5. Inspection and servicing of basic engine parts
119R1
(2) Measuring piston ring gap
Press the piston ring onto a piston liner and measure
the piston ring gap with a gauge. Press on the ring
about 30mm from the bottom of the liner.
(3) Removing the piston rings
1) Thoroughly clean the ring grooves when removing
piston rings.
2) The side with the manufacturer’s mark should
face up.
3) After fitting the piston ring, make sure it moves
easily and smoothly.
4) Stagger the piston rings at 120° intervals, making
sure none of them line up with the piston.
3YM30/3YM20/2YM15 mm
Standard
Limit
Top ring gap
0.15-0.30
0.390
Second ring gap
0.18-0.33
0.420
Oil ring gap
3YM30
0.20-0.45
0.540
3YM20
2YM15
0.15-0.35
0.44
Approx.
30 mm
Head surface
Cylinder block
Piston ring
Gap
Make the punched manufacturer's
mark face upward.
(Piston ring)
1st piston ring
2st piston ring
Oil ring
2st piston ring
120
120
120
1st piston ring
Oil ring
120
120
120
Oil ring
2nd piston ring
1st piston
ring
Direction of
piston pin
Direction of side pressure
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...