Predator Engines PREDATOR 212 Assembly instructions

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Email our technical support at: [email protected]
ITEMS 68120, 68121,
68136, 68306
Read this material before using this product.
Failure to do so can result in serious injury.
SAVE THIS MANUAL.
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.
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.
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.
Owner’s Manual & Safety Instructions
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.
Only use OUTSIDE
and far away from
windows, doors,
and vents.
Manual Revised 11k

Page 2 For technical questions, please call 1-800-520-0882. Horizontal Engines
Table of Contents
Specifications ............................................. 2
Safety ......................................................... 3
Setup .......................................................... 6
Operation.................................................... 8
Maintenance.............................................. 14
Troubleshooting......................................... 18
Warranties ................................................. 20
Parts Lists and Diagrams .......................... 22
Specifications
Description 68120, 68121 68136 68306
Displacement 212cc 346cc 420cc
Engine Type Horizontal Single Cylinder 4 stroke OHV
Cooling System Forced air cooled
Fuel Type 87+ octane unleaded gasoline
Capacity 1 Gallon 1 Gallon 1 Gallon
Engine Oil Type SAE 10W-30 above 32° F
5W30 at 32° F or below
Capacity 0.5 Quart 1.16 Quart 1.16 Quart
Run Time @ 50% Load
with full tank 3 hr.
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) Counterclockwise
Shaft
Shaft 3/4″ x 2.41″ 1″ x 3.48″ 1″ x 3.48″
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
Spark Plug Type NGK®BP-6ES
NHSP® / Torch®F6TC NHSP® / Torch®F6TC NHSP® / Torch®F6TC
Gap 0.7 - 0.8 mm
Valve Clearance Intake 0.10 - 0.15 mm
Exhaust 0.15 - 0.20 mm
Speed Idle 1,800 ± 50 RPM
SAFETY OPERATION MAINTENANCESETUP

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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.
Indicates a hazardous situation which, if not avoided,
could result in minor or moderate injury.
Addresses practices not related to personal injury.
Symbol Definitions
Symbol Property or Statement
RPM Revolutions Per Minute
HP 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.
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.
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
SAFETYOPERATIONMAINTENANCE SETUP

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Set up Precautions
1. Gasoline fuel and fumes are flammable, and
potentially explosive. Use proper fuel storage
and handling procedures. Do not store fuel
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.
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.
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.
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.
SAFETY OPERATION MAINTENANCESETUP

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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.)
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.
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.
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.
SAVE THESE INSTRUCTIONS.
Operating Precautions (cont.)
SAFETYOPERATIONMAINTENANCE SETUP

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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.
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.
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.
Battery Setup Instructions
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
65′
47′
212′
3.
Starting Relay
Motor Starter Assembly
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.
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.
REV 11j
SAFETY OPERATION MAINTENANCESETUP

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Engine Controls
Starter
Handle
Oil Drain Plug
Air Filter
Fuel Valve
Choke
Fuel Cap
Throttle
Engine
Switch
(Electric
Start Models)
Muffler
Dipstick
Starter
(Electric
Start Models)
Serial
Number
Location
(Write on front
cover of manual.)
Engine
Switch
(Manual Start
Models)
SAFETYOPERATIONMAINTENANCE SETUP

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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.
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.
4.
Full level
Full level
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.
SAFETY OPERATION MAINTENANCESETUP

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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.
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.
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.
SAFETYOPERATIONMAINTENANCE SETUP

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Manual Start
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.
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.
4. Turn the Engine Switch on.
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.
CHOKE RUN
1
2
3
OI
ON
4
5
ON
OFF
SAFETY OPERATION MAINTENANCESETUP

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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.
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
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.
CHOKE RUN
6
OI
OFF
SAFETYOPERATIONMAINTENANCE SETUP

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Electric Start (if equipped)
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.
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.
4. Turn the Engine Switch to START.
CHOKE RUN
1
2
3
ON
OFF START 4START
SAFETY OPERATION MAINTENANCESETUP

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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.
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
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.
CHOKE RUN
5
OFF
SAFETYOPERATIONMAINTENANCE SETUP

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Maintenance
WARNING
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.
Procedure Before
Each Use
Monthly or
every 20
hr. of use
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
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 **
*Service more frequently when used in dusty areas.
**These items should be serviced by a qualified technician.
SAFETY OPERATION MAINTENANCESETUP

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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. 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.
Engine Oil Change
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.
7.
Full level
Full level
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.
10W-30
30
5W-30
-20 0 20 40 60 80 100°F
SAE Viscosity Grades
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

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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:
• 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
1.
Spark
Plug
Cap
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
Brand 68120, 68121 68136 68306
NGK®BP-6ES
NHSP® / TORCH®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.
SAFETY OPERATION MAINTENANCESETUP

Page 17For technical questions, please call 1-800-520-0882.Horizontal Engines
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.
b.
Drain Plug
Sediment Cup
(some engines)
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 18 For technical questions, please call 1-800-520-0882. Horizontal Engines
Troubleshooting
Problem Possible Causes Probable Solutions
Engine will not start FUEL RELATED:
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.
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. 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.
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. 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.
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.
SAFETY OPERATION MAINTENANCESETUP

Page 19For technical questions, please call 1-800-520-0882.Horizontal Engines
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.
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.)
Engine stops
suddenly
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. 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.
Engine stops when
under heavy load
1. Dirty air filter
2. Engine running cold.
1. Clean or replace element.
2. Allow engine to warm up prior
to operating equipment.
Engine knocks 1. Old or low quality gasoline.
2. Engine overloaded.
3. Incorrect spark timing, deposit
buildup, worn engine, or other
mechanical problems.
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.
Engine backfires 1. Impure or low quality gasoline.
2. Engine too cold.
3. Intake valve stuck or overheated engine.
4. Incorrect timing.
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.
Follow all safety precautions whenever diagnosing or servicing the equipment or engine.
SAFETYOPERATIONMAINTENANCE SETUP

Page 20 For technical questions, please call 1-800-520-0882. Horizontal Engines
Warranties
Limited 90 Day Warranty
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.
SAFETY OPERATION MAINTENANCESETUP