Yanmar Raw Water Pump Questions

[Homer Shannon]

I spent way too much time researching this, but I think I have the water-side seal issue resolved.

I was able to find seals that would fit with and have a stainless garter, but none were available through standard consumer distribution channels. Eventually, I came upon this post on another forum, https://forums.sailboatowners.com/th...al.1249925773/. One of the posters noted that Viton seals are well suited for the application. The required 10x25x7 seal is available through Amazon for $9.99 with free shipping. It will take over a week to arrive and the search for it on Amazon was a bit challenging. Here's the Amazon link https://www.amazon.com/EAI-Double-St...ustrial&sr=1-2. I think this will be a good upgrade from the standard, commonly NOK, seal that does not have a stainless garter.

[Jim Cate]

Homer, FWIW I have routinely replaced the springs with o-rings when purchasing for several decades now. Everywhere I've been the counter guy at the seal/bearing shop knew the drill and did so for the cost (~15-20 cents) of the o-ring. Seems to have worked so far!

Just a thought if you don't want to wait for delivery from Amazon (unknowable these days, at least here in Oz).

Jim

[Homer Shannon]

Jim, thanks for that. If it were July, I'be at a shop looking at O rings right now! As it is December and the boat is on the hard, I can wait a week for the better seal to arrive. I won't have the rebuild kit until early next week anyway.

Interestingly, I took a hard look at the old lip seal today to confirm any markings or numbers on it. The seal is an NOK AE 0279 A. This number does not come up in any current NOK listings. The closest I could find was an AE 0279 A2, which indicates a double lip. The one I have appears to be double lip. The metal frame of the seal is very rusted and causing corrosion on the inside of the seal. The garter spring, which is specified as carbon steel in the specification of the current model, is in good shape with just a touch of tarnish on it. Go figure.

At any rate, the rubber of the seal is very hard and the thing is probably junk. I never noticed any leaking from the pump, but it hardly seems likely that the seal was working well. How much this was contributing to the pump's weak operation is hard to say.

[Boatyarddog]

Originally Posted by Lepke

The pump is above the oil level. Once the impeller is out, you have access to both ends of the retaining screw. Use a penetrating oil on both ends. When you reassemble, use a thread coating like never-seize and you won't have to worry about removing the screw next time.
I'd buy the complete kit. Rebuilding the pump is easy. There's probably a YouTube video.

Stainless probably won't be frozen to the lobe.
I'm sure the oil splash is the lubrication here.

I don't think I'd use antisieze here for reassembly.

In fact I'd use a drop of blue Loctite, on clean dry screw threads.

Why?
If that screw lets loose in the pump housing, ouch, and are you going to retrieve it easily?
Removing screws installed with Loctite is simple as using a heat source, propane torch, heat gun, to warm up the part to be removed, it will be easily removable if ever needed to again.
My two cents.
Boatyarddog

[Homer Shannon]

Boatyarddog: You are correct - the screw does not corrode to the lobe. It's stainless into bronze. I agree a drop of blue Locktite should be used as the screw holds with only about three threads. What is important for anyone wondering about this assembly is that the hole through the pump body is NOT threaded and the little phillips machine screw just goes right through it. On my pump, it looks like a little sealant was put in there. There is a copper washer under the screw head, but some low grade sealant, butyl tape or pumber's putty perhaps, wrapped around the screw before insertion seems like a good idea. I also think some kind of thin sealant between the cam and pump body might be a help. Not sure what to use on this - maybe one layer of teflon tape? A drop or two of paint?

[Dieseldude]

A stainless screw in a brass body by only three threads seems like a candidate for loctite. In addition to helping to retain the threads, it will also seal out water to prevent corrosion. What grade of loctite, I am not sure between low, medium, or high strength. I do not know the size of the screw and thread pitch. I think that I would go with at least medium strength loctite. For future dismantle, a bit of heat should soften up the loctite. Of course threads must be well cleaned. Might need to chase the female threads with a tap. I would use a taper or "plug" tap and not go all the way to the tap max diameter. Just run it deep enough to remove dirt, bit not disturb metal, or you could make excessive clearance. A spray of brake clean and blast of compressed air on the threads will help too.

[Wotname]

Originally Posted by Homer Shannon

.........
On my pump, it looks like a little sealant was put in there. There is a copper washer under the screw head, but some low grade sealant, butyl tape or pumber's putty perhaps, wrapped around the screw before insertion seems like a good idea. I also think some kind of thin sealant between the cam and pump body might be a help. Not sure what to use on this - maybe one layer of teflon tape? A drop or two of paint?

I have never put anything between the cam and the pump body and see no reason for doing it even though I am a 'belts and braces' sort of guy.

As for the screw, I normally put a small drop of low grade loctite there but I know of many who don't bother. There is zero tension of the thread, only a tiny amount of static compression and the shear (of which is some but not a lot) is only in one direction and relativity constant (when the pump is operating).

Disclaimer - I am not a pump design engineer .

[Homer Shannon]

This project just does not want to let me finish. A month ago I ordered a rebuild kit. It was an open-box but allegedly complete kit at a good price. It arrived and did not have the cam or the water side seal. I contacted the seller, who agreed to get me the missing parts. After waiting for over two weeks and unable to reach the seller again, I went and purchased the cam an seal separately. With all the parts in hand I finally got a chance to start the rebuild. But wait... there's more.

Turns out the rebuild kit does not include the 26mm snap ring, which my pump is mysteriously missing. Also, the screw for the cam is only 10mm long. The stock screw is 12mm and that is not long enough if you use the copper sealing washer. This washer was not installed in my pump and I think I see the reason why. You really need a 14mm screw if you want to get more than a single thread holding the cam in place.

Well, these two little parts are not easy to find. The snap ring is findable but only if you want to purchase 50. The screw is available in 16mm, which I can cut down, but I'll have to pay about $10 in freight for a $0.09 part. I have not got my orders in yet but I think I'll order a dozen or so of the screws, and with the 50 snap rings, I'll have a lifetime supply for everyone in this forum that needs one. PM me if just happen to need one of these.

[Compass790]

Wow I feel your pain. Too late now but bearing supply places have snap rings, at least they do here. However I do remember an American owner I worked for saying that he loved buying bits in NZ because you could buy one of instead of a packet tho that is dying out now. Really hope your pump can lift water better after your saga!

[Homer Shannon]

Well, I caught a break this afternoon. I had to go to Manchester, NH and I stopped by an auto parts place, then a good hardware store I know of. I stuck out at the auto parts store but the hardware store came through. They didn't have any metric snap rings but a 1.25" measures 28.1mm, uncompressed, and that is just about exactly the dimension of the uncompressed 26mm ring. In any event, this snap ring only has to act as a stop for the oil seal and the pump got along without it for at least 22 years. The hardware store also had M4 stainless machine screws. They did not have 14mm, which is what I need, so I grabbed two 20mm screws, which I will check and cut down as necessary. All in for $2.36 and I'm looking to get this project back on track.

[Wotname]

Originally Posted by Homer Shannon

Well, I caught a break this afternoon. I had to go to Manchester, NH and I stopped by an auto parts place, then a good hardware store I know of. I stuck out at the auto parts store but the hardware store came through. They didn't have any metric snap rings but a 1.25" measures 28.1mm, uncompressed, and that is just about exactly the dimension of the uncompressed 26mm ring. In any event, this snap ring only has to act as a stop for the oil seal and the pump got along without it for at least 22 years. The hardware store also had M4 stainless machine screws. They did not have 14mm, which is what I need, so I grabbed two 20mm screws, which I will check and cut down as necessary. All in for $2.36 and I'm looking to get this project back on track.

Good to hear that the tide has turned in your favour .
Necessity is the mother of invention!

[Compass790]

Maaate thats mor like it!
Had I realised snap ring was only there to hold oil seal cuda said that a bit of 601 Loctite or any threadlocker you had probably wuda done the trip if you put it on clean & dry.

[Homer Shannon]

I have to wonder if the 26mm snap ring just rusted away. It is not a special ring in any way and it is outside of the oil seal (but not in the water chamber). There was no evidence of rusting but the groove couldn't even be seen until I started scraping around looking for it. The oil seal didn't seen to care a bit.

[Wotname]

Originally Posted by Homer Shannon

I have to wonder if the 26mm snap ring just rusted away. It is not a special ring in any way and it is outside of the oil seal (but not in the water chamber). There was no evidence of rusting but the groove couldn't even be seen until I started scraping around looking for it. The oil seal didn't seen to care a bit.

Quite possibly!

[Homer Shannon]

Time to close this thread out. I put the pump together this morning without any further difficulties. I did note that the blades of impeller in the rebuild kit are way stiffer than the blades on the one season old impeller that was in the pump. In the end, I guess I never know if it was the cam, the seals, the impeller or something else that caused the pump's weak performace. It can now start and pump from about 20", which is a bit less than I expected but will be acceptable for the boat. I made this little vide of it running: https://1drv.ms/v/s!AiR9KzpBmPlsidEc...2pW_A?e=AM8p7e

Many thanks to all of you who contributed information. I'll take all the help and advise I can get!