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US-17
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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-
0.7 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
lowemission 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 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.
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.
5.
Reinstall the fan cover and the filter cover.
Spark Arrester
WARNING
POTENTIAL HAZARD
•
Muffler surface becomes hot whenTrimmer
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
•
M a k e s u re t h e m u f f l e r i s c o o l b e f o re
inspecting and cleaning the spark arrester.
Air Filter Cover
Cylinder Cover
High Tension
Lead Boot
Knob
Cooling
Fins
Knob
Summary of Contents for BT23L
Page 67: ......
