Testing Engine Compression - Westerbeke 8.0KW-60Hz Service Manual

ENGINE ADJUSTMENTS
TESTING ENGINE COMPRESSION
Make certain 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 install
the compression gauge/adapter combination to 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 kgf/cm2) at 290 rpm.
MAXIMUM PERMISSIBLE DIFFERENCE BETWEEN CYLINDERS
42.7 psi (3 kgf/cm2)
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-hull).
TESTING ENGINE
COMPRESSION
LOW COMPRESSION
ADAPTER
\\'hen low compression is found, determine the cause
by
applying a small amount 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.
AIR INTAKE FILTER/SILENCER
INTAKE
& FILTER
The filter cartridge should be cleaned every 100 operating
hours. Tap the cartridge on a fiat surface to dislodge loose
dirt or clean with compressed air.
If
the filter cartridge is
badly contaminated or oily, replace it.
Engines
&
Generators
48