The recommended clearance for the intake and exhaust is 0.003 –
0.006 in. (0.076 – 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.
Exhaust
Adjusting Nut
Exhaust
Clearance:
.003-.006 in.
(.076-0.152 mm)
Intake Valve
Stem
Intake Clearance:
.003–.006 in.
(.076–0.152 mm)
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. 31).
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. (0.635 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.
2. Clean dirt from around the spark plug. Remove the spark plug
from the cylinder head by turning a 5/8 in. socket
WARNING:
Do not sand blast, scrape or clean
electrodes. Grit in the engine could damage the
cylinder.
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. 36).
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, 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.
MAINTENANCE AND REPAIR INSTRUCTIONS
Exhaust
Rocker Arm
Feeler Gauge
Exhaust Valve Stem
Fig. 35
0.025 in.
(0.635 mm.)
Fig. 36
Muffler
Slot
CLEANING
WARNING:
turn your unit off and allow it to cool before you clean or
service it.
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.
12
Spark Arrestor Screen
Tab
Spark Arrestor Cover
Fig. 37
To avoid serious personal injury, always
Screw