More Oberdorfer Raw Water Pump Info

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
In my opinion yes. I'm not a big fan of the clamps holding in my Oberdorfer.
I thought it might be possible to leave some of the flange on the -16 and use the bolt holes, rather than the clamps, but there is not enough room on the engine block for the larger flange, so I went with the clamps.
 
Jan 22, 2008
214
Catalina 310 #147 Oakville Yacht Squadron
I thought it might be possible to leave some of the flange on the -16 and use the bolt holes, rather than the clamps, but there is not enough room on the engine block for the larger flange, so I went with the clamps.
Not sure if it will come through or not, but I tried to attach a shot of my custom Sherwood. Being in fresh water, I do not anticipate the seal failures experienced by many. Also given a much easier and controlled assembly there is much less chance of a gasket or O-ring leak on that stupid intermediate plate.
My mind is still boggled that Sherwood didn't fire the geek that designed that pump; he certainly wasn't either a mechanic or a DIY owner.
Peter
 

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gpd955

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Feb 22, 2006
1,164
Catalina 310 Cape May, NJ
How ironic that this topic is so recent and my 3 season old(probably 15 hour use) Sherwood was going drip, drip, drip at the first start of the season. Gonna give the Oberdorfer a shot this time!
 

KZW

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May 17, 2014
831
Catalina 310 #307 Bluewater Bay, FL
How ironic that this topic is so recent and my 3 season old(probably 15 hour use) Sherwood was going drip, drip, drip at the first start of the season. Gonna give the Oberdorfer a shot this time!
As the cost of the -908 has risen to become prohibitive, if you have access to a grinder, or hack saw and Dremel tool, suggest the -16 and rework the flange.
 
May 2, 2012
276
Catalina 310 Toronto, Ontario
I finally found a source here in Canada for the N202M16 (FNFP) OBERDORFER - LIP SEAL TYPE;

Now, what I'm not sure of is what these mean LIP SEAL TYPE & FNFP. Has anyone any idea what they mean and is it going to have any effect on the installation of the pump on my M-25XPB. I know I have to cut & grind a bit here and there.

Cheers
2 Old Pirates:D
 

gpd955

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Feb 22, 2006
1,164
Catalina 310 Cape May, NJ
As the cost of the -908 has risen to become prohibitive, if you have access to a grinder, or hack saw and Dremel tool, suggest the -16 and rework the flange.
Already ordered it and received it (2 days). Question KZW....is there a gasket needed on the -908 or is it already there, under the metal? It's hard to tell in the horrible light I have.
 

KZW

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May 17, 2014
831
Catalina 310 #307 Bluewater Bay, FL
Already ordered it and received it (2 days). Question KZW....is there a gasket needed on the -908 or is it already there, under the metal? It's hard to tell in the horrible light I have.
The -908 has a paper gasket. The -16 has an O-ring.
 

gpd955

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Feb 22, 2006
1,164
Catalina 310 Cape May, NJ
Gotcha. Thought I had a defective product.

My picture didn't upload from the mobile site so FWIW here it is! Ironically when I saw my picture on the computer as opposed to on the phone, and thanks to the flash, I was able to see the lip seal, which is a little different than on the Sherwood.

Thanks for the quick reply!
 

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gpd955

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Feb 22, 2006
1,164
Catalina 310 Cape May, NJ
Oberdorfer -908 popped right in. Not a single drip. Well worth the few extra $ for the simplicity. Now to recondition the Sherwood as an emergency spare!
 
May 2, 2012
276
Catalina 310 Toronto, Ontario
CSOB_00_365 MMI 502 flange pump ...... just found out that this won't work on the M-25XPB Universal. Right from the horses mouth. You need an adapter which costs $115 US. + $289 US. = $404 :eek: ........ definitely not worth it. Back to the modified N202M-16.

Cheers
2 OLD PIRATES
 
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Feb 14, 2012
1
Westsail 32 Rio Dulce Guatemala
Here is a potential problem with the Sherwood G-908 (or Westerbeke 42175) and possibly the Oberdorfer N202M-908 as well;

I have a Universal (Westerbeke) M50B with the Sherwood G-908 pump. Fortunately I was at the dock when the Sherwood simply quit pumping. I recently replaced the impeller (12-15 engine hrs ago) but I opened the pump to check if somehow the impeller was at fault but it appeared fine. It was at that point I 'bumped' the engine and found the impeller was not turning. I removed the pump housing and found the internal drive shaft was rotating just fine.

A Universal/Westerbeke mechanic informed me it was a problem he has repaired a number of times. Apparently the 'Tab A' on the Sherwood pump only engages 'Slot B' on the internal drive shaft MAYBE by about 1 mm. After a while the end of Tab A becomes worn and simply does not engage the drive shaft anymore (in my case <1000hrs). His solution is to have a welder build up the length of Tab A (or the face of the internal drive shaft, ideally both) another couple mm such that it extends deeper into the slot of the drive shaft. Additionally, it may be possible to mill the face of the pump a tad (so the shaft extends deeper) without compromising the structural integrity of the pump housing. Every teeny bit gained extending the pump shaft tab into the slot helps.

Note although the mechanic told me of this problem before he even knew what engine I had, this may only apply to a Universal/Westerbeke M50B. I am considering replacing the Sherwood pump with an Oberdorfer N202M-908 which is the recommended 'drop in replacement' (per mounting requirements). However, if it is an 'exact' replacement I'm concerned the length the Oberdorfer pump shaft tab is the same as the Sherwood. Comparing dimensional line drawings of the Oberdorfer with Sherwood dimensions I find the Oberdorfer shaft length is .55 while the Sherwood looks to be .518 (as best I can measure it with a micrometer). While better, I'm not entirely convinced it is enough.
 
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Nov 16, 2012
1,037
Catalina 310, 2000, #31 31 Santa Cruz
I finally looked at the pump on our engine (M25XPB) and was happy to see it's the Oberdorfer N202M-16. So somebody did the replacement already for me! I wanted to replace the impeller and o-ring, and while tracking down parts discovered that the o-ring is a standard size #034, Viton. You can buy a bag of 25 for $10 from McMaster, compared to $10-15 each from Oberdorfer. Just an FYI.

Turns out the impeller has the circlip installed, so I'm stymied until I remember to bring my circlip tool down to the boat. Luckily the impeller looks to be in pretty good shape.
 
May 7, 2011
281
C - 30 # 3573 Lake NormanNC formerly Bflo NY
Turns out the impeller has the circlip installed, so I'm stymied until I remember to bring my circlip tool down to the boat. Luckily the impeller looks to be in pretty good shape.
Owners with the Oberdorfer 202M series pumps should remove the cir-clip and deep six it. There is no reason to have it and it serves no function once the pump is installed on the engine (M-25, XP, or newer B-series engines.

I put an article on the C34.org TechWiki site that explains why and the history of searching this out. Removing the cir-clip makes for an easy and quick change out of the impeller (yah know, like when you've overheated, the engine is down, and you;re headed toward a reef.)

Ken
 
May 7, 2011
281
C - 30 # 3573 Lake NormanNC formerly Bflo NY
To avoid the fight with the bolts next time you have to remove the pump, I would recommend using some kind of anti-seize. I use Tef-Gel and Lanocote depending on the use.
Care to share the cost of the pump?
Alternately, with a new 202M-908 pump for the B-series engines or a 202M-15/16 pump for the M-25/XP/XPAs, I offer a no charge kit to replace the bolts with stainless studs and nylock flange nuts -- eliminating threading and torquing the bolts into the crappy metal on the gear cover once and for all.

Ken K
 
Nov 16, 2012
1,037
Catalina 310, 2000, #31 31 Santa Cruz
Owners with the Oberdorfer 202M series pumps should remove the cir-clip and deep six it. There is no reason to have it and it serves no function once the pump is installed on the engine (M-25, XP, or newer B-series engines.

I put an article on the C34.org TechWiki site that explains why and the history of searching this out. Removing the cir-clip makes for an easy and quick change out of the impeller (yah know, like when you've overheated, the engine is down, and you;re headed toward a reef.)

Ken
I remember reading that article. Great story! Thanks for all your help.
 
Feb 26, 2004
22,760
Catalina 34 224 Maple Bay, BC, Canada
Removing the cir-clip makes for an easy and quick change out of the impeller (yah know, like when you've overheated, the engine is down, and you;re headed toward a reef.)

I always felt a spare shaft with an impeller already mounted is quite quicker. :)

But Ken's right.
 
May 2, 2012
276
Catalina 310 Toronto, Ontario
What makes me laugh is that Oberdorfer has acknowledge that there is a need for the 908 and also must know that the 16 is being altered.
My question is to them is, wouldn't you sell a hell-of-a-lot more 908s if you brought the price more in line with the 16s ? DAH !!! :confused:
Outside of the base there is NO difference between the 908 and 16.:yikes:
I know I sure wouldn't hesitate to buy one.

Cheers
2 Old Pirates