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Adjust Idle Speed Screw
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l
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
screwdriver in between the Air
Filter Cover and the Engine
Cover (Fig. 27). Turn the idle
speed screw in, clockwise, 1/8
Fig. 27
of a turn at a time (as needed)
until the engine idles smoothly.
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 unit serviced by a Sears or other qualified service dealer.
ROCKER ARM CLEARANCE
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l
unit off and allow it to cool before cleaning or servicing it.
This requires disassembly
of the engine. If you feel unsure or unqualified to
perform this task, take the unit to a Sears or other qualified service dealer.
NOTE:
Inspect the valve to rocker arm clearance with a feeler gauge per
the Maintenance
Schedule.
• 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 seven (7) screws
on the back of the engine
cover with an appropriate
screwdriver
(Fig. 28).
2.
Disconnect
the spark plug
wire.
Fig. 28
3.
Clean dirt from around the
spark plug. Remove the
Rocker
Arm
_q['------
Screw
spark plug from the cylinder
cover
head by turning a 5/8 in.
socket counterclockwise.
4.
Remove the engine cover
(Fig. 28).
5.
Clean dirt from around the
rocker arm cover. Remove the
screw holding the rocker arm
SparkPlug
cover with an appropriate
Hole
screwdriver (Fig. 29). Remove
Fig. 29
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. Look in the spark plug hole to view
the piston (Fig. 29).
• Both rocker arms move freely, and both valves are closed.
If these statements
are not true, repeat step 6 until positions
are correct.
7.
Slide the feeler gauge between the rocker arm and the top of each
valve stem. Measure the clearance between the valve stem and rocker
arm (Fig. 30). 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 30 and 31.
8.
If the clearance
is not within
AdjustingNuts
specification:
a. Turn the adjusting nut using
a 5/16 inch (8 mm) wrench
INTAKE
or nut driver (Fig. 30).
EXHAUST
° To increase clearance, turn
the adjusting nut
Rocker
counterclockwise.
Arms
° To decrease clearance,
turn the adjusting nut
clockwise.
b. Recheck both clearances,
Fig. 30
and adjust as necessary.
9.
Reinstall the rocker arm
__
!
cover using a new gasket.
Feeler
Gauge
Torque the screw to 20-30
in*lb (2.2-3.4 N*m).
0.003-0.006
in.
10.
Check the spark plug and
reinstall. See Replacing the
(0.076-0.152
r am)"
Spark Plug.
11.
Replace the spark plug wire.
12.
Reinstall the engine cover.
Check alignment
of the
cover before tightening
the
Fig. 31
screws. Tighten screws.
REPLACING
THE SPARK PLUG
Use a Champion
RDZ4H or a replacement
part number 753-05784 spark
plug. The correct air gap is 0.025 in. (0.635 mm.). Remove the plug and
check its condition per the Maintenance
Schedule.
1.
Stop the engine and allow it to cool. Remove the eight (7) screws on the
back of the engine cover with an appropriate
screwdriver (Fig. 28).
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.
i
oonots nd st
so eo oe
in the engine could damage the cylinder.
4.
Replace cracked, fouled or
dirty spark plug. Set the air
gap at 0.025 in. (0.635 mm.)
using a feeler gauge (Fig. 32).
5.
Install a correctly-gapped
spark plug in the cylinder
head. Turn the 5/8 in. socket
clockwise
until snug.
6.
Reconnect spark plug and
engine cover
If using a torque wrench torque to:
110-120 in.°lb. (12.3-13.5 N=m)
Do not overtighten.
SPARK ARRESTOR
MAINTENANCE
0.025 in.
(0.635 mm)
t
Fig. 32
I _
I WARNING:
To avoid serious personal injury, alway sturn the
unit off and allow it to cool before cleaning or servicing it.
Inspect the spark arrestor per the
Muffler
Spark Arrestor
Maintenance
Schedule.
\
_-I
Screen
rear engine
/
Cover
1.
Remove the
cover. See Rocker Arm
_ --
/
T-25
Clearance.
r_
_J_
Screw
2.
With an appropriate
screwdriver,
remove the 2
_h_ _)
,:_,_
screws attaching the spark
arrestor cover to the muffler
Slot
(Fig. 33).
T-20
Screw
i" _3w'_
3.
Pull the tab on the spark
arrestor cover out of the
Fig. 33
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 screws.
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