Yanmar 3YM30 Sevice Manual page 106

4. Disassembly and reassembly
(7) Turning the engine over
Stand up the engine on the flywheel housing.
(8) Mounting the gear case
Apply the liquid gasket to the gear case and mount the
gear case and lube oil line O-ring onto the cylinder
block.
NOTE:
1) When mounting the gear case, match up the two
knock pins of the cylinder block.
2) Be sure to coat the O-ring for the cylinder block
lube oil line with grease when assembling, so
that it does not get out of place.
(9) Mounting the piston and connecting rod
1) Reassemble the piston and connecting rod.
NOTE:
1) When reassembling the piston and connecting
rod, make sure that the parts are assembled with
the correct orientation.
2) Install each piston ring on the piston, with the
punched manufacturer's mark facing upward.
3) The piston ring joints shall be staggered at by
120° intervals. Do not position the top ring joint
vertical to the piston pin. The coil expander joint
shall be opposite to the oil ring joint.
Cylinder block
Flywheel housing
Make the punched manufacturer's
mark face upward.
Second
ring joint
Expander joint
91
(Piston ring)
Oil ring joint
Top ring joint
(Ring joints)