Maintenance
67
EMU3077A
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 bolts to remove the ECM
(Electronic control module) cover.
2.
Remove the bolts that are securing the
ignition coil, and then remove the ignition
coil. Do not use any tools to remove or
install the ignition coil, otherwise the igni-
tion coil coupler may get damaged.
3.
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 al-
low external sparks, which could lead
to explosion or fire.
[EWM00562]
4.
Be sure to use the specified spark plug,
otherwise the engine may not operate
properly. Before fitting the spark plug,
measure the electrode gap with a wire
thickness gauge; replace it if out of spec-
ification.
1. Bolts
2. ECM (Electronic Control Module) cover
1. Bolts
2. Ignition coil
Standard spark plug:
LFR6A-11
U6P27AE0.book Page 67 Friday, December 6, 2013 6:17 PM