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BF15A water pump/impeller question

H

hammerdog

New member
I searched the forum and could not find an answer to this issue. I replaced the impeller on my 1999 Honda BF15A. When changing it, I noticed a buildup of oil sludge on top of the pump housing. I cleaned it all off and everything runs fine. I last changed that impeller in 2008 and I do not remember seeing all that oil sludge back then. I change my oil every (6) months and have not noticed unusual oil usage. It is common to have oil sludge build up like that from the exhaust or do I have another issue?
 
First thing I'll say is that I have not seen what you are describing before so I'm just exercising the noodle here.

I don't think it would be exhaust since it is not routed through this area. But, it IS near there and if there were a crack in the case, then who knows?

Since the pump is driven off of the mainshaft, it is certainly possible that you have a bit of a leak in the engine seal up above. Did you notice any wetness or other indicators for that when you had it apart?

The other thing is that the shift shaft seal could leak and allow gear oil to get into that area. Same for the mainshaft seal in the gear case. Have you checked the gear oil recently?

Another thought is about what type of water do you operate in. If you are in a busy harbor, for instance, you could have driven through some oil on the surface that found it's way into that space. It is not hermetically sealed from the outside so that is a possibility.

Like I said, just thinkin' out loud.

Good luck.
 
I did not notice any oil leaking from above and have never found the engine oil low which would indicate oil leak. I did replace the gear oil last year, but have not checked it recently. Engine seems to run fine, but I was concerned about having an issue. I only troll freshwater lakes, so no issue with dirty water. I will remove the lower housing after I use the motor for a couple of trips and see if there is any more sludge build up.
 
Well, maybe you'll get a better answer between now and then. Don't forget to update to let us know what you find.
 
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