I'm still researching the correct pump. I've pretty much determined the issue with the Oberdorfer is the spacing between inlet and outlet when one tries to re-use the elbows from the Sherwood. There isn't enough clearance for the second elbow to swing past the first elbow. I think installing one of the elbows then cutting a bit off the barb on the second elbow is the solution. The Oberdorfer N202M-837 is simply an Oberdorfer N202M-908 with two short barb elbows and about $70 added to the price.
The online pricing for the 908 varies significantly. Lowest so far is $326. Dennis C. Touche' 35-1 #83 Mandeville, LA On Thu, Mar 29, 2018 at 1:04 PM, Matthew L. Wolford via CnC-List < cnc-list@cnc-list.com> wrote: > I’ll need to see what I have, but I believe the pump on my Westerbeke 40 > is the brass plate version you described. A significant problem with my > pump is inadequate suction. We have looked repeatedly to see if impeller > pieces were sucked into the system (found a couple). The suction is so > weak that I need to do the funnel-from-on-high routine to get the system > working after spring launch. I also sometimes need to do the funnel > routine after being heeled over and bouncing around in bad weather. I > would welcome a more powerful pump. > > *From:* Dennis C. via CnC-List <cnc-list@cnc-list.com> > *Sent:* Thursday, March 29, 2018 1:01 PM > *To:* CnClist <CnC-List@cnc-list.com> > *Cc:* Dennis C. <capt...@gmail.com> > *Subject:* Stus-List Universal / Westerbeke Sherwood raw water pump > upgrade > > For those of us who have Universal or Westerbeke diesels that use the > Sherwood G908 clamp mount raw water pump, here's some news. (The > Westerbeke number is sometimes 42175.) > > Changing the impeller on the Sherwood is a bit of a pain because the bolts > come in from behind. You can either remove the pump by removing the two > clamps, or remove the pump case by removing the 3 bolts and lifting the > case off. Then you have to make sure the o-ring is properly seated upon > reassembly. > > Another issue with the Sherwood is that it often leaks. Unlike many pumps > that have a shaft seal, the Sherwood impeller seals against a brass wear > plate on the back of the pump. If the wear plate, which is fairly thin, > bows outward or has excessive wear, the pump will leak raw water. In a > salt water environment, this tends to have a deleterious effect on the > engine front. > > I replaced the thin wear plate on my Sherwood with a thicker stainless > wear plate that I found on eBay. That helped reduce a nagging leak. > > Although I don't need it yet, I found a drop in replacement, Oberdorfer > N202M-908. This pump is a more traditional design with shaft seals. > Access to the impeller is from the front by removing the cover plate. > > The Oberdorfer N202M pump has been around for many years and is a standard > marine engine raw water pump. A version is used on the good old Atomic 4. It > fits many marine diesels by being available in several models. The > differences are in the mounts for attaching it to the engine. Some > resourceful boat owners have modified Oberdorfer N202M-16's to fit the > clamp mount configuration. Oberdorfer now offers the clamp mount as the > 908 model. > > I found one thread on a Catalina owners site which questioned the pumping > capacity of the Oberdorfer on an M-35 engine. I was not able to find the > capacities of the two pumps but found many posts from boatowners who were > using the Oberdorfer N202 series pumps on various Westerbekes and > Universals successfully. > > The other good news is the Oberdorfer is a fraction of the cost of the > Sherwood. > > I'm considering replacing the Sherwood with the Oberdorfer even though the > Sherwood is doing fine....right now. > > Dennis C. > Touche' 35-1 #83 > Mandeville, LA > > ------------------------------ > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > >
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