Testing Engine Compression - Westerbeke 11.5KW-60Hz Service Manual

ENGINE ADJUSTMENTS
TESTING ENGINE COMPRESSION
Make certafu the oil level (dipstick) is at the correct level
and the air intake filter is clean. The battery and starter motor
must also be in good condition.
a. Warm the engine to normal operating temperature.
b. Move the control lever to a position for shutting off the
fuel. (Disconnect the wires if a fuel shutdown solenoid
is used).
c. Remove all the glow plugs from the engine and histall
the
compression gauge/adapter combination tq the
cylinder on which the compression is to be measured.
d. Close the raw water seacock (thru-hull).
e. Crank the engine and allow the gauge to reach a
maximum reading, then record that reading.
f. Repeat this process for each cylinder.
COMPRESSION PRESSURE 427 psi (30 kgl/cm2j at 290 rpm.
MAXIMUM PERMISSIBLE DIFFERENCE BETWEEN CYLINDERS
42.7 psi (3 kgl/cm2j
NOTE:
If
the readings are below the limit, the engine needs
repair.
g. Re-install the glow plugs (use anti-seize compound on
the threads) and reset the fuel shut-off to the run position.
h. Open the raw water seacock (thru-huU).
AIR INTAKE FILTER/SILENCER
INTAKE
& FILTER
The filter cartridge should be cleaned every 100 operating
hours. Tap the cartridge on a flat suiface to dislodge loose .
dirt or clean with compressed air. If the filter cartridge is
badly contaminated or oily, replace it.
. NOTE: Failure to properly maintain the air
intake filter can result in engine oil
consumption and filter deterioration
and ingestion into the engine.
TESTING ENGINE
COMPRESSION
~ _ _ _ ~.C:OMIPRESSI(IN GAUGE
I""'--rr:z:..--
ADAPTER
LOW COMI'RESSION.
."
..
When low compression is found, determine the cause by
applying a smallamount.of oil in the cylinder
thru
the glow
plug hole. Allow the oil to settle.
Install the pressure gauge and repeat the above test. If the .
compression reading rises dramatically, the fault is with the
rings.
If
the compression valve does not rise, the problem is
with the valves.
A slight rise in compression would indicate a problem with
both the rings and the valves.
Eriglnes& Generators
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