Yanmar 4JH4E - Intake and Exhaust Rocker Arms

5. Inspection and servicing of basic engine parts
192
5.2.7 Intake and exhaust rocker arms
The wear of rocker arm and rocker arm bushing
may change opening/closing timing of the valve,
and may in turn affect the engine performance
according to the extent of the change.
(1) Rocker arm shaft and rocker arm bushing
Measure the outer diameter of the shaft and
the inner-diameter of the veering, and replace
if wear exceeds the limit.
Replace the rocker arm bushing if it moves
and replace the entire rocker arm if there is no
tightening clearance.
(2) Rocker arm spring
Check the rocker arm spring and replace it if it
is corroded or worn.
(3) Rocker arm and valve cap retainer.
Inspect the contact surface of the rocker arm
and replace it if there is abnormal wear or
flaking.
mm
Standard Limit
Outside dia of intake and
exhaust rocker arm shaft.
15.966-15.984 15.955
Intake and exhaust rocker
arm bushing inside dia.
16.000-16.020 16.090
Rocker arm shaft and bushing
clearance at assembly
0.016-0.054 0.140
011086-00X