16
OL944D 11/13
Servicing
SP7. VALVE CLEARANCES
1. Readjust valve clearance after first 50 hours of opera
-
tion. Check valves every 500 hours thereafter.
2. Check the valves when the engine is cold.
3. Rotate the crankshaft in a clockwise direction, using
a turning socket, from the front
of the engine
to bring
the first piston to the top dead center on the
compression stroke. When the mark on the crankshaft
pulley aligns with the pointer on the timing gear case
stop turning. Make sure the rocker arms of the No. 1
cylinder are loose at TDC. If they are not, rotate the
crankshaft one complete turn.
Figure 6:
Timing Mark
4. Measure the valve clearance for No. 1 cylinder, with a
feeler gauge.
Standard valve clearances for a cold engine are:
Intake (IN)........................0.0098 in. (0.25 mm)
Exhaust (EX)....................0.0098 in. (0.25 mm)
5. To adjust valve clearance, loosen the lock nut on the
adjustment screw. Insert a feeler gauge between the
rocker arm and the valve stem cap. Adjust, while
measuring the clearance, until the feeler gauge slides
with a slight drag. Tighten the lock nut and recheck
the clearance (
Figure 7
).
Figure 7:
Valve Adjustment
6. Adjust the remaining valves turning the engine 180
0
in the cylinder order of 1-3-4-2.
7. Replace the rocker arm cover.
