ENGINE
6LPA Service Manual
5-25
Cylinder Head
12/05
© 2007 Yanmar Marine International
• If the seat position on the valve face is too high
(Figure 5-34), refinish the valve seat using
cutters having angles as listed in the chart
below and a 45° cutter.
Figure 5-34
Figure 5-34
1 – 45° Angle
2 – (See Valve Seat Angle Chart)
4. Hand-lap the valve and valve seat using an
abrasive compound (Figure 5-35).
Figure 5-35
Figure 5-35
5. After lapping, clean the valve and valve seat.
Valve Spring Inspection
1. Measure the straightness of the valve spring
using a square:
• Maximum deviation: 2.0 mm (0.079 in.)
(Figure 5-36, (1))
If the measured deviation exceeds the specified
maximum, replace the valve spring.
Figure 5-36
Figure 5-36
2. Measure the free length of the valve spring
using calipers (Figure 5-37).
• Yellow Mark: 49.6 mm (1.953 in.)
• Blue Mark: 49.6 mm (1.953 in.)
If the measured free length is not within
specifications, replace the valve spring.
Figure 5-37
Figure 5-37
Valve Seat Angle Chart
Intake
Exhaust
70°
65°
(1)
(2)
0004959
0004960
(1)
0004961
0004962