Craftsman 316.79191 - Manual (Page 13)

13
MAINTENANCE AND REPAIR INSTRUCTIONS
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. See Figures 36 and 37.
8.
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.
9. Reinstall the rocker arm cover using a new gasket. Torque the
screw to 20–30 in•lb (2.2–3.4 N•m).
10. Check the spark plug and reinstall. See Replacing the Spark Plug.
11. Replace the spark plug wire.
12. Reinstall the engine cover. Check alignment of the cover before
tightening the screws. Tighten screws.
REPLACING THE SPARK PLUG
Use a replacement part number 753-05255 or Champion spark
plug, #RDZ19H. 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.
Remove the six (6) screws on the
back of the engine cover with a
Flat-head or T-25 Torx screwdriver
(Fig. 34).
2. Grasp the plug wire firmly and pull
the cap from the spark plug.
3. Clean dirt from around the spark plug. Remove the spark plug
from the cylinder head by turning a 5/8 in. socket
counterclockwise.
4. Replace cracked, fouled or dirty spark plug. Set the air gap at
0.025 in. (0.635 mm.) using a feeler gauge (Fig. 38).
5. 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 rear
engine 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 the spark arrestor diverter out of the muffler. Remove
the spark arrestor diverter.
4. Remove the spark arrestor screen from the spark arrestor
diverter.
5. Clean the spark arrestor screen with a wire brush or replace it.
6. Reinstall the spark arrestor screen, spark arrestor diverter and
screws.
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.
REPLACEMENT LINE
Adjusting Nuts
Feeler Gauge
Rocker Arms
Fig. 36
INTAKE
EXHAUST
Feeler Gauge
Adjusting Nut
Rocker Arm
.003–.006 in.
(.076–.152 mm)
Valve Stem
Fig. 37
0.025 in.
(0.635 mm)
Fig. 38
WARNING: Do not sand blast, scrape or clean
electrodes. Grit in the engine could damage the
cylinder.
WARNING: To avoid serious personal injury, always
turn your unit off and allow it to cool before you clean or
service it.
Fig. 39
Muffler
Spark Arrestor
Screen
T-30 Screw
T-25
Screw
Slot
Spark Arrestor
Cover