Operator’s Manual
Front Tine
Cultivator
Model
21A-120R000
IMPORTANT: Read safety rules and instructions carefully before operating equipment.
Warning: This unit is equipped with an internal combustion engine and should not be used on or near any unimproved forest-
covered, brush-covered or grass-covered land unless the engine’s exhaust system is equipped with a spark arrester meeting
applicable local or state laws (if any). If a spark arrester is used, it should be maintained in effective working order by the operator.
In the State of California the above is required by law (Section 4442 of the California Public Resources Code). Other states may have
similar laws. Federal laws apply on federal lands. A spark arrestor for the muffler is available through your nearest engine authorized
service dealer or contact the service department, 550 N. 54th Street, Chandler, Arizona 85226-2434.
MTD SOUTHWEST INC 550 N. 54TH STREET, CHANDLER, ARIZONA 85226-2434
PRINTED IN U.S.A. FORM NO. 770-10456
PART NO. 10120 rev. A (11/00)
2
TABLE OF CONTENTS
Content Page
Important Safe Operation Practices.................................................................... 3, 4
Assembling Your Cultivator .................................................................................. 5
Know Your Cultivator ........................................................................................... 8
Operating Your Cultivator..................................................................................... 9
Making Adjustments ............................................................................................ 12
Maintaining Your Cultivator.................................................................................. 13
Off-Season Storage............................................................................................. 15
Troubleshooting.................................................................................................... 15
Parts List.............................................................................................................. 16
FINDING MODEL NUMBER
This Operator’s Manual is an important part of your new cultivator. It will help you assemble, prepare and
maintain the unit for best performance. Please read and understand what it says.
Before you start assembling your new equipment, please locate the model plate on
the unit and copy the information from it to the space provided below. The information on
the model plate is very important if you need help from our Customer Support
Department or an authorized dealer.
•You can locate the model number by standing in the operating position behind the unit and looking
on the left side of the engine next to the On/Off Stop Control Switch. A sample model plate is
explained below. For future reference, please copy the model number and the serial number of the
equipment in the space below.
CALLING CUSTOMER SUPPORT
If you have difficulty assembling this product or have any questions regarding the controls, operation or
maintenance of this unit, please call the Customer Support Department.
Call 1- (800)-345-8746, or in Canada 1- (800)-668-1238, to reach a Customer Support
representative. Please have your unit’s model number and serial number ready when you
call. See previous section to locate this information. You will be asked to enter the serial
number in order to process your call.
Copy the model number here:
Copy the serial number here:
Copy the parent part number here:
3
SECTION 1: IMPORTANT SAFE OPERATION PRACTICES
This Symbol Points Out Important Safety Information Which, If Not Followed, Could Endanger The
Personal Safety And/or Property Of Yourself And Others. Read And Follow All Instructions In This
Manual Before Attempting To Operate Your Cultivator. Failure To Comply With These Instructions
May Result In Personal Injury. When You See This Symbol–Heed Its Warning.
DANGER: Your cultivator was built to be operated according to the rules for safe operation in this
manual. As with any type of power equipment, carelessness or error on the part of the operator can
result in serious personal injury. This cultivator is capable of amputating hands and feet. Failure to
observe the following instructions could result in serious injury or death.
WARNING: Engine Exhaust, some of its constituents, and certain vehicle components contain or emit
chemicals known to State of California to cause cancer and birth defects or other reproductive harm.
GENERAL OPERATION
• Read the instructions carefully. Be familiar with the
controls and proper use of the unit.
• Do not operate this unit when tired, ill, or under the
influence of alcohol, drugs, or medication.
• Children and teens under the age of 15 must not
use the unit, except for teens guided by an adult.
• All guards and safety attachments must be installed
properly before operating the unit.
• Inspect the unit before use. Replace damaged
parts. Check for fuel leaks. Make sure all fasteners
are in place and secure. Replace parts that are
cracked, chipped, or damaged in any way. Do not
operate the unit with loose or damaged parts.
• Carefully inspect the area before starting the unit.
Remove all debris and hard or sharp objects such
as glass, wire, etc.
• Clear the area of children, bystanders, and pets.
At a minimum, keep all children, bystanders and
pets outside a 50 feet (15 m) radius; there still may
be a risk to bystanders from thrown objects.
Bystanders should wear eye protection. If you are
approached, stop the unit immediately.
• Squeeze the throttle control and check that it
returns automatically to the idle position. Make all
adjustments or repairs before using unit.
• Never start or run the unit inside a closed room or
building. Breathing exhaust fumes can kill. Operate
this unit only in a well ventilated area
outdoors.
•Wear safety glasses or goggles that are marked as
meeting ANSI Z87.1 standards, and ear/hearing
protection when operating this unit. Wear a face or
dust mask if the operation is dusty.
•Wear heavy, long pants, boots, gloves and long
sleeve shirt. Do not wear, short pants, sandals or
go barefoot.
•To reduce the risk of injury associated with objects
being drawn into rotating parts, do not wear loose
clothing, jewelry, scarves, etc. Secure hair above
shoulder level.
• Use the unit only in daylight or good artificial light.
• Keep outside surfaces free from oil and fuel.
•Be sure the tines are not in contact with anything
before starting the unit.
•Avoid accidental starting. Be in the starting
position whenever pulling the starter rope. The
operator and unit must be in a stable position while
starting. See Operating Your Cultivator.
• Use the right tool. Only use this tool for the
purpose intended.
• Use extreme caution when reversing or pulling the
unit towards you.
• Do not overreach, take extra care when working on
steep slopes or inclines. Always keep proper footing and balance.
• Always hold the unit with both hands when
operating. Keep a firm grip on the handlebar grips.
• Keep hands, face, and feet at a distance from all
moving parts. Do not touch or try to stop the tines
when they are rotating. Do not operate without
guards in place.
• Do not touch the engine, muffler or gearbox. These
parts get extremely hot from operation. When
turned off they remain hot for a short time.
• Do not operate the engine faster than the speed
needed to do the job. Do not run the engine at high
speed when not in use.
• Always stop the engine when operation is delayed
or when walking from one location to another.
• Do not force unit. It will do the job better and with
less likelihood of injury at a rate for which it was
designed.
CHILDREN
•Tragic accidents can occur if the operator is not
alert to the presence of small children. Children are
often attracted to the tilling activity. Never assume
that children will remain where you last saw them.
• Keep children out of the work area and under the
watchful eye of a responsible adult other than the
operator.
• Be alert and turn the unit off if a child enters the
area.
• Never allow children under the age of 15 to
operate the cultivator.
4
SERVICE
• Use extreme care in handling gasoline and other
fuels. They are extremely flammable and the vapors
are explosive.
• Store fuel only in containers specifically designed
and approved for the storage of such materials.
•Avoid creating a source of ignition for spilled fuel.
Do not start the engine until fuel vapors dissipate.
• Always stop the engine and allow it to cool before
filling the fuel tank. Never remove the cap of the
fuel tank, or add fuel, when the engine is hot. Never
operate the unit without the fuel cap securely in
place. Loosen the fuel tank cap slowly to relieve
any pressure in the tank.
• Mix and add fuel in a clean, well-ventilated area
outdoors where there are no sparks or flames.
Slowly remove the fuel cap only after stopping
engine. Do not smoke while fueling or mixing fuel.
Wipe up any spilled fuel from the unit immediately.
• Move the unit at least 30 feet (9.1 m) from the fueling source and site before starting the engine. Do
not smoke, keep sparks and open flames from the
area while adding fuel or operating the unit.
• Stop the engine for maintenance, repair, to install or
remove the tines. The unit must be stopped and
the tines no longer turning to avoid injury.
• The tines become very sharp from use. Always
wear heavy gloves when handling, removing,
installing or cleaning the tines.
• Use only replacement parts and accessories
approved by the manufacturer for this unit. These
are available from your authorized service dealer.
Use of any non approved parts or accessories
could lead to serious injury to the user, or damage
to the unit, and void your warranty.
• This unit has a clutch. The tines remain stationary
when the engine is idling. If they do not, have the
unit adjusted by an authorized service technician.
• Keep unit clean of vegetation and other materials.
They may become lodged between the tines and
gearbox or guard.
•To reduce fire hazard, replace faulty muffler and
spark arrestor, keep the engine and muffler free
from grass, leaves, excessive grease or carbon
build up.
• Never store the unit, with fuel in the tank, inside a
building where fumes may reach an open flame or
spark.
• Allow the engine to cool before storing or transporting. Be sure to secure the unit while transporting.
• Store the unit in a dry place, either locked up or up
high to prevent unauthorized use or damage.
Keep out of the reach of children.
• Clean the tines with a hose and water. Wipe the
tines with a light machine oil to prevent rust.
• Never douse or squirt the engine with water or any
other liquid. Keep handles dry, clean and free from
debris. Clean after each use, see Off-Season
Storage.
• Keep these instructions. Refer to them often and
use them to instruct other users. If you loan someone this unit, also loan them these instructions.
WARNING – YOUR RESPONSIBILITY: Restrict the use of this power machine to persons
who read, understand and follow the warnings and instructions in this manual and on the machine.
•WARNING - READ OPERATOR'S MANUAL
Read the Operator’s Manual(s) and follow all warnings and safety instructions.
Failure to do so can result in serious injury to the operator and/or bystanders.
• WEAR EYE AND HEARING PROTECTION
Thrown objects and loud noise can cause severe eye injury and hearing loss. Wear eye protection
meeting ANSI Z87.1 standards and ear protection when operating this unit.
• KEEP BYSTANDERS AWAY
Keep all bystanders, especially children and pets, at least 50 feet (15 m) from the operating area.
• THROWN OBJECTS CAN CAUSE SEVERE INJURY
Do not operate unit without proper attachments and guards in place.
• HOT SURFACE WARNING
Do not touch a hot muffler, cylinder or gearbox. You may get burned. These parts get extremely hot
from operation. When turned off they remain hot for a short time.
• CULTIVATORS – ROTATING TINES CAN CAUSE SEVERE INJURY
Stop the engine and allow the tines to stop before installing or removing tines, or before cleaning or
performing any maintenance. Keep hands and feet away from rotating tines.
Your yard and garden cultivator has been completely
assembled except for the handlebar, throttle cable
and wheel bracket assembly. A large phillips
screwdriver is needed for assembly.
Removing Unit From Carton
1. Carefully unpack the contents and insure that
nothing is damaged. Unwrap the throttle cable
without bending or kinking it.
WARNING: Do not cut the plastic strap
off the handle bar. The strap is under
tension and can cause serious personal
injury if cut.
2. Squeeze the handle bar and slide the plastic
strap down and off. See Figure 1.
NOTE: Do not squeeze the handlebar too tight.
Excessive squeezing can cause the handlebar to kink.
5
SECTION 2: ASSEMBLING YOUR CULTIVATOR
SETTING UP YOUR CULTIVATOR
Installing The Wheel Bracket Assembly
WARNING: To avoid injury from the tines,
wear heavy gloves and a long sleeve
shirt when installing the wheel bracket
assembly.
1. With the unit on it’s side, place the wheel bracket
assembly on the underside of the tine guard. See
Figure 2.
2. Install a carriage bolt through each of the slotted
holes in the wheel bracket and into the tine
guard.
3. On the top side of the tine guard, install a lock
washer and a wing nut onto each of the bolts.
See Figure 2.
4. Make sure the square shoulder of the bolts are
through the slotted holes in the wheel bracket.
Tighten the wing nuts. See Figure 3.
NOTE: Do not over tighten the wing nuts. Loosening
the wing nuts allow the wheel height to be adjusted.
Figure 1
Figure 2
Figure 3
Squeeze
Together
Plastic
Strap
Wing Nut &
Lock Washer
Tine
Guard
Wheel
Bracket
Assembly
6
Installing The Handlebar
1. Position the mounting brackets by rotating them
until the foot on the bracket rests against the
engine. See Figure 4.
2. Place the handlebar between the bottom and
middle clamp pieces. See Figure 5.
3. While holding the three pieces together, position
the handlebar underneath the shaft tube and align
with the top clamp.
NOTE: The holes in the clamp assembly will line up
only when assembled correctly.
4. One at a time, hold a hex nut in the bottom clamp
recess with a finger and install a screw through
the clamp assembly. Start screw with a large
Phillips screwdriver. do the same with the other
three (3) nuts and screws. Do not tighten until you
make the handle adjustment.
5. Position the two (2) handlebar clamps with one on
each side near the top of the handlebar. Swing the
handlebar up until it sets to the outside of the two
mounting brackets on the engine. See Figure 6.
NOTE: Positioning the handlebar onto the mounting
brackets may require slightly spreading the handlebar.
6. Slide the two (2) handlebar clamps down over the
mounting brackets. See Figure 7.
NOTE: It may be required to loosen or remove the
thumb screws on the handlebar clamps to spread
them to fit over the mounting brackets.
7. Center the handlebar and tighten the two (2)
mounting bracket clamps and the four (4)
handlebar clamp screws evenly until the
handlebar is secure. See Figures 7 and 8.
Bottom
Clamp
Nut (4)
Middle
Clamp
Thumb
Screw
Mounting
Bracket
Mounting Brackets
Mounting
Bracket
Spacer
Nut
Foot
Foot
Handlebar
Screw (4)
Top
Clamp
Handlebar Clamp
Handlebar
Handlebar
Figure 5
Figure 4
Figure 6
Figure 7
Figure 8
7
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Throttle Wire Hole
Throttle
Wire Slot
Throttle Cable Assembly
1. Wrap the throttle wire once around the handlebar.
See Figure 9.
2. Depress the throttle trigger and locate hole for the
throttle wire. See Figure 10.
3. With the throttle trigger depressed, place the barrel end of the throttle wire inside the hole of the
trigger. See Figure 11.
4. Release the throttle trigger and guide the cable
up into the slot of the trigger housing.
5. Push the throttle cable housing into the trigger
housing until it snaps into place. See Figure 12.
6. Route the throttle cable through the clip on the
right handlebar mounting bracket. See Figure 13.
NOTE: Ensure the throttle cable is fitting into the
guide at the carburetor plate on the engine. If it does
not, the throttle will not work properly. See Figure 9.
Throttle Cable
Carburetor
Plate Guide
Mounting
Bracket
Throttle
Cable
Engine
8
Figure 14
SECTION 3: KNOW YOUR CULTIVATOR
Tines
Primer Bulb
Choke Control
Air Filter/
Muffler Cover
Spark
Plug
Muffler
On/Off Stop
Control
STOP/OFF (O)
START/ON (I)
Throttle
Control
Wheel Bracket
Assembly
Shaft Tube Grip
Read this operator’s manual and safety rules before
operating your cultivator. Compare illustrations in
Figure 14 with your cultivator to familiarize yourself
with the location of various controls and adjustments.
Save this manual for future reference.
Application
Use this unit for tilling sod and light to medium soil.
Also for tilling in garden areas, around trees, etc.
Throttle Control
The throttle control trigger is located below the right
handlebar grip. It controls the engine speed. See
Figure 14.
On/Off Stop Control
The On/Off Stop control switch is located on the left
side mounting bracket. It is used to turn the unit on
and off. The switch must be in the START position to
start the unit. See Figure 14.
Choke Control
The choke control is located above the air filter/muffler
cover. It is used to enrich the fuel mixture when starting
a cold engine. See Figure 14.
Primer Bulb
The primer bulb is located to the left of the air
filter/muffler cover. It is used to draw fuel into the
carburetor when starting a cold engine or after
refueling the unit. See Figure 14.
Wheel Bracket Assembly
The wheel bracket assembly is used to help move the
unit when not in use and control the tilling depth
when in use. Refer to OPERATING YOUR
CULTIVATOR in Section 4.
Tines
The tilling tines are used to cultivate, furrow, and
prepare your garden for seeding.
9
SECTION 4: OPERATING YOUR CULTIVATOR
Oil and Gas Mixing Instructions
Old and/or improperly mixed fuel are the main
reasons for the unit not running properly. Be sure to
use fresh, clean unleaded fuel. Follow the instructions
carefully for the proper fuel/oil mixture.
Definition of Blended Fuels
Today's fuels are often a blend of gasoline and
oxygenates such as ethanol, methanol or MTBE
(ether). Alcohol-blended fuel absorbs water. As little
as 1% water in the fuel can make fuel and oil separate. It forms acids when stored. When using alcoholblended fuel, use fresh fuel (less than 60 days old).
Using Blended Fuels
If you choose to use a blended fuel, or its use is
unavoidable, follow recommended precautions.
• Always use fresh fuel mix per your operator's
manual.
• Use the fuel additive STA-BIL® or an equivalent.
• Always agitate the fuel mix before fueling the unit.
•Drain the tank and run the engine dry before
storing the unit.
Using Fuel Additives
The use of fuel additive, such as STA-BIL® Gas
Stabilizer or an equivalent, will inhibit corrosion and
minimize the formation of gum deposits. Using a fuel
additive can keep fuel from forming harmful deposits
in the carburetor for up to six (6) months. Add 0.8 oz.
(23 ml.) of fuel additive per gallon of fuel according to
the instructions on the container. NEVER add fuel
additives directly to the unit's fuel tank.
CAUTION: For proper engine operation
and maximum reliability, pay strict
attention to the oil and fuel mixing
instructions on the 2-cycle oil container.
Using improperly mixed fuel can
severely damage the engine.
Thoroughly mix the proper ratio of 2-cycle engine oil
with unleaded gasoline in a separate fuel can. Use a
32:1 fuel/oil ratio. Do not mix them directly in the
engine fuel tank. See Figure 15 for specific gas and
oil mixing ratios.
NOTE: Two gallons (7.6 liters) of unleaded gasoline
mixed with one 8 oz. (236 ml.) bottle of Arnold 2 Cycle
Oil makes a 32:1 fuel/oil ratio OR one gallon (3.8 liters)
of unleaded gasoline mixed with one 4 oz. (120 ml.)
bottle of Arnold 2 Cycle Oil makes a 32:1 fuel/oil ratio.
WARNING: Gasoline is extremely
flammable. Ignited Vapors may explode.
Always stop the engine and allow it to
cool before filling the fuel tank. Do not
smoke while filling the tank. Keep sparks
and open flames at a distance from the
area.
WARNING: Remove fuel cap slowly to
avoid injury from fuel spray. Never
operate the unit without the fuel cap
securely in place.
WARNING: Add fuel in a clean, well
ventilated area outdoors. Wipe up any
spilled fuel immediately. Avoid creating
a source of ignition for spilt fuel. Do
not start the engine until fuel vapors
dissipate.
NOTE: Dispose of the old fuel/oil mix in accordance
to Federal, State, and Local regulations.
Filling The Fuel T ank
Fill or add fuel to the tank only when the cultivator is
in a horizontal position. See figure 16.
+
OR
UNLEADED GAS ARNOLD 2 CYCLE OIL
2 US. GALLONS + 8.0 FL. OZ.
(7.6 LITERS) (236 ml)
1 US. GALLON
+ 4.0 FL. OZ.
(3.8 LITERS) (120 ml)
MIXING RATIO - 32:1
Figure 15
Figure 16
10
Choke Control
Full Choke
Position (A)
Starter
Rope
Throttle
Control
Primer Bulb
Starting Engine
WARNING: Avoid accidental starting. Be
in the starting position when pulling the
starter rope. See Figure 19. The operator
and unit must be in a stable position
while starting to avoid serious personal
injury.
WARNING: Operate this unit only in a
well ventilated area outdoors. Carbon
monoxide exhaust fumes can be lethal
in a confined area.
1. Mix gas with oil. Fill fuel tank with fuel/oil mixture.
See Oil and Gas Mixing Instructions.
2. Put the On/Off Stop Control in the START (I)
position. See Figure 17.
3. Fully press and release primer bulb slowly 5 to 7
times. Fuel should be visible in the bulb. If fuel is
not visible, press three (3) more times, or until it
is. See Figure 18.
4. Place the choke lever in the FULL choke position
(A ). See Figure 18.
5. With the unit on the ground, squeeze the throttle
control and pull starter rope briskly. See Figure
18. Continue pulling until the engine sounds as
though it wants to run (normally 2 to 5 pulls).
NOTE: Squeeze the throttle control until the engine
has started and warmed up.
6. Place the choke lever in the PARTIAL choke
position (B ). See Figure 18.
NOTE: The unit will not run in the FULL choke
position (A ).
7. Pull starter rope briskly 1 to 3 times to start the
engine. See Figure 19.
8. If the engine does not start, repeat steps
4 through 7.
Run
Position (C)
Partial Position (B)
NOTE: If the engine floods while trying to start, place
the choke lever in the RUN position (C ). Squeeze
the throttle control. Pull the starter rope briskly. The
engine should start within three (3) to eight (8) pulls.
9. Squeeze the throttle control to warm up engine
for 5 to 10 seconds. Place the choke lever in the
RUN position (C ). See Figure 18.
NOTE: Choking is unnecessary when starting a warm
engine. Put the On/Off Stop Control in the START (I)
position and start in PARTIAL Choke
position (B ). See Figures 17 and 18.
To Stop Engine
1. Release your hand from the throttle control. See
Figure 19. Allow the engine to cool down by
idling.
2. Put the On/Off Stop Control in the STOP (O)
position. See Figure 17.
On/Off Stop
Control
STOP/OFF (O)
START/ON (I)
Figure 17
Figure 18
Figure 19
11
Shaft Tube
Grip
Figure 20
Figure 20
Transporting the Unit
WARNING: To prevent serious personal
injury, always stop the engine when
operation is delayed or when transporting the unit from one location to another.
1. Stop the engine.
2. Slide the wheel bracket assembly all the way
down.
3. Tilt the unit back until the tines clear the ground.
4. Push or pull the unit to the next location to be
cultivated.
NOTE: The cultivator can also be carried by the shaft
tube grip. See Figure 21.
Using Your Cultivator
WARNING: Dress properly to reduce the
risk of injury when operating this unit.
Do not wear loose clothing or jewelry.
Wear eye and ear/hearing protection.
Wear heavy, long pants, boots and
gloves. Do not wear short pants, sandals
or go barefoot.
1. Move the cultivator to the work area prior to
starting the engine. The cultivator may be
transported by pushing it on wheels or carrying it
by the shaft tube grip.
WARNING: To prevent serious personal
injury, never pick-up or carry the unit
while the engine is running.
2. Start the unit per Starting Instructions.
3. With the engine running and the tines off the
ground, depress the throttle control to increase the
engine speed.
4. Holding both of the handlebar grips firmly, slowly
lower the cultivator until the tines make contact
with the ground. See Figure 20.
5. As cultivating action begins, pull back on the
cultivator so that the tines can penetrate the
ground.
6. Once the ground has been broken, continue at a
moderate pace until you are familiar with the
controls and the handling of the cultivator.
7. Pull the cultivator backwards to improve the depth
of cultivation and reduce your effort.
8. If the tines are digging too deep or not deep
enough, adjust the tines per Adjusting Tine Depth.
WARNING: To prevent serious injury,
never do adjustments, maintenance or
repairs with unit running. Disconnect
spark plug wire to ensure the unit will
not start.
1. Stop the engine and disconnect the spark plug wire.
2. Loosen (do not remove) the two wing nuts on the
tine guard. See Figure 20.
3. Slide the wheel bracket assembly down for
shallower and up for deeper tine penetration.
4. Once the tines are in the desired position, tighten
the wing nuts, making sure that the carriage bolts
are seated properly through the bracket.
5. If the tine depth is not correct, repeat steps 2 to 4.
6. Reconnect the spark plug wire.
Figure 21
Down
Up
Adjusting Tine Depth
Tine adjustment will vary depending on the type of
soil being cultivated and how it will be used.
Generally, adjusting the tines to break the soil 4 to 6
inches is
recommended for most gardens. Adjust the tines as
follows:
12
SECTION 5: MAKING ADJUSTMENTS
WARNING: To prevent serious injury,
never do adjustments, maintenance or
repairs with unit running. Always do
maintenance and repairs on a cool unit.
Disconnect spark plug wire to ensure
the unit will not start.
Wheel Adjustments
To adjust the wheel height, refer to OPERATING
YOUR CULTIVATOR in Section 4.
Carburetor Adjustments
WARNING: If any adjustments are made
to the engine while the engine is running
(e.g. carburetor), keep clear of all moving
parts. Be careful of heated surfaces and
muffler.
The idle speed adjuster of the engine is adjustable
through the air filter/muffler cover. See Figure 22.
NOTE: Careless adjustments can seriously damage
your unit. An authorized service dealer should make
carburetor adjustments.
Check Fuel Mixture
Old and/or improperly mixed fuel is usually the reason
for the unit not running properly. Drain and refill the
tank with fresh, properly mixed fuel prior to making
any adjustments. Refer to OPERATING YOUR CULTIVATOR in Section 4.
Clean Air Filter
The condition of the air filter is important to the
operation of the unit. A dirty air filter will restrict air
flow and change the air/fuel mixture. This is often
mistaken for an out of adjustment carburetor. Check
the condition of the air filter before adjusting the idle
speed adjuster. Refer to MAINTAINING YOUR
CULTIVATOR in Section 6.
Adjusting Idle Speed
WARNING: This unit will need to be
running during idle speed adjustment.
Wear protective clothing and observe all
safety instructions to prevent serious
personal injury.
If after checking the fuel mixture and cleaning the
air filter the engine still will not idle, adjust the idle
speed screw as follows.
1. Start the engine and let it run about 2-3 minutes
at a high idle to warm up. Refer to OPERATING
YOUR CULTIVATOR in Section 4.
NOTE: Ensure the tines are not in contact with the
ground when adjusting the idle.
2. Release the throttle control and let the engine
idle. If the engine stops, insert a small phillips or
flat blade screwdriver into the hole in the air filter/muffler cover. Turn the idle speed screw in,
clockwise, 1/8 of a turn at a time (as needed) until
the engine idles smoothly. See Figure 22.
NOTE: The tines should not rotate when the engine
idles.
3. If the tines rotate when the engine idles, turn the
idle speed screw counterclockwise 1/8 of a turn
at a time (as needed), to reduce idle speed.
Checking the fuel mixture, cleaning the air filter, and
adjusting the idle speed screw should solve most
engine problems.
If not and:
• The engine will not idle,
• The engine hesitates or stalls on acceleration,
• There is a loss of engine power,
have the carburetor adjusted by an authorized service
dealer.
Idle Speed Screw
Figure 22
Engine Specifications
Engine Type … … … … … … …Air-Cooled, 2-Cycle
Displacement … … … … … … … … … … … 31cc
Idle Speed R.P.M. … … … … … … 2,800-3,600 rpm
Operating R.P.M. … … … … … … 6,700-9,000 rpm
Fuel/Oil Mixture Ratio. … … … … … … … … … 32:1
WARNING: To avoid serious personal
injury, always turn the unit off, allow it
to cool and disconnect the spark plug
before you clean or perform any
maintenance on it.
Lubrication
Gearbox-The gearbox is pre-lubricated and sealed at
the factory.
Trouble Shooting
Refer to the trouble shooting chart for more information.
Engine
IMPORTANT: Never run your engine without air
cleaner completely assembled.
Air Filter Maintenance
1. Place the choke control in the PARTIAL choke
position (B).
NOTE: The choke control must be in the PARTIAL
choke position (B) to remove the air filter/muffler
cover. See Figure 23.
2. Remove the four (4) screws securing the air
filter/muffler cover. See Figure 23. Use a flat blade
or # T20 Torx bit screwdriver.
3. Pull the cover from the engine. Do not force.
4. Remove the air filter from behind the air filter/
muffler cover. See Figure 24.
4. Wash the filter in detergent and water. Rinse the
filter thoroughly. Squeeze out excess water. Allow
it to dry completely.
5. Apply enough clean SAE 30 oil to lightly coat the
filter. See Figure 25.
6. Squeeze the filter to spread and remove excess
oil. See Figure 25.
13
Figure 23
Figure 24
SECTION 6: MAINTAINING YOUR CULTIVATOR
Maintenance Schedule
These required maintenance procedures should be performed at the frequency stated in the table. They should
also be included as part of any seasonal tune-up.
FREQUENCY MAINTENANCE REQUIRED
Before Starting Engine Fill fuel tank with correct oil and fuel mixture.
Every 10 Hours Clean and re-oil air filter.
Every 50 Hours or Seasonal Check spark plug condition and gap.
Choke Control
Screws
Screws
Partial Choke
Position (B)
Air Filter
Figure 25
14
7. Replace the air filter inside the air filter/muffler
cover. See Figure 24.
NOTE: Operating the unit without the air filter and air
filter/muffler cover assembly, will VOID the warranty.
8. Place the air filter/muffler cover over the back of
the carburetor and muffler.
NOTE: The choke control must be in the PARTIAL
choke position (B) to install the air filter/muffler cover.
See Figure 23.
9. Insert the four (4) screws into the holes in the air
filter/muffler cover and tighten. See Figure 23.
Use a flat blade or # T20 Torx bit screwdriver. Do
not over tighten. Do not force.
Figure 26
Figure 27
Figure 28
Replacing The Spark Plug
Use a Champion RDJ7Y spark plug (or equivalent).
The correct air gap is 0.020 inch (0.5 mm). Remove
the plug after every 50 hours of operation to check its
condition.
1. Stop the engine and allow it to cool. Grasp the
plug wire firmly and pull the cap from the spark
plug.
2. Clean dirt from around the spark plug. Remove
the spark plug from the cylinder head by turning a
5/8 in. socket counterclockwise.
NOTE: Replace cracked, fouled or dirty spark plug.
3. Set the air gap at 0.020 inch (0.5 mm) using a
feeler gauge. See Figure 26.
CAUTION: Do not sand blast, scrape, or
clean electrodes. Grit in the engine could
damage the cylinder.
4. Install a correctly gapped spark plug in the cylinder head. Tighten by turning the 5/8 inch socket
clockwise until snug.
If using a torque wrench torque to;
110-120 in.•lb. (12.3-13.5 N•m).
Do not over tighten.
0.020 inch
(0.5 mm)
Clevis Pin Clip
Felt
Cushion
Shaft
Felt
Cushion
Tine Hubs
Align Tips
R
R
L
L
Clevis Pin
Tine Removal And Replacement
All 4 tines should be replaced at the same time
because they will wear evenly through normal use.
Work on one side at a time.
WARNING: To prevent serious personal
injury, always wear heavy gloves when
handling the tines.
1. Put the On/Off Stop Control in the STOP (O)
position and disconnect the spark plug wire.
2. Remove the clevis pin clips and clevis pins. See
Figure 27.
3. Remove the tines and felt cushions from the
shaft.
4. Clean and oil the shaft.
5. The tines are stamped with the letter "R" or "L" to
identified their position on each side of the gearbox when facing the front of the unit.
6. Replace the tines and felt cushions onto the shaft
with the hubs on the tines facing each other.
7. Ensure the tips on tines are aligned in the same
direction with each other before reinstalling the
clevis pins and pin clips. See Figure 28.
8. Repeat this procedure on the opposite side.
NOTE: When installed correctly, there will be an "R"
and "L" tine on each side of the gearbox and the
tips on the tines line up in the same direction. It is
important that the tines are installed correctly.
15
SECTION 7: OFF SEASON STORAGE
SECTION 8: TROUBLE SHOOTING GUIDE
If the unit will be stored for an extended time,
1. Drain all fuel from the fuel tank into a container.
Do not use fuel that has been stored for more
than 60 days. Dispose of the old fuel in
accordance to local regulations.
2. Start the engine and allow it to run until it stalls.
This ensures that all fuel has been drained from
the carburetor.
3. Allow the engine to cool. Remove the spark plug
and put 1 oz. (30 ml) of high quality motor oil
into the cylinder. Pull the starter rope slowly to
distribute the oil. Reinstall the spark plug.
NOTE: Remove the spark plug and drain all of the oil
from the cylinder before attempting to start the unit
after storage.
4. Thoroughly clean the unit and inspect for any
loose or damaged parts. Repair or replace
damaged parts and tighten loose screws, nuts or
bolts.
5. Wipe the tines with an oiled rag to prevent rust.
The unit is ready for storage.
• Never store the unit with fuel in the tank where
fumes may reach an open flame or spark.
• Allow the engine to cool before storing.
• Store the unit in a locked up area to prevent
unauthorized use or damage.
• Store the unit in a dry, well ventilated area. Do not
store next to corrosive materials, such a fertilizer.
• Store the unit out of the reach of children.
ENGINE WILL NOT START
ENGINE WILL NOT IDLE
ENGINE WILL NOT
ACCELERATE
ENGINE LACKS POWER
OR STALLS WHEN UNDER
LOAD
On/Off Stop Control in the STOP
position
Empty fuel tank
Primer bulb wasn't pressed enough
Engine flooded
Old or improperly mixed fuel
Fouled spark plug
Air Filter is Plugged
Old or improperly mixed fuel
Improper carburetor adjustment
Old or improperly mixed fuel
Improper carburetor adjustment
Old or improperly mixed fuel
Improper carburetor adjustment
Cultivator tines bound with dirt or
grass
Turn the On/Off Stop Control to START
Fill fuel tank
Press primer bulb fully and slowly 5-7
times
Use starting procedure with choke
control in the RUN position
Drain fuel tank / Add fresh fuel mixture
Replace or clean the spark plug
Replace or clean the air filter
Drain fuel tank / Add fresh fuel mixture
Refer to MAKING ADJUSTMENTS,
Section 5.
Drain fuel tank / Add fresh fuel mixture
Refer to MAKING ADJUSTMENTS,
Section 5.
Drain fuel tank / Add fresh fuel mixture
Refer to MAKING ADJUSTMENTS,
Section 5.
Stop the unit, switch the On/Off Stop
Control to STOP, clean and remove
any debris binding the tines
Trouble Possible Cause(s) Corrective Action
16
41
1
2
3
8
10
12
3
4
5
7
6
11
15
16
50
51
14
13
20
52
22
17
18
19
21
37
38
39
40
4241
32
33
26
27
28
30
41
34
36
35
30
25
44
29
43
49
45
46
47
48
24
31
23
9
SECTION 9: PARTS LIST FOR MODEL 21A-120R000
17
1. 182059 Air Cleaner/Muffler Cover Assembly
(includes 2 & 41)
2. 180350 Air Cleaner Filter
3. 180351 Carburetor Mounting Screw
Assembly
4. 180226 Wavey Washer
5. 182160 Choke Lever Assembly (includes 6)
6. 182161 Choke Knob and Screw
7. 182162 Choke Lever and Plate (includes 5)
8. 182062 Carburetor Assembly W/Limiter
Caps (includes 9 & 21)
9. 610675 Carburetor Gasket
10. 181860 Carb Mount Screw
11. 181801 Primer and Hose Assembly
12. 182063 Carb Mount Assembly (includes 10)
13. 684451 Reed Assembly
14. 182790 Power Shaft Assembly
15. 612115 Carburetor Mount Gasket
16. 182791 Crank Case Service Assembly
(includes 10, 14 & 24)
17. 612134 Rear Mounting Pad
18. 180046 Fuel Tank Assembly
(includes 19-21)
19. 181559 Fuel Cap Assembly
20. 181168 Fuel Return Line
21. 682039 Fuel Line Assembly
22. 145308 Front Mounting Pad
23. 683065 Shroud Assembly
24. 181861 Shroud Screw
25. 182064 Shroud Extension and Stand
26. 182736 Flywheel Assembly
27. 181065 Spacer
28. 181597 Recoil Pulley Assembly
29. 613102 Recoil Spring
30. 181441 Pulley Retainer Assembly
31. 611061 Rope Guide
32. 180317 Fuel Tank Guard Assembly
33. 181079 Pull Handle
34. 613103 Rope
35. 181912 Housing Screw
36 182776 Starter Housing Assembly
(includes items 28-31, 33-35)
37 182368 Clutch Washer
38 182369 Clutch Rotor Assembly
39 153592 Clutch Drum Assembly
40 180098 Clutch Cover Assembly
(includes 41)
41 181345 Clutch Cover Screw
42 153597 Upper Clamp Assembly
43 181937 Module Assembly
44 181580 Wire Lead
45 610311 Spark Plug
46 182065 Exhaust Gasket
47 182174 Muffler Assembly (includes 46 & 48)
48 182464 Muffler Mounting Bolt Assembly
49 181622 Cylinder Assembly
(includes 51 & 52)
50 684449 Piston and Rod Assembly
51 610674 Cylinder Gasket
52 182723 Cylinder Bolt
* 180011 Engine Gasket Kit
* 180602 O.E.M. Carburetor Repair Kit
(Walbro)
* 180090 O.E.M. Carburetor Repair Kit (Zama)
* 181069 Gasket-Diaphragm Repair Kit
(Walbro)
* 180091 Gasket-Diaphragm Repair Kit
(Zama)
* 180530 Piston Ring
* 182792 Short Block Assembly
(includes 45, 49-52)
* 181501 Starter Housing Screw Set
* 181873 Carburetor Limiter Cap Set (Walbro)
* 181562 Carburetor Limiter Cap Set (Zama)
* 610309 Crankcase Seal
* 181599 Clutch Springs (Qty. 2)
* not shown
Part No. Part Description
Ref.
No.
Part No. Part Description
Ref.
No.
MODEL 21A-120R000
18
1
1
3
2
4
11
12
13
10
17
18
19
20
22
25
21
26
22
28
27
27
29
30
24
23
24
28
29
14
15
16
9
6
7
8
6
9
5
MODEL 21A-120R000
19
1 181573 Throttle Trigger and Cable Assembly
2 180942 Handle Bar w/Clamp Assemblies
(includes 3-5)
3 612831 Grip
4 612021 Tube Closure
5 181503 Clamp Assembly
6 147501 Engine Bracket Mounting Hardware
7 181574 Engine Mount Bracket, R.H.
8 181504 Engine Mount Bracket, L.H.
9 682035 Switch Assembly
10 683295 Handle Bracket Assembly
(includes 11-16)
11 181811 Screw
12 181812 Upper Handle Clamp
13 181813 Middle Handle Clamp
14 181814 Lower Handle Clamp
15 181815 Nut
16 145569 Anti-Rotation Screw
17 181575 Grip
18 180943 Drive Shaft Housing Assembly
19 181577 Flexible Drive Shaft
20 181578 Retainer Sleeve (includes 21)
21 180288 Sleeve Retainer Bolt
22 147467 Wheel Bracket Mounting Hardware
23 182781 Guard
24 181579 Guard Mounting Hardware
25 180320 Wheel Bracket Assembly
26 180944 Wheel Assembly
27 147473 Tine Fastener Assembly
28 182729 Tine Assembly (Left Outer or Right
Inner)
29 182730 Tine Assembly (Left Inner or Right
Outer)
30 182750 Gear Box Assembly
* 182780 Arnold 2-Cycle Oil
* not shown
MODEL 21A-120R000
Part No. Part Description
Ref.
No.
Part No. Part Description
Ref.
No.
MANUFACTURER’S LIMITED WARRANTY FOR:
No implied warranty, including any implied warranty of
merchantability or fitness for a particular purpose,
applies after the applicable period of express written
warranty above as to the parts as identified. No other
express warranty or guaranty , whether written or oral,
except as mentioned above, given by any person or
entity, including a dealer or retailer, with respect to
any product shall bind MTD. During the period of the
Warranty, the exclusive remedy is repair or replacement of the product as set forth above. (Some states
do not allow limitations on how long an implied warranty
lasts, so the above limitation may not apply to you.)
The provisions as set forth in this Warranty provide
the sole and exclusive remedy arising from the sales.
MTD shall not be liable for incidental or consequential
loss or damages including, without limitation, expenses incurred for substitute or replacement lawn care
services, for transportation or for related expenses, or
for rental expenses to temporarily replace a warranted product. (Some states do not allow limitations on how
long an implied warranty lasts, so the above limitation
may not apply to you.)
In no event shall recovery of any kind be greater than the
amount of the purchase price of the product sold.
Alteration of the safety features of the product shall void
this Warranty. You assume the risk and liability for loss,
damage, or injury to you and your property and/or to
others and their property arising out of the use or misuse
or inability to use the product.
This limited warranty shall not extend to anyone other
than the original purchaser, original lessee or the person
for whom it was purchased as a gift.
How State Law Relates to this Warranty: This warranty
gives you specific legal rights, and you may also have
other rights which vary from state to state.
To locate your nearest service dealer dial
1-800-345-8746 in the United States or
1-800-668-1238 in Canada.
MTD Southwest Inc
550 N. 54th Street
Chandler, AZ 85226 U.S.A.
The limited warranty set forth below is given by MTD
SOUTHWEST INC (“MTD”) with respect with new
merchandise purchased and used in the United States, its
possessions and territories.
MTD warrants this product against defects in material and
workmanship for a period of two (2) years commencing on
the date of original purchase and will, at its option, repair or
replace, free of charge, any part found to be defective in
material or workmanship. This limited warranty shall only
apply if this product has been operated and maintained in
accordance with the Operator’s Manual furnished with the
product, and has not been subject to misuse, abuse,
commercial use, neglect, accident, improper maintenance,
alteration, vandalism, theft, fire, water or damage because
of other peril or natural disaster. Damage resulting from the
installation or use of any accessory or attachment not
approved by MTD for use with the product(s) covered by
this manual will void your warranty as to any resulting damage. This warranty is limited to ninety (90) days from the
date of original retail purchase for any MTD product that is
used for rental or commercial purposes, or any other
income-producing purpose.
HOW TO OBTAIN SERVICE: Warranty service is available,
WITH PROOF OF PURCHASE THROUGH YOUR LOCAL
AUTHORIZED SERVICE DEALER. To locate the dealer in
your area, please check for a listing in the Yellow Pages or
contact the Customer Service Department of MTD SOUTHWEST INC by calling 1-800-345-8746 or writing to 550 N.
54th Street, Chandler, Arizona 85226 or if in Canada call
1-800-668-1238. No product returned directly to the factory will be accepted unless prior written permission has been
extended by the Customer Service Department of MTD
SOUTHWEST INC.
This limited warranty does not provide coverage in the
following cases:
A. Tune-ups - Spark Plugs, Carburetor Adjustments,
Filters
B. Wear items - Starter Pulley, Starter Ropes, Tines
C. MTD does not extend any warranty for products sold
or exported outside of the United States of America,
its possessions and territories, except those sold
through MTD’s authorized channels of export distribution.
MTD reserves the right to change or improve the design
of any MTD Product without assuming any obligation to
modify any product previously manufactured.
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