Spark Plugs; Oil Pressure; Engine Compression Test; Water Pump Belt - Westerbeke 3.5 SBCG Operator's Manual

ENGINE ADJUSTMENTS
ENGINE COMPRESSION TEST
To check the engine's compression pressure, warm up the
engine, then shut it down.
1. Remove both spark plug caps and both spark plugs.
2. Install a compression adapter and gauge in a spark
plug hole.
3. Close the thru hull valve (seacock).
4. Crank the engine several times quickly so that the gauge
pointer reaches it's maximum.
STANDARD COMPRESSION PRESSURE AT 500 RPM:
71 PSI (5± 1 Kg/em') (0.4± 0.1 MPa)
5. Test the compression pressure on the other cylinder.
If either cylinder is below the standard try adding a
small amount of engine oil through the spark plug hole
and repeat the test.
(a) If additional oil causes an increase of pressure,
the piston ring and/or cylinder may be worn
or damaged.
(b) If additional oil does not increase compression
pressure suspect poor valve contact, valve seizure
or valve wear.
6. Reinstall the two plugs, connect the wires and open the
thru hull valve (seacock).
OIL PRESSURE
The lubricating system is a pressure feeding system using an
oil pump. The engine oil is drawn from the oil sump by the
oil pump, which drives the oil, under pressure, through the
oil filter and various lubricating parts in the engine. The oil
then returns to the oil sump to repeat the continuous cycle.
When the oil pressure exceeds the specified pressure, the oil
pushes open the relief valve in the oil pump and returns to
the oil.sump, keeping the oil pressure within it's specified
range.
NOTE:
A newly starter (cold) engine may have an oil
pressure up to 40 psi. A warmed engine can have an oil
pressure as low as 30 psi. Oil pressure will vary depending
on the load placed on the generator.
WATER PUMP BELT
To remove, replace or adjust the belt, loosen the pivot bolt
and release the adjusting bolt. Slide the water purilp bracket
to slacken the belt for removal. When replacing or adjusting
the belt, tighten so to have a 3/8" - 112" deflection at its
widest span.
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TESTING OIL PRESSURE
To test the. oil pressure, remove the oil switch and install a
mechanical oil pressure gauge, in it's place, it will b.e
necessary to connect the two switch wires together for the
engine to run. After warming up the engine, with the engine
speed at 2200 rpm, read the oil pressure gauge.
OIL PRESSURE: between 30 and 40 psi at 2200 rpm