Raw water pump leaking

[heritage]

Engine is a Yanmar 2gm20f, marinized in Japan. I believe the pump is an Oberdorfer, but can't find any markings except C-388. The cover plate for the pump is stainless steel and the bolts take a socket instead of screwdriver. The water drips from the weep holes. I took the pump apart and found crevice corrosion on the ss shaft where the water seal was located. The rebuild kit does not include the pump shaft. So I'm thinking: New pump.

Sticker shock time. New pump $488!

The European marinized version of the 2gm20f and 3gm30f both use a Johnson built pump that sells for $224 and the impeller sells for half the price of the Japanese pump. So I'm considering mounting a Johnson pump on my engine. Have any of you done that? The mounting bolts on my old pump are 7mm apart which is about 2 3/4". Is that the same as the Johnson pump? Hoses can be changed to fit either pump.

 

[Stu Jackson]

www.depcopump.com

 

[kloudie1]

Sure looks like the same pump as on the Yanmar 3GMF/2GMF/HMF series. The thing can be rebuilt with new bearings, new impeller, and a new seal.. The shaft where the seal touches can be repaired with a little sleeve made to do that by the SKF folks.
http://www.skf.com/us/products/seal...als/wear-sleeves/skf-speedi-sleeve/index.html
Take the pieces to a good machine shop and they can help.
I don't have the relevant dimensions on my pump..
I am going to guess that someone rebuilt/modified it in the past.. a stainless cover is not normal..

 

[heritage]

Sure looks like the same pump as on the Yanmar 3GMF/2GMF/HMF series. The thing can be rebuilt with new bearings, new impeller, and a new seal.. The shaft where the seal touches can be repaired with a little sleeve made to do that by the SKF folks.
http://www.skf.com/us/products/seal...als/wear-sleeves/skf-speedi-sleeve/index.html
Take the pieces to a good machine shop and they can help.
I don't have the relevant dimensions on my pump..
I am going to guess that someone rebuilt/modified it in the past.. a stainless cover is not normal..

The skf sleeve should work if I can find the right size. The bearings are in good shape. Thanks Kloudie1.

 

[Ken13559]

Search this forum. There's an instruction I posted sometime back on rebuilding the pump. Its cheap and easy. You can get all parts like seal, bearings, C-clips from car parts stockist. Shaft you have to get from your Yanmar dealer or whoever carry Johnson parts.
I'm travelling now so not able to re-post the instructions now.

 

[Warren Milberg]

I bought a new pump for a 2GM20f from Depco and it was a Johnson. Cost about $200. Very happy with it. Depco is great to deal with. Give them a call, tell them what you need, and get a quote.

 

[Dalliance8918]

A welding shop can tig weld the crevice corrosion. All you need to do is clean it up, or have a machine shop do it. I had crevice corrosion on my prop shaft under the lass drop s.s. collar. had it tigged, and then cleaned up at machine shop.