Yanmar 4LHA Water Pump Gasket

[Dougcole]

Does anyone know if there is a gasket on the engine (oil) side of the raw water pump on a Yanmar 4LHA-stp?

I've got a new, very slow, mystery oil leak on both motors in exactly the same spot, forward port side corner, basically under the raw water pumps. I recently had both of my raw water pumps rebuilt and the leaks seem to have started then. I've never noticed a gasket when I have pulled the pumps before but maybe I just missed it?

The timing and location of the leas seems kind of coincidental.

Thanks.

 

[Cigatoo]

There is a rubber o ring between the pump and gear housing on the 4lhdte. Probably the same on yours. Did you remember to remove the old o ring before installing the new o ring.

 

[Dougcole]

Pulled the pumps today. No O ring on either pump, I'm assuming Depco (the company that rebuilt the pumps) left them off. Pretty sure this is going to cure the leak.