Need Help with Yanmar 3GMF Oil Leak

[H34Rich]

Hello. Anybody out there experienced with replacing the Rear (crankshaft) Oil Seal mounted in the Metal Housing at the Flywheel? Oil is leaking out from the bottom of the Flywheel Housing. Before I attempt to remove the Coupling, Clutch Assembly and Flywheel Housing to get at the Seal, it would be great to hear from someone who has done this repair before. The engine is still in the boat, which is sitting at the dock. Thankyou!

 

[fredr]

There is a steel oil line that goes in the back of the cyl head. It feeds the rocker arms. It is a hollow bolt with copper washers to seal. Could that be leaking?
Is it leaking any where else? There is a crank case breather in the valve cover that has steel wool in it. If it is restricted it could cause the seal to leak. A out of center shaft coupling will also cause a rear main leak.
If it is the rear main. There is the seal housing behind the flywheel.I think the seal can be removed with out removing the rear main seal housing. If you remove the housing, there is an "O" ring that goes on the insde to seal between the block and rear main seal housing. Doing this in the boat will be very difficult. The shaft has to move back to pull the trans...

fred

 

[H34Rich]

Thanks very much Fred for your input. I'll first check the steel oil line. I did check the breather today, it seems to be okay. As far as removing the trans, etc., it sounds like a big job while still in the boat. Maybe I can get lucky and find a leaking oil line. Thanks again.
Capt. Rich