Water Impeller Housing

Meanwhile

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As I'm rebuilding my water pumps on Yamaha F250 & LF250, I noted some rough build up that looks like caulk on the inside of the impeller housing. Both housings have this in the same place. It is not crustyvlike salt, very much like a caulk that was smeared. This has me stumped. Any ideas, is this common? This is the first time I've done these engines.

Randy20200224_165455.jpg20200224_165459.jpg20200224_165515.jpg20200224_165519.jpg15825926153851678591735271666163.jpg
 

DennisG01

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Just looks like someone used a little gasket adhesive (or maybe just regular caulk?) between the SS cup and plastic housing. Nothing wrong with that.
 

Meanwhile

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OK, I scraped it out anyway.
Thanks for the feedback.

As an aside, the pistachio hull made me look all the harder at the previous work.20200224_190814.jpg
 

leeccoll

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OMG Now that's naughty-cally hilarious :D

Those seashells turn up in the most unlikely places....

It's good you are up to the challenge Randy!
 
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seasick

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I guess it could be grease. I had the same residue on mine but I know for sure that it wasn't white grease that was used for the previous rebuild. I don't know how blue marine grease could end up like white goo. Maybe it can.The housing had some scratches also so I just replaced it. It was 6 years old.
 

DennisG01

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I don't know about all engines, but in many service manuals they recommend a gasket adhesive to help keep the cup in place. But the cup is keyed to stay put.
 

seasick

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Yup, it's keyed and a relatively tight fit. On my housing and the one in the photo, there is an accumulation of the gunk right where the input slot of the metal housing is. That leads me to believe it is something that gets scrapped off the insides of the metal cup and then gets deposited in the small gap. I really thought it was housing material that got ground down or melted down into goo.