Yanmar 3YM30 Service Manual page 107

4. Disassembly and reassembly
(30) Removing the gear case
1) Remove the gear case from the cylinder block.
2) Remove the O-rings from the lube oil passage.
NOTE
1) When mounting the gear case, match up the two
knock pins for cylinder block.
2) Be sure to coat the O-rings for the cylinder block
lube oil passage with grease when assembling, so
that it does not get out of place.
(31)Loosening the main bearing bolts.
Loosen the main bearing bolts. Don't remove them.
(32)Turning the engine over
Turn the engine over, with the cylinder head mounting
surface facing down.
NOTE:
Make sure that the cylinder head positioning pins on
the cylinder block do not come in contact with the
wood block.
(33)Removing the flywheel housing
Remove the flywheel housing with the oil seal from the
cylinder block.
Liquid gasket
O-ring
Pos iti oning pin
Flywheel housing
Liquid gasket
87
Gear case
Knock pin
O-ring
Knock pin
O-ring
Knock pin
(two)
Oil seal
Cylinder block