Page 1
Owner’s Manual & Safety Instructions
Save This Manual Keep this manual for the safety warnings and precautions, assembly, operating,
inspection, maintenance and cleaning procedures. Write the product’s serial number in the back of the manual
near the assembly diagram (or month and year of purchase if product has no number). Keep this manual and
the receipt in a safe and dry place for future reference.
212, 346 and 420 cc
Horizontal Engines
Using an engine indoors
CAN KILL YOU IN MINUTES.
Engine exhaust contains carbon monoxide.
This is a poison you cannot see or smell.
NEVER use inside
a home or garage,
EVEN IF doors and
windows are open.
Manual Revised 11k
When unpacking, make sure that the product is intact
and undamaged. If any parts are missing or broken,
please call 1-800-520-0882 as soon as possible.
Copyright© 2010 by Harbor Freight Tools®. All rights reserved.
No portion of this manual or any artwork contained herein may be reproduced in
any shape or form without the express written consent of Harbor Freight Tools.
Diagrams within this manual may not be drawn proportionally. Due to continuing
improvements, actual product may differ slightly from the product described herein.
Tools required for assembly and service may not be included.
Only use OUTSIDE
and far away from
windows, doors,
and vents.
Visit our website at: http://www.harborfreight.com
Email our technical support at: tech@harborfreight.com
ITEMS 68120, 68121,
68136, 68306
Read this material before using this product.
Failure to do so can result in serious injury.
SAVE THIS MANUAL.
Page 2
Table of Contents
Specifications ............................................. 2
Safety ......................................................... 3
Setup .......................................................... 6
SAFETY OPERATION MAINTENANCESETUP
Operation .................................................... 8
Specifications
Description 68120, 68121 68136 68306
Displacement 212cc 346cc 420cc
Engine Type Horizontal Single Cylinder 4 stroke OHV
Cooling System Forced air cooled
Fuel
Engine Oil
Run Time @ 50% Load
with full tank
Sound Level at 22 feet 104 dB 108 dB 108 dB
Bore x Stroke 70 mm x 55 mm 83 mm x 64 mm 90 mm x 66 mm
Compression Ratio 8.5:1
Rotation viewed from PTO
(power takeoff - the output shaft)
Type 87+ octane unleaded gasoline
Capacity 1 Gallon 1 Gallon 1 Gallon
Type SAE
Capacity 0.5 Quart 1.16 Quart 1.16 Quart
Shaft 3/4″ x 2.41″ 1″ x 3.48″ 1″ x 3.48″
Maintenance .............................................. 14
Troubleshooting ......................................... 18
Warranties ................................................. 20
Parts Lists and Diagrams .......................... 22
10W-30 above 32° F
5W30 at 32° F or below
3 hr.
Counterclockwise
Shaft
Spark Plug
Valve Clearance
Speed Idle 1,800 ± 50 RPM
Keyway 3/16″ (4.76 mm) 1/4″ (6.35 mm) 1/4″ (6.35 mm)
End Tapped 5/16″ - 24 UNF 3/8″ - 24 3/8″ - 24
Type
Gap 0.7 - 0.8 mm
Intake 0.10 - 0.15 mm
Exhaust 0.15 - 0.20 mm
NGK® BP-6ES
NHSP® / Torch® F6TC
NHSP® / Torch® F6TC NHSP® / Torch® F6TC
Page 2 For technical questions, please call 1-800-520-0882. Horizontal Engines
Page 3
WARNING SYMBOLS AND DEFINITIONS
This is the safety alert symbol. It is used to alert you to potential personal injury hazards.
Obey all safety messages that follow this symbol to avoid possible injury or death.
Indicates a hazardous situation which, if not avoided,
will result in death or serious injury.
Indicates a hazardous situation which, if not avoided,
could result in death or serious injury.
Symbol Definitions
Symbol Property or Statement
RPM
HP
Revolutions Per Minute
Horsepower
WARNING marking concerning
Risk of Eye Injury. Wear ANSI-approved
safety goggles with side shields.
Read the manual before set-up and/or use.
WARNING marking concerning
Risk of Hearing Loss.
Wear hearing protection.
Indicates a hazardous situation which, if not avoided,
could result in minor or moderate injury.
Addresses practices not related to personal injury.
Symbol Property or Statement
WARNING marking concerning
Risk of Respiratory Injury.
Operate engine OUTSIDE and far away
from windows, doors, and vents.
WARNING marking concerning
Risk of Fire while handling fuel.
Do not smoke while handling fuel.
WARNING marking concerning
Risk of Fire.
Do not refuel while operating.
Keep flammable objects away from engine.
SAFETYOPERATIONMAINTENANCE SETUP
Safety Warnings
WARNING! Read all instructions.
Failure to follow all instructions listed below may result in fire, serious injury and/or DEATH.
The warnings and precautions discussed in this manual cannot cover all possible conditions and
situations that may occur. It must be understood by the operator that common sense and caution
are factors which cannot be built into this product, but must be supplied by the operator.
SAVE THESE INSTRUCTIONS
Page 3For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 4
Set up Precautions
1. Gasoline fuel and fumes are flammable, and
potentially explosive. Use proper fuel storage
and handling procedures. Do not store fuel
SAFETY OPERATION MAINTENANCESETUP
or other flammable materials nearby.
2. Have multiple ABC class fire extinguishers nearby.
3. Operation of this equipment may create sparks
that can start fires around dry vegetation. A spark
arrestor may be required. The operator should
contact local fire agencies for laws or regulations
relating to fire prevention requirements.
Operating Precautions
1. CARBON MONOXIDE HAZARD
Using an engine indoors CAN KILL
YOU IN MINUTES.
Engine exhaust contains carbon
monoxide. This is a poison you cannot
see or smell.
NEVER use inside a home or garage,
EVEN IF doors and windows are open.
Only use OUTSIDE and far away from windows,
doors, and vents.
2. Keep children away from the equipment,
especially while it is operating.
3. Keep all spectators at least six feet
from the Engine during operation.
4. Fire Hazard! Do not fill gas tank while engine is
running. Do not operate if gasoline has been spilled.
Clean spilled gasoline before starting engine.
Do not operate near pilot light or open flame.
5. Do not touch engine during use. Let
engine cool down after use.
6. Never store fuel or other flammable
materials near the engine.
7. Only use a suitable means of transport and
lifting devices with sufficient weight bearing
capacity when transporting the Engine.
8. Secure the Engine on transport vehicles to
prevent the tool from rolling, slipping, and tilting.
9. Industrial applications must follow
OSHA requirements.
4. Set up and use only on a flat, level,
well-ventilated surface.
5. Wear ANSI-approved safety goggles, heavy-duty
work gloves, and dust mask/respirator during set up.
6. Use only lubricants and fuel recommended
in the Specifications chart of this manual.
10. Do not leave the equipment unattended when it is
running. Turn off the equipment (and remove safety
keys, if available) before leaving the work area.
11. Engine can produce high noise levels.
Prolonged exposure to noise levels above 85
dBA is hazardous to hearing. Always wear
ear protection when operating or working
around the gas engine while it is operating.
12. Wear ANSI-approved safety glasses, hearing
protection, and NIOSH-approved dust mask/
respirator under a full face shield along
with steel-toed work boots during use.
13. People with pacemakers should consult their
physician(s) before use. Electromagnetic fields in
close proximity to a heart pacemaker could cause
pacemaker interference or pacemaker failure.
Caution is necessary when near the
engine’s magneto or recoil starter.
14. Use only accessories that are recommended
by Harbor Freight Tools for your model.
Accessories that may be suitable for one
piece of equipment may become hazardous
when used on another piece of equipment.
15. Do not operate in explosive atmospheres,
such as in the presence of flammable
liquids, gases, or dust. Gasoline-powered
engines may ignite the dust or fumes.
16. Stay alert, watch what you are doing and
use common sense when operating this
piece of equipment. Do not use this piece of
equipment while tired or under the influence
of drugs, alcohol or medication.
17. Do not overreach. Keep proper footing and
balance at all times. This enables better control
of the equipment in unexpected situations.
18. Use this equipment with both hands
only. Using equipment with only one hand
can easily result in loss of control.
19. Dress properly. Do not wear loose clothing or
jewelry. Keep hair, clothing and gloves away
from moving parts. Loose clothes, jewelry or
long hair can be caught in moving parts.
Page 4 For technical questions, please call 1-800-520-0882. Horizontal Engines
Page 5
Operating Precautions (cont.)
20. Parts, especially exhaust system components,
get very hot during use. Stay clear of hot parts.
21. Do not cover the engine or
equipment during operation.
22. Keep the equipment, engine, and
surrounding area clean at all times.
23. Use the equipment, accessories, etc., in accordance
with these instructions and in the manner intended for
the particular type of equipment, taking into account
the working conditions and the work to be performed.
Use of the equipment for operations different from
those intended could result in a hazardous situation.
24. Do not operate the equipment with known
leaks in the engine’s fuel system.
25. This product contains or, when used, produces a
chemical known to the State of California to cause
cancer and birth defects or other reproductive harm.
(California Health & Safety Code § 25249.5, et seq.)
Service Precautions
1. Before service, maintenance, or cleaning:
a. Turn the engine switch to its “OFF” position.
b. Allow the engine to completely cool.
c. Then, remove the spark plug
cap from the spark plug.
2. Keep all safety guards in place and in
proper working order. Safety guards include
muffler, air cleaner, mechanical guards,
and heat shields, among other guards.
3. Do not alter or adjust any part of the
equipment or its engine that is sealed by the
manufacturer or distributor. Only a qualified
service technician may adjust parts that may
increase or decrease governed engine speed.
4. Wear ANSI-approved safety goggles, heavy-duty
work gloves, and dust mask/respirator during service.
5. Maintain labels and nameplates on the equipment.
These carry important information.
If unreadable or missing, contact
Harbor Freight Tools for a replacement.
6. Have the equipment serviced by a qualified repair
person using only identical replacement parts.
This will ensure that the safety of the equipment
is maintained. Do not attempt any service or
maintenance procedures not explained in this
manual or any procedures that you are uncertain
about your ability to perform safely or correctly.
7. Store equipment out of the reach of children.
26. When spills of fuel or oil occur, they must be
cleaned up immediately. Dispose of fluids and
cleaning materials as per any local, state, or
federal codes and regulations. Store oil rags in
a bottom-ventilated, covered, metal container.
27. Keep hands and feet away from moving parts. Do
not reach over or across equipment while operating.
28. Before use, check for misalignment or binding of
moving parts, breakage of parts, and any other
condition that may affect the equipment’s operation.
If damaged, have the equipment serviced
before using. Many accidents are caused
by poorly maintained equipment.
29. Use the correct equipment for the application.
Do not modify the equipment and do not use the
equipment for a purpose for which it is not intended.
8. Follow scheduled engine and
equipment maintenance.
Refueling:
1. Do not smoke, or allow sparks, flames,
or other sources of ignition around the
equipment, especially when refuelling.
2. Do not refill the fuel tank while the
engine is running or hot.
3. TO PREVENT FUEL LEAKAGE AND FIRE
HAZARD, do not fill fuel above the bottom of
fuel strainer for the 68121, 212cc engine.
68121 Max Fuel
DO NOT OVERFILL!
4. Do not fill fuel tank to the top. Leave a little
room for the fuel to expand as needed.
5. Refuel in a well-ventilated area only.
6. Wipe up any spilled fuel and allow excess
to evaporate before starting engine.
To prevent FIRE, do not start the engine
while the smell of fuel hangs in the air.
SAFETYOPERATIONMAINTENANCE SETUP
SAVE THESE INSTRUCTIONS.
Page 5For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 6
Set Up
Read the ENTIRE IMPORTANT SAFETY INFORMATION section at the beginning of this manual
including all text under subheadings therein before set up or use of this product.
SAFETY OPERATION MAINTENANCESETUP
TO PREVENT SERIOUS INJURY:
Operate only with proper spark arrestor installed.
Operation of this equipment may create sparks that
can start fires around dry vegetation.
A spark arrestor may be required.
The operator should contact local fire
agencies for laws or regulations relating
to fire prevention requirements.
At high altitudes, the engine’s carburetor, governor
(if so equipped), and any other parts that control
the fuel-air ratio will need to be adjusted by a
qualified mechanic to allow efficient high-altitude
use and to prevent damage to the engine and
any other devices used with this product.
Battery Setup Instructions
Model 68120: The emission control system for this
engine is warranted for standards set by the U.S.
Environmental Protection Agency. For warranty
information, refer to the last pages of this manual.
Models 68306, 68121, and 68136: The emission
control system for this Generator’s Engine is
warranted for standards set by the U.S. Environmental
Protection Agency and by the California Air Resources
Board (also known as CARB). For warranty
information, refer to the last pages of this manual.
WARNING! DO NOT INSTALL THIS
ENGINE ON A VEHICLE.
1. Place a fully charged, lead-acid 12 volt,
300 CCA, 36 Ah battery (not included) in
a stable, flat location near the engine.
2. Only use cables sized to match their length
according to the following chart:
Cable Gauge
(lower gauge numbers
mean thicker cables)
Maximum
Cable Length
6 5′
4 7′
2 12′
Motor Starter Assembly
Starting Relay
4. Attach the negative cable to the
negative battery terminal.
5. Connect the negative cable securely to one
of the engine mounting bolts, as shown in
the diagram below. Connect cable securely to
prevent disconnection and short circuits.
Connect Negative
Battery Cable to a
Mounting Bolt
6. Coat the terminals and cable ends with
a corrosion-preventive coating.
3.
Attach the positive cable from the positive
battery terminal to the Positive Terminal on
the starter solenoid (uncovered terminal),
shown above. Connect cable securely to
prevent disconnection and short circuits.
Page 6 For technical questions, please call 1-800-520-0882. Horizontal Engines
REV 11j
Page 7
Engine Controls
Air Filter
Fuel Cap
SAFETYOPERATIONMAINTENANCE SETUP
Engine
Switch
(Electric
Start Models)
Starter
Handle
Muffler
Throttle
Choke
Oil Drain Plug
Fuel Valve
Dipstick
Starter
(Electric
Start Models)
Serial
Number
Location
(Write on front
cover of manual.)
Engine
Switch
(Manual Start
Models)
Page 7For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 8
Operation
Read the ENTIRE IMPORTANT SAFETY INFORMATION section at the beginning of this manual
including all text under subheadings therein before set up or use of this product.
SAFETY OPERATION MAINTENANCESETUP
Pre-Start Checks
Inspect engine and equipment looking for damaged, loose, and missing parts before set up
and starting. If any problems are found, do not use equipment until fixed properly.
Checking and Filling Engine Oil
NOTICE: Your Warranty is VOID if the engine’s
crankcase is not properly filled with oil before
each use. Before each use, check the oil level.
Do not run the engine with low or no engine oil.
Running the engine with no or low engine oil
WILL permanently damage the engine.
1. Make sure the engine is stopped and is level.
2. Close the Fuel Valve.
3. Clean the top of the Dipstick and the area around it.
Remove the Dipstick by threading it counterclockwise,
and wipe it off with a clean lint free rag.
Full level
4.
Reinsert the Dipstick without threading it in and
remove it to check the oil level. The oil level
should be up to the full level as shown above.
5. If the oil level is at or below the low mark add the
appropriate type of oil until the oil level is at the
proper level. SAE 10W-30 oil is recommended
for general use. (The SAE Viscosity Grade chart
on page 15 in the Service section shows other
viscosities to use in different average temperatures.)
6. Thread the dipstick back in clockwise.
NOTICE: Do not run the engine with too little oil.
The engine will be permanently damaged.
Full level
Page 8 For technical questions, please call 1-800-520-0882. Horizontal Engines
Page 9
Checking and Filling Fuel
WARNING! TO PREVENT SERIOUS
INJURY FROM FIRE:
Fill the fuel tank in a well-ventilated area
away from ignition sources. If the engine is
hot from use, shut the engine off and wait
for it to cool before adding fuel.
Do not smoke.
1. Clean the Fuel Cap and the area around it.
2. Unscrew and remove the Fuel Cap.
3. If needed, fill the Fuel Tank to about 1 inch
under the fill neck of the Fuel Tank with
87 octane or higher unleaded gasoline.
Starting the Engine
Before Starting the Engine
Before starting the engine:
a. Follow the Set Up Instructions in the equipment manual to prepare the equipment.
b. Inspect the equipment and engine.
c. Fill the engine with the proper amount and type of both fuel and oil.
d. Read the Equipment Operation section in the equipment manual.
Note: Do not use gasoline containing more than
10% ethanol (E10). Do not use E85 ethanol.
Note: Do not use gasoline that has been stored in a
metal fuel container or a dirty fuel container. It can
cause particles to enter the carburetor, affecting
engine performance and/or causing damage.
4. Then replace the Fuel Cap.
5. Wipe up any spilled fuel and allow excess
to evaporate before starting engine.
To prevent FIRE, do not start the engine
while the smell of fuel hangs in the air.
SAFETYOPERATIONMAINTENANCE SETUP
Page 9For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 10
Manual Start
SAFETY OPERATION MAINTENANCESETUP
1. To start a cold engine, move the Choke to the
CHOKE position.
To restart a warm engine, leave the Choke in the
RUN position.
2. Open the Fuel Valve.
1
CHOKE RUN
2
3. Slide the Throttle or Speed Control Lever to 1/3
away from the SLOW position (the “turtle”).
Note: Some tools have a Speed Control Lever located
elsewhere on the tool which functions the same as the
Throttle. Use the Speed Control Lever in place of the Throttle
when the tool is so equipped.
OFF
4. Turn the Engine Switch on.
3
ON
O
I
ON
4
5. Grip the Starter Handle of the Engine loosely and pull
it slowly several times to allow the gasoline to flow into
the Engine’s carburetor. Then pull the Starter Handle
gently until resistance is felt. Allow Cable to retract fully
and then pull it quickly. Repeat until the engine starts.
Note: Do not let the Starter Handle snap back against the engine.
Hold it as it recoils so it doesn't hit the engine.
Page 10 For technical questions, please call 1-800-520-0882. Horizontal Engines
5
Page 11
6. Allow the Engine to run for several seconds.
Then, if the Choke lever is in the CHOKE position,
move the Choke Lever very slowly to its RUN position.
Note: Moving the Choke Lever too fast could stall the engine.
6
IMPORTANT: Allow the engine to run at no load for five minutes with no
load after each start-up so that the engine can stabilize.
7. Adjust the Throttle as needed.
8. Break-in Period:
a. Breaking-in the engine will help to ensure proper equipment and engine operation.
b. The operational break-in period will last about 3 hours of use. During this period:
• Do not apply a heavy load to the equipment.
• Do not operate the engine at its maximum speed.
c. The maintenance break-in period will last about 20 hours of use. After this period:
• Change the engine oil.
Under normal operating conditions subsequent maintenance follows the schedule
explained in the MAINTENANCE AND SERVICING section.
Stopping the Engine
CHOKE RUN
SAFETYOPERATIONMAINTENANCE SETUP
1. To stop the engine in an emergency,
turn the Engine Switch off.
2. Under normal conditions, use the following procedure:
a. Slide the Throttle or Speed Control
Lever to SLOW (the “turtle”).
b. Turn the Engine Switch off.
c. Close the Fuel Valve.
OFF
O
I
Page 11For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 12
Electric Start (if equipped)
SAFETY OPERATION MAINTENANCESETUP
1. To start a cold engine, move the Choke to the
CHOKE position.
To restart a warm engine, leave the Choke in the
RUN position.
1
CHOKE RUN
2. Open the Fuel Valve.
3. Slide the Throttle or Speed Control Lever to 1/3
away from the SLOW position (the “turtle”).
Note: Some tools have a Speed Control Lever located
elsewhere on the tool which functions the same as
the Throttle. Use the Speed Control Lever in place
of the Throttle when the tool is so equipped.
2
3
ON
4. Turn the Engine Switch to START.
Page 12 For technical questions, please call 1-800-520-0882. Horizontal Engines
OFF START
4
START
Page 13
5. Allow the Engine to run for several seconds.
Then, if the Choke lever is in the CHOKE position,
move the Choke Lever very slowly to its RUN position.
Note: Moving the Choke Lever too fast could stall the engine.
5
IMPORTANT: Allow the engine to run at no load for five minutes with no
load after each start-up so that the engine can stabilize.
6. Adjust the Throttle as needed.
7. Break-in Period:
a. Breaking-in the engine will help to ensure proper equipment and engine operation.
b. The operational break-in period will last about 3 hours of use. During this period:
• Do not apply a heavy load to the equipment.
• Do not operate the engine at its maximum speed.
c. The maintenance break-in period will last about 20 hours of use. After this period:
• Change the engine oil.
Under normal operating conditions subsequent maintenance follows the schedule
explained in the MAINTENANCE AND SERVICING section.
Stopping the Engine
CHOKE RUN
SAFETYOPERATIONMAINTENANCE SETUP
1. To stop the engine in an emergency,
turn the Engine Switch off.
2. Under normal conditions, use the following procedure:
a. Slide the Throttle or Speed Control
Lever to SLOW (the “turtle”).
b. Turn the Engine Switch off.
c. Close the Fuel Valve.
OFF
Page 13For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 14
Maintenance
WARNING
SAFETY OPERATION MAINTENANCESETUP
TO PREVENT SERIOUS INJURY FROM ACCIDENTAL STARTING:
Turn the Power Switch of the equipment to its “OFF” position, wait for the engine to cool, and disconnect
the spark plug cap before performing any inspection, maintenance, or cleaning procedures.
TO PREVENT SERIOUS INJURY FROM EQUIPMENT FAILURE:
Do not use damaged equipment. If abnormal noise, vibration, or excess
smoking occurs, have the problem corrected before further use.
Follow all service instructions in this manual. The engine may fail critically if not serviced properly.
Many maintenance procedures, including any not detailed in this manual, will need to be
performed by a qualified technician for safety. If you have any doubts about your ability to safely
service the equipment or engine, have a qualified technician service the equipment instead.
Cleaning, Maintenance, and Lubrication Schedule
Note: This maintenance schedule is intended solely as a general guide. If performance decreases or if
equipment operates unusually, check systems immediately. The maintenance needs of each piece of equipment
will differ depending on factors such as duty cycle, temperature, air quality, fuel quality, and other factors.
Note: The following procedures are in addition to the regular checks and maintenance
explained as part of the regular operation of the engine and equipment.
Monthly or
every 20
hr. of use
Procedure
Brush off outside of engine
Check engine oil level
Check air cleaner
Check deposit cup
Change engine oil
Clean/replace air cleaner
Check and clean spark plug
1. Check/adjust idle speed
2. Check/adjust valve clearance
3. Clean fuel tank, strainer
and carburetor
4. Clean carbon build-up from
combustion chamber
Replace fuel line if necessary
Before
Each Use
*Service more frequently when used in dusty areas.
**These items should be serviced by a qualified technician.
Every 3 mo. or
50 hr. of use
*
Every 6 mo. or
100 hr. of use
Yearly or
every 300
hr. of use
** **
Every
2 Years
**
Page 14 For technical questions, please call 1-800-520-0882. Horizontal Engines
Page 15
Checking and Filling Fuel
Engine Oil Change
WARNING! TO PREVENT SERIOUS
INJURY FROM FIRE:
Fill the fuel tank in a well-ventilated area
away from ignition sources. If the engine is
hot from use, shut the engine off and wait
for it to cool before adding fuel.
Do not smoke.
1. Clean the Fuel Cap and the area around it.
2. Unscrew and remove the Fuel Cap.
3. If needed, fill the Fuel Tank to about 1 inch under
the fill neck of the Fuel Tank with 87 octane or
higher unleaded gasoline. For the 68121, fill to
the bottom of the fuel strainer ONLY, see below.
68121 Max Fuel
DO NOT OVERFILL!
WARNING! TO PREVENT FUEL LEAKAGE AND
FIRE HAZARD, do not fill fuel above the bottom
of fuel strainer for the 68121, 212cc engine.
Note: Do not use gasoline containing more than
10% ethanol (E10). Do not use E85 ethanol.
Note: Do not use gasoline that has been stored in a
metal fuel container or a dirty fuel container. It can
cause particles to enter the carburetor, affecting
engine performance and/or causing damage.
4. Then replace the Fuel Cap.
5. Wipe up any spilled fuel and allow excess
to evaporate before starting engine.
To prevent FIRE, do not start the engine
while the smell of fuel hangs in the air.
CAUTION! Oil is very hot during operation and can
cause burns. Wait for engine to cool before changing oil.
1. Make sure the engine is stopped and is level.
2. Close the Fuel Valve.
3. Place a drain pan (not included) underneath
the crankcase’s drain plug.
4. Remove the drain plug and, if possible,
tilt the crankcase slightly to help drain
the oil out. Recycle used oil.
5. Replace the drain plug and tighten it.
6. Clean the top of the Dipstick and the area around it.
Remove the Dipstick by threading it counterclockwise,
and wipe it off with a clean lint free rag.
Full level
7.
Add the appropriate type of oil until the oil level is at
the full level. SAE 10W-30 oil is recommended for
general use.
The SAE Viscosity Grade chart shows other
viscosities to use in different average temperatures.
Full level
SAE Viscosity Grades
30
10W-30
5W-30
-20 0 20 40 60 80 100°F
Average outdoor temperature
8. Thread the dipstick back in clockwise.
CAUTION! Do not run the engine with too little oil.
The engine will be permanently damaged.
SAFETYOPERATIONMAINTENANCE SETUP
Page 15For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 16
Air Filter Element Maintenance
1. Remove the air filter cover and the
air filter elements and check for dirt.
Clean or replace as described below.
2. Cleaning:
SAFETY OPERATION MAINTENANCESETUP
• For “paper” filter elements:
To prevent injury from dust and debris,
wear ANSI-approved safety goggles,
NIOSH-approved dust mask/respirator, and
heavy-duty work gloves. In a well-ventilated
area away from bystanders, use pressurized
air to blow dust out of the air filter. If this
does not get the filter clean, replace it.
• For foam filter elements:
Wash the element in warm water and
mild detergent several times. Rinse.
Squeeze out excess water and allow it to dry
completely. Soak the filter in lightweight oil
briefly, then squeeze out the excess oil.
3. Install the new filter or the cleaned filter.
Secure the Air Cleaner Cover before use.
Spark Plug Maintenance
Spark
Plug
Cap
1.
Disconnect spark plug cap from end of plug.
Clean out debris from around spark plug.
2. Using a spark plug wrench, remove the spark plug.
3. Inspect the spark plug:
If the electrode is oily, clean it using a clean, dry
rag. If the electrode has deposits on it, polish it
using emery paper. If the white insulator is cracked
or chipped, the spark plug needs to be replaced.
Recommended Spark Plugs
NGK
NHSP
Brand
®
® /
TORCH
68120, 68121 68136 68306
®
BP-6ES
F6TC F6TC F6TC
NOTICE: Using an incorrect spark
plug may damage the engine.
4. When installing a new spark plug, adjust the
plug’s gap to the specification on the Technical
Specifications chart. Do not pry against the
electrode, the spark plug can be damaged.
5. Install the new spark plug or the cleaned spark plug
into the engine. Gasket-style: Finger-tighten until the
gasket contacts the cylinder head, then tighten about
1/2-2/3 turn more.
Non-gasket-style: Finger-tighten until the plug
contacts the head, then tighten about 1/16 turn more.
NOTICE: Tighten the spark plug properly.
If loose, the spark plug will cause the engine
to overheat. If overtightened, the threads
in the engine block will be damaged.
6. Apply dielectric spark plug boot protector
(not included) to the end of the spark
plug and reattach the wire securely.
Page 16 For technical questions, please call 1-800-520-0882. Horizontal Engines
Page 17
Storage
When the equipment is to remain idle for longer than
20 days, prepare the engine for storage as follows:
1. CLEANING:
Wait for engine to cool, then clean engine with
dry cloth. NOTICE: Do not clean using water.
The water will gradually enter the engine
and cause rust damage. Apply a thin coat
of rust preventive oil to all metal parts.
2. FUEL:
WARNING! TO PREVENT SERIOUS
INJURY FROM FIRE:
Drain the fuel tank in a well-ventilated area
away from ignition sources. If the engine is
hot from use, shut the engine off and wait
for it to cool before draining fuel.
Do not smoke.
a. Place a funnel leading to a proper gasoline
container below the carburetor.
Sediment Cup
(some engines)
Drain Plug
b.
Remove the drain bolt from the bottom of the
carburetor bowl and allow the fuel to drain.
c. Remove the small sediment cup next to the bowl
and allow the fuel to drain from there as well.
d. Open the fuel valve. After all fuel has
drained, reinstall the drain bolt and sediment
cup (if equipped). Tighten securely.
3. LUBRICATION:
a. Change engine oil.
b. Clean out area around spark plug. Remove
spark plug and pour one tablespoon of engine
oil into cylinder through spark plug hole.
c. Replace spark plug, but leave spark
plug cap disconnected.
d. Pull Starter Handle to distribute oil in cylinder.
Stop after one or two revolutions when you
feel the piston start the compression stroke
(when you start to feel resistance).
4. BATTERY:
Disconnect battery cables (if equipped).
Recharge batteries monthly while in storage.
5. STORAGE AREA:
Cover and store in a dry, level, well-ventilated
area out of reach of children. Storage area
should also be away from ignition sources, such
as water heaters, clothes dryers, and furnaces.
6. AFTER STORAGE:
Before starting the engine after storage, keep
in mind that untreated gasoline will deteriorate
quickly. Drain the fuel tank and change to fresh
fuel if untreated gasoline has been sitting for
a month, if treated gasoline has been sitting
beyond the fuel stabilizer’s recommended
time period, or if the engine does not start.
SAFETYOPERATIONMAINTENANCE SETUP
Page 17For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 18
Troubleshooting
Problem Possible Causes Probable Solutions
Engine will not start FUEL RELATED:
SAFETY OPERATION MAINTENANCESETUP
1. No fuel in tank or fuel valve closed.
2. Choke not in CHOKE position, cold engine.
3. Gasoline with more than 10% ethanol
used. (E15, E20, E85, etc.)
4. Low quality or deteriorated, old gasoline.
5. Carburetor not primed.
6. Dirty fuel passageways.
7. Carburetor needle stuck.
Fuel can be smelled in the air.
8. Too much fuel in chamber. This can be
caused by the carburetor needle sticking.
9. Clogged Fuel Filter.
IGNITION (SPARK) RELATED:
1. Spark plug cap not connected securely.
2. Spark plug electrode wet or dirty.
3. Incorrect spark plug gap.
4. Spark plug cap broken.
5. Circuit breaker tripped
(electric start models only).
6. Incorrect spark timing or
faulty ignition system.
COMPRESSION RELATED:
1. Cylinder not lubricated. Problem after long
storage periods.
2. Loose or broken spark plug. (Hissing
noise will occur when trying to start.)
3. Loose cylinder head or damaged
head gasket. (Hissing noise will
occur when trying to start.)
4. Engine valves or tappets
mis-adjusted or stuck.
FUEL RELATED:
1. Fill fuel tank and open fuel valve.
2. Move Choke to CHOKE position.
3. Clean out ethanol rich gasoline from fuel
system. Replace components damaged
by ethanol. Use fresh 87+ octane
unleaded gasoline only.
Do not use gasoline with more than
10% ethanol (E15, E20, E85, etc.).
4. Use fresh 87+ octane unleaded gasoline.
Do not use gasoline with more than
10% ethanol (E15, E20, E85, etc.).
5. Pull on Starter Handle to prime.
6. Clean out passageways using
fuel additive. Heavy deposits
may require further cleaning.
7. Gently tap side of carburetor float
chamber with screwdriver handle.
8. Turn Choke to RUN position.
Remove spark plug and pull the start
handle several times to air out the
chamber. Reinstall spark plug and
set Choke to CHOKE position.
9. Replace Fuel Filter.
IGNITION (SPARK) RELATED:
1. Connect spark plug cap properly.
2. Clean spark plug.
3. Correct spark plug gap.
4. Replace spark plug cap.
5. Reset circuit breaker. Check wiring and
starter motor if breaker continues to trip.
6. Have qualified technician diagnose/
repair ignition system.
COMPRESSION RELATED:
1. Pour tablespoon of oil into spark
plug hole. Crank engine a few
times and try to start again.
2. Tighten spark plug. If that does not work,
replace spark plug. If problem persists,
may have head gasket problem, see #3.
3. Tighten head. If that does not remedy
problem, replace head gasket.
4. Have qualified technician diagnose/
repair ignition system.
Follow all safety precautions whenever diagnosing or servicing the equipment or engine.
Page 18 For technical questions, please call 1-800-520-0882. Horizontal Engines
Page 19
Problem Possible Causes Probable Solutions
Engine misfires 1. Spark plug cap loose.
2. Incorrect spark plug gap or
damaged spark plug.
3. Defective spark plug cap.
4. Old or low quality gasoline.
5. Incorrect compression.
Engine stops
suddenly
Engine stops when
under heavy load
Engine knocks 1. Old or low quality gasoline.
Engine backfires 1. Impure or low quality gasoline.
1. Low oil shutdown.
2. Fuel tank empty or full of impure or low
quality gasoline.
3. Defective fuel tank cap creating
vacuum, preventing proper fuel flow.
4. Faulty magneto.
5. Disconnected or improperly
connected spark plug cap.
1. Dirty air filter
2. Engine running cold.
2. Engine overloaded.
3. Incorrect spark timing, deposit
buildup, worn engine, or other
mechanical problems.
2. Engine too cold.
3. Intake valve stuck or overheated engine.
4. Incorrect timing.
1. Check wire connections.
2. Re-gap or replace spark plug.
3. Replace spark plug cap.
4. Use only fresh 87+ octane
unleaded gasoline.
Do not use gasoline with more than
10% ethanol (E15, E20, E85, etc.).
5. Diagnose and repair compression.
(Use Engine will not start:
COMPRESSION RELATED section.)
1. Fill engine oil to proper level. Check
engine oil before EVERY use.
2. Fill fuel tank with fresh 87+ octane
unleaded gasoline.
Do not use gasoline with more than
10% ethanol (E15, E20, E85, etc.).
3. Test/replace fuel tank cap.
4. Have qualified technician service magneto.
5. Secure spark plug cap.
1. Clean or replace element.
2. Allow engine to warm up prior
to operating equipment.
1. Fill fuel tank with fresh 87+ octane
unleaded gasoline.
Do not use gasoline with more than
10% ethanol (E15, E20, E85, etc.).
2. Do not exceed equipment’s load rating.
3. Have qualified technician
diagnose and service engine.
1. Fill fuel tank with fresh 87+ octane
unleaded gasoline.
Do not use gasoline with more than
10% ethanol (E15, E20, E85, etc.).
2. Use cold weather fuel and oil
additives to prevent backfiring.
3. Have qualified technician
diagnose and service engine.
4. Check engine timing.
SAFETYOPERATIONMAINTENANCE SETUP
Follow all safety precautions whenever diagnosing or servicing the equipment or engine.
Page 19For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 20
Warranties
Limited 90 Day Warranty
SAFETY OPERATION MAINTENANCESETUP
Harbor Freight Tools Co. makes every effort to assure that its products meet high quality and durability standards, and
warrants to the original purchaser that this product is free from defects in materials and workmanship for the period
of 90 days from the date of purchase. This warranty does not apply to damage due directly or indirectly, to misuse,
abuse, negligence or accidents, repairs or alterations outside our facilities, criminal activity, improper installation,
normal wear and tear, or to lack of maintenance. We shall in no event be liable for death, injuries to persons or
property, or for incidental, contingent, special or consequential damages arising from the use of our product. Some
states do not allow the exclusion or limitation of incidental or consequential damages, so the above limitation of
exclusion may not apply to you. THIS WARRANTY IS EXPRESSLY IN LIEU OF ALL OTHER WARRANTIES,
EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS.
To take advantage of this warranty, the product or part must be returned to us with transportation charges prepaid.
Proof of purchase date and an explanation of the complaint must accompany the merchandise. If our inspection
verifies the defect, we will either repair or replace the product at our election or we may elect to refund the purchase
price if we cannot readily and quickly provide you with a replacement. We will return repaired products at our expense,
but if we determine there is no defect, or that the defect resulted from causes not within the scope of our warranty,
then you must bear the cost of returning the product.
This warranty gives you specific legal rights and you may also have other rights which vary from state to state.
Emission Control System Warranty
United States Emission Control Defects
Warranty Statement
(for Model 68120)
The United States Environmental Protection Agency (herein EPA)
and Harbor Freight Tools (herein HFT) are pleased to explain the
emission control system warranty on your 1997 and later Small Off-
Road Engine (herein engine). Within the United States, new off-road,
spark-ignition engines certified for model year 1997 and later, must be
designed, built and equipped to meet the stringent anti-smog standards
set forth by the EPA. HFT must warrant the emission control system on
your engine for the periods of time described below, provided there has
been no abuse, neglect or improper maintenance of your engine.
Your emission control system may include parts such as the
carburetor or fuel-injection system, and the ignition system. Also
included may be hoses, belts, connectors and other emission-related
assemblies.
Where a warrantable condition exists, HFT will repair your engine
at no cost to you including diagnosis, parts and labor.
California and United States Emission Control
Defects Warranty Statement
(for Models 68306, 68121, and 68136)
The California Air Resources Board (herein CARB), the United
States Environmental Protection Agency (herein EPA), and Harbor
Freight Tools (herein HFT) are pleased to explain the emission control
system warranty on your 1995 and later Small Off-Road Engine (herein
engine). In California, the engine must be designed, built and equipped
to meet the State’s stringent anti-smog standards. Elsewhere within the
United States, new off-road, spark-ignition engines certified for model
year 1997 and later, must meet similar standards set forth by the EPA.
HFT must warrant the emission control system on your engine for the
periods of time described below, provided there has been no abuse,
neglect or improper maintenance of your engine.
Your emission control system may include parts such as the
carburetor or fuel-injection system, and the ignition system. Also
included may be hoses, belts, connectors and other emission-related
assemblies.
Where a warrantable condition exists, HFT will repair your engine
at no cost to you including diagnosis, parts and labor.
Manufacturer’s Warranty Coverage
The 1995 and later engines are warranted for two (2) years. If
any emission-related part on your engine is defective, the part will be
repaired or replaced by HFT.
Page 20 For technical questions, please call 1-800-520-0882. Horizontal Engines
Page 21
Harbor Freight Tools Emission Control Defects
Warranty Coverage
Engines are warranted for a period of two (2) years relative to
emission control parts defects, subject to the provisions set forth below.
If any emission related part on your engine is defective, the part will be
repaired or replaced by HFT.
Owner’s Warranty Responsibilities
• As the engine owner, you are responsible for the performance
of the required maintenance listed in your Owner’s Manual. HFT
recommends that you retain all receipts covering maintenance
on your engine, but HFT cannot deny warranty solely for the lack
of receipts or for your failure to ensure the performance of all
scheduled maintenance.
• As the engine owner, you should, however, be aware that HFT
may deny you warranty coverage if your engine or a part has failed
due to abuse, neglect, improper maintenance, or unapproved
modifications.
• You are responsible for shipping your engine to a HFT warranty
station as soon as a problem exists. Contact the HFT Customer
Service department at the number below to make shipping
arrangements. The warranty repairs should be completed in a
reasonable amount of time, not to exceed 30 days.
If you have any questions regarding your warranty rights and
responsibilities, you should contact the Harbor Freight Tools Customer
Service Department at 1-800-520-0882.
Harbor Freight Tools Emission Control Defects
Warranty Provisions
1. Length of Coverage
HFT warrants to a first retail purchaser and each subsequent
purchaser that the engine is free from defects in materials and
workmanship that cause the failure of warranted parts for a
period of two (2) years after the date of delivery to the first retail
purchaser.
2. No Charge Repair or Replacement
Repair or replacement of any warranted part will be performed at
no charge to the owner if the work is performed through a warranty
station authorized by HFT. For emissions warranty service, contact
the HFT Customer Service Department at 1-800-520-0882.
3. Consequential Damages Coverage
Coverage under this warranty shall also extend to the failure of any
engine components caused by the failure of any warranted part
while it is still covered under this warranty.
4. Coverage Exclusions
Warranty claims shall be filed in accordance with the provisions
of the HFT warranty policy explained in the box at the top of the
previous page. HFT shall not be liable for any loss of use of the
engine, for any alternative usage, for any damage to goods, loss of
time, or inconvenience. Warranty coverage shall also be excluded
for any part which fails, malfunctions, or is damaged due to failure
to follow the maintenance and operating instructions set forth in the
Owner’s Manual including, but not limited to:
a) Use of parts which are not authorized by HFT
b) Improper installation, adjustment or repair of the engine or of
any warranted part unless performed by an authorized warranty
center
c) Failure to follow recommendations on fuel use contained in the
Owner’s Manual
d) Improper or inadequate maintenance of any warranted parts
e) Repairs performed outside of the authorized warranty
service dealers
f) Alterations by changing, adding to or removing parts from
the engine.
5. Service and Maintenance
Component parts which are not scheduled for replacement as
required maintenance or are scheduled only for regular inspection
to the effect of “repair or replace as necessary” are warranted for
the warranty period. Any warranted part which is scheduled for
replacement as required maintenance is warranted for the period
of time up to the first scheduled replacement point for that part.
Any replacement part, provided it is equivalent in durability and
performance, may be used in performance of maintenance or
repairs. The owner is responsible for commissioning a qualified
technician/mechanic to perform all required maintenance, as
outlined in the Inspection, Cleaning, and Maintenance section in
this manual.
6. Warranted Parts
1) Fuel Metering System
i) Carburetor and its internal parts.
ii) Fuel pump (if so equipped).
iii) Cold start enrichment system.
2) Air Induction System
i) Intake pipe/manifold.
ii) Air cleaner.
3) Ignition System
i) Spark plug.
ii) Magneto ignition system.
4) Catalyst System (if so equipped)
i) Exhaust pipe stud.
ii) Muffler.
iii) Catalytic converter (if so equipped).
5) Miscellaneous Items Used in Above Systems
i) Vacuum, temperature and time sensitive valves and
switches.
ii) Hoses, belts, connectors, and assemblies.
SAFETYOPERATIONMAINTENANCE SETUP
PLEASE READ THE FOLLOWING CAREFULLY
THE MANUFACTURER AND/OR DISTRIBUTOR HAS PROVIDED THE PARTS LIST AND ASSEMBLY DIAGRAM
IN THIS MANUAL AS A REFERENCE TOOL ONLY. NEITHER THE MANUFACTURER OR DISTRIBUTOR
MAKES ANY REPRESENTATION OR WARRANTY OF ANY KIND TO THE BUYER THAT HE OR SHE IS
QUALIFIED TO MAKE ANY REPAIRS TO THE PRODUCT, OR THAT HE OR SHE IS QUALIFIED TO REPLACE
ANY PARTS OF THE PRODUCT. IN FACT, THE MANUFACTURER AND/OR DISTRIBUTOR EXPRESSLY
STATES THAT ALL REPAIRS AND PARTS REPLACEMENTS SHOULD BE UNDERTAKEN BY CERTIFIED AND
LICENSED TECHNICIANS, AND NOT BY THE BUYER. THE BUYER ASSUMES ALL RISK AND LIABILITY
ARISING OUT OF HIS OR HER REPAIRS TO THE ORIGINAL PRODUCT OR REPLACEMENT PARTS
THERETO, OR ARISING OUT OF HIS OR HER INSTALLATION OF REPLACEMENT PARTS THERETO.
Page 21For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 22
Parts Lists and Diagrams
68120 212cc Parts List
SAFETY OPERATION MAINTENANCESETUP
Part Description Qty.
1 Gasket, Cylinder Head 1
2 Cover Asm., Cylinder Head 1
3 Gasket, Cylinder Head Cover 1
4 Tube, Breather 1
5 Bolt 4
6 Stud 1
7 Stud 1
8 Stud 2
9 Pin 2
10 Bolt, Cylinder Head 4
11 Plug, Spark 1
12 Head Asm., Cylinder 1
13 Crankcase Asm. 1
14 Sensor, Engine Oil 1
15 Gear Asm., Governor 1
16 Arm, Governor 1
17 Bolt, Drain Plug 2
18 Washer 2
19 Bearing 1
20 Seal, Oil 1
21 Washer 1
22 Pin 1
23 Bolt 2
24 Cover, Crankcase 1
25 Bearing 1
26 Seal, Oil 1
27 Gasket, Crankcase 1
28 Pin 2
29 Dipstick Asm., Oil 1
30 Plug Asm., Engine Oil 1
31 Bolt 6
32 Crankshaft Asm. 1
33 Clip, Piston Pin 2
34 Piston 1
35 Pin, Piston 1
36 Rod, Connecting 1
37 Ring, The First 1
38 Ring, The Second 1
39 Ring Set, Oil 1
40 Camshaft Asm. 1
41 Valve, Exhaust 1
42 Valve, Intake 1
43 Seat, Valve Spring 1
44 Retainer_ Exhaust Valve 1
45 Rotator, Valve 1
46 Guide, Seal 1
47 Tappet, Valve 2
48 Lifter, Valve 2
49 Plate Asm., Lifter Stopper 1
50 Bolt, Valve Adjusting 2
Part Description Qty.
51 Rocker, Valve 2
52 Nut_ Valve Adjusting 2
53 Nut, Valve Lock 2
54 Spring, Valve 2
55 Starter Asm., Recoil 1
56 Bolt 3
57 Shroud 1
58 Shroud, Cylinder Body 1
59 Shield,Lower 1
60 Protector, Oil 1
61 Switch Asm., Stop Engine 1
62 Bolt 2
63 Bolt 1
64 Collar 1
65 Bolt 1
66 Bolt 4
67 Carburetor Asm. 1
68 Gasket, Air Cleaner 1
69 Gasket, Carburetor 1
70 Plate, Carburetor Insulator 1
71 Gasket, Carburetor Insulator 1
72 Nut 2
73 Cleaner, Air 1
74 Bolt 1
75 Gasket, Exhaust Outlet 1
76 Nut 2
77 Muffler Asm. 1
78 Tank, Fuel 1
79 Strainer, Fuel 1
80 Cover, Fuel Tank 1
81 Outlet Asm., Fuel Tank Oil 1
82 Collar 2
83 Tube, Fuel 1
84 Bolt 1
85 Nut 2
86 Nut, Flywheel 1
87 Pulley,Starter 1
88 Impeller 1
89 Flywheel Asm. 1
90 Bolt 2
91 Coil, Ignition 1
92 Control Asm., Throttle 1
93 Bolt 2
94 Spring, Governor 1
95 Rod, Governor 1
96 Spring, Throttle Valve Returning 1
97 Bolt, Governor Support 1
98 Nut 1
99 Support Asm., Governor 1
Record Product’s Serial Number Here:
Note: If product has no serial number,
record month and year of purchase instead.
Page 22 For technical questions, please call 1-800-520-0882. Horizontal Engines
Note: Some parts are listed and shown for
illustration purposes only, and are not available
individually as replacement parts.
Page 23
68120 212cc Assembly Diagram
56
56
56
55
80
79
88
78
85
85
82
82
81
83
84
21
99
98
97
92
96
94
95
16
22
15
17
18
19
89
20
91
13
18
17
61
63
60
64
87
90
90
66
66
66
57
65
59
86
62
73
66
58
62
72
72
SAFETYOPERATIONMAINTENANCE SETUP
93
93
28
27
28
29
25
26
31
31
31
31
31
24
30
31
77
76
14
23
32
40
36
34
33
76
23
42
49
47
47
48
48
33
35
39
1
38
37
8
75
8
11
10
3
2
46
41
54
54
43
44
45
9
10
10
50
50
51
51
52
52
53
53
9
7
6
71
12
10
4
5
5
5
5
74
68
67
69
70
Page 23For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 24
68121 212cc Parts List
Part Description Qty.
SAFETY OPERATION MAINTENANCESETUP
1 Gasket, Cylinder Head 1
2 Cover Asm., Cylinder Head 1
3 Gasket, Cylinder Head Cover 1
4 Tube, Breather 1
5 Bolt 4
6 Stud 1
7 Stud 1
8 Stud 2
9 Pin 2
10 Bolt, Cylinder Head 4
11 Plug, Spark 1
12 Head Asm., Cylinder 1
13 Crankcase Asm. 1
14 Sensor, Engine Oil 1
15 Gear Asm., Governor 1
16 Arm, Governor 1
17 Bolt, Drain Plug 2
18 Washer 2
19 Bearing 1
20 Seal, Oil 1
21 Washer 1
22 Pin 1
23 Bolt 2
24 Cover, Crankcase 1
25 Bearing 1
26 Seal, Oil 1
27 Gasket, Crankcase 1
28 Pin 2
29 Dipstick Asm., Oil 1
30 Plug Asm., Engine Oil 1
31 Bolt 6
32 Crankshaft Asm. 1
33 Clip, Piston Pin 2
34 Piston 1
35 Pin, Piston 1
36 Rod, Connecting 1
37 Ring, The First 1
38 Ring, The Second 1
39 Ring Set, Oil 1
40 Camshaft Asm. 1
41 Valve, Exhaust 1
42 Valve, Intake 1
43 Seat, Valve Spring 1
44 Retainer_ Exhaust Valve 1
45 Rotator, Valve 1
46 Guide, Seal 1
47 Tappet, Valve 2
48 Lifter, Valve 2
49 Plate Asm., Lifter Stopper 1
50 Bolt, Valve Adjusting 2
51 Rocker, Valve 2
52 Nut_ Valve Adjusting 2
53 Nut, Valve Lock 2
54 Spring, Valve 2
Part Description Qty.
55 Starter Asm., Recoil 1
56 Bolt 3
57 Shroud 1
58 Shroud, Cylinder Body 1
59 Shield,Lower 1
60 Protector, Oil 1
61 Switch Asm., Stop Engine 1
62 Bolt 2
63 Bolt 1
64 Collar 1
65 Bolt 1
66 Bolt 4
67 Carburetor Asm. 1
68 Gasket, Air Cleaner 1
69 Gasket, Carburetor 1
70 Plate, Carburetor Insulator 1
71 Gasket, Carburetor Insulator 1
72 Nut 2
73 Cleaner, Air 1
74 Bolt 1
75 Gasket, Exhaust Outlet 1
76 Nut 2
77 Muffler Asm. 1
78 Bolt 2
79 Gasket, Auxiliary Air Valve Flange 1
80 Valve, Muffler Auxiliary 1
81 Tank, Fuel 1
82 Strainer, Fuel 1
83 Cap, Fuel 1
84 Outlet Asm., Fuel Tank Oil 1
85 Clamp 4
86 Tube, Fuel 1
87 Bolt 1
88 Nut 2
89 Vent, Vapor 1
90 Hose, Vapor Rubber 1
91 Band 2
92 Collector, Vapor 1
93 Clamp 2
94 Hose, Air Cleaner Rubber 1
95 Nut, Flywheel 1
96 Pulley,Starter 1
97 Impeller 1
98 Flywheel Asm. 1
99 Bolt 2
100 Coil, Ignition 1
101 Control Asm., Throttle 1
102 Bolt 2
103 Spring, Governor 1
104 Rod, Governor 1
105 Spring, Throttle Valve Returning 1
106 Bolt, Governor Support 1
107 Nut 1
108 Support Asm., Governor 1
Page 24 For technical questions, please call 1-800-520-0882. Horizontal Engines
Page 25
68121 212cc Assembly Diagram
56
56
56
83
82
55
81
88
97
98
20
100
13
18
107
101
84
87
106
85
88
86
85
93
94
85
89
91
91
108
103
104
93
85
90
105
21
92
16
22
15
17
18
19
61
63
60
65
59
64
96
17
95
99
99
66
66
66
57
66
58
62
62
73
72
72
SAFETYOPERATIONMAINTENANCE SETUP
102
102
28
27
28
29
25
26
31
31
31
31
31
24
30
31
77
76
76
14
23
32
40
36
34
33
75
78
78
79
23
42
49
47
47
48
48
33
35
39
1
38
37
8
80
8
11
10
3
2
46
41
54
54
43
44
45
9
10
10
50
50
51
51
52
52
53
53
9
67
7
6
12
10
4
5
5
5
5
70
71
74
68
69
Page 25For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 26
68136 346cc Parts List
Part Description Qty.
SAFETY OPERATION MAINTENANCESETUP
1 Gasket, Cylinder Head 1
2 Cover Asm., Cylinder Head 1
3 Gasket, Cylinder Head Cover 1
4 Tube, Breather 1
5 Bolt Asm., Cylinder Head Cover 1
6 Stud 2
7 Stud 2
8 Pin 2
9 Bolt, Cylinder Head 4
10 Plug, Spark 1
11 Head Asm., Cylinder 1
12 Crankcase Asm. 1
13 Seal, Oil 1
14 Sensor, Engine Oil 1
15 Frame, Fuel Tank Installation 1
16 Plug, Rubber 1
17 Protector, Oil 1
18 Bolt 1
19 Washer_ Flat 2
20 Bolt, Drain Plug 2
21 Clip 1
22 Arm, Governor 1
23 Seal, Oil 1
24 Pin 1
25 Bolt 4
26 Bolt 2
27 Washer_ Flat 1
28 Bearing 1
29 Cover, Crankcase 1
30 Gasket, Crankcase 1
31 Plug Asm., Engine Oil 1
32 Dipstick Asm., Oil 1
33 Pin 2
34 Bolt 7
35 Bearing 1
36 Gear Asm., Governor 1
37 Seal, Oil 1
38 Bearing 1
39 Crankshaft Asm. 1
40 Shaft Asm., Balancing 1
41 Ring Set, Oil 1
42 Clip, Piston Pin 2
43 Piston 1
44 Pin, Piston 1
45 Rod, Connecting 1
46 Ring, The First 1
47 Ring, The Second 1
48 Camshaft Asm. 1
49 Valve, Exhaust 1
50 Valve, Intake 1
51 Seat, Valve Spring 1
52 Retainer, Exhaust Valve 1
53 Rotator, Valve 1
54 Guide, Seal 1
55 Tappet, Valve 2
56 Lifter Asm., Valve 2
Part Description Qty.
57 Plate Asm., Lifter Stopper 1
58 Bolt, Valve Adjusting 2
59 Rocker, Valve 2
60 Nut, Valve Adjusting 2
61 Nut, Valve Lock 2
62 Spring, Valve 2
63 Retainer, Valve Spring 1
64 Starter Asm., Recoil 1
65 Bolt 3
66 Shroud 1
67 Shroud, Cylinder Body 1
68 Bolt 1
69 Bolt 5
70 Carburetor Asm. 1
71 Gasket, Air Cleaner 1
72 Gasket, Carburetor 1
73 Plate, Carburetor Insulator 1
74 Gasket, Inlet 1
75 Nut 2
76 Cleaner, Air 1
77 Bolt 1
78 Nut 3
79 Gasket, Exhaust Outlet 1
80 Nut 2
81 Muffler Asm. 1
82 Gasket, Aux. Air Valve Flange 1
83 Valve, Muffler Aux. Air 1
84 Bolt 2
85 Tank, Fuel 1
86 Strainer, Fuel 1
87 Cover, Fuel Tank 1
88 Outlet Asm., Fuel Tank Oil 1
89 Collar 5
90 Tube, Fuel 1
91 Clamp 1
92 Nut 2
93 Valve, One Way 1
94 Hose, Fuel Vapor Rubber 1
95 Hose, Air Cleaner Rubber 1
96 Collector, Fuel Vapor 1
97 Bolt 2
98 Cover, Fuel Vapor Collector 1
99 Nut, Flywheel 1
100 Pulley,Starter 1
101 Impeller 1
102 Flywheel Asm. 1
103 Bolt 2
104 Coil, Ignition 1
105 Control Asm., Throttle 1
106 Bolt 2
107 Spring, Throttle Valve Returning 1
108 Rod, Governor 1
109 Support Asm., Governor 1
110 Nut 1
111 Bolt, Governor Support 1
112 Spring, Governor 1
Page 26 For technical questions, please call 1-800-520-0882. Horizontal Engines
Page 27
68136 346cc Assembly Diagram
65
65
65
65
69
64
107
108
109
111
110
112
105
106
97
98
96
97
87
86
89
89
85
94
93
92
88
27
24
89
95
92
89
91
89
25
15
25
90
25
40
33
30
33
18
17
20
21
106
22
23
28
25
39
48
16
19
13
14
26
26
45
101
102
104
12
19
20
49
8
8
1
42
7
44
66
99
100
103
55
50
7
67
103
55
56
56
6
6
11
69
69
69
69
68
76
77
75
75
71
SAFETYOPERATIONMAINTENANCE SETUP
43
32
37
34
34
34
34
34
34
36
38
35
29
31
34
42
81
79
78
78
78
80
84
82
84
83
80
9
41
47
10
46
63
62
52
9
70
9
53
5
74
9
57
54
58
58
62
59
60
59
51
60
61
61
2
72
73
4
3
Page 27For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 28
68306 420cc Parts List
SAFETY OPERATION MAINTENANCESETUP
Part Description Qty.
1 Gasket, Cylinder Head 1
2 Cover Asm., Cylinder Head 1
3 Gasket, Cylinder Head Cover 1
4 Tube, Breather 1
5 Bolt Asm., Cylinder Head Cover 1
6 Stud 2
7 Stud 2
8 Pin 2
9 Bolt, Cylinder Head 4
10 Plug, Spark 1
11 Head Asm., Cylinder 1
12 Crankcase Asm. 1
13 Seal, Oil 1
14 Sensor, Engine Oil 1
15 Frame, Fuel Tank 1
16 Plug, Rubber 1
17 Protector, Oil 1
18 Bolt 1
19 Washer_ Flat 2
20 Bolt, Drain Plug 2
21 Clip 1
22 Arm, Governor 1
23 Seal, Oil 1
24 Pin 1
25 Bolt 4
26 Bolt 2
27 Washer_ Flat 1
28 Bearing 1
29 Cover, Crankcase 1
30 Gasket, Crankcase 1
31 Plug Asm., Engine Oil 1
32 Dipstick Asm., Oil 1
33 Pin 2
34 Bolt 7
35 Bearing 1
36 Gear Asm., Governor 1
37 Seal, Oil 1
38 Bearing 1
39 Crankshaft Asm. 1
40 Shaft Asm., Balancing 1
41 Ring Set, Oil 1
42 Clip, Piston Pin 2
43 Piston 1
44 Pin, Piston 1
45 Rod, Connecting 1
46 Ring, The First 1
47 Ring, The Second 1
48 Camshaft Asm. 1
49 Valve, Exhaust 1
50 Valve, Intake 1
51 Seat, Valve Spring 1
52 Retainer, Exhaust Valve 1
53 Rotator, Valve 1
54 Guide, Seal 1
55 Tappet, Valve 2
56 Lifter Asm., Valve 2
57 Plate Asm., Lifter Stopper 1
58 Bolt, Valve Adjusting 2
59 Rocker, Valve 2
60 Nut, Valve Adjusting 2
61 Nut, Valve Lock 2
Part Description Qty.
62 Spring, Valve 2
63 Retainer, Valve Spring 1
64 Starter Asm., Recoil 1
65 Bolt 4
66 Shroud 1
67 Shroud, Cylinder Body 1
68 Bolt 1
69 Bolt 5
70 Carburetor Asm. 1
71 Gasket, Air Cleaner 2
72 Gasket, Carburetor 1
73 Plate, Carburetor Insulator 1
74 Gasket, Inlet 1
75 Nut 2
76 Cleaner, Air 1
77 Bolt 1
78 Nut 3
79 Gasket, Exhaust Outlet 1
80 Nut 2
81 Muffler Asm. 1
82 Gasket, Aux. Air Intake Valve 1
83 Valve, Aux. Air Intake 1
84 Bolt 2
85 Tank, Fuel 1
86 Strainer, fuel 1
87 Cover, Fuel Tank 1
88 Outlet Asm., Fuel Tank Oil 1
89 Collar 5
90 Tube, Fuel 1
91 Clip 1
92 Nut 2
93 Valve, One Way 1
94 Hose, Fuel Vapor Rubber 1
95 Hose, Air Cleaner Rubber 1
96 Collector, Fuel Vapor 1
97 Bolt 2
98 Cover, Fuel Vapor Collector 1
99 Nut, Flywheel 1
100 Pulley, Starter 1
101 Impeller 1
102 Flywheel Asm. 1
103 Bolt 1
104 Cap, Spark Plug 1
105 Coil Asm., Charge 1
106 Bolt 2
107 Coil, Ignition 1
108 Bolt 2
109 Control Asm., Throttle 1
110 Bolt 2
111 Spring, Throttle Returning 1
112 Rod, Governor 1
113 Support Asm., Governor 1
114 Nut 1
115 Bolt, Governor Support 1
116 Spring, Governor 1
117 Motor Asm.,Starting 1
118 Bolt 2
119 Relay, Starting 1
120 Bolt 2
121 Switch,Control 1
122 Bolt 2
Page 28 For technical questions, please call 1-800-520-0882. Horizontal Engines
Page 29
68306 420cc Assembly Diagram
119
65
65
65
65
120
117
118
118
122
121
112
115
114
116
97
87
86
32
37
34
34
34
34
34
109
98
96
97
89
93
89
85
34
94
92
92
88
38
34
122
111
113
110
110
27
24
89
95
89
91
89
90
33
33
36
35
29
31
25
25
40
30
21
22
23
28
25
15
25
39
48
64
101
102
18
17
20
16
107
19
13
12
19
20
50
49
8
14
26
45
42
81
79
78
78
8
1
26
42
7
44
7
43
9
41
46
9
47
10
63
62
52
53
69
66
99
100
108
108
55
55
56
56
6
6
11
9
9
57
54
58
58
62
59
51
60
61
2
69
69
67
70
74
73
59
60
61
4
3
69
69
68
76
77
72
75
75
71
SAFETYOPERATIONMAINTENANCE SETUP
80
84
82
80
83
84
5
Page 29For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 30
Mounting Hole Diagrams
Note: Not to scale.
SAFETY OPERATION MAINTENANCESETUP
ITEM 68120 / 68121 212cc
6.38 in. / 162mm
2.6 in. / 66mm
ITEM 68136 346cc and ITEM 68306 420cc
7.72 in. / 196mm
4.13 in. / 105mm
1.6 in. / 40.5mm
2.97 in. / 75.5mm
3.17 in. / 80.5mm
4.06 in. / 103mm
3.39 in. / 86mm
Page 30 For technical questions, please call 1-800-520-0882. Horizontal Engines
Page 31
Power Take-Off Diagrams
Note: Not to scale.
ITEM 68120 / 68121 212cc
4x5/16-24UNF
5/16-24UNF
0.1875 in. / 4.78mm
Ø3.625 in. / 92mm
4.17 in. / 106mm
Ø0.75 in. / 19.05mm
0.64 in.
/ 16.36mm
ITEM 68136 346cc and ITEM 68306 420cc
2.43 in. / 61.7mm
1.79 in. / 45.5mm
0.67 in.
/ 17mm
SAFETYOPERATIONMAINTENANCE SETUP
5/16-24UNF
Ø3.625 in. / 92mm
Ø6.5 in. / 165.1mm
Ø5.75 in.
/ 146mm
Ø5 in. /
127mm
(30°)
(30°)
5.25 in. / 133.5mm
(45°)
(45°)
0.25 in. / 6.35mm
Ø1 in. / 25.4mm
0.36 in. / 9.13mm
3.48 in. / 88.5mm
Ø1.17 in. / 29.7mm
2.2 in. / 56mm
2.84 in. / 72.2mm
3/8-24UNF
1.1 in. / 28mm
Page 31For technical questions, please call 1-800-520-0882.Horizontal Engines
Page 32
3491 Mission Oaks Blvd. • PO Box 6009 • Camarillo, CA 93011 • (800) 520-0882
www.harborfreight.com
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