Greasing; Cleaning And Adjusting Spark Plug - Yamaha F40H Owner's Manual

EMU28945

Greasing

Yamaha grease A (water resistant grease)
Yamaha grease D (corrosion resistant grease; for propeller shaft)
EMU44851

Cleaning and adjusting spark plug

The spark plug is an important engine com-
ponent and is easy to inspect. The condition
of the spark plug can indicate something
about the condition of the engine. For exam-
ple, if the center electrode 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 re-
move and inspect the spark plug because
heat and deposits will cause the spark plug
to slowly break down and erode.
(1) Remove the spark plug caps from the
spark plugs.
(2) Remove the spark plug. If electrode ero-
sion becomes excessive, or if carbon
and other deposits are excessive, you
should replace the spark plug with an-
other of the correct type. WARNING!
When removing or installing a spark
plug, be careful not to damage the in-
sulator. A damaged insulator could
allow external sparks, which could
lead to explosion or fire.
Maintenance
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