Correct Spark Plug Heat Rang - Arctic Cat Cougar Service Manual

LUBRICATION, MAINTENANCE AND TUNE-UP 101
cylinder when the plug is removed, caus-
ing serious engine damage.
2. Remove all the spark plugs, then attach the
plugs back to the spark plug wires and ground
the plugs to the cylinder head.
0
0 0
0
@
@
0
0 0 0
CAUTION
If
the plugs are not grounded during the
compression test, the CD/ ignition could
be damaged.
3. Screw a compression gauge into one spark
plug hole, or if you have a press-in type gauge,
hold it firmly in position.
4. Check that the emergency cut-out switch is in
the OFF position.
5. Hold the throttle wide open and crank the
engine several revolutions until the gauge gives
its highest reading. Record the reading, indicat-
ing the cylinder location (MAG end, center or
PTO end). Remove the pressure tester and relieve
the pressure valve.
6. Repeat Steps 3, 4 and 5 for the other cylin-
der(s).
7. There should be no more than a 10 percent
difference in compression between cylinders.
8. If the compression is very low, it is likely that
a ring is broken or there is a hole in the piston.
9. Reinstall the spark plugs and reconnect the
spark plug wires.
Correct Spark Plug Heat Range
The proper spark plug is very important in
obtaining maximum performance and reliability.
The condition of a used spark plug can tell a
trained mechanic a lot about engine condition
and fuel mixture.
Select plugs of the heat range designed for the
loads and conditions under which the snowmo-
bile will be operated. Use of spark plugs with
incorrect heat ranges can result in a seized piston,
scored cylinder wall or damaged piston crown.
In general, use a hot plug for low speeds and
low temperatures. Use a cold plug for high
speeds, high engine loads and high temperatures.
The plug should operate hot enough to bum off
unwanted deposits, but not so hot that they bum
themselves or cause preignition. The insulator of
a spark plug that is the correct heat range will be