Oberdorfer raw water pump leaking water

windblown

Junior Member
We replaced the impeller on our Oberdorfer raw-water pump two days ago (Universal Mx25, Ericson 32-3). It went reasonably well, though getting the snap ring back on was quite challenge. Since then, we see a steady drip of water (when the engine is running) from the bottom of the pump where it attaches to the engine. We have tightened the nuts there as much as we can, but they are very hard to get to. It's possible that we had this leak before changing the impeller, and we missed it. The raw water is certainly flowing better now, judging from the output. What does the leak mean? Do we need to pull the raw-water pump?
 

Christian Williams

E381 - Los Angeles
Moderator
Blogs Author
If the leak is the mating of the Oberdorfer with the engine block, you may need a new gasket. The pumps are quite easy to take off and put back on.

If the drip is coming out of the shaft, through the opening on the underside, it may be that the bearing is shot. That happened to me. It drips and slowly gets worse. You can rebuild the pump. I bought a new one.

The leak is apparently not coming from the face plate that accesses the impeller, because that would be easy to see.

http://www.ericsonyachts.org/infoexchange/showthread.php?12806-M25-Raw-Water-Pump-Replacement
 
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windblown

Junior Member
If the leak is the mating of the Oberdorfer with the engine block, you may need a new gasket. The pumps are quite easy to take off and put back on.

If the drip is coming out of the shaft, through the opening on the underside, it may be that the bearing is shot. That happened to me. It drips and slowly gets worse. You can rebuild the pump. I bought a new one.

The leak is apparently not coming from the face plate that accesses the impeller, because that would be easy to see.

http://www.ericsonyachts.org/infoexchange/showthread.php?12806-M25-Raw-Water-Pump-Replacement

Thank you so much. I will double-check exactly where the drip is coming from, and then try the gasket replacement. My tendency would be to buy a new pump rather than rebuild. Seems like a new pump every 34 years is a reasonable investment.
 

Alan Gomes

Sustaining Member
Thank you so much. I will double-check exactly where the drip is coming from, and then try the gasket replacement. My tendency would be to buy a new pump rather than rebuild. Seems like a new pump every 34 years is a reasonable investment.
Or, one other option might be to ship it off to Depco Pump for a rebuild.
 

windblown

Junior Member
Or, one other option might be to ship it off to Depco Pump for a rebuild.
I like this idea to have the rebuilt pump as a spare. Also, might consider tinkering with it a bit as a winter project. (Although, the winter project list is long. . . )
 

jreddington

Member III
Pump grease

Tagging onto this thread. What is the proper grease for the grease cup on these pumps? I'm due to refill it. What's in there is a white grease.
 

sharonov

Member II
....getting the snap ring back on was quite challenge...
Can somebody give a definitive answer as to if that ring is really necessary? Every time I have to tackle it I recall seeing somewhere on the net that it is not needed but FUD prevents me from discarding it.
 

Alan Gomes

Sustaining Member
Can somebody give a definitive answer as to if that ring is really necessary? Every time I have to tackle it I recall seeing somewhere on the net that it is not needed but FUD prevents me from discarding it.
The definitive answer is "No, it's not necessary."

At least not unless you are planning to remove the entire pump from the engine and want to be 100% sure that the shaft cannot slip out of the *back* of the pump. But you are asking about whether it is necessary to have in place when the pump is mounted on the engine in its normal operating configuration. In that case you don't need it at all. It is not necessary to hold the impeller in place, which is already held captive by the cover plate.

On my previous two boats fitted with this pump I removed the snap ring and never had a problem. Nor do I see how there could be one.
 

Kevin A Wright

Member III
On the Perkins M20 I had in my E27, there was no snap ring or place to put one. Then I went to replace the impeller on the Universal in my new E35. There was some language involved shortly after discovering this 'feature'.

Kevin Wright
E35 Hydro Therapy
 
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