Spark Plug; Muffler/Spark Arrester - Arctic Cat Altera 300 Service Manual

NOTE: The engine must be warm and the battery

must be fully charged for this test.
5. While holding the throttle lever in the full-open posi-
tion, crank the engine over with the electric starter
until the gauge shows a peak reading (five to 10
compression strokes).
NOTE: The compression should be within a range

of 210-230 psi in the full-open throttle position.
6. If compression is abnormally low, verify the follow-
ing items.
A. Starter cranks engine over.
B. Gauge functions properly.
C. Throttle lever in the full-open position.
D. Valve/tappet clearance correct.
E. Valve not bent or discolored.
F. Valve seat not discolored.
NOTE: To service valves, see Engine/Transmission -

Servicing Top-Side Components.
7. Pour 29.5 ml (1 fl oz) of oil into the spark plug hole,
attach the gauge, and test compression.
8. If compression is now evident, service the top end
(see Engine/Transmission - Servicing Top-Side
Components).

Spark Plug

A light brown insulator indicates that the plug and
air/fuel ratio are correct. A white or dark insulator indi-
cates that the engine may need to be serviced or the car-
buretor may need to be adjusted. To maintain a hot,
strong spark, keep the plug free of carbon.
ATV-0051
CAUTION
Before removing the spark plug, make sure to clean the
area around the spark plug. Dirt could enter engine
when removing or installing the spark plug.
Adjust the gap to 0.8-0.9 mm (0.032-0.036 in.) for proper
ignition. Use a wire feeler gauge to check the gap.
8
ATV0052B
A new spark plug should be tightened 1/2 turn once the
washer contacts the cylinder head. A used spark plug
should be tightened 1/8-1/4 turn once the washer contacts
the cylinder head.

Muffler/Spark Arrester

The muffler has a spark arrester which must be periodi-
cally cleaned. At the intervals shown in the Periodic
Maintenance Chart, clean the spark arrester using the fol-
lowing procedure.
! WARNING
Wait until the muffler cools to avoid burns.
1. Remove the cap screw (1) securing the spark arrester
(2) to the muffler assembly; then carefully remove
the spark arrester.
KM139A
2. Using a soft wire brush, clean the carbon from the
screen (3) taking care not to tear or damage the
screen.