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10
MAINTENANCE AND REPAIR INSTRUCTIONS
WARNING: To avoid serious personal injury, always
turn your unit off and allow it to cool before you clean or
service it.
The recommended clearance for the intake and exhaust is .003 – .006
in. (.076 – 0.152 mm). Use a standard automotive feeler gauge at .005
(0.127mm). The feeler gauge should slide between the rocker arm and valve
stem with a slight amount of resistance, without binding. Figure 35 shows
how to measure the clearance.
10. If the clearance is not within specification:
a. Turn the adjusting nut using a 5/16 inch (8 mm) wrench or nut
driver (Fig. 35).
• To increase clearance, turn the adjusting nut counterclockwise.
• To decrease clearance, turn the adjusting nut clockwise.
b. Recheck both clearances, and adjust as necessary.
11. Reinstall the rocker arm cover using a new gasket. Torque the
screw to 20–30 in•lb (2.2–3.4 N•m).
12. Reinstall the engine cover. Check alignment of the cover before
tightening the screws. Tighten screws.
13. Reinstall the muffler cover. Slip the rear tab on the muffler cover
into the engine cover rear slot. Then slide the remaining slots into
the tabs until they snap into place (Fig. 30).
14. Check the spark plug and reinstall. See Replacing the Spark Plug.
15. 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. (0.655 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.
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. (0.655
mm.) using a feeler gauge (Fig. 36).
4. Install a correctly-gapped spark plug
in the cylinder head. Turn the 5/8 in.
socket clockwise until snug.
Adjusting Nuts
Feeler Gauge
Rocker Arms
Fig. 34
INTAKE
EXHAUST
Fig. 35
Feeler Gauge
Exhaust
Adjusting Nut
Exhaust
Rocker Arm
Exhaust Valve Stem
Intake Valve
Stem
.003–.006 in.
(.076–0.152 mm)
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, remove the screw
attaching the spark arrestor cover to the muffler (Fig. 37).
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 1 oz. (30
ml) of high quality motor oil into the cylinder. Pull the starter rope
slowly to distribute the oil. Reinstall the spark plug.
NOTE: Remove the spark plug and drain all of the oil from the
cylinder before attempting to start the 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.
0.025 in.
(0.655 mm.)
Fig. 36
Fig. 37
Muffler
Spark Arrestor Screen
Spark Arrestor Cover
Screw
Tab
Slot
WARNING: Do not sand blast, scrape or clean
electrodes. Grit in the engine could damage the cylinder.