Dumped the Sherwood for an Oberdorfer pump

cjm1 · Aug 13, 2014

Good move to the Oberdorfer pump. I have heard Sherwood is kind of a weak pump but no first hand experience with it. I have over 800 hrs on 5432 and never a problem with the Oberdorfer (I think it is a 232 model). I renew the impeller about every 8 years or so.

gregorybross · Aug 13, 2014

Bob4203 said:
Geez, what's with these Sherwood Raw water pumps? I started up my M-18 only to find I had no water coming out the back! I took the cover off the Sherwood to find that the impellor (installed last year) was missing half the vanes!

My earlier posts on a leaking (water shaft seal) on the Sherwood warranted a new pump or a rebuild, but I did not think that the slight weeping would have any impact on the impellor as its flooding all the time from the intake.

Anyways, I researched and found the Oberdorfer for $235.00 with gasket and free delivery (prices ran the gamut on these things) and look forward to installing. I will replace the old hoses and take the heat exchanger off to check for blockage from any impellor parts.

Any secrets to installation?

Anyone have similar issues with the Sherwood?

Bob'88
Mark II

I recently replaced my Sherwood RWP with a Oberdorfer as the Sherwood was leaking sea water into the crankcase. The Oberdorfer is a much better unit in my opinion. Simple installation. I used some gasket sealant where it mounts to the engine block.

Greg

Scotty C-M · Aug 13, 2014

I've also had very good luck with the Oberdorfer (on my previous boat, a Catalina 34).

However, I hope you are checking the impeller every year (or so). Eight years is a long time for them to last.

Donnybrook · Aug 13, 2014

I changed to an Oberdorfer. Sherwood pumps are very difficult to rebuild. Oberdorfers are pretty easy. When shopping for an Oberdorfer, look for one that has the O ring instead of a gasket on the cover plate. The paper gaskets are a pain. Get a new gasket that goes between the pump and the engine. Make sure you have good water flow from the thru hull. You should not have had a failure on the impeller in just one season.

cjm1 · Aug 13, 2014

Another big help after a winter lay up is just a touch of Vaseline on the impeller before spring start up and pre prime with water so you don't startup with a dry impeller.

JK_Boston_Catalina310 · Aug 13, 2014

I have a slightly different motor but I made the change. I had to fabricate the base because it didn't just bolt on for my model. Still worth the effort.

Anonymous 121765 · Aug 14, 2014

Bob,

There's a forum thread here called "Impeller housing". I posted my thoughts on the poorly designed Sherwood pumps.

I said the Sherwood is poorly designed vs. Oberdorfer. The sh**t Sherwood is made up of 19 separate pieces for assembly. Are you kidding me?

Look at an exploded view & you can see why it fails. The Oberdorfer by comparison, far fewer parts without all the circle clips etc. Look at an exploded view of the Oberdorfer & the design & engineering speaks for itself.

As a designer, when I see a POOR design, what makes me furious, is that a project manager somewhere actually approved it.

Just goes to show you, "Not all engineers are created equal therefore, not all designs are created equal as a result".

CR

Anonymous 121765 · Aug 14, 2014

Bob,

Just throw the Sherwood out pal. Why save something that failed you?

I had two go bad on me in less than three years. Plus they charge an arm & a leg for this piece of Sh**t.

CR

jrowan · Aug 15, 2014

I agree Ron. I wonder if the later Universal engines accept a direct bolt on of the Oberdorfer pump, as my older model engine has a two part shaft, which notches together together to fit my 5411 engine. Do the later models use only a single piece shaft?

Anonymous 121765 · Aug 16, 2014

JR,

Hey dude. Here's something to find out what will work. I had the 5411, changed to a 3-blade, made my first Keys trip & blew the seals by the time I got back.

Just for info call Yacht Specialties in St. Pete. They rep universals(now Westerbeke).
727.822.2628, they will be able to tell you what will work. They're a good bunch of guys.

CR

Stu Jackson · Aug 16, 2014

CR's rreply #9 explained very well why the S is a POS, in detail, in addition to the rotten design with the screwy bolt access.

Many, many, many of our skippers have changed them out.

Here's a link to an M35 story, but the swap out on an M25 series or M18 should be more straightforward. If you have any questions, call Depco Pump in FL, THE guys to buy it from, too.

http://www.c34.org/wiki/index.php?title=Replacing_a_Sherwood_Water_Pump_with_an_Oberdorfer

You could do a search on this forum about Oberdorfer and have some more reading, too.

Dump the Sherwood.