Spark Plug; Cylinder Cooling Fins - Maruyama M42BK-QC Manuel Du Propriétaire

Spark Plug

Maintenance Interval
● The spark plug should be removed from the engine
and checked after each 25 hours of operation.
● 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-
0.7mm).
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
lowemission engines. For best results, use the
exact replacement.
.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.
2. Loosen the knob and lift off the cylinder cover.
3. Clean all dirt and debris from the cooling fins and
from around the cylinder base.
4. DO NOT overlook cleaning of the cooling air
intake area below the crankcase and above the
fuel tank! This area must be free of debris and
obstruction for the engine to cool properly.
5. Reinstall the cylinder and air filter covers.
Knob
— US-21 —
Cylinder Cover
Cooling Fins