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COMPRESSION ‐‐ This is necessary for the engine to reach
its maximum efficiency.
Loss can be due to a leak occurring from the valves, rings
or cylinder head.
This can be checked by spinning the flywheel counter‐
clockwise. If the compression is adequate the flywheel
should rebound sharply.
Or perform a compression test
A compression test checks the air pressure built up in the
cylinder as the piston comes up, and the air is
compressed.
This test will gauge the condition of the intake and
exhaust valves, piston rings and cylinder walls, and head
gaskets or other sealing components,
Preparing the unit for the test
Remove all the Sparkplug(s).
Connect Battery Charger if equipped with electric start)
On single cylinder engine, with compression release,
engine may need to be rotated backwards. Refer to the
engine manufactures documentations.
Crank engine a consistent number of compression
strokes.
Note the compression pressure.
On multiple cylinder engines, the actual compression
reading is not as important at the relationship between all
cylinders.
NOTE: There are too many factors that can result in all
cylinders reading low.
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