Raw Water Pump update

[Stephen K]

Awhile back, I posted that my Sherwood G908 raw water pump was dripping a slight bit of oil at the weep holes. As background, you need to know that the prior owner just replaced this pump before I bought the boat 3 1/2 years ago and since then I have only approx. 60 hours of use on the engine(I sail on an inland lake and try to run the engine up to temperature as often as possible).

The good advice from this panel was to get my pump repaired. I heeded the advice and that project finally came up to the top of the list, so I removed the pump and brought it home for a rebuild. (I had allready bought new seals and gaskets for the job).

I took the pump apart, removed the "C" clip from the shaft and started to press out the shaft....but it did not budge . I sprayed a liberal dose of PB blaster and called it a day. Next day I tried to get the shaft out and still no movement:cussing:. The people at DEPCO said this was not normal, so I sent the pump to them for inspection and a quote to rebuild. They seem to be really good service oriented people at DEPCO. I am ticked off at a couple of things on the Sherwood pump...1. the difficulty to do a self repair and 2. the cost of parts compared to Oberdorfer. It's easy to simply write a check and fix the problem, but I feel like I am being gyped out of an opportunity to learn how to repair the pump, see how it works and solve the problem on my own.

I will probably get the pump rebuilt and reinstall it, but I am concerned from my own experience (and others on the C34 site) that the Sherwood pump repair cycle is more frequent than the Oberdorfer. I have a source for a brand new Oberdorfer at a great price....I could just buy that and switch... what would you do?

 

[sailingdog]

I'd go with the Oberdorfer, especially if it is better designed, more reliable and less expensive to repair.

 

[Stu Jackson]

Uhm, ditch the Sherwood. We love our Oberdorfer, and have learned to spell much better because of it.

 

[Stephen K]

I bought the Oberdorfer and am looking forward to installing it. I will report back with an update on how it is working out.

I did have DEPCO rebuild my Sherwood pump (I had already purchased the seals, so it was just incremental labor cost)...I will keep it as a back-up or could sell it at a good price if anyone is interested.

 

[Bob S]

Stephen,

It's a coincidence but I just pulled my pump off this evening. I cleaned (wire wheeled) the bronze impeller housing but the base appears to be cast iron. I read Mainsail's rebuild and it looked like something I could do. I'll be trying to remove the shaft tomorrow. I wish they made a repair kit like the one Maine got for his. Can you buy Gaco Seals from anyone other than a marine supply house like Torrenson? I'm sure the bearing can be purchased from an industrial supply house for half the price. The shaft, if needed is obviously a custom to Sherwood product so there is no choice but to buy it from them.

How does the Oberdorfer mount? The Sherwood has 2 brass clips that hold the housing to the engine. What engine do you have?

I have the M25XP and it uses Sherwood Pump 302648 which has been replaced by Westerbeke #42175 @ $394.24.

I'd like to hear how the change over goes for you.

 

[tgorsline]

Stephen, I'm having the same issues you went through regarding the leaking Sherwood G908 pump on my Universal 35M with only 260 hours! Took me two hours today to get the pump off and yes the two bolts are 10mm and are best accessed with a small 10mm wrench. I did find it best to take off the drive belt to get better access to the bolts.
Which Oberdorfer model P/N did you end up purchasing and how much cheaper did you find it to be over the Sherwood. I might be interested in your rebuilt sherwood pump if you interested in selling it. Can't believe I now have two days invested in this water pump project and not much to show for it!

 

[BarryL]

Hello,

I have experience with the Universal M18 and M25 engines. According to the shop manual, both came with either Sherwood or Oberdorfer pumps. When I bought the boats, both had Oberdorfer pumps. I know that my M25 engine originally came with Sherwood but the notes I have from the original owner state that he did not like the Sherwood and replaced it with Oberdorfer.

It just so happens that I just finished rebuilding my Oberdorfer pump. It is an N202M-15. You can buy pumps and rebuild kits from a number of places. I found the best price here:

goodboatgear.com

No affiliation except as a customer.

FYI, it was easy to rebuild the pump - took about 30 minutes.

Barry

 

[Bob S]

Wow, I got the shaft out of my raw water pump. If you look closely you can see the inner race of what remains of a bearing still on the shaft. I soaked the pump in mineral spirits overnight to loosen up the gunk before trying to remove the shaft. I have a small arbor press but if I didn't I would not have been able to remove it. There where 3 very rusted balls left from what was once a bearing. There was a 1/4" play in the shaft before I started to remove it. This was a disaster waiting to happen!

Stephen, where did you buy the Oberdorfer?

 

[Stephen K]

Stephen,

How does the Oberdorfer mount? The Sherwood has 2 brass clips that hold the housing to the engine. What engine do you have?

I have the M25XP and it uses Sherwood Pump 302648 which has been replaced by Westerbeke #42175 @ $394.24.

I'd like to hear how the change over goes for you.

I was instructed to mount the Oberdorfer using the 2 available holes and don't use the mounting brackets that the Sherwood model uses. I purchased shorter bolts (1/4 x 20) 1/2" and will mount straight on the engine. I'll report back after the installation and running the engine.

 

[Stephen K]

Which Oberdorfer model P/N did you end up purchasing and how much cheaper did you find it to be over the Sherwood. I might be interested in your rebuilt sherwood pump if you interested in selling it. Can't believe I now have two days invested in this water pump project and not much to show for it!

I bought Oberdorfer model 202M-15. I found it new on E-bay at a great price...I got lucky. I needed to order the "elbows" and found those at McMaster Carr.

The DEPCO folks are terrific. They rebuilt my pump (new seals, gaskets, impeller) and they even painted it the "Universal sliver" color. They said my shaft and bearnings were just fine. :dance:

If my Oberforfer works out, I'd be willing to sell the Sherwood at a nice discount vs. a new pump. Just click on my profile and send me a private message or e-mail and we can talk.

 

[Bob S]

Thanks Stephen,

I think Tgorsline was interested in buying it. I am in the process of cleaning up the cast iron base and plan to rebuild mine as a backup. I ordered that same Oberdorfer Pump here:

http://www.adiesel.com/store/OB-N202M-15.html

Not sure how the pricing compares but it seams like a fair price.

 

[Stu Jackson]

rwp weep holes

see: http://c34.org/bbs/index.php/topic,5078.msg31322.html#msg31322

As I recall, our Oberdorfer has three bolts to the engine.

 

[Bob S]

Stephen,

The bolts are 6mm x 1 not 1/4-20. I just checked mine.

 

[Glenn17467]

I replaced my Sherwood G908 two years ago. Bought from Marineparts.com, about $275 plus shipping. I asked about the brass clips but would have to buy the whole pump assembly from Torrsen. Mine were fine so I reused them. I see nothing wrong with the pump other than it is a little harder to get access to the impeller. I think the main concern on any of the pumps is to be sure the drain holes open and the inlet to the HX is open. If the drain holes clog or rust over and the HX inlet clogs, as in my case, raw water can be forced back into the engine passed the shaft seal.

 

[Stu Jackson]

...and the inlet to the HX is open. if...the HX inlet clogs...

That's gonna happen anyway, even if the pump is fine, because the inlet to the HX is where the salt drops out. Those inlet ports need to be checked at least every year or so, requiring usually the removal of the HX. Most folks won't tell ya this, and I have a friend who uses a LymeAway solution to clean his HX, where he uses a bucket at the inlet to the rwp. Works for him, I take mine off and check it.

If you're in fresh water...

 

[Stephen K]

Oberdorfer installed

Stephen,

The bolts are 6mm x 1 not 1/4-20. I just checked mine.

Thanks Bob...you saved me a lot of frustration as I saw your post before heading to the boat. I picked up 6mm x 1 bolts. You are correct as that is the right size.

The Oberdorfer insallation went ok. It took a little to figure out the orientation. The M25XP in the C-30 is a tight area to work. The pump is not difficult to mount, the water hoses are tough. The hoses are not very flexible, so getting the pump elbows angled properly is very helpfull. Before the installation I put a little liquid dish soap in the impeller area for initial lubrication.

Once ready to go, I fired up the engine and was suprised to see how quickly water came out the exhaust. I ran the engine for 15 minutes at low RPM in gear and all was well. I did have a drop of oil around the pump mounting gasket, so I may take it off and add some brand of liquid gasket.

My newly rebuilt Sherwood will serve as a back-up or can be sold if anyone is interested in a good deal. Many thanks to all for your help.