Sherwood Pump G-3

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Paulus

Searched the message board and found on G-908 pumps.  My M25xp engine has a G-3 sherwood pump.  Would like to rebuild this pump this winter.
Appreciate any help. Paul
Cool Change 1989 #944

KWKloeber

Quote from: Paulus on January 21, 2016, 08:15:43 AM
Searched the message board and found on G-908 pumps.  My M25xp engine has a G-3 sherwood pump.  Would like to rebuild this pump this winter.
Appreciate any help. Paul

Thst's a G-903, no longer sold due to westerbeke proprietary rights.   Identical to the 908.
Go with an oberdorfer replacement. Ask those who have! 
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Stu Jackson

#2
Paul, go to either or both the C34 tech wiki or the 101 Topic.  There is also a rebuild article in the tech notes online.

Like these:

This link is important because it shows the tool that Ron Hill built to get the old seals out (1/4 inch hex head Allen wrench ground down to fit).  second picture, link to Ron's article:  http://www.c34.org/mainsheet/pdf/May_2002.pdf

The C34 Tech wiki also has that article:  http://www.c34.org/wiki/index.php?title=Raw_water_pump,_impellers_and_cooling_system
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Paulus

Thanks, found the article in Wiki under engine.  I had replaced this one about 8 years ago finally getting around to rebuilding it.  This was the original pump on my 1989 boat.
Thanks again, Paul
Cool Change 1989 #944

Paulus

#4
G 3 Sherwood pump is not the same as G903 or G908.  Depco had a separate parts list for the G3.  It has no seal at the engine side, the bearings are lubricated by engine oil.
The cost of rebuilding was only $30.oo .  Will serve as a backup. 
Thanks,
Paulus
Cool Change 1989 #944

KWKloeber

#5
Quote from: Paulus on February 04, 2016, 06:43:37 AM
G 3 Sherwood pump is not the same as G903 or G908.  Depco had a separate parts list for the G3.  It has no seal at the engine side, the bearings are lubricated by engine oil.
The cost of rebuilding was only $30.oo .  Will serve as a backup. 
Thanks,
Paulus

The Sherwood G3 (discontinued) is a bolt-on pump with 1-1/2" ports.  Something is amiss.
Pic below and also the pump print.

Ken



Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Paulus

Thanks Ken, called Depco again and they want to see a pic of my pump.  They are going to hold the order until they can view the pump.  He does think that these two pumps have the same parts on the inside??
Thanks,
Paulus
Cool Change 1989 #944

KWKloeber

Quote from: Paulus on February 04, 2016, 07:58:22 AM
Thanks Ken, called Depco again and they want to see a pic of my pump.  They are going to hold the order until they can view the pump.  He does think that these two pumps have the same parts on the inside??
Thanks,
Paulus

Is the "G3" on a tag or on the casting?

If you haven't been -- talk to no one but George C at Depco -- he's Da Man on marine pumps.  I was just emailing him re: the casting no. vs the pump no.

Ken
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Paulus

Ken, it is stamped on the casting  Paul
Cool Change 1989 #944

KWKloeber

Quote from: Paulus on February 04, 2016, 08:48:14 AM
Ken, it is stamped on the casting  Paul

Paul,

That's a casting number, not the pump model number.  The pump model is on a metal tag (probably lost) on a screw.
You have a G-903 pump - some of the parts (seal, bearing, cover - whatever) are often shared between multiple pumps so the model numbers are not stamped on the parts.

The "best" pump -- all things considered -- is the bolt-on BRONZE Oberdorfer, doing away with the stupid CAST IRON Sherwood and the even more stupid clip attaching system.  There's M25 owners who have ruined their camshafts when the Sherwood pump seizes up and snaps off the drive fork inside the engine.  YBYC

Ken
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Paulus

Ken,
you were right, it is a 903.  Same diameter shaft as the G 3.  The G 908 has a larger shaft.  Which oberdorfer pump would you recommened for my M25xp?
Rebuilding my old pump for a back up. 
Thanks, Paulus
Cool Change 1989 #944

Stu Jackson

#11
Quote from: Paulus on February 04, 2016, 11:48:47 AM
Which oberdorfer pump would you recommened for my M25xp?


Paul, from the tech wiki:  Rebuilding an OBERDORFER Raw Water Pump with Flix includes MODEL numbers for the Oberdorfer replacement pumps, see reply #12:  http://c34.org/bbs/index.php/topic,6766.0.html
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

KWKloeber

Quote from: Paulus on February 04, 2016, 11:48:47 AM
Ken,
you were right, it is a 903.  Same diameter shaft as the G 3.  The G 908 has a larger shaft.  Which oberdorfer pump would you recommened for my M25xp?
Rebuilding my old pump for a back up. 
Thanks, Paulus

The N202M-16, which has 1/2" ports, and is a bolt-on (instead of the Sherwood clips.)



You can certainly reuse the same bolts for the Sherwood clips, but with a new Ob pump I've put together a N/C kit to install stainless studs and stainless nylock flange nuts instead of reusing the bolts (so no lock washer necessary) and you're no longer threading and torquing bolts into the cast metal gear cover when you service the pump.

In addition, the Sherwood elbows are cast brass, (not bronze as most people think.)  They're ok if in fresh water, but for salt they are not recommended.  I also always recommend replacing the elbows with straight-in hose barbs to eliminate the additional restriction on the inlet/outlet.  I also use the OEM Kubota mounting gasket, which is better than the Westerbeke gasket.

The other issue is that the hoses should be double clamped (not possible with the Sherwood elbows.)  Unfortunately there's no decent bronze hose barbs available, but there's other options. 

Lastly, the Ob pump come with a cir-clip on the shaft (to the untrained eye it appears to hold the impeller in place.)  It's useless and the only function is it makes it more difficult to switch out the impeller (critical in an emergency when you've left the thru hull closed, overheating, shut down, and drifting toward a breakwall (been there.) 

See my article on the circlip:

http://www.c34.org/wiki/index.php?title=Why_do_some_of_our_engines_have_different_Oberdorfer_sea_water_pumps_than_others,_and_what_about_that_cir-clip_%22holding_the_impeller_on%22%3F


Email me off list if interested.
http://c34.org/bbs/index.php?action=emailuser;sa=email;msg=62998


Cheers,
Ken
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Stu Jackson

#13
Quote from: KWKloeber on February 04, 2016, 12:36:54 PM

The N202M-16, which has 1/2" ports,

Before you spring for 1/2" ports, make sure what size your HX ports are.  IIRC, my old hoses were 1/2" but when I replaced my HX I found the PO or someone else had clamped 1/2" hose on a 5/8" HX port!!!  I was NOT amused.   :D  I simply replaced the ports on the pump to 5/8".

You should be able to get whatever size you actually need from Depco when you order the pump, or from Ken, too.
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

KWKloeber

Quote from: Stu Jackson on February 04, 2016, 01:29:40 PM
Quote from: KWKloeber on February 04, 2016, 12:36:54 PM

The N202M-16, which has 1/2" ports,

Before you spring for 1/2" ports, make sure what size your HX ports are.  IIRC, my old hoses were 1/2" but when I replaced my HX I found the PO or someone else had clamped 1/2" hose on a 5/8" HX port!!!  I was NOT amused.   :D  I simply replaced the ports on the pump to 5/8".

You should be able to get whatever size you actually need from Depco when you order the pump, or from Ken, too.

The M-16 pump port size is 1/2" female NPT, but the hose barbs (should be) 1/2" NPT x 5/8" barb.  Stu, if you had 1/2" barbs on the pump they are unusual - or are you saying that the pump hose elbows were indeed 5/8" -- but that had a 12" hose on them??

The raw water inlet barb on the M-25, M-25XP, and M-25XPA heat exchangers are 5/8".

Ken
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain