Yanmar 4BY - Replacing Valve Stem Seals

ENGINE
BY Service Manual
5-29
Cylinder Head
IMPORTANT
Mark all valve train components so they can
be installed in their original locations.
Note: Record all measurements taken during
inspection.
Inspection of Valve Guides
Figure 5-27
1. Insert a NEW valve so the end is flush with the
valve spring end of the valve guide.
2. Install dial indicator OEM No. 00 2 510 or
similar as shown (Figure 5-27).
3. Move valve back and forth while reading dial
indicator.
Results: If measurement exceeds specification,
the cylinder head and valves must be replaced.
Specifications
Replacing Valve Stem Seals
1. Remove the valve spring. It is not necessary to
remove valve.
Figure 5-28
2. Press special tool OEM No. 11 6 370 onto valve
stem seal and turn (Figure 5-28).
3. Remove special tool together with valve stem
seal.
Figure 5-29
4. Lubricate valve stem and install special tool
OEM No.111960.
5. Coat new valve stem seal (Figure 5-29, (1))
with oil and install over tool. Remove special
tool OEM No. 11 1 960.
CAUTION
Any part which is found defective as a
result of inspection or any part whose
measured value does not satisfy the
standard or limit must be replaced.
0000119en
Inspection Item Limit
Valve Guide
Wear
Intake
0.5 mm
(0.020 in.)
Exhaust