Engine Adjustments; Valve Clearance Adjustment; Drive Belt Adjustment - Westerbeke 20.0 BEDA Operator's Manual

ENGINE ADJUSTMENTS
NOTE:
WESTERBEKE recommends that the following engine adjust-
ments be performed by a competent engine mechanic. The information
below is provided to assist the mechanic.
VALVE CLEARANCE ADJUSTMENT
NOTE:
Retorque the cylinder head bolts before adjusting the
engine's valves. See TORQUING THE CYLINDER HEAD
BOLTS.
A
CAUTION:
Adjust the valve clearance when the
engine is cold. Valves are adjusted by cylinder in the
firing order of the engine. Tighten the cylinder head bolts
to the specified torque before adjusting the valves.
Pull off the air breather pipe from the rocker cover, and take
off the rocker cover bolts and the rocker cover to expose the
rocker shaft and valve assembly.
Position the No. 1 piston at Top Dead Center (TDC) on its
compression stroke and adjust the # 1, 2, 3 and 6 valves as
illustrated.
Position the No. 4 piston at TDC of its compression stroke
and adjust the # 4, 5, 7 and 8 valves. The valves are num-
bered 1 to 8 from the front of the engine to the back.
Adjust each valve's clearance by inserting a 0.012 inch (0.3
mm) feeler gauge between the rocker arm and the valve
stem. Make sure to adjust all valves to 0.012 inches (0.3 mm)
while the engine is cold.
VALVE ADJUSTMENT SEQUENCE
WHEN NO. 4 CYLINDER IS AT TOP DEAD CENTER
4 4 ~~
2
.4EXH~UST
I
41NTAKE
. I
2E~HAUST
31NTAKE
3 EXHAUST
I
3
2 INTAKE 1 INTAKE
11
EXH~UST
I
2 1 1
WHEN NO.1 CYLINDER IS ATTOP DEAD CENTER
DRIVE BELT ADJUSTMENT
For your safety, Westerbeke generator models come equipped
with belt guards that cover over the belt(s) on the front of the
engine. ("Out of sight - out of mind." The belt guard is NOT
installed for that purpose.) Operators are advised that proper
inspection, service, and maintenance is required.
Drive belts must be properly tensioned. Loose drive belts
will not provide proper alternator charging and will eventu-
ally damage the alternator. Drive belts that are too tight will
pull the alternator out of alignment and/or cause the alterna-
tor to wear out prematurely. Excessive drive belt tension can
also cause rapid wear of the belt and reduce the service life
of the fresh water pump's bearing. A slack belt or the pres-
ence of oil on the belt can cause belt slipping, resulting in
high operating temperatures.
The drive belt is properly adjusted if the belt can be deflected
no less than 3/8 inch (10mm) and no more than 1/2 inch
(12mm) as the belt is depressed with the thumb at the mid-
point between the two pulleys on the longest span of the belt.
A spare belt or belts should always be carried on board.
A.
WARNING: Never attempt to check or adjust the
drive belt's tension while the engine is in operation.
Adjusting Belt Tension
1. Remove the belt guard.
2. Loosen the alternator adjusting strap bolt and the base
mounting bolt.
3. With the belt loose, inspect for wear, cracks, and frayed
edges.
4. Pivot the alternator on the base mounting bolt to the left
or right as required, to loosen or tighten.
5. Tighten the base mounting bolt and the adjusting strap
bolt.
6. Operate the generator for about 5 minutes then shut down
and recheck the belt tension.
7. Replace the guard.
Engines
&
Generators
28