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2. Clean dirt from around the spark plug. Remove the spark
plug from the cylinder head by turning a 5/8 in. socket
counterclockwise.
3. Replace cracked, fouled or dirty spark plug. Set the air gap
at 0.025 in. (0.635 mm.) using a feeler gauge (Fig. 38).
4. Install a correctly-gapped spark plug in the cylinder head.
Turn the 5/8 in. socket clockwise until snug.
If using a torque wrench torque to:
110-120 in.•lb. (12.3-13.5 N•m)
Do not over tighten.
SPARK ARRESTOR MAINTENANCE
1. Remove the muffler cover. See Rocker Arm Clearance.
2. With a flat blade screwdriver or Torx T-20 bit and a T-25 bit,
remove the screws attaching the spark arrestor diverter to
the muffler (Fig. 39).
3. Pull the tab on the spark arrestor cover out of the muffler.
Remove the spark arrestor cover.
4.
Remove the spark arrestor screen from the spark arrestor cover.
5. Clean the spark arrestor screen with a wire brush or replace it.
6.
Reinstall the spark arrestor screen, spark arrestor cover and screw.
CLEANING
Use a small brush to clean off the outside of the unit. Do not use strong detergents. Household cleaners
that contain aromatic oils such as pine and lemon, and solvents such as kerosene, can damage plastic
housing or handle. Wipe off any moisture with a soft cloth.
STORAGE
• Never store the unit with fuel in the tank where fumes may reach an open flame or spark.
• Allow the engine to cool before storing.
• Lock up the unit to prevent unauthorized use or damage.
• Store the unit in a dry, well-ventilated area.
• Store the unit out of the reach of children.
LONG TERM STORAGE
1. Drain all gasoline from the gas tank into a container. Do not use gas that has been stored for more
than 60 days. Dispose of the old gasoline in accordance to Federal, State, and Local regulations.
2. Start the engine and allow it to run until it stalls. This ensures that all gasoline has been drained
from the carburetor.
3. Allow the engine to cool. Remove the spark plug and put 5 drops of high quality motor oil into the
cylinder. Pull the starter rope slowly to distribute the oil. Reinstall the spark plug.
NOTE: Remove the spark plug and drain all of the oil from the cylinder before attempting to start the
trimmer after storage.
4. Change the oil, referring to Changing the Oil. Dispose of the old oil in accordance to Federal, State
and Local regulations.
5. Thoroughly clean the unit and inspect for any loose or damaged parts. Repair or replace damaged
parts and tighten loose screws, nuts or bolts. The unit is ready for storage.
TRANSPORTING
• Allow the engine to cool before transporting.
• Secure the unit while transporting.
• Drain the gas tank before transporting.
• Tighten gas cap before transporting.
Muffler
Fig. 39
Slot
Fig. 38
0.025 in.
(0.635 mm.)
WARNING:
To avoid serious personal injury, always turn the unit off and allow it to cool
before you clean or service it.
Spark Arrestor
Screen
Diverter
T-25
Screw
T-20 Screw
6
MAINTENANCE AND REPAIR INSTRUCTIONS
If, after checking the fuel and cleaning the air filter, the engine still
will not idle, adjust the idle speed screw as follows:
1. Start the engine and let it run at a high idle for a minute to
warm up. Refer to Starting/Stopping Instructions.
2.
Release the throttle trigger and let the engine idle. If the engine
stops, insert a small phillips or flat blade screwdriver into the hole
in the air filter/muffler cover (Fig. 32). Turn the idle speed screw in,
clockwise, 1/8 of a turn at a time (as needed) until the engine
idles smoothly.
3. If the engine appears to be idling too fast, turn the idle speed
screw counterclockwise 1/8 of a turn at a time (as needed),
to reduce idle speed.
Checking the fuel, cleaning the air filter, and adjusting the idle
speed should solve most engine problems. If not and all of the
following are true:
• the engine will not idle
• the engine hesitates or stalls on acceleration
• there is a loss of engine power
Have the carburetor adjusted by an authorized service dealer.
ROCKER ARM CLEARANCE
This requires disassembly of the engine. If you feel unsure or unqualified
to perform this, take the unit to an authorized service center.
NOTE: Inspect the valve to rocker arm clearance with a
feeler gauge after the first 10 hours of operation and
then every 25 hours of operation thereafter.
• The engine must be cold when checking or adjusting the valve
clearance.
• This task should be performed inside in a clean, dust free area.
1. Remove the five (5) screws on back of the engine cover
with a Flat-head or T-20 Torx screwdriver (Fig. 33).
2. Remove the screw behind the engine cover with a Flat-
head or T-25 Torx screwdriver (Fig. 34).
3. Disconnect the spark plug wire.
4. Clean dirt from around the spark plug. Remove the spark
plug from the cylinder head by turning a 5/8 in. socket
counterclockwise.
5. Remove the engine cover (Fig. 33 & 34).
6. Clean dirt from around the rocker arm cover. Remove the
screw holding the rocker arm cover with a large flat blade
screwdriver or Torx T-25 bit (Fig. 35). Remove the rocker
arm cover and gasket.
7. Pull the starter rope slowly to bring the piston to the top of
its travel, (known as top dead center). Check that:
• The piston is at the top of its travel while looking in the
spark plug hole (Fig. 36)
• Both rocker arms move freely, and both valves are closed
If these statements are not true, repeat this step.
8. Slide the feeler gauge between the rocker arm and the
valve return spring. Measure the clearance between the
valve stem and rocker arm (Fig. 37). Measure both the
intake and exhaust valves.
The recommended clearance for both intake and exhaust is .003 – .006 in.
(.076 – 0.152 mm). Use a standard automotive .005 in. (0.127 mm) feeler
gauge. The feeler gauge should slide between the rocker arm and valve
stem with a slight amount of resistance, without binding. Figure 38 and 39
show how to measure the clearance.
9. If the clearance is not within specification:
a. Turn the adjusting nut using a 5/16 inch (8 mm) wrench or nut
driver (Fig. 37).
• To increase clearance, turn the adjusting nut
counterclockwise.
• To decrease clearance, turn the adjusting nut clockwise.
b. Recheck both clearances, and adjust as necessary.
10. Reinstall the rocker arm cover using a new gasket. Torque
the screw to 20–30 in•lb (2.2–3.4 N•m).
11. Reinstall the engine cover. Check alignment of the cover
before tightening the screws. Tighten screws.
12.
Check the spark plug and reinstall. See Replacing the Spark Plug.
13. Replace the spark plug wire.
REPLACING THE SPARK PLUG
Use a replacement part number 791-180852B spark plug. The
correct air gap is 0.025 in. (0.635 mm.). Remove the plug after
every 25 hours of operation and check its condition.
1. Stop the engine and allow it to cool. Grasp the plug wire
firmly and pull the cap from the spark plug.
Fig. 29
Air Filter Cover
Fig. 31
Cover Hinge
Slots
Fig. 30
Back Plate
Idle Ajustment Screw
Fig. 32
Remove
Screws
Fig. 33
Muffler
Fig. 34
Screw
Rocker Arm Cover
Fig. 35
Spark Plug Hole
Adjusting Nuts
Fig. 36
INTAKE
Exhaust Valve
Stem
Fig. 37
Exhaust
Adjusting Nut
WARNING:
To avoid serious personal injury,
always turn the unit off and allow it to cool
before you clean or service it.
WARNING:
To avoid serious personal injury,
always turn the unit off and allow it to cool
before you clean or service it.
CAUSE ACTION
Empty fuel tank Fill fuel tank with fuel
Primer bulb wasn't pressed enough Press primer bulb fully and slowly 10 times
Old fuel Drain gas tank and add fresh fuel
Fouled spark plug Replace or clean the spark plug
Plugged spark arrestor Clean or replace spark arrestor
When it is above 40°F outside & the Cold Weather
Start Lever is in the CLOSED / START position
Flip the Cold Weather Start Lever to RUN /
OPEN
When it is below 40°F outside & the Cold Weather
Start Lever is in the RUN / OPEN position
Flip the Cold Weather Start Lever to CLOSED /
START and follow the Starting Instructions
CAUSE ACTION
Air filter is plugged Replace or clean the air filter
Old fuel Drain gas tank and add fresh fuel
Improper carburetor adjustment
Adjust according to the Carburetor Adjustments
section or take to an authorized service dealer
for an adjustment
CAUSE ACTION
Old fuel Drain gas tank and add fresh fuel
Improper carburetor adjustment
Adjust according to the Carburetor Adjustments
section or take to an authorized service dealer
for an adjustment
Cutting attachment bound with grass Stop the engine and clean the cutting attachment
Dirty air filter Clean or replace the air filter
Plugged spark arrestor Clean or replace spark arrestor
TROUBLESHOOTING
ENGINE WILL NOT START
ENGINE WILL NOT ACCELERATE
ENGINE WILL NOT IDLE
Feeler
Gauge
Exhaust
Rocker Arm
0.003–0.006 in.
(0.076–0.152 mm)
Intake Valve
Stem
Feeler
Gauge
Rocker Arms
EXHAUST
Engine
Cover
Remove Screws
MAINTENANCE AND REPAIR INSTRUCTIONS