Cylinder Cooling Fins; Spark Arrester - Maruyama B420L Manuel Du Propriétaire/De L'utilisateur

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.
.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.
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 cover and the air filter
cover.
Knob

Spark Arrester

POTENTIAL HAZARD
• Muff ler surface becomes hot when
Trimmer/Brushcutter is in operation and
remains hot for some time after the
engine is shut off.
WHAT CAN HAPPEN
• Contact with hot muffler surfaces could
cause a burn.
HOW TO AVOID THE HAZARD
• Make sure the muff ler is cool before
inspecting and cleaning the spark
arrester.
Maintenance Interval
• The spark arrester should be inspected and cleaned
after every 25 hours of use.
• Replace the screen if it cannot be thoroughly
cleaned, or if it is damaged.
Spark Arrester Maintenance
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. Remove a screw located on the side of the exhaust
outlet holds the spark arrester in place.
— US-22 —
Cylinder Cover
Cooling Fins
WARNING