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4.
Apply enough clean SAE 30
motor oil to lightly coat the
filter (Fig. 21).
5.
Squeeze the filter to spread
and remove excess oil (Fig. 22).
6.
Replace the filter (Fig. 19).
NOTE:
Operating the unit
without the air filter, will
VOID the warranty.
7.
Reinstall the air filter cover.
Position the slots on the top
of the air filter cover onto the
tabs at the top of the back
plate (Fig. 19).
8.
Swing the cover down until
the tab on the air filter
backplate snaps into place in
the slot on the air filter cover
(Fig. 19).
IDLE SPEED ADJUSTMENT
The idle speed of the engine is
adjustable. An idle adjustment screw is between the air filter cover and the
engine starter housing (Fig. 23).
NOTE:
Careless adjustments can seriously damage the unit. Aside from
idle speed, only a Sears or other qualified service dealer should
make carburetor adjustments.
First, Check Fuel
Old fuel is usually the reason for improper unit performance. Drain and refill
the tank with fresh fuel prior to making any adjustments. Refer to Oil and
Fuel Information.
Second, Clean Air Filter
The condition of the air filter is important to the operation of the unit. A dirty
air filter will restrict air flow. This is often mistaken for an out of adjustment
carburetor. Check the condition of the air filter before adjusting the idle
speed screw. Refer to Air Filter Maintenance.
Third, Adjust Idle Speed Screw
WARNING:
The cutting attachment may spin during idle speed
adjustments. Wear protective clothing and observe all safety
instructions to prevent serious personal injury.
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 in between the Air Filter Cover and
the Engine Cover (Fig. 23). Turn the idle speed screw in, clockwise, 1/8
of a turn at a time (as needed) until the engine idles smoothly.
NOTE:
The cutting attachment should not rotate when the engine idles.
3.
If the cutting attachment rotates when the engine idles, 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 any of the following are true have the
unit serviced by a Sears or other qualified service dealer:
• the engine will not idle
• the engine hesitates or stalls on acceleration
• there is a loss of engine power
ROCKER ARM CLEARANCE
WARNING:
To avoid serious personal injury, always turn the
unit off and allow it to cool before cleaning or maintaining it.
This requires disassembly of the engine. If unsure or unqualified to perform this,
take the unit to a Sears or other qualified service dealer.
NOTE:
Inspect the valve to rocker arm clearance with a feeler gauge after
the first 10 hours of operation and every 40 hours of operation.
• 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 six (6) screws on the back of the engine cover with a Flat-
head or T-25 Torx screwdriver (Fig. 24).
MAINTENANCE & REPAIR INSTRUCTIONS
Fig. 21
Fig. 22
Idle Adjustment
Screw
Fig. 23
2.
Disconnect the spark plug wire.
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.
Remove the engine cover
(Fig. 24).
5.
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. 25). Remove the rocker
arm cover and gasket.
6.
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. This should be done by
looking into the spark plug hole.
(Fig. 25)
• Both rocker arms move freely,
and both valves are closed
If these statements are not true,
repeat step 6.
7.
Slide the feeler gauge between
the rocker arm and the valve
return spring. Measure the
clearance between the valve
stem and rocker arm (Fig. 27).
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. See Figures 26 and 27.
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. 27).
• 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
Champion
Use a replacement
is 0.025 in. (0.635 mm). Remove the plug after every 40 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. 24).
WARNING:
Do not sand blast, scrape or clean spark plug
electrodes. Grit in the engine could damage the cylinder.
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
8
View of the Rear Engine Cover
Screws
Fig. 24
Screw
Rocker Arm
Cover
Spark Plug
Hole
Fig. 25
Adjusting Nuts
INTAKE
Rocker
Arms
Fig. 26
Exhaust
Rocker Arm
Adjusting
Nut
0.003–0.006 in.
(0.076–0.152 mm)
Fig. 27
®
#RDZ4H spark plug
. The correct air gap
0.025 in.
(0.635 mm)
Fig. 28
Screws
EXHAUST
Feeler
Gauge
Valve Stem
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