Yamaha F350 Owner's Manual page 115

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 out-
board motor to a Yamaha dealer. You should
periodically remove and check the spark
plug because heat and deposits will cause
the spark plug to slowly break down and
erode.
To remove the spark plug
1. Remove the covers of both port and
starboard sides.
1
1. Cover
2. Remove the bolt that is securing the ig-
nition coil, and then remove the ignition
coil. NOTICE: Do not use any tools to
remove or install the ignition coil.
Otherwise, the ignition coil coupler
could be damaged.
1
ZMU07704
[ECM02330]
2
1. Bolt
2. Ignition coil
3. Remove the spark plug. 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.
To check the spark plug
1. Check the condition of the spark plug. If
electrode erosion becomes excessive or
carbon and other deposits are exces-
sive, replace the spark plug with the
specified plug.
Standard spark plug:
LFR6A-11
2. Measure the spark plug gap using a
thickness gauge. If the spark plug gap is
out of specification, replace the spark
plug with the specified plug.
Maintenance
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ZMU07702
[EWM00561]
109