Oberdorfer pump

[Ralph Masters]

Quick question for Stu or Ron, When looking at the front of the raw water pump on a 25xp engine which way does the impeller rotate. Clock wise or counter clock wise??

Ralph

[KWKloeber]

Quick question for Stu or Ron, When looking at the front of the raw water pump on a 25xp engine which way does the impeller rotate. Clock wise or counter clock wise??

Ralph

CCW. With the pump installed (7-o'clock-ish), the inzie from your thru hull is the BOTTOM port, the outzie to the Hx, the TOP port.

kk

[KWKloeber]

Oh, and when replacing the pump or the impeller, read my post on TechWiki about the cir-clip on the shaft and why it's on there.

kk

[crieders]

And stay away from Oberdorfer
Stay with Sherwood

[Ron Hill]

Ralph : It doesn't make any difference which way you have the blades facing when replacing an impeller.
After the first revolution all the blades will be in their correct position!!

Just use some liquid detergent to lube the inside of the pump cavity and the impeller blades.

A thought

[Stu Jackson]

And stay away from Oberdorfer
Stay with Sherwood

WADR, absolutely backwards.

[Ralph Masters]

Ron,
That was my guess, just stick it in.  I'm rebuilding an old pump, putting the new seals in tomorrow and putting the rest back together.
I'm not sure how old this pump was but I tried the little tool you show and I could not get it to move.
I ended up putting a carrige bolt down in it and drove the old seal out using that and a BFH.
Cleaning up the casing with CLR to get the green stuff out and reassemble tomorrow.
The one I got from a reputable guy on this web site has been working perfectly now for about 3 months, thanks Ron.

[KWKloeber]

And stay away from Oberdorfer
Stay with Sherwood

WADR, absolutely backwards.

See  http://c34.org/wiki/index.php?title=File:Camshaft_after_Sherwood_pumps_seize_up.jpg

kk

[Stu Jackson]

Further to Ken's link, here's a discussion of the shafts between the older & newer pumps.


http://c34.org/bbs/index.php/topic,6766.msg45766.html#msg45766

[KWKloeber]

Further to Ken's link, here's a discussion of the shafts between the older & newer pumps.


<<<In some of the OLD literature for M25 engines, there was a discussion that said, essentially, "If you pull out the shaft, you WILL have to remove the pump to reinsert the shaft."

That was because there was a female end on the shaft and a male end on the engine side.

The "newer" (mine's a 1986) Oberdorfer pumps have male end on the shaft and a female end on the engine side. >>>



http://c34.org/bbs/index.php/topic,6766.msg45766.html#msg45766

Stu,

I have to take issue with/correct the statement about "old" and "new" pumps having different shafts. 

My '84 M-25 had a female shaft pump, and another M-25 a year older had the male shaft.  It not a matter of the age of the pump or engine, it's which Ob pump that Universal/Westerbeke had and installed on any particular engine.  Two engines on the line in the same year (or month even) -- one could have had a female shaft, and the other a male shaft.   In fact, I still have my adapter plate and shaft adapter -- and I could buy a brand new Ob 202M-07 pump, and it would fit my M25 and have a female shaft.

ken

[Stu Jackson]

Yeah, we're splitting hairs.     I think we all understand the way the engines were made, thanks to your excellent wiki article, and that some "newer" engines could have the "older" shafts.  In the larger scheme of things, the "old style" shafts eventually stopped being installed in the C34s.  IIRC, from Ron's many reports, it was only a handful of the earlier hulls.  The purpose of my linked report was, as part of the pump rebuild photos, was to show how the two parts - shaft and insid engine - mated.  Thanks for the clarifications.

[Ron Hill]

Ralph : Good for you on the carriage bolt!! 
I just made my tool so I made sure that the wall of the pump housing didn't get scratched.
 
You can use any object even a screwdriver just as long as you don't scratch or scar the inside wall!!