Yanmar 1GM User Manual page 116

110
ROCKER ARMS
(3GM, 3Gr.,30, 3HM AND
3HM35 MODELS
CHAPTER SIX
E
Flat
INTAKE
EXHAUST
6. Inspect and measure the inside diameter of the rocker
arm bushing and the outside diameter of the rocker arm
shaft. Replace the rocker arm or rocker arm shaft if the
measurements exceed the specifications listed in Tables
1-3.
NOTE
The rocker arm and bushing are available
only as a unit.
7. Reassemble and reinstall the rocker arm assembly by
reversing the removal procedure. On 30M, 30M30, 3HM
and 3HM35 engines, identify the intake and exhaust
valves as shown in Figure 16, then position them on the
shaft in the order shown in Figure 17.
8. Adjust the valve clearance as described in Chapter
Three.
VALVES AND VALVE SEATS
Servicing the valves, guides and valve seats must be
done by a dealer or machine shop, as special knowledge
and expensive machine tools are required.
A general practice among those who do their own ser-
vice is to remove the cylinder head, perform all disassem-
bly except valve removal and take the head to a dealer or
machine shop for inspection and service. Since the cost is
low relative to the required effort and equipment, this is
usually the best approach, even for experienced mechan-
ics. The following procedures are provided to acquaint the
home mechanic with the procedure.
VALVE COMPONENTS
1. Wear cap
2. Keys
3. Valve spring retainer
4. Valve spring
5. Valve seal
6. Exhaust valve guide
7. Intake valve guide
8. Exhaust valve
9. Intake valve