Water Pump Gasket

shank

.
Apr 20, 2016
83
Catalina 27 Lake Champlain
I'm going to be putting in a new Oberdorfer water pump on my Universal 5411 to replace a Sherwood pump this weekend. The new pump comes with a gasket which sits between the pump and engine block. Do I also need to put some type of gasket maker product like Permatex on there or will that just mess up the new gasket? I don't want anything permanent on there either so it will be easier to replace the pump next time. Thanks
 
Dec 25, 2000
5,045
Hunter Passage 42 Shelter Bay, WA
If it were my boat I would seek technical advice either from the vendor where you purchased the pump, or the maker. That way you can be sure you're getting the correct information. I've never had to replace that gasket, but have replaced the pump cover gasket.
 

dmax

.
Jul 29, 2018
489
O'Day 35 Buzzards Bay
When I replaced a Sherwood pump with an Oberdorfer I did not use any sealant on the gasket and it didn't leak - just make sure the mating surface on the block is clean. Permatex is used instead of a gasket, not with one, it is a gasket maker. There are gasket sealants that are thinner if you're worried but shouldn't be necessary.
 

shank

.
Apr 20, 2016
83
Catalina 27 Lake Champlain
Thanks. I was leaning toward not using the Permatex. Did you have any trouble getting the old bolts which mount the pump to the engine block out?
 

dmax

.
Jul 29, 2018
489
O'Day 35 Buzzards Bay
I didn't have any trouble with the bolts - hopefully you won't either. If you have the time, spray some PB Blaster on them and give it some time (hours, days if possible) to work prior to unbolting.
 

shank

.
Apr 20, 2016
83
Catalina 27 Lake Champlain
I replaced the raw water pump today and it went really well. For anyone else out there with the later model Sherwood here and you want to replace it with a "drop-in replacement" Oberdorfer with no modifications needed, then you want Oberdorfer model n202m-908 and buy it from Depco Pump in Clearwater FL, as many others have suggested. Depco was really great. Note how this one mounts to the engine in the photos which is different from other models. The only minor issue I had was that because the Oberdorfer is slightly narrower than than the Sherwood, there was not enough room for the two elbow adapters to spin freely into the holes without bumping into each other. I took some 50 grit sandpaper and a palm sander and sanded one of them down a couple of cm which worked well with the soft brass.

I ran the engine with the new Oberdorfer at the mooring for about 30 mins on the mooring and noticed that the volume of water flow coming out of the stern water exit hole was greater and more consistent. The Sherwood would kind of spit or burp out a big glug of water every 3-4 seconds and there was a steady stream with the Oberdorfer. Maybe the Sherwood had an enlarged prostate?

Does anyone think that it would be worthwhile to rebuild the old Sherwood and use it as a backup or should I just dump it?

Anyway, thank you to those who posted advice to me on this and for your previous posts to others on the same topic. It was very helpful.
 

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NYSail

.
Jan 6, 2006
2,735
Beneteau 423 Mt. Sinai, NY
I didn't have any trouble with the bolts - hopefully you won't either. If you have the time, spray some PB Blaster on them and give it some time (hours, days if possible) to work prior to unbolting.
Make sure you don’t get pb blaster on any gasket as it will eat through it creating new issues.

Good luck
Greg
 
Dec 25, 2000
5,045
Hunter Passage 42 Shelter Bay, WA
Somewhat related to this thread, returned from a few days on the water with plans to replace the sea water pump impeller on our Yanmar 4jH2-TE. This impeller has been on the boat before we purchased her in 2002. It has over a thousand hours on it and I suspected it would show signs of wear. Had a spare on board so this morning went about removing it. Removed four SS bolts and the cover came right off. Used a pair of needle nose pliers to gently work the impeller out. Cleaned up the face and original 'O' ring cover seal with some glycerine lubricate that came with the new impeller as well as a liberal application on the impeller vanes and inside the pump housing, which Yanmar recommended. They emphasized not to use any petroleum based lubricates on the impeller or pump housing as it will destroy the material.

Put everything back together, primed the pump and opened the sea water through hull. Started the engine and she pumped water right away with no leaks. The old impeller looks brand new. No missing vanes, no cracks where the vane is molded to the hub, so will keep as a spare. Could not believe it was in such good condition after all these years and hours of use.
 
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Likes: jssailem
Dec 25, 2000
5,045
Hunter Passage 42 Shelter Bay, WA
As a foot note, Yanmar used an 'O' ring as a seal between the cover and the housing. Still in good condition, so applied some glycerin and rubbed it in. Should be good for another thousand or two hours.