5. Inspection and servicing of basic engine parts
110R1
5.2.3 Intake/exhaust valves, valve guides
(1) Wearing and corrosion of valve stem
Replace the valve stem is excessively worn or
corroded.
(2) Inspection of valve seat wear and contact surface
Inspect for valve seat scratches and excessive wear. Check to make sure the contact surface is normal.
The seat angle must be checked and adjusted if the valve seat contact surface is much smaller than the
width of the valve seat.
NOTE:
Keep in mind the fact that the intake and discharge valve have different diameters.
(3) Valve sink
Over long periods of use and repeated lapping,
combustion efficiency may drop. Measure the sinking
distance and replace the valve and valve seat if the
valve sink exceeds the tolerance.
mm
Valve stem
outside dia.
Standard
Limit
Intake
5.960-5.975
5.90
Exhaust
5.945-5.960
5.90
mm
Standard
Limit
Valve sink
0.4-0.6
0.8
30 mm
Measurement point
Measurement point
60 mm
(Valve sink depth)
Valve sinking depth
(Valve sink)
Depth micrometer
Summary of Contents for 3YM30
Page 1: ...M9961 03E101 3YM30 3YM20 2YM15...
Page 22: ...1 General 1 4 Engine outline 1 3YM30 with KM2P 1 marine gear 6R1...
Page 23: ...1 General 2 3YM30C with SD20 sail drive 7R1...
Page 24: ...1 General 3 3YM20 with KM2P 1 marine gear 8...
Page 26: ...1 General 5 2YM15 with KM2P 1 marine gear 9 2R1...
Page 27: ...1 General 6 2YM15C with SD20 sail drive 185 9 3R1...
Page 30: ...1 General 3 2YM15 with KM2P 1 marine gear 11 2R1...
Page 31: ...1 General 11 3R1 4 2YM15C with sale drive SD20...