Oberdorfer N202M-908 Raw Water Pump Installation

[Jack McDonald]

For those that installed the Oberdorfer N202M-908 as a replacement for the Sherwood Raw Water Pump, I have a couple of questions:
Did you also order the Oberdorfer 12456 Mounting Kit?
- or -
Did you try to reuse some of the mounting parts from the Sherwood? (such as the angle brackets and the elbow fittings for hose connections)

If you ordered the 12456 Mounting Kit, you notice that the diameter for the elbow hose connections is smaller. Was that an issue, as regards water flow?

Did you install the gasket dry, or did you pre-lube it with anything? (the gasket I'm talking about is the one for mounting the pump to the engine block)

Thanks for any and all help,
Jack
Friendship #80

[TBOT422]

I just completed the installation. I did not purchase the mounting kit (an extra $100). I mounted the pump with the 2 original clamps and bought 2 new brass elbows at a local hose and hydraulic store for $7 each. They did require a few seconds on a bench grinder to shorten one of them enough that you are able to turn the second elbow past the first elbow. That allowed me to rebuild the old pump at Depco to have as a spare.
You might be able to accomplish similar by using one standard elbow on the outlet and a street elbow with straight hose barb adapter on the inlet. Finding the right brass street elbow might be a challenge.

[Amnesia]

So I don't understand what got shortened or how much? The hose barb?

[Amnesia]

Do you have part numbers for gaskets, replacement impellers etc?

Thanks

[SeaBreeze]

For Amnesia - impeller and gasket kit from Depco is OB6593k. To others, i purchased from Depco a drop in Oberdorfer replacemeny for the Sherwood. No modifications required. No additional fittings, adaptors, etc required. I'm on the boat travelling and the receipt is at home so I am sorry I can not give you the exact Oberdorfer pump number. But Depco Pump can identify it. My application is a 2002 M35B
Rick
Sea Breeze

[TBOT422]

So I don't understand what got shortened or how much? The hose barb?

Originally I bought a pair of 1/2 MPT x 3/4" hose barb elbows. I then realized the hose from the pump to the heat exchanger was a 7/8" hose. I could not find a 1/2 MPT x 7/8" elbow anywhere. Of course they do make them somewhere as the Sherwood pump has one on it, but I wanted to have a complete plug replaceable spare so I wanted both pumps to have the elbows on them. What I found was that the OD of 1/2" pipe is approximately 7/8", so I bought a 1/2" street elbow and a short nipple. I had to grind off the corner of the street elbow and about 1/8" off the tip of the inlet hose barb. Being brass, it only took a few seconds on a bench grinder. This is what it looks like.

Elbow1a.JPG (24.47 KiB) Viewed 12935 times

Elbow3a.JPG (30.11 KiB) Viewed 12935 times

Elbow2a.jpg (50.75 KiB) Viewed 12935 times

[Amnesia]

Thank you for the clarification and pictures!

[Mark Sutherland]

Hi Rick/Sea Breeze,

If it's convenient, could you provide the part number for your perfect-fit-right-out-of-the-box Oberdorfer Pump from Depco? Thanks.

[SeaBreeze]

Mark/Dunrobin III
To answer your question - the Depco invoice I received calls out the following:
OB N202M-908 pump $399.25
WB 302678 gasket $1.40
OB 6593K Spare impeller kit with gasket and O ring. $43.20
OB 5373 Retaining ring for drive shaft. $12.80

The first two items are necessary, the last two items are spares. I did not see this specidic part number on the Depco or the Oberdorfer web sites. I think I got it after discussion with a Depco rep via phone call. It may be a relatively new product to target Sherwood replacement market. Mot sure about that. It was a truely drop in replacement to the Shirwood on my 2003 Universal M35B. I think I did have to realign one of the hose 90 degree elbows a fraction of a turn.
Rick

[Amnesia]

I bought this pump at AMAZON for $333.50 in Jun.

No install kit required, only a gasket....the same Westerbeke gasket you would use for the Sherwood pump.

Mike
Amnesia
C350 #169

[Amnesia]

By the way, after actually using the pump for a couple of months....despite the oberdorfor having a significantly smaller impeller than the sherwood, I haven't noticed any difference in engine temp, nor in the sense of water flow out of the exhaust

[Mark Sutherland]

Hi Everyone. I was on the phone with Corey at Depco Pumps yesterday. I have a 2006 Universal M35B engine and was looking to replace my Sherwood pump with the Oberdorfer pump. Up until now, the latest recommended Oberdorfer replacement pump that I’ve seen was the N202M-908. Depco said this was the correct pump, but that it did not include the necessary modified plumbing fittings (apparently the original Sherwood fittings need to be modified to work with the Oberdorfer replacement pump on the M35B engine). He said that part number N202M-837 is the same as the N202M-908, but it includes all of the needed modified fittings, gasket, etc. The cost for the kit was $468. I also bought the Impeller/gasket/O-ring kit OB 6593K ($47), Lip seals(2) OB 5463 ($21.85 ea), and Pump-block Gasket WB 302678 ($1,40). Corey said that if/when the pump begins to “weep”, it’s usually the outer most (forward) lip seal (there are 2) so it’s good to have a spare.

[Amnesia]

Regarding the original Sherwood pumps...

Is there somewhere that will rebuild them economically?

I don't have the tools or wherewithal to do it myself.

Otherwise I'll just get another oberdorfer as back up

[KenKrawford]

Mike, Depco should be able to rebuild the pump for you. http://www.depcopump.com/

[tmh]

Am considering the Oberdorfer as a replacement for the original Sherwood pump. Due to ease of changing the impeller from the front. Have heard that Sherwood has changed the pump part number but do not know if it now opens from the front to change the impeller. Does anyone have experience with this?

Also spoke with Dorian at DEPCO-Clearwater who says that I need the kit as well part # N202M 837 for $533.90 to go on my 2004 M35BC

Mike
Irish Ayes
C350 #229
Pensacola, Fl

[TBOT422]

Mike,

You do not need the kit to install the Oberdorfer pump. Refer to my previous comments and photos on this thread for what I did. The spacing between the inlet and outlet ports are different, so there is some modifications you need to do to standard plumbing elbows to make them fit, or you may be able to use the existing elbows from the Sherwood. I chose to use new elbows and have the Sherwood rebuilt by Depco to use as a spare. I can swap out the entire pump in about 20 minutes rather than trying to replace the impeller if the pump fails. Realistically replacing the impeller doesn't fix the usual failure mode of the Sherwood pump which is leaking at the shaft, so I preferred to just carry it as a spare whenever the Oberdorfer eventually fails.

[Mark Sutherland]

Hi Mike,

I just installed the kit that you're referring to about 3 weeks ago. I had the boat out and under power for over 2 hours a couple weeks ago. Engine ran at 162 degrees, as always. My mechanic had not previously seen the OB/Sherwood swap-out before, but said he was impressed with it and of course the ease of changing the impeller. As far as the comment about "not needing the kit", the kit has the modified elbows in it, so if you don't want to modify the elbows yourself, then by the kit, which I believe is the part number you cited in your post. I cited all my part numbers in my earlier post from Nov 3, 2017 above. Good luck.

[jbd3]

I just got off the phone with Depco who is rebuilding my Sherwood pump. Total cost $180 tested with alcohol and supposedly now leak free with all new soft parts and some clips. Just another data point.

[roostermt]

Hey guys.

I bought the above mentioned kit and the elbows they sent me would fit a 1/2 inch hose not the 7/8 hose to the heat exchanger. I called them (Depco) and they said that was the correct size (1/2) and I must have something modified.

Any insight on this. Struggling to find a solution to the fittings.

Rooster

[wolfe10]

On Westerbeke's website:

https://www.westerbeke.com/parts%20manu ... 0final.pdf

Page 53 shows 1/2" male NPT to 7/8" hose as PN 030183.

Westerbeke Corporation
150 John Hancock Road
Myles Standish Industrial Park
Taunton, MA 02780

Telephone: (508) 823-7677