Figure 4-5. Outboard View of port propulsion unit.
arm (fig. 4-9). Adjust the push rod to obtain a smooth
4-21. Exhaust Valve Clearance Adjustment
"pull" on the feeler gage.
a. General. The correct exhaust valve clearance at
(5) Remove the feeler gage. Hold the push rod
normal engine operating temperature is important for
with 5/16-inch wrench and tighten the locknut with a 1/2-
smooth, efficient operation of the engine. Whenever the
cylinder head is overhauled, the exhaust valves are
(6) Recheck the clearance. At this time, if the
reconditioned or replaced, or the valve operating
adjustment is correct, the 0.011 inch feeler gage, J9708,
mechanism is replaced or disturbed in any way, the valve
will pass freely between the valve stem and the rocker
clearance must first be adjusted to the cold setting to
arm, but the 0.013 inch feeler gage will not pass through.
allow for normal expansion of the engine parts during the
(7) Check and adjust the remaining valves in
engine warm-up period. This will insure a valve setting
the same manner as outlined above.
that is close enough to the specified clearance to prevent
c. Exhaust Valve Clearance Adjustment (Hot
damage to the valves when the engine is started.
b. Exhaust Valve Clearance Adjustment (Cold
(1) Maintaining the normal engine operating
temperature -is particularly important when making the
(1) Place the governor throttle control lever in
final valve clearance adjustment. If the engine is allowed
the NO-FUEL position. Pull engine stop control out.
to cool off before setting any of the valves, the clearance
(2) Rotate the crankshaft until the injector
when running at full load may become insufficient.
follower is fully depressed on the cylinder to be adjusted.
(2) With the engine at normal operating
(3) Loosen the push rod locknut.
temperature (160-185 F.), recheck the exhaust valve
(4) Place a 0.013 inch feeler gage, tool J9708,
clearance with feeler gage J9708. At this time, if the
between the valve stem and the rocker
valve clearance is correct, the 0.008-inch feeler gage will
pass freely between