I tried to replace the damage raw water pump impeller on my Yanmar
2QM20 today and found it frozen on the shaft. It’s the slide on keyway
type without a set screw and the bronze impeller hub seems to have
frozen to the stainless steel shaft.

I cut the rubber away so I could get vice grips on it but it is really
stuck on there. It was only put in new last spring. I’m going to let
the boatyard replace it but this is something I really would not want
to be dealing with anchored on some lee shore with a damaged rig. I’m
going to buy a gear puller if I can find one that fits but cutting the
rubber away would be no picnic in rough conditions either.

Is there anything that can be put on the shaft that will prevent this?
Or, should I remove the impeller and grease the whole thing every
month or so?

--

Roger Long