 1)
2. Set the PTO switch to "DISENGAGE" (OFF) position.
3. Set the motion control levers to the "NEUTRAL LOCK"
position.
4. Turn the key switch to "START" position.
5. The engine must not crank.
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40 PERIODIC SERVICE

BChecking OPC System BChecking Carbon Canister Air Filter

The OPC (Operator Presence Control) system in your Check the carbon canister air filter every 50 hours of
machine are designed to protect you while operating. operation. (more often under extremely dusty or dirty
Please check these OPC system periodically - daily is conditions.)
best - to test function of the OPC system before operation.

To avoid serious injury:

To avoid serious injury: A Always stop the engine, set the parking brake,
A Do not allow anyone near the machine while remove the key, and disengage PTO.
testing.
A If the machine does not pass one of the 1. Remove the carbon canister air filter.
following tests, do not operate the machine.
See your local KUBOTA Dealer.

(1) Canister air filter (A) Air port

(2) Carbon canister

(1) Parking brake lever 2. Check to see if the carbon canister air filter is worn out,
(2) Motion control lever damaged or dirty.
(3) Key switch 3. If the air filter is dirty, wash the air filter in warm water
(4) PTO switch with detergent. Then rinse the air filter thoroughly until
(5) Seat switch
all traces of detergent are eliminated. Squeeze out
excess water. (do not wring.) Allow the air filter to air
Test 1 (OPERATOR ON THE SEAT) dry. Do not use high pressure air to clean filter.
1. Start the engine. 4. If the air filter is worn out, damaged or too dirty to wash
2. Do not set the parking brake. clean, replace it with a new one.
3. Set the PTO switch to "DISENGAGE" (OFF) position. 5. Reinstall the carbon canister air filter.
4. Stand up. (Do not get off the machine.)
5. The engine must shut off.
A Operating in dusty condition may require more
Test 2 (OPERATOR ON THE SEAT) frequent maintenance than above.
1. Start the engine.
2. Do not set the parking brake.
3. Set the PTO switch to "ENGAGE" (ON) position.
4. Stand up. (Do not get off the machine.)
5. The engine must shut off.

A If the engine remains running in Test 1 through 2,

consult your local KUBOTA Dealer to have the unit
checked before operation.
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PERIODIC SERVICE 41

[Z125E]
BChanging Engine Oil (Z122E, Z125E)

To avoid serious injury:

A Be sure to stop the engine and remove the key
before changing the oil.
A Allow engine to cool down sufficiently; oil can
be hot and may cause burns.

1. To change the used oil, unhook the drain hose, direct

the hose down and open the drain valve.

A The used oil can be drained out more easily if the

engine is warm. (1) Engine oil port (A) "UPPER LEVEL"
(2) Oil level dipstick (B) "LOWER LEVEL"
[Z122E, Z125E]
3. To check the oil level. Remove the dipstick, wipe it
clean, insert it and draw it out again. Check to see that
the oil level is between the 2 marks.

A Do not overfill.

(1) Drain hose

(2) Drain valve
(3) Hook

2. Fill with the new oil up to the upper level on the

dipstick.

[Z122E]

(1) Engine oil port (A) "UPPER LEVEL"

(2) Oil level dipstick (B) "LOWER LEVEL"
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42 PERIODIC SERVICE

BReplacing Engine Oil Filter (Z122E, Z125E)

To avoid serious injury:

A Engine oil is a toxic substance. Dispose of
used oil properly. Contact your local
authorities for approved disposal methods or
possible recycling.

To avoid serious injury:

A Be sure to stop the engine and remove the key
before changing the oil and the oil filter (1) Engine oil filter cartridge (A) "MOUNTING SURFACE"
cartridge.
A Allow engine to cool down sufficiently; oil can
be hot and may cause burns.

The oil filter cartridge must be changed every 50 service

hours or annually.
Always use a genuine oil filter.

1. The drain plug is located on the starter side of the oil

pan. Clean the area around the oil drain plug and the
oil fill cap/dipstick.
2. Remove the drain plug and the oil fill cap/dipstick.
3. Allow the oil to drain and then reinstall the drain plug.
4. Remove the old filter and wipe off the filter adapter with
a clean cloth.
5. Place a new replacement filter in a shallow pan with
the open end up. Pour new oil, of the proper type, in
through the threaded center hole. Stop pouring when
the oil reaches the bottom of the threads. Allow a
minute or 2 for the oil to be absorbed by the filter
material.
6. Apply a thin film of clean oil to the rubber gasket on the
new oil filter.
7. Install the new oil filter to the filter adapter. Hand
tighten the filter clockwise until the rubber gasket
contacts the adapter, then tighten the filter an
additional 1/2 to 3/4 turn.
8. Fill the engine with the proper oil to the "FULL" or "F"
mark on the dipstick. Always check the oil level with
the dipstick before adding more oil.
9. Reinstall the oil fill cap/dipstick and tighten securely.
10. Start the engine and check for oil leaks. Recheck oil
level before placing the engine into service.
Stop the engine, correct any leaks, and allow a minute
for the oil to drain down, then recheck the level on the
dipstick.

A To prevent extensive engine wear or damage, always

maintain the proper oil level in the crankcase. Never
operate the engine with the oil level below the "ADD"
or "L" mark or above the "FULL" or "F" mark on the
dipstick.
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PERIODIC SERVICE 43

EVERY 100 HOURS

BChecking Muffler and Spark Arrester (if
equipped) BChanging Engine Oil (Z121S, Z125S)

Running engines produce heat. Engine parts, To avoid serious injury:

especially muffler, become extremely hot. A Be sure to stop the engine and remove the key
Severe thermal burns can occur on contact. before changing the oil.
Combustible debris, such as leaves, grass, brush, A Allow engine to cool down sufficiently; oil can
etc. can catch fire. be hot and may cause burns.
To avoid serious injury: 1. To change the used oil, remove the drain hose from
A Allow muffler, engine cylinder and fins to cool the clamp, direct the hose down and remove the drain
before touching. plug.
A Remove accumulated debris from muffler area
and cylinder area.
A It is a violation of California Public Resource A The used oil can be drained out more easily if the
Code, Section 4442, to use or operate the engine is warm.
engine on any forest-covered, brush-covered,
or grass-covered land unless the exhaust [Z121S, Z125S]
system is equipped with a spark arrester, as
defined in Section 4442, maintained in effective
working order. Other states or federal
jurisdictions may have similar laws. Contact
the original equipment manufacturer, retailer,
or dealer to obtain a spark arrester designed
for the exhaust system installed on this engine.
A Replacement parts must be of the same design
and installed in the same position as the
original parts. Other parts may not perform as
well, may damage the unit, and may result in
injury.

Remove accumulated debris from muffler area and

cylinder area. Inspect the muffler for cracks, corrosion, or (1) Drain plug
other damage. Remove the spark arrester, if equipped,
and inspect for damage or carbon blockage. If damage is 2. Fill with the new oil up to the upper level on the
found, install replacement parts before operating. dipstick.

[Z121S, Z125S]

(1) Engine oil port (A) "UPPER LEVEL"

(2) Oil level dipstick (B) "LOWER LEVEL"
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44 PERIODIC SERVICE

3. To check the oil level. Remove the dipstick, wipe it

clean, insert it and draw it out again. Check to see that BReplacing Air Cleaner Element (Z121S,
the oil level is between the 2 marks.
Z125S)
Every 100 hours of operation or annually replace the
A Do not overfill. paper element.

BReplacing Precleaner Element (Except [Z121S, Z125S]

1. Unlatch the cover and remove the air cleaner cover.
Z125E)
2. Remove the air cleaner element and precleaner.
(See "Cleaning Precleaner Element (Except Z125E)" in
"EVERY 25 HOURS" in "PERIODIC SERVICE" section.)

BReplacing Air Cleaner Element (Z122E,

Z125E)
(See "Cleaning Air Cleaner Element (Z122E, Z125E)" in
"EVERY 25 HOURS" in "PERIODIC SERVICE" section.)

(1) Air cleaner cover (A) "UNLATCH"

(B) "REMOVE"

3. Remove the precleaner from the paper element.

(1) Air cleaner cover (A) Air intake

(2) Air cleaner element
(3) Precleaner

4. Replace a dirty, bent, or damaged element with a

genuine part. Handle the new element carefully; do not
use if the sealing surfaces are bent or damaged.
5. Clean the air cleaner base as required and check
condition.
6. Reinstall the precleaner over the paper element and
install in air intake.
7. Reinstall the air cleaner cover and secure with the 2
latches.
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PERIODIC SERVICE 45

[Z125E]
A Operating the engine with loose or damaged air
cleaner components could allow unfiltered air into the
engine causing premature wear and failure.

BCleaning Engine Shroud

To avoid serious injury:

A Make sure engine is cool to the touch before
removing shrouds.

1. Remove the engine shroud mounting bolts and detach

the shroud.
2. Check to see if the engine's cooling fins are blocked (1) Shroud
with dust and dirt. Clean them with compressed air if
required. [Z121S, Z125S]

To avoid serious injury:

A Always shield eyes and face from air deposits
and objects.

[Z122E]

(1) Shroud

(1) Shroud
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46 PERIODIC SERVICE

[Z121S, Z125S]
BChecking Spark Plug
Every 100 hours of operation check the spark plug
condition and gap. Annually replace the spark plug.

1. Remove the spark plug wire from spark plug.

2. Use a spark plug wrench to remove plug.

A This engine is equipped with resistor-type spark plug.

3. Inspect spark plug for cracked porcelain, pitted

electrodes, or other wear and damage. Replace spark
plug if necessary.

[Z122E]
(1) Spark plug (both sides)

4. Check spark plug gap with gap gauge.

Recommended spark plug CHAMPION XC12YC

(1) Spark plug (both sides)

[Z125E]

(A) 0.76 mm (0.03 in.)

(1) Spark plug (both sides)

Downloaded from https://www.rsmanuals.com
PERIODIC SERVICE 47

BChecking Fuel Lines

To avoid serious injury:

A Be sure to stop the engine and remove the key
when attempting to make the following checks
and changes.
A Never fail to check the fuel lines periodically.
The fuel lines are subject to wear and aging.
Fuel may leak out onto the running engine,
causing a fire.

The fuel line connections should be checked annually or

every 100 hours of operation, whichever occurs first. (1) Fuel line
1. The fuel line is made of rubber and ages regardless of (2) Pipe clamp
service period. (3) 2 way valve (assembled in the fuel tank)
2. If the fuel line, clamps and fuel filter are found
damaged or deteriorated, replace them.

A When the fuel line is disconnected for maintenance or

repair, close both ends of the fuel line with a piece of
clean cloth or paper to prevent dust and dirt from
entering. In addition, particular care must be taken not
to admit dust and dirt into the fuel pump. Entrance of
dust and dirt causes malfunction of the fuel pump.

(1) Fuel line

(2) Pipe clamp
(3) Carbon canister
(4) Fuel filter

(1) Fuel valve (A) "CLOSE" (OFF)

(2) Fuel tank (B) "OPEN"
(3) Fuel line
(4) Pipe clamp

(1) Fuel line

(2) Pipe clamp
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48 PERIODIC SERVICE

BBattery Condition

To avoid the possibility of battery explosion:

For the refillable type battery, follow the
instructions below.
A Do not use or charge the refillable type battery
if the fluid level is below the LOWER (lower limit
level) mark. Otherwise, the battery component
parts may prematurely deteriorate, which may
shorten the battery's service life or cause an
explosion. Check the fluid level regularly and
add distilled water as required so that the fluid
(1) Fuel line level is between the UPPER and LOWER levels.
(2) Pipe clamp
(3) Fuel pump

To avoid serious injury or death:

A When the battery is being activated, hydrogen
and oxygen gases in the battery are extremely
explosive. Keep open sparks and flames away
from the battery at all times, especially when
charging the battery.

To avoid serious injury:

A Batteries, battery posts, terminals and related
accessories contain lead and lead compounds,
and other chemicals known to the State of
California to cause cancer and birth defects or
other reproductive harm. WASH HANDS
(1) Fuel line (A) Muffler
(2) Pipe clamp (B) Carburetor
AFTER HANDLING.
A Never remove the battery cap while the engine
is running.
A Keep electrolyte away from eyes, hands and
clothes. If you are spattered with it, wash it
away completely with water immediately and
get medical attention.
A Keep open sparks and flames away from the
battery at all times. Hydrogen gas mixed with
oxygen becomes very explosive.
A Wear eye protection and rubber gloves when
working around battery.

The factory-installed battery is of non-refillable type.

If the battery is weak, charge the battery or replace it
with new one.
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PERIODIC SERVICE 49

A Mishandling the battery shortens the service life and

adds to maintenance costs.
The original battery is maintenance free, but needs
some servicing.
If the battery is weak, the engine will be difficult to start
and the lights will be dim. It is important to check the
battery periodically.
A When exchanging an old battery for new one, use
battery of equal specification in table below.

Reserve Cold Normal

Battery Volts
Capacity Cranking Charging
Type (V)
(min) Amps Rate(A)

U1-300 12 45 300 6.5

(1) Battery (+): Positive terminal
(2) Ground cable (-): Negative terminal
(For non-accessible maintenance-free type batteries.)
Maintenance-free, non-accessible batteries are designed 1. To slow charge the battery, connect the battery
to eliminate the need to add water. Yet the volume of positive terminal to the charger positive terminal and
electrolyte above plates may eventually become depleted the negative to the negative, then charge for at least 1
hour at 6.5 amperes.
due to abnormal conditions such as high heat or improper
2. A boost charge is only for emergencies. It will partially
regulator setting. Use a voltmeter to check the state of
charge the battery at a high rate and in a short time.
charge. (See reference chart below to determine if When using a boost-charged battery, it is necessary to
charging is necessary.) recharge the battery as early as possible.
Battery voltage Reference state of charge Failure to do this will shorten the battery's service life.
3. When the specific gravity of electrolyte is between
12.6 100%(Full charge) 1.27 and 1.29 the charging is completed.
12.4 75%
C Battery for storage
12.2 50% 1. When storing the machine for a long period, remove
the battery from machine, adjust the electrolyte to the
12.0 25%
proper level and store in a dry place out of direct
11.8 0% sunlight.
2. The battery self-discharges while it is stored.
C Battery Charging Recharge it once every 3 months in hot seasons and
once every 6 months in cold seasons.

To avoid serious injury or death:

A When the battery is being activated, hydrogen
and oxygen gases in the battery are extremely
explosive. Keep open sparks and flames away
from the battery at all times, especially when
charging the battery.

To avoid serious injury:

A When disconnecting the cable from the battery,
start with the negative terminal first. When
connecting the cable to the battery, start with
the positive terminal first.
A Never check battery charge by placing a metal
object across the posts.
Use a voltmeter or hydrometer.
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50 PERIODIC SERVICE

[Z121S, Z125S]
BAdjusting Throttle Cable 1. Move the throttle lever to the "FAST" position.
[Z122E, Z125E]
1. Move the throttle lever to the "FAST" position.

(1) Throttle lever

2. Make sure the throttle arm (A) contacts the choke arm
(1) Throttle lever (B).
2. Attempt to pass a pin (A) with a diameter of 3 mm
through the holes indicated.

(1) Bolt (A) Throttle arm

(2) Throttle lever cable sheath (B) Choke arm
(P) "PULL"
(1) Bolt (A) Pin with a diameter of 3 mm (Q) "CONTACT"
(2) Throttle lever cable sheath (B) Hole
(P) "PULL" 3. If not possible, loosen the bolt (1) and pull the throttle
lever cable sheath (2) in the direction of the arrow until
3. If not possible, loosen the bolt (1) and pull the throttle
throttle arm (A) contact the choke arm (B). And then
lever cable sheath (2) in the direction of the arrow so
tighten the bolt (1).
that the pin (A) passes through all the required holes
(B). And then tighten the bolt (1).
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PERIODIC SERVICE 51

BReplacing Engine Oil Filter (Z121S, Z125S)

To avoid serious injury:

A Engine oil is a toxic substance. Dispose of
used oil properly. Contact your local
authorities for approved disposal methods or
possible recycling.

To avoid serious injury:

A Be sure to stop the engine and remove the key
before changing the oil and the oil filter (1) Engine oil filter cartridge (A) "MOUNTING SURFACE"
cartridge.
A Allow engine to cool down sufficiently; oil can
be hot and may cause burns.

The oil filter cartridge must be changed every 100 service

hours.
Always use a genuine oil filter.

1. The drain plug is located on the starter side of the oil

pan. Clean the area around the oil drain plug and the
oil fill cap/dipstick.
2. Remove the drain plug and the oil fill cap/dipstick.
3. Allow the oil to drain and then reinstall the drain plug.
4. Remove the old filter and wipe off the filter adapter with
a clean cloth.
5. Place a new replacement filter in a shallow pan with
the open end up. Pour new oil, of the proper type, in
through the threaded center hole. Stop pouring when
the oil reaches the bottom of the threads. Allow a
minute or 2 for the oil to be absorbed by the filter
material.
6. Apply a thin film of clean oil to the rubber gasket on the
new oil filter.
7. Install the new oil filter to the filter adapter. Hand
tighten the filter clockwise until the rubber gasket
contacts the adapter, then tighten the filter an
additional 3/4 to 1 turn.
8. Fill the engine with the proper oil to the "FULL" or "F"
mark on the dipstick. Always check the oil level with
the dipstick before adding more oil.
9. Reinstall the oil fill cap/dipstick and tighten securely.
10. Start the engine and check for oil leaks. Recheck oil
level before placing the engine into service.
Stop the engine, correct any leaks, and allow a minute
for the oil to drain down, then recheck the level on the
dipstick.

A To prevent extensive engine wear or damage, always

maintain the proper oil level in the crankcase. Never
operate the engine with the oil level below the "ADD"
or "L" mark or above the "FULL" or "F" mark on the
dipstick.
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52 PERIODIC SERVICE

EVERY 200 HOURS

BChecking Hydraulic Hose

To avoid serious injury:

A Be sure to stop the engine, remove the key, and
relieve pressure before checking and replacing
the hydraulic hose.
A Allow the transmission case to cool down
sufficiently; oil can be hot and may cause
burns.

Check to see if hydraulic hoses are properly fixed every

200 hours of operation. (1) Hose clamp
1. Check to see that all lines and hose clamps are tight (2) Hydraulic hose
and not damaged.
2. If hoses and clamps are found worn or damaged,
replace or repair them at once.

(1) Hydraulic hose

(2) Hose clamp
(3) Transaxle fluid tank

(1) Hose clamp

(2) Transaxle fluid tank
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PERIODIC SERVICE 53

EVERY 400 HOURS

BReplacing Transaxle Oil Filter Cartridge

To avoid serious injury:

A Park the machine on a firm and level surface.
A Apply the parking brake.
A Be sure to stop the engine and remove the key
before changing or checking the oil.
A Allow transmission case to cool down
sufficiently; oil can be hot and may cause
burns.

1. Apply the bypass valve.

(See "Hydrostatic Transaxle Bypass Rods" in
"TRANSPORTING" in "OPERATING THE MACHINE"
section.)
2. Remove the hex head bolts (4), and filter guard (3).
Clean any loose debris from around the perimeter of
the oil filter (2).
3. Place an oil drain pan (12" or more diameter and 8 qt.
capacity is optimal) beneath the oil filter. Remove the
oil filter (2) and discard it.

A Always replace the filter when preforming any internal

maintenance to the transaxle.

4. After the oil has drained, inspect all parts for excessive
(1) Transaxle (A) FRONT
wear or damage. Replace if necessary.
(2) Transaxle oil filter (B) OIL LEVEL
5. Wipe the filter base surface off and apply a film of new (3) Filter guard
oil to the gasket of the new replacement filter (Hydro- (4) Hex flange head bolt
Gear part number 52114). (5) Breather port plug
6. Install the new filter by hand, turn 3/4 to 1 full turn after
the filter gasket contacts the filter base surface.
7. Re-install the filter guard (3) with 3 hex head bolts (4).
Torque bolts (4) to 7.35 N-m (5.42 lbf-ft) securely.
8. Repeat steps 2-7 on the opposite side transaxle drive.
9. Drain old oil filters of all free flowing oil prior to
disposal. Place used oil in appropriate containers and
deliver to an approved recycling collection facility.
10. Remove the breather port plug (9) from the left side
and right side transaxles prior to filling with oil. This will
allow the transaxles to vent during oil fill.
11. Remove the cap from the transaxle fluid tank located
on the machine frame.
12. Fill with 20W-50 motor oil until oil just appears at the
bottom of the breather port. Install the breather port
plug (5) into transaxle. Torque the plug (5) to 20.34 N-
m (15.0 lbf-ft).
13. Continue to fill the transaxles through the transaxle
fluid tank until the "Full Cold" line is reached on the
transaxle fluid tank.
14. Re-install the transaxle fluid tank cap by hand. Be
careful to not overtighten.
15. Proceed to the purge procedure.
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54 PERIODIC SERVICE

C Purging Procedures
Due to the effects air has on efficiency in hydrostatic drive
EVERY 500 HOURS
applications, it is critical that it is purged from the system. BElectric Clutch Adjustment
The electric clutch serves 2 functions in the operation of
Air creates inefficiency because its compression and
the mower. In addition to starting and stopping the power
expansion rate is higher than that of the oil approved for
flow to the cutter blades, the clutch also acts as a brake to
use in hydrostatic drive systems.
assist in stopping blade rotation when the PTO is switched
These purge procedures should be implemented any time off or the operator presence control is interrupted.
a hydrostatic system has been opened to facilitate
When the clutch is disengaged, the air gap between the
maintenance or the oil has been changed.
armature and rotor must be adjusted to 0.4 mm (0.015 in.)
The resulting symptoms in hydrostatic systems may be: for proper operation. The air gap adjustment is made at 3
1. Noisy operation. bolts on the clutch. There are 3 inspection windows, one
2. Lack of power or drive after short term operation. next to each adjusting bolt. (See the figure below.)
3. High operation temperature and excessive expansion
of oil.

Before starting, make sure the transaxle is at the proper

oil level. If it is not, fill to the specifications outlined in this
manual.

The following procedures are best performed with the

machine drive wheels off the ground. Then repeated
under normal operating conditions. If this is not possible,
then the procedure should be performed in an open area
free of any objects or bystanders.
1. Disengage the brake if activated.
2. With the bypass valve open and the engine running,
slowly move the motion control levers in both forward
and reverse directions (5 or 6 times).
3. With the bypass valve closed and the engine running,
slowly move the motion control levers in both forward
and reverse directions (5 to 6 times). Check the oil
level, and add oil as required after stopping the
engine.
4. It may be necessary to repeat Steps 2 and 3 until all
the air is completely purged from the system. When
the transaxle operates at normal noise levels and
moves smoothly forward and reverse at normal
speeds, then the transaxle is considered purged.

BChanging Transaxle Fluid

(See "Replacing Transaxle Oil Filter Cartridge" in "EVERY
(1) Inspection window (x3) (A) Electric clutch
400 HOURS" in "PERIODIC SERVICE" section.)
1. Locate the inspection windows on the clutch.
2. Place a 0.4 mm (0.015 in.) feeler gauge in the slot
between the rotor and the armature. (See the figure.)
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PERIODIC SERVICE 55

EVERY AFTER 500 HOURS

BCleaning Combustion Chamber
If you do not have the proper tools and/or are not
mechanically proficient, consult your local KUBOTA
Dealer for this service.

EVERY 1 YEAR
BReplacing Precleaner Element (Except
Z125E)
(See "Cleaning Precleaner Element (Except Z125E)" in
"EVERY 25 HOURS" in "PERIODIC SERVICE" section.)

(A) Electric clutch

(P) "INSERT 0.4 mm (0.015 in.) FEELER GAUGE HERE"
BReplacing Air Cleaner Element (Z122E,
Z125E)
3. Tighten or loosen the adjusting nut as needed to (See "Cleaning Air Cleaner Element (Z122E, Z125E)" in
achieve the 0.4 mm (0.015 in.) air gap. (See the "EVERY 25 HOURS" in "PERIODIC SERVICE" section.)
figure.) Perform this operation at all 3 inspection
windows.
BReplacing Air Cleaner Element (Z121S,
Z125S)
(See "Replacing Air Cleaner Element (Z121S, Z125S)" in
"EVERY 100 HOURS" in "PERIODIC SERVICE" section.)

BChanging Engine Oil (Z122E, Z125E)

(See "Changing Engine Oil (Z122E, Z125E)" in "EVERY
50 HOURS" in "PERIODIC SERVICE" section.)

BReplacing Engine Oil Filter (Z122E, Z125E)

(See "Replacing Engine Oil Filter (Z122E, Z125E)" in
"EVERY 50 HOURS" in "PERIODIC SERVICE" section.)

BReplacing Fuel Filter (Z122E, Z125E)

(A) Electric clutch
(See "Checking Fuel Lines" in "EVERY 100 HOURS" in
(Q) Adjustment nut
"PERIODIC SERVICE" section.)
This adjustment should be done every 500 hours of
operation or annually, whichever comes first. In cases BChecking Muffler and Spark Arrester (if
where the machine is heavily used, air gap settings should equipped)
be checked more often. (See "Checking Muffler and Spark Arrester (if equipped)"
in "EVERY 50 HOURS" in "PERIODIC SERVICE"
If the air gap is too narrow, the clutch armature may drag
section.)
when disengaged, resulting in premature failure.

BReplacing Spark Plug

BChecking Engine Valve Clearance (Z121S, (See "Checking Spark Plug" in "EVERY 100 HOURS" in
Z125S) "PERIODIC SERVICE" section.)
Consult your local KUBOTA Dealer for this service.
BChecking Engine Valve Clearance (Z122E,
Z125E)
Consult your local KUBOTA Dealer for this service.
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56 PERIODIC SERVICE

EVERY 2 YEARS SERVICE AS REQUIRED

BReplacing Hydraulic Hose BReplacing Fuses
Consult your local KUBOTA Dealer for this service. Replacement of the fuse
1. Raise the operator's seat.
BReplacing Fuel Lines 2. Remove the blown fuse.
3. Place a new fuse of the same capacity in position.
Consult your local KUBOTA Dealer for this service.

BReplacing Engine Breather Hose

Consult your local KUBOTA Dealer for this service.

BReplacing Carbon Canister Air Filter

(See "Checking Carbon Canister Air Filter" in "EVERY 50
HOURS" in "PERIODIC SERVICE" section.)

(1) Fuse location

(2) Slow blow fuse

A If the new fuse happens to blow out within a short time,

contact your dealer for inspection and repair. Never
"jump" the fuse with wire or foil, or install a larger
capacity fuse than is recommended.

C Protected circuit
CAPACITY
FUSE NO. Protected circuit
(A)
5 Start
5 Operator control
10 PTO clutch
(1)
15 Accessories
- -
- -
Slow blow fuse Check circuit against
(2)
30 wrong battery connection
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PERIODIC SERVICE 57

BChecking and Replacing Blade

To avoid serious injury:

A Be sure to stop the engine and remove the key.
A Blades may be sharp. When you handle blades,
wear heavy gloves or wrap end of blade with a
rag.

C Checking
The blade cutting edges should be kept sharp at all times.
Sharpen the cutting edges, if they resemble blade (B).
Replace the blades if they appear similar to blade (C).
(1) Block (A) "LOOSEN"

3. To sharpen the blades yourself, clamp the blade

securely in a vise.
Use a large mill file and file along the original bevel
until sharp.
4. To check the blade for balance, place a small rod
through the center hole. If the blade is not balanced,
file the heavy side of the blade until balance is
achieved.
5. To attach blades, be sure to install the cup washer
between the blade and bolt head. Then tighten the bolt
securely.
6. Before checking or replacing the blade, wipe grass
and mud off the top and inside of the mower.
(A) New blade Especially clean up the inside of the belt cover,
(B) Worn blade because otherwise the belt life will be reduced.
(C) Cracked blade
[RCK48P, RCK54P]
C Replacing
1. Dismount the mower deck from the machine.
(See "DISMOUNTING THE MOWER DECK" in
"MOWER MOUNTING" section.)
Then turn it over to expose the blades.
2. Wedge a block of wood between the blade and mower
housing or use a box wrench over the pulley nut to
prevent the spindle from rotating while removing the
blade bolts; loosen the blade bolt as illustrated.

A Use the proper metric size box or socket wrench to

tighten or loosen the blade mounting bolt.

(1) Spindle holder

(2) Blade
(3) Cup washer
(4) Bolt

A Tighten the bolts of the outer blades from 103 to 118

N-m (76 to 87 lbf-ft) of torque.
A The blade bolts have Right hand threads. Turn them
counterclockwise to loosen.
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58 PERIODIC SERVICE

A To prolong the service life of the blades, reposition

them as shown in the figure below periodically. BMower Belt Replacement
1. Remove the mower deck from the machine according
to the procedure "DISMOUNTING THE MOWER
DECK".
2. Remove the left and right hand shield from the mower
deck.
3. Remove the tension pulley, and remove the belt.
4. To install a new belt, reverse the above procedure.

A Tighten the tension pulley bolt securely 77.6 to 90.2 N-

m (8.0 to 9.2 kgf-m, 57.1 to 66.5 lbf-ft).

(1) LH blade
(2) Center blade
(3) RH blade

(1) Tension pulley (3) Bolt

(2) Belt (4) Shield
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ADJUSTMENT 59

ADJUSTMENT
MOTION CONTROL LEVER
BHST NEUTRAL
1. Lift-up and secure with jack stands or blocking the rear
of the machine frame.
To avoid serious injury:
2. Remove both rear wheels.
A Park the machine on a firm and level surface.
3. Start the engine, and run at maximum speed.
A If it is necessary to run the engine in an
4. Place the motion control lever in "NEUTRAL LOCK"
enclosed area, use a gas tight exhaust pipe
position.
extension to remove the fumes.
5. Loosen the 3 bolts of the guide plate.
A Always try to work in a well-ventilated area.
Adjust the guide plate position until the rear axle
A Lift up and secure with jack stands or blocking
rotation stops.
the rear of the machine, do not run the machine
6. Tighten the rear bolt and place the lever in "NEUTRAL
while adjusting.
LOCK" position. Check that the rear axle does not
Remove rear wheels.
rotate.
A Do not adjust only one of the following
If the axle does not stop rotating, adjust the "HST
adjustments; exclude "MOTION CONTROL
NEUTRAL" again.
LEVER ALIGNMENT".
They are interlinked.
A If you feel you are unable to make the following 23.6 to 27.4 N-m
adjustments correctly and safely, please Tightening torque (2.4 to 2.8 kgf-m,
contact your local KUBOTA Dealer. 17.4 to 20.2 lbf-ft)

A Right and left motion control levers can be adjusted 7. Adjust the other side "HST NEUTRAL" equally.
independently. 8. After adjustment, make sure to stop the engine
immediately.

[RH]

(1) Guide plate (A) Motion control lever

(2) Speed adjust plate
(3) Bolt (front)
(4) Bolt (rear)
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60 ADJUSTMENT

[LH]
BMAXIMUM SPEED (FORWARD)
Consult your local KUBOTA Dealer for this service.

BMOTION CONTROL LEVER ALIGNMENT

C Check the alignment
Check the gap and space between the levers, at the
maximum forward position.
Gap: 0 to 2 mm
Recommendation
(0 to 0.08 in.)

If positions of the control levers are unequal, an

adjustment is necessary.

(1) Guide plate (A) Motion control lever

(2) Speed adjust plate
(3) Bolt (front)
(4) Bolt (rear)

9. Push the motion control lever until it contacts the

speed adjust plate and reaches the end of its range of
motion. Then move the speed adjust plate to 2-3 mm
backward and tighten 2 front bolts securely.

23.6 to 27.4 N-m

Tightening torque (2.4 to 2.8 kgf-m,
17.4 to 20.2 lbf-ft)

10. If at full speed the machine pulls one direction or the (A) "GAP"
other, it is an indication that one wheel is turning faster
than the other.
To adjust the condition, proceed as follows:
(1) Park the machine on a firm and level surface. To avoid serious injury:
(2) Stop the engine. A Park the machine on a firm and level surface.
(3) Loosen 2 front bolts of faster side. A Stop the engine, remove the key and apply the
(4) Move the speed adjust plate to backward. parking brake.
(5) Tighten 2 front bolts securely.

23.6 to 27.4 N-m

Tightening torque (2.4 to 2.8 kgf-m,
17.4 to 20.2 lbf-ft)
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ADJUSTMENT 61

C Aligning the control levers

MOWER DECK LEVEL
1. Stop the engine and apply the parking brake. BANTI-SCALP ROLLERS
Lever position (High or Low)
2. Remove the bolts and select the motion control lever
position, high or low. To avoid serious injury:
3. Tighten the bolts. A Park the machine on a firm and level surface.
A Apply the parking brake.
A Stop the engine and remove the key.
A Wait for all moving parts to stop.

A The flattest cut can be achieved by having the anti-

scalp rollers adjusted off the ground.
Check anti-scalp roller adjustments each time the
mower deck cutting height is changed.
It is recommended that all the anti-scalp rollers be kept
off the ground to minimize scuffing.

1. Check the machine tire pressure.

Inflate tires to the correct pressure. (See "TIRES AND
WHEELS" section.)
2. Start the engine.
(1) Bolt (A) High position 3. Raise up the mower deck to the transport position.
(2) Flange nut (Also the top end of the lift.)
(3) Tab slot 4. Turn the cutting height control dial to adjust height.
5. Lower the mower deck.
Lever alignment (Right and Left) 6. Adjust the height of the front side anti-scalp roller to
4. Loosen the bolts. one of 4 positions to approximately 19 mm (3/4 in.)
5. Slide both levers forward or rearward to the desired between rollers and the ground.
position within tab slots until levers are aligned. Adjust 3 rollers to the same height.
6. Tighten the bolts.

(1) Front side anti-scalp roller (H) 19 mm (3/4 in.)

7. Install the roller with attaching hardware.

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62 ADJUSTMENT

BLEVEL MOWER DECK (Side-to-Side)

To avoid serious injury:

A Park the machine on a firm and level surface.
A Apply the parking brake.
A Disengage PTO (OFF).
A Stop the engine and remove the key while
checking or adjusting the level of the mower
deck.

A Check the machine tire pressure.

Inflate tires to the correct pressure.
(See "TIRES AND WHEELS" section.) (S) Side

C Checking level (Side-to-Side) C Adjusting level (Side-to-Side)

1. Raise up the mower deck to the transport position.
(Also the top end).
A Mower deck anti-scalp rollers should not contact the
2. Turn the cutting height set dial to the 3 in. cutting
ground.
height position.
1. Raise the mower deck to the transport position. (Also 3. Place 51 mm (2 in.) height wood blocks under each
the top end). side of the mower deck.
2. Turn the cutting height set dial to the 3 in. cutting Anti-scalp rollers must not rest on the wood block.
height position. 4. Lower the mower deck.
3. Lower the mower deck. 5. Position mower blade in the Side-to-Side position.
4. Position the right mower blade in the Side-to-Side 6. Loosen the jam nuts of the right side of the machine.
position.
7. Adjust the cutting height fine tuning bolts to set 76
5. Measure from outside blade tip to the level surface
mm (3 in.) blade height.
with a short ruler or leveling gauge.
Front and rear side bolts must be adjusted.
Reference 8. Jam the nuts.
Height of the blade 9. Adjust the left side equally.
76 mm (3 in.) 10. Check the side-to-side level and if it is not level,
at the flat surface
adjustment is necessary.

A There is a difference of the blade height between on

the flat surface and ground.

6. Check that the left side blade is same height.

The difference between both measurements should
be less than 3 mm (1/8 in.).
7. If the Side-to-Side adjustment is not within the given
tolerance, adjustment is necessary.

Side-to-Side adjustment Less than 3 mm (1/8 in.)

(1) Cutting height fine tuning bolt

(2) Jam nut
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ADJUSTMENT 63

Less than 6 mm (1/4 in.)

BLEVEL MOWER DECK (Front-to-Rear) Front-to-Rear
Front side must be lower
adjustment
than Rear side.

To avoid serious injury:

A Park the machine on a firm and level surface. C Adjusting level (Front-to-Rear)
A Engage the parking brake. 1. Raise up the mower deck to the transport position.
A Disengage PTO. (Also the top end).
A Stop the engine and remove the key while 2. Turn the cutting height set dial to the 3 in. cutting
checking or adjusting the level of the mower height position.
deck. 3. Place 51 mm (2 in.) height wood blocks under each
side of the mower deck.
Anti-scalp rollers must not rest on the wood block.
A Check the machine tire pressure. 4. Lower the mower deck.
Inflate tires to the correct pressure. 5. Loosen the jam nuts of the front side of the machine.
(See "TIRES AND WHEELS" section.) 6. Adjust the cutting height fine tuning bolts to set 76 mm
(3 in.) blade height.
C Checking level (Front-to-Rear)
Both front side bolts must be adjusted.
7. Jam the nuts.
A Mower deck anti-scalp rollers should not contact the 8. Adjust the other side equally.
ground.

1. Raise the mower deck to the transport position. (Also A The difference between both measurements should
the top end). be less than 6 mm (1/4 in.).
2. Turn the cutting height set dial to the 3 in. cutting Front side must be lower than rear side.
height position.
9. Check the front-to-rear level and if it is not level,
3. Lower the mower deck.
adjustment is necessary.
4. Position the right mower blade in the Front-to-Rear
position.
5. Measure from the right front blade tip to the level
surface with a short ruler or leveling gauge.
6. Turn the blade 180 and measure from right rear blade
tip to the level surface.
7. Check that the left side blade has the same dimension.
The difference between both measurements should
be less than 6 mm (1/4 in.).
Front side must be lower than rear side.
8. If the Front-to-Rear adjustment is not within the given
tolerance, adjustment is necessary.

(1) Cutting height fine tuning bolt

(2) Jam nut

(A) Front
(B) Rear
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64 ADJUSTMENT

GENERAL TORQUE SPECIFICATION

American standard cap screws
Metric cap screws
with UNC or UNF threads
GR.5 GR.8 Class 8.8 Class 10.9
SAE grade No. Property class

(lbf-ft) 8 - 9.6 12 - 14.4 (lbf-ft) 7.2 - 8.3

1/4 (N-m) 10.7 - 12.9 16.1 - 19.3 M6 (N-m) 9.81 - 11.3
(kgf-m) 1.11 - 1.33 1.66 - 1.99 (kgf-m) 1.0 - 1.15
(lbf-ft) 17 - 20.5 24 - 29 (lbf-ft) 17.4 - 20.2 21.7 - 25.3
5/16 (N-m) 23.1 - 27.8 32.5 - 39.3 M8 (N-m) 23.6 - 27.4 29.4 - 34.3
(kgf-m) 2.35 - 2.84 3.31 - 4.01 (kgf-m) 2.4 - 2.8 3.0 - 3.5
(lbf-ft) 35 - 42 45 - 54 (lbf-ft) 35.5 - 41.2 44.9 - 52.1
3/8 (N-m) 47.5 - 57.0 61.0 - 73.2 M10 (N-m) 48.1 - 55.8 60.8 - 70.5
(kgf-m) 4.84 - 5.82 6.22 - 7.47 (kgf-m) 4.9 - 5.7 6.2 - 7.2
(lbf-ft) 80 - 96 110 - 132 (lbf-ft) 57.2 - 66.5 76.0 - 86.8
1/2 (N-m) 108.5 - 130.2 149.2 - 179.0 M12 (N-m) 77.5 - 90.1 103 - 117
(kgf-m) 11.07 - 13.29 15.22 - 18.27 (kgf-m) 7.9 - 9.2 10.5 - 12.0
(lbf-ft) 110 - 132 160 - 192 (lbf-ft) 91.2 - 108 123 - 144
9/16 (N-m) 149.2 - 179.0 217.0 - 260.4 M14 (N-m) 124 - 127 167 - 196
(kgf-m) 15.22 - 18.27 22.14 - 26.57 (kgf-m) 12.6 - 15.0 17.0 - 20.0
(lbf-ft) 150 - 180 220 - 264 (lbf-ft) 145 - 166 192 - 224
5/8 (N-m) 203.4 - 244.1 298.3 - 358.0 M16 (N-m) 196 - 225 260 - 303
(kgf-m) 20.75 - 24.91 30.44 - 36.53 (kgf-m) 20.0 - 23.0 26.5 - 31.0
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ADJUSTMENT 65

TIGHTENING TORQUE CHART

Thread Hexa-Bolt No mark 7T
size Head size
d (mm) B (mm) lbf-ft N-m kgf-m lbf-ft N-m kgf-m

13.0 - 15.2 17.8 - 20.6 1.9 - 2.1 17.5 - 20.3 23.5 - 27.5 2.4 - 2.8
M8 12 or 13
(14.1 1.1) (19.2 1.4) (2.0 0.1) (18.9 1.4) (25.5 2.0) (2.6 0.2)
28.9 - 33.3 39.3 - 45.1 4.0 - 4.6 35.4 - 41.2 48.1 - 55.9 4.9 - 5.7
M10 14 or 17
(31.1 2.2) (42.2 2.9) (4.3 0.3) (38.3 2.9) (52.0 3.9) (5.3 0.4)
46.3 - 53.5 62.8 - 72.6 6.4 - 7.4 57.1 - 66.5 77.6 - 90.2 8.0 - 9.2
M12 17 or 19
(49.9 3.6) (67.7 4.9) (6.9 0.5) (61.8 4.7) (83.9 6.3) (8.6 0.6)
79.6 - 92.6 107.9 - 125.5 11.0 - 12.8 91.1 - 108.5 123.6 - 147.0 12.6 - 15.0
M14 19 or 22
(86.1 6.5) (116.7 8.8) (11.9 0.9) (99.8 8.7) (135.3 11.7) (13.8 1.2)

A Figure "7" on the top of the bolt indicates that the bolt is of special material.
A Before tightening, check the figure on the top of bolt.
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66 STORAGE

STORAGE
REMOVING THE MOWER FROM STORAGE
To avoid serious injury: 1. Check the tire inflation pressure and adjust as
A To reduce fire hazards, allow the engine and required.
exhaust system to cool before storing the 2. Install the battery. Before installing the battery, be sure
machine in an enclosed space or near it is fully charged.
combustible materials. 3. Do daily checking. (See "DAILY CHECK" in
A To avoid the danger of exhaust fume "PERIODIC SERVICE" section.)
poisoning, do not operate the engine in a 4. Check all fluid levels. (engine oil, hydrostatic oil)
closed building without proper ventilation. 5. Start the engine. Shut the engine off and walk around
A Do not clean the machine with engine running. the machine and make a visual inspection looking for
A To avoid fire hazards, Do not leave grass and evidence of oil or other fluids.
leaves in the mower and the grass catcher. 6. Run engine a couple of minutes before you put engine
A When storing, remove the key from the key under load.
switch to avoid operation by unauthorized
persons.

When the machine will not be operated for over 2 months,

clean the machine and perform the following operations
before storage.
1. Repair parts as necessary.
2. Check bolts and nuts and tighten as necessary.
3. Apply grease or engine oil to parts most likely to rust.
4. Inflate the tires to a little above the standard pressure
levels. (Approximately 110%)
5. Lower the mower to the ground.
6. Remove the battery from the machine, recharge it,
adjust the electrolyte to the proper level, and store in a
cool dry place.
The battery discharges over time even while in
storage. Recharge it once a month in hot seasons and
once every 2 months in cold seasons.
7. Drain fuel tank, fuel lines, and carburetor, or use a fuel
stabilizer, to prevent deterioration of the gasoline. If
you choose to use a fuel stabilizer, follow the
manufacturers recommendations, and add the correct
amount for the capacity of the fuel system. Fill the fuel
tank with clean, fresh gasoline. Run the engine for 2 to
3 minutes to get stabilized fuel into the carburetor.
8. Store the machine where it is dry and sheltered from
rain. Cover the machine with a vinyl tarp.
9. Moisture content in most grasses can damage the
mower and grass catcher if these components are not
properly cleaned after use.
Make sure the mower and the grass catcher are clean
and completely empty before storage.
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TROUBLESHOOTING 67

TROUBLESHOOTING
ENGINE TROUBLESHOOTING
If something is wrong with the engine, refer to the table below for the cause and its corrective measure.
Symptom (If) Cause Remedy
Engine is difficult to start or A No operator on the seat. A Sit on the operator's seat.
will not start.
A Parking brake lever not in the proper A Apply the parking brake.
position.
A PTO switch not in the proper position. A Make sure PTO switch is in
"DISENGAGED" (OFF) position.
A Motion control levers not in the proper A Make sure motion control levers are in
position. "NEUTRAL LOCK" position.
A Key switch is not in the proper position. A Make sure key switch is in "ON"
position.
A No fuel. A Replenish fuel.
A Improper or stale fuel. A Replace fuel and the fuel filter.
(Fuel quality is poor.)
A Water or dirt in the fuel system. A Replace fuel and see your Kubota
dealer.
A Fuel hose or fuel filter clogged or A Clean or replace fuel lines, and see
damaged. your Kubota dealer.
A Air cleaner is clogged. A Clean or replace the air cleaner.
A Spark plug defective. A Adjust the spark plug gap or replace
the spark plug.
A Check the spark plug wire connection.
A Fuse is blown. A Replace the fuse.
A Engine oil viscosity is wrong. A Use oils of different viscosities,
depending on ambient temperature.
A Battery becomes weak and the engine A Clean battery cables and terminals.
does not turn over quick enough.
A Charge the battery.
A In cold weather, always remove the
battery from the engine, charge and
store it indoors. Install it on the machine
only when the machine is going to be
used.
A Over choking or choke is adjusted A Check and see your Kubota dealer.
incorrectly.
Insufficient engine power. A Insufficient or dirty fuel. A Check the fuel system.
A Fuel filter is clogged. A Replace the fuel filter.
A Air cleaner is clogged. A Clean or replace the air cleaner.
A Spark plug defective. A Adjust the spark plug gap or replace it.
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68 TROUBLESHOOTING

Symptom (If) Cause Remedy

Engine stops suddenly. A Insufficient fuel. A Refuel.
A Check the fuel valve position.
A Check the carburetor fuel valve
position.
Rough engine running. A Spark plug defective. A Adjust the spark plug gap or replace it.
A Spark plug wire defective. A See your Kubota dealer.
A Carburetion problems. A See your Kubota dealer.
A Ignition coil defective. A See your Kubota dealer.
A Choke is adjusted incorrectly. A See your Kubota dealer.
A Fuel hose or fuel filter clogged or A Clean or replace fuel lines, and see
damaged. your Kubota dealer.
A Improper or stale fuel. A Replace fuel and the fuel filter.
(Fuel quality is poor.)
A Air cleaner is clogged. A Clean or replace the air cleaner.
Exhaust fumes are colored. A Overload. A Reduce load.
(Black, Dark or Gray)
A Low grade fuel is used. A Use specified fuel.
A Fuel filter is clogged. A Replace the fuel filter.
A Air cleaner is clogged. A Clean or replace the air cleaner
element.
A Choke is not fully opened. A Check the choke position.
Exhaust fumes are colored. A Excessive engine oil. A Reduce to the specified oil level.
(White or Blue)
A Piston ring is worn or stuck. A See your Kubota dealer.
Engine overheats. A Engine is overloaded. A Lower speed or reduce load.
A Engine oil is insufficient. A Replenish engine oil.
A Engine air intake screen and cooling A Clean the air intake screen and cooling
fins are dirty. fins.
A Air cleaner element is plugged. A Clean or replace the air cleaner
element.
A Engine speed is too low. A Operate at the "FAST" speed.
A Operating ground speed is too fast. A Operate the machine at the slower
ground speed.
Engine knocks. A Stale or low octane fuel. A Use specified fuel.
A Engine overloaded. A Lower ground speed or reduce load.
A Engine speed is too low. A Operate at the "FAST" speed.
Engine will not idle. A Spark plug defective. A Adjust the spark plug gap or replace it.
A Faulty spark plug. A Replace the spark plug.
A Carburetion problem. A See your Kubota dealer.

If you have any questions, contact your local KUBOTA Dealer.

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TROUBLESHOOTING 69

BATTERY TROUBLESHOOTING
Symptom (If) Cause Remedy Preventive measure
Starter does not function. A Battery overused until A Charge battery A Charge the battery properly.
lights are dim. sufficiently.
A Battery has not been
recharged.
A Poor terminal A Clean the terminal A Keep the terminal clean and
connection. and tighten securely. tight.
Apply grease and treat with
anti-corrosives.
A Battery life expired. A Replace battery.
From beginning starter A Insufficient charging. A Charge battery A Battery must be serviced
does not function, and sufficiently. properly before initial use.
lights soon become dim.
When viewed from top, A Battery was used with A Add distilled water A Regularly check the
the top of plates look an insufficient amount and charge the electrolyte level.
whitish. of electrolyte. battery.
A Battery was used too A Charge battery A Charge the battery properly.
much without sufficiently.
recharging.
Recharging is impossible. A Battery life expired. A Replace battery.
Terminals are severely A Poor terminal A Clean the terminal A Keep the terminal clean and
corroded and heat up. connection. and tighten securely. tight.
Apply grease and treat with
anti-corrosives.
Battery electrolyte level A There is a crack or pin A Replace battery.
drops rapidly. holes in the electrolytic
cells.
A Charging system A Contact your local
trouble. KUBOTA Dealer.

If you have any questions, contact your local KUBOTA Dealer.

MACHINE TROUBLESHOOTING
Symptom (If) Cause Remedy
Machine operation is not A Hydrostatic transaxle fluid is A Replenish oil.
smooth. insufficient.
A Filter is clogged. A Replace the filter.
Machine does not move while A Parking brake is on. A Release the parking brake.
engine is running.
A Transaxle fluid level is insufficient. A Replenish oil.
Machine moves when motion A Hydrostatic lever linkage is not A Ask your dealer for hydrostatic lever
control levers are in "NEUTRAL correctly adjusted. linkage adjustment.
LOCK" position.
(Engine is operated.) A Control linkage pivots are sticking. A Full up and lubricate linkage.

If you have any questions, contact your local KUBOTA Dealer.

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70 TROUBLESHOOTING

MOWER TROUBLESHOOTING
Symptom (If) Cause Remedy
Blade does not rotate. A PTO system is not normal: A See your Kubota Dealer.
PTO system malfunctioning.
A PTO system is normal: A Replace.
Broken mower belt.
Mower belt slipping. A Weaken tension spring. A Replace.
A Worn mower belt. A Replace.
A Mower plugged. A Unplug and clean mower deck.
A Debris in pulleys. A Clean.
Discharge chute A Grass too wet. A Wait for grass to dry.
plugged.
A Grass too long. A Raise cutting height and cut grass twice.
A Cutting too low. A Raise cutting height.
A Engine rpm too low. A Mow at full throttle.
A Ground speed too fast. A Slow down.
Streaking of grass uncut. A Ground speed too fast. A Slow down.
A Engine rpm too low. A Mow at full throttle, check and reset
engine rpm.
A Grass too long. A Cut grass twice.
A Blades dull or damaged. A Replace blades or have blades
sharpened.
A Debris in mower deck. A Clean mower deck.
Uneven cut. A Mower deck not level. A Level mower deck.
A Ground speed too fast. A Slow down.
A Blades dull. A Have blades sharpened.
A Blades worn or damaged. A Replace blades.
A Low tire inflation. A Add air to correct pressure.
A Anti-scalp rollers not adjusted correctly. A Adjust anti-scalp rollers.
A Wheels pressure not adjusted correctly. A Set both tire pressure to the correct
pressure.
(See "TIRES" in "TIRES AND WHEELS"
section.)
Blades scalping grass. A Cutting height too low. A Raise cutting height.
A Turning speed too fast. A Reduce speed on turns.
A Ridges in terrain. A Change mowing pattern.
A Rough or uneven terrain. A Adjust wheels pressure and anti-scalp
rollers.
A Anti-scalp rollers not adjusted correctly. A Adjust wheels pressure and anti-scalp
rollers.
A Bent blade(s). A Replace blade(s).
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TROUBLESHOOTING 71

Symptom (If) Cause Remedy

Excessive vibration. A Debris on mower deck or in pulleys. A Clean mower deck and pulleys.
A Damaged mower belt. A Replace mower belt.
A Damaged pulleys. A Replace pulleys.
A Pulleys out of alignment. A Check pulleys.
A Blades out of balance. A Have blades balanced.
Mower loads down A Engine rpm too low. A Mow at full throttle, check and reset
machine. engine rpm.
A Ground speed too fast. A Slow down.
A Debris wrapped around mower spindles. A Clean mower.
A Front of deck too low. A Adjust mower deck.
(See "MOWER DECK LEVEL" in
"ADJUSTMENT" section.)

If you have any questions, contact your local KUBOTA Dealer.

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72 INDEX

INDEX
Air Cleaner Element (Z121S, Z125S).............44 MOTION CONTROL LEVER ALIGNMENT ... 60
Air Cleaner Element (Z121S, Z125S).............55 Movable Parts................................................ 35
Air Cleaner Element (Z122E, Z125E).............37 Mower Belt Replacement .............................. 58
Air Cleaner Element (Z122E, Z125E).............44 Mower Lift Pedal ............................................ 17
Air Cleaner Element (Z122E, Z125E).............55 Muffler and Spark Arrester (if equipped) ....... 43
Air Intake Screen............................................34 Muffler and Spark Arrester (if equipped) ....... 55
Amount of Fuel and Refueling........................33 OPC System .................................................. 40
ANTI-SCALP ROLLERS ................................61 Operator's Seat.............................................. 16
Battery Condition............................................48 Parking Brake Lever ...................................... 17
Blade ..............................................................57 Precleaner Element (Except Z125E) ............. 36
Carbon Canister Air Filter...............................40 Precleaner Element (Except Z125E) ............. 44
Carbon Canister Air Filter...............................56 Precleaner Element (Except Z125E) ............. 55
Combustion Chamber ....................................55 PTO Switch.................................................... 23
Electric Clutch Adjustment .............................54 Remove and Install Front Caster Wheels ...... 26
Engine Break-in..............................................15 Seat Belt ........................................................ 16
Engine Breather Hose ....................................56 Spark Plug ..................................................... 46
Engine Oil (Z121S, Z125S) ............................43 Spark Plug ..................................................... 55
Engine Oil (Z122E, Z125E) ............................41 Starting .......................................................... 24
Engine Oil (Z122E, Z125E) ............................55 Throttle Cable ................................................ 50
Engine Oil Filter (Z121S, Z125S) ...................51 Throttle Lever ................................................ 11
Engine Oil Filter (Z122E, Z125E) ...................42 Throttle Lever ................................................ 17
Engine Oil Filter (Z122E, Z125E) ...................55 Tire Pressure ................................................. 34
Engine Oil Level .............................................32 Transaxle Fluid .............................................. 54
Engine Shroud................................................45 Transaxle Fluid Level .................................... 35
Engine Start System.......................................39 Transaxle Oil Filter Cartridge......................... 53
Engine Valve Clearance (Z121S, Z125S) ......55 Warm-up and Transmission Oil in the Low
Engine Valve Clearance (Z122E, Z125E) ......55 Temperature Range ...................................... 13
Fuel Filter (Z122E, Z125E).............................55
Fuel Gauge.....................................................12
Fuel Lines.......................................................47
Fuel Lines.......................................................56
Fuses..............................................................56
Hour Meter .....................................................12
HST NEUTRAL ..............................................59
Hydraulic Hose ...............................................52
Hydraulic Hose ...............................................56
Hydrostatic Transaxle Bypass Rods ..............21
Immediately Stop the Engine if:......................12
Inflation Pressure ...........................................25
Inflation Pressure ...........................................34
Key Switch......................................................11
LEVEL MOWER DECK (Front-to-Rear) .........63
LEVEL MOWER DECK (Side-to-Side)...........62
Light Switch ....................................................16
Lubricating Oil for New Machines...................15
Machine Break-in ...........................................15
MAXIMUM SPEED (FORWARD)...................60
Motion Control Lever ......................................18