Swapping raw water pumps

Sanman

.
Aug 28, 2006
109
- - Birmingham, AL
Hi Guys!
Quick question, Need to change my impeller at some point, and I was going to do last week, But as I began the process, I realized that the pumps bolts are facing the engine block and I didnt have enough room to get at the bolts...:doh:

The pump is on a Universal Mx 25 B. The pump is a surflo and has the marking "-4" on the pump. I'd like to swap the pump out to one that is more easily accessible with a cover plate on the front, because this one looks to be a complete PITA.

What make should I look at, and how big of a deal is it to change out the pump?

I realize that if I ask 4 fellow sailors a question I'll get 5 different answers, but figured I would ask anyway! :D

Thanks in advance!
 

Bob S

.
Sep 27, 2007
1,805
Beneteau 393 New Bedford, MA
I think you'll find an overwhelming consensus will be the Oberdorfer N202M-15 or -16 depending on the NPT threads you prefer.
 
Jul 1, 2004
398
Catalina 30 Atlanta GA
I just bought an Oberdorfer N202M-15 (Google this and watch the wide range of prices out there!!). I paid $237.00 + shipping.

I am going to install it this weekend on my Universal M-18. I noticed it did not come with a rear gasket that faces the engine block. Do I really need a gasket here since the bearings seal out water and oil and the shaft comes out of a flange to fit internally into the block?

My old Sherwood did have a gasket at this rear attachment location, but I would rather opt for some liquid type sealant (small bead around the flange) as recommended by one installer.

Please advise on the gasket...........:confused:

Thanks all

Bob
1988 Mark II
"Breezin II"
 
Sep 22, 2013
24
Catalina 30 NOB Norfolk W5CDR
I have been reading several posts, in several places, about the Sherwood to Oberdorfer water pump change out. What I haven't seen is a compatibility note for the M3-20B engine.

Which Oberdorfer pump is appropriate for my engine? The original attachment of my Sherwood pump is a clamp-on system, not a direct bolt on unit.

Thanks in advance,

Sean
s/v NAMELESS