3.
Clean the electrodes with a stiff brush.
.024" - .028" (0.6 - 0.7 mm)
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.
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 cylin-
der 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.
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-23 —
Knob
Cylinder Cover
Cooling Fins