EMK36010-X
CLEANING AND ADJUSTING SPARK
PLUG
The spark plug is an important engine
component and is easy to inspect. The
condition of the spark plug can indicate
something about the condition of the
engine. For example, if the center elec-
trode porcelain is very white, this could
indicate an intake air leak or carburetion
problem in that cylinder. Do not attempt
to diagnose any problems yourself.
Instead, take the outboard motor to a
Yamaha dealer. You should periodically
remove and inspect the spark plug
because heat and deposits will cause the
spark plug to slowly break down and
erode. If electrode erosion becomes
excessive, or if carbon and other deposits
are excessive, you should replace the
spark plug with another of the correct
type.
Standard spark plug:
Refer to SPECIFICATIONS, Page 4-1.
Before fitting the spark plug, measure the
electrode gap with a wire thickness
gauge; adjust the gap to specification if
necessary.
Standard plug gap:
Refer to SPECIFICATIONS, Page 4-1.
When fitting the plug, always clean the
gasket surface and use a new gasket.
Wipe off any dirt from the threads and
screw in the spark plug to the correct
torque.
Standard plug torque:
Refer to SPECIFICATIONS, Page 4-1.
4-12
GB