Impeller Cover Plate leak

I changed the impeller the other day on a 1986 Westerbeke generator and when tested, it leaked water at the base of the cover plate ( drip per second ).
I cleaned the cover plate inside and out and covered the new paper gasket with a coating of oil prior to screwing it back in place. Checked the screws after noticing the drip, but they were all tight.
Wondering if a double gasket might be the answer. Anybody have this happen to them?

Don't know if this will work with your generator, but it worked great on our main engine (Yanmar);

Welcome to Speedseal

It happened to us. Check the face of the pump. We scratched the face getting an impellor out. If it's smooth with no nicks, try flipping the cover plate over with a new gasket.

Cantina, you say "cleaned the cover plate inside and out". Did you scrape the mating surface of the pump body as well as the cover plate? Some of the old paper gasket can easily get left behind on the pump flange. It may be difficult to see, but it will make the joint leak. Let us know what you find.

Thanks all...I will check out Speedseal Murray, thanks.
Larry, I cleaned the plate on both sides with a wire brush and it looked almost like new.
Maybe a wire brush should not be used, not sure. I will remove the plate and try a new
( thicker) gasket and possibly flip the plate. I did notice some wear on the inside of the plate due to the spinning of the impeller, but not along the edges where it might cause a leak.
Mike, I'll be looking close when I reopen, but doubt if there was any gasket remaining.
I will repost with my result. Thanks again.

Doubling the gasket usually isn't a good idea on an impeller pump. You're also moving the cover plate face away from the impeller.

Make sure that the cover plate is completely flat and true. No scratches or grooves worn in the plate. Same for the pump face, it also must be true to seal properly. If you have some very fine, like 400 - 600 grit sand/emery paper, lay it face up on a flat surface. Slide the pump cover, face down, over the sand paper lightly in a circular motion. Observe the plate face for any uneven wear. That will show any uneven spots on the cover.

(Cantina--- Sent you a Private Message about cover plates.)

I had the same problem on a 8.0 Westerbeke, I had replaced the impeller & the plate, turned out the bottom of the plate was making contact against a raised area on the pump body where the lower hose nipple is. I filed a small chamfer on the new plate & problem solved, these were genuine westie parts. Good luck

Flipping the backplate (if flawed) is a good recommendation.

Another option to improve your gasket seal is to use a very thin coat of Permatex Ultra Black sealant. With rubber gloves on, place a dab of sealant on your index fingertip and mix it slightly with the thumb and index fingertips. Slide the gasket between these fingertips, spreading the sealant thinly along both surfaces of the gasket. When you're done, you'll have a very thin coating on the gasket with no globs or gaps.



(Cantina, no private message sent. I have shared my input here on the public forum.)

Double-gasket is asking for a worse leak. You may have either scratched it or might have missed just a tiny piece of old gasket material. If it didn't leak before and does now, you probably missed something simple. Look again. I'm sure you'll find it.

Greetings,
Mr. FW. Thank you for sharing. I suspect Mr. Marin is discussing under cover plates. Shhhhh......

Cantina
It's also possible the cover plate is slightly distorted. A neat trick for correcting something like this is to fasten a 6" self adhesive DA sander disc (320 is good) on a pane of glass purchased at the hardware store. The glass is "true" and you can swirl your cover plate on the sandpaper- effectively "lapping" and removing high spots.

If the sealing face on the pump body has any dings, raised spots from prying or left over gasket bits that can all be removed and flattened with the use of a stone.
A 2 x 8" stone and some wd 40 or similar will flatten and clean the face . Just be carefull to not bear down on any one place , keep moving it.
If there are high spots they will very quickly show as shiny when the surrounding area is dull.
You are not trying to remove a bunch of metal, just clean and knock off high spots.
Same for the cover plate or the sandpaper on glass as suggested.
Tighten the screws in a pattern snugging a bit at a time rather than tighten one all the way and then go to the next.

It Works!! I ended up flipping the cover plate. The inside was scored and the outside had no serial numbers or engravings, so I sanded it first, cleaned it and ended up cutting a new gasket from gasket paper I bought at an engine parts store. I first coated both sides of the new gasket with "Gasgacinch" gasket sealer and screwed it back on. NO DRIPS. Thanks for the advice.

Well done!

Cantina said:

It Works!!

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When ever I replace a cover plate I use SS allen head machine screws.

These can be easily removed by touch , no need to see a screw head or screwdriver slot.

As the can fall on assembly , either use masking tape to hold it on to the wrench , or purchase a dozen .

Any large glass shop will have scrap glass from a broken table or similar.

Have them cut and edge a piece of 1/2 in or thicker about the size of a book will not break in a drawer and is nice and flat.

Fine sandpaper works for some things , but coarse valve grinding compound does a better job.

Greetings,
When lapping, polishing on a piece of glass or flat, a figure "8" motion is more effective and even than a circular one. Turning the piece 90 degrees every so often helps as well.

Somebody should compile all these great tips into a BOOK!! How bout Marin?

Cantina said:

Somebody should compile all these great tips into a BOOK!! How bout Marin?

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Cantina, I've sent you a PM.
NA...... Just kidding

Who's Marin? Oh ya, that former contributing member...now PM poster child. He could compile them...maybe even has...but he probably wouldn't share them publicly with the forum.

Frenchie, PMs received...just haven't read them.

Personally I'm enjoying the peace and quiet!!

Cantina said:

Somebody should compile all these great tips into a BOOK!! How bout Marin?

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What, you didn't get the book that was PM'ed to you??

(Cantina--- Sent you a PM re book idea.) (Al-- Sent you a PM re bozos.)

Oh great. Just what I need. Another unread PM from Frenchie!

Greetings,
RE: Marin's seeming silence....
Elmer Fudd, 1950 & 2003 - YouTube

Forkliftt said:

Cantina, I've sent you a PM.
NA...... Just kidding

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