Cleaning And Adjusting Spark Plug - Yamaha FT25B Owner's Manual

Maintenance
F20AET, F25AE, F25AET, FT25BET
EMU28953

Cleaning and adjusting spark plug

EWM00560
WARNING
When removing or installing a spark plug,
be careful not to damage the insulator. A
damaged insulator could allow external
sparks, which could lead to explosion or
fire.
EWM01550
WARNING
The engine will still be very hot when it
has just been turned off. Take extremely
care so that neither you nor anyone else
gets burnt. To avoid burns, work on the
engine when it has cooled down.
The spark plug is an important engine com-
58
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. If electrode
erosion becomes excessive, or if carbon and
other deposits are excessive, you should re-
place the spark plug with another of the cor-
ZMU02827