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Spark Plug
Maintenance Interval
• The spark plug should be removed from the
engine and checked after each 25 hours of opera-
tion.
• Replace the spark plug after every 100 hours of
operation.
Spark Plug Maintenance
1.
Twist the high tension lead boot on the spark plug
back and forth a couple of times to loosen the
boot, then pull the boot off of the spark plug.
2.
Remove the spark plug.
3.
Clean the electrodes with a stiff brush.
4.
Adjust the electrode air gap to .024-.028 in (0.6-
0.7 mm).
5.
Replace the spark plug if it is oil-fouled, damaged,
or if the electrodes are worn down.
6.
Do not overtighten the spark plug when installing.
The tightening torque is 95-148 in. lbs. (10.7-16.6
N·m).
7.
Always use only the specific heat range of spark
plug. This is particularly critical with today's low-
emission engines. For best results, use the exact
replacement.
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.024" - .028" (0.6 - 0.7 mm)
Cylinder Cooling Fins
Maintenance Interval
The cylinder cooling fins should be cleaned after every
25 hours of operation, or once a week, whichever
comes first.
Air must flow freely around and through the cylinder
cooling fins to prevent engine overheating. Leaves,
grass, dirt and debris buildup on the fins will increase
the operating temperature of the engine, which can
reduce engine performance and shorten engine life.
Cooling Fin Cleaning
1.
With the engine at ambient (room) temperature,
loosen the knob and remove the air filter cover.
Knob
High Tension Lead Boot
Air filter Cover
Knob
2.
Twist the high tension lead boot on the spark plug
back and forth a couple of times to loosen the
boot, then pull the boot off of the spark plug.
3.
Loosen the knob and lift off the cylinder cover.
4.
Clean all dirt and debris from the cooling fins and
from around the cylinder base.
— US-26 —
Cylinder Cover
Cooling Fins
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