Checking The Spark Plugs - Yamaha RX10GTW Owner's Manual

WARNING
@
G
Do not drive the snowmobile with the shroud or
covers unfastened or removed.
G Keep your body and clothing away from rotating
parts when servicing the snowmobile with the
shroud or covers removed.
G
Do not touch the hot muffler and engine during or
immediately after operation.
@
CAUTION :
@
Make sure that all cables, leads, etc., are in place
when installing the shroud and covers.
@
NOTE:
@
When installing the shroud and covers, be sure to turn
the fasteners and top cover bolts completely until they
stop; about 1/4 turn after they are seated.
@
ESU03681

Checking the spark plugs

The spark plug is an important engine component and is
easy to inspect. The condition of the spark plug can indi-
cate the condition of the engine. Check the coloration on
the white porcelain insulator around the center electrode.
The ideal coloration at this point is a medium to a light
tan color for a snowmobile that is being ridden normally.
If a spark plug shows a distinctly different color, there
could be something wrong with the engine. For example,
a very white center electrode porcelain color could indi-
cate an intake track air leak or carburetion problem for
that cylinder. Do not attempt to diagnose such problems
yourself. Instead, take the snowmobile to a Yamaha
dealer for inspection and possible repairs. You should
periodically remove and inspect the spark plug because
heat and deposits will cause a spark plug to slowly break
down and erode. Consult a Yamaha dealer before chang-
ing to a different type of spark plug.
Specified spark plug:
R CR9EB (NGK)
8-7