General Maintenance; Compression Test - Polaris Magnum 2x4 Service Manual

Compression Test - 2 Stroke
1 . Remove spark plug and install compression tester.
2. Connect high tension lead to a good ground on engine.
3. Open throttle and crank engine until maximum reading
is obtained (approximately 3-5 revolutions).
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Compression Test - 4 Stroke
NOTE: 4-Stroke engines are equipped with an automatic
decompressor. Compression readings will vary in propor-
tion to cranking speed during the test. Average compres-
sion (measured) is about 50-90 psi during a compression
test.
Smooth idle generally indicates good compression. Low
engine compression is rarely a factor in running condition
problems above idle speed. Abnormally high compres-
sion can be caused by a decompressor malfunction, or
worn or damaged exhaust cam lobes. Inspect camshaft
and automatic decompression mechanism if compression
is abnormally high.
A cylinder leakage test is the best indication of engine
condition on models with automatic decompression. Fol-
low manufacturer's instructions to perform a cylinder leak-
age test. (Never use high pressure leakage tester as
crank seals may dislodge and leak).
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Polaris Industries Inc. 2.15
MAINTENANCE
General Maintenance
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