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JAS's picture
JAS
Last seen: 5 months 1 day ago
Joined: 12/16/12
Posts: 256
Update on Oberdorfer water pump replacement

Just an FYI for anyone thinking of replacing their Sherwood water pump with the Oberdorfer ​​n202m-15 on an Universal M-35.

The replacement went pretty smooth for the most part.  I encountered a couple of hickups during the replacement.  No big deal, but I thought learning about them might save some time for someone who has the job planned in the not too distant future.

1. I had to order a 90 degree nipple because the water inlet and outlet hoses are located closer together on the Oberdorfer causing the 90 degree nipples to run into each other when you try to thread them on.  To solve this problem I ordered a single 90 degree nipple from Catalina Direct that has a shorter barb for the hose, thus creating the clearence necessary to screw it on.  Unfortunately, the new 90 degree nipple is meant for a different hose size than the original, so I elected to use my dremel tool to quickly grind down the barb on one of the original Sherwood  fittings until there was enough clearance to thread it onto the Oberdorfer.  Once I had the right clearence, I simply smoothed out the rough edges and voila, worked like a charm...and I didn't have to buy new hoses!

2.  The Sherwood only requires two bolts to attach it to the engine block.  The Oberdorfer takes four bolts.  I thought about only using the two bolts to attach it, but then I thought "how stupid would that be when bolts are so cheap!"  There are indeed four threaded bolt holes in the engine that perfectly match the bolt pattern on the Oberdorfer.  However, the two unused bolt holes had allen screws in place of bolts to keep them sealed up.  So I backed them out and bought 4 new bolts and lock washers.  I didn't reuse the old bolts because they are too long and bottom out before they get a chance to tighten down on the Oberdorfer, so I bought the next size shorter.  The new bolts are stainless steel...I hope that's not a problem in terms of dissimilar metals (anybody know anything about that?).  And finally, as many others have talked about, I had to slightly grind down the top left side of the Oberdorfer mounting bracket so it would clear a post the sticks out of the M-35 just above it.

3.  I finished off by pouring water in the Oberdorfer water pump and the hoses to prime it before attachment.  This prevents the impeller from burning up when you first start it.  I would have not have thought to do that if it were not for this website!

Anyway, hope this helps someone who might be thinking about doing the job in the near future.  It was quite easy...even when you add in the grinding and the extra trip to the hardware store for new bolts/lockwashers.

Joel Schwartz
s/v Get-A-Grip
1993 Catalina 36 Hull #1259
Newport Beach, California

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Joel Schwartz
s/v Get-A-Grip
1993 Catalina 36 Hull #1259
Newport Beach, California
Catboat Willy's picture
Catboat Willy
Last seen: 22 hours 31 min ago
Joined: 12/22/14
Posts: 234

Joel;
 It seems as if there are several different models of the Oberdorfer pump that can be used on the Universal  M-35 engine. I'm curious as to how you were led to the model N202M-15 pump. Reason I ask is that when I went through this process, I spoke with both Oberdorfer in Syracuse and an outfit called DEPCO PUMP here in the Tampa area and explined that I have the M-35 engine. They both recommended the new  model Oberdorfer N202M-908 since it has a circular base and no grinding would be necessary  to modify the pump base to fit on to the engine.  . (see picture below)
That pump came with two hose nipples, bolts and clamps from Oberdorfer that fit the pump on to the engine. But I certainly do like the idea of fitting the extra bolts as you have done.
For what it's worth, I got about 350 hours of operation out of that pump before it was sent out for rebuilding to Cardinal Pump in St. Louis, MO. Seems they'll rebuild them for cheaper than you and I can buy the rebuild kit.Cardinal Pumps are also know as PUMPSANDPARTSONLINE.
All the best, Bill

Attachments
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Bill Dolan 1990 Catalina C-36 MKI - Hull #1041  'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Port Charlotte, FL
'You are never out of work if you own a boat'

 
JAS's picture
JAS
Last seen: 5 months 1 day ago
Joined: 12/16/12
Posts: 256

Hi Bill,

I had no idea that there were other Oberdorfer pumps to choose from.  I believe I saw the N202M-15 advertised as a replacement for the Sherwood on the Catalina Direct website.  But I found it significantly cheaper somewhere else, so I purchased it there.  However, the place I bought it from did not include, nor did they sell, the gasket that is required between the pump and the engine.  So I had to track down a gasket before I could complete the job.

Had I known about your version of the Oberdorfer pump, I probably would have went with that because it more closely matches the mounting setup of the original Sherwood pump.  But now that I have the experience of putting the N202M-15 on my engine, I think I prefer the four bolt version as it strikes me as the more robust setup of the two.  That said, either model is better than the Sherwood as certified by virtually every boater out there...so both pumps are more than up to the task.

Just out of curiosity, did the new hose nipples that came with your unit match your original hoses, or did you have to buy new ones?

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Joel Schwartz
s/v Get-A-Grip
1993 Catalina 36 Hull #1259
Newport Beach, California
JAS's picture
JAS
Last seen: 5 months 1 day ago
Joined: 12/16/12
Posts: 256

One curiosity question regarding Bill's pictures above:

Does anyone know what that brass looking bolt/cap on the right side of Bill's water pump is for? I have the same bolt/cap on mine.  I took it out of my unit thinking it is designed to poor water down as part of the priming process, but all I found was what looked like a wax seat/seal that the end of the bolt butts up against at the bottom of the threads.  In the center of the wax seat/seal is the tinniest pinprick of a hole.  Does anyone know what that thing is for?

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Joel Schwartz
s/v Get-A-Grip
1993 Catalina 36 Hull #1259
Newport Beach, California
LeslieTroyer's picture
LeslieTroyer
Last seen: 1 day 3 hours ago
Joined: 3/13/16
Posts: 456

I think the bolt/cap is where the grease cup would go if fitted.  The grease cup gets 1/2 turn every 10hrs

Les

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Les & Trish Troyer
Mahalo 
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 
JAS's picture
JAS
Last seen: 5 months 1 day ago
Joined: 12/16/12
Posts: 256

Hi Les, my Oberdorfer did not come with any instructions.  There was no grease inside my grease cup when I opened it up.  Is the grease necessary?  If so, what kind of grease?  How much should I fill it with grease?  Am I damaging the water pump by running it without grease in the grease cup?  Inquiring minds want to know!!!

Thanks a bunch--JAS

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Joel Schwartz
s/v Get-A-Grip
1993 Catalina 36 Hull #1259
Newport Beach, California
JAS's picture
JAS
Last seen: 5 months 1 day ago
Joined: 12/16/12
Posts: 256

For whoever might be following this "grease cup" thread.  It turns out I bought an older Oberdorfer ​N202M-16 water pump.  The older one has the grease cup on it.  There is a newer ​N202M-16 that sells for a bit more on the Catalina Direct website, and I am sure elsewhere, that has done away with the need for a grease cup.  I totally would have bought that one instead of my current model, had I known about it.  The idea that you have to remember to turn the grease cup every couple of motoring days is something I would rather not have to remember, not have to clean out, not have to refill, and not have to hassle with in general.  Oh well, what is done is done.  Hopefully someone sees this thread before they buy the same pump so they can avoid the same mistake I just made.  It's not a huge mistake by any means, but it is an extra aggravation that was totally avoidable had I known better--JAS

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Joel Schwartz
s/v Get-A-Grip
1993 Catalina 36 Hull #1259
Newport Beach, California
Haro's picture
Haro
Last seen: 7 hours 48 min ago
Joined: 11/7/14
Posts: 240

My Oberdorfer N202M-16 that I had to modify the mounting base for M35B engine is identical to your pump with the bolt under it. I was told that this was to drain the liquid from the pump. I have never added any grease or turned it. I believe it is fastened with white pipe thread tape and can not be turned. I have several 100 hours on it and works just fine without any grease. This pump was originally designed to pump Mild chemicals so it can be used for any type of application. Grease cup is used on N202M-07 and earlier
See the link below

http://www.downwindmarine.com/Oberdorfer-Model-202M-Rubber-Impeller-Pumps-Universal-Engines-p-91002307.html

 

Catboat Willy's picture
Catboat Willy
Last seen: 22 hours 31 min ago
Joined: 12/22/14
Posts: 234

Joel;
 There was a good discussion on all of this here on the site. Check out https://www.catalina36.org/forum/technical-discussion/raw-water-pumps

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Bill Dolan 1990 Catalina C-36 MKI - Hull #1041  'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Port Charlotte, FL
'You are never out of work if you own a boat'

 
pierview
Last seen: 2 weeks 2 days ago
Joined: 9/27/09
Posts: 476

Joel... the nipples did not work on mine..... one hose is larger in diameter than the other but the two new nipples were of the same, smaller diameter. I used the old  larger ripple from the Sherwood and it worked fine.

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Chuck Parker
HelenRita 2072 Mk II
2002 Tall Rig - Winged Keel
Atlantic Highlands, NJ

Catboat Willy's picture
Catboat Willy
Last seen: 22 hours 31 min ago
Joined: 12/22/14
Posts: 234

Joel.

Let me see if I can answer a few questions; After a discussion with Oberdorfer, here is what I found. First; The brass fitting on the pump housing (small brass  bolt) is used to connect a pressure gauge -( if required) It's used more in industrial applications and  most of our sailboat motors do not need it.

Second; This pump uses a special type of carbon-graphite bearing on the main shaft lip seal and does not require any type of lubrication hence the absence of a grease cup. As a matter of fact, certain types of lubricants can be harmful to the shaft lip seal.

Third; The N202M-908  is a newly designed pump offering from Oberdorfer that went into production in late 2014 and became available in early 2015. The pump was designed for Universal Engines that are currently using the Sherwood Pump and should fit any Kubota/Universal engine without the grinding as required on earlier Oberdorfer type -15 and -16 pumps.

Fourth; The pump is available either as a stand alone or in kit form. The KIT is supplied with all necessary parts for installation including, new elbows, mounting ears, high tensile  strength metric screws and gaskets. The elbows are set for the standard 5/8's I.D. inch hose as used on our engines. It's Important to note - that because of the close spacing of the pump's water outlets, your  elbows that are currently used on the existing Sherwood Pump, may not fit on this pump with out modification. This is why the elbows are supplied in the 'kit'. I installed the 'KIT'

Fifth; The pump only is identified with the Oberdorfer model number; N202M-908

The 'KIT' containing the pump and all parts required for installation is identified as Oberdorfer model number; N202M-837 and will only be stocked by certain dealers. This kit is not as yet listed on the Oberdorfer website (? they just haven't gotten around to up dating the website ! ).
The price for the 'KIT' is currently $385.00 in stock in St. Louis, MO and shipped from;  https://www.pumpsandpartsonline.com/shop/oberdorfer-pumps/rubber-impelle....
Tel; 314-628-0100
Mention the Catalina Association and receive free shipping.
Replacement Impellers are $28.00 each.

One other interesting comment from our my discussion with Oberdorfer was why raw-water pumps generally fail. Not surprisingly, it's because they run out of water rather than get worn out. The biggest culprit seems to be a blocked or restricted flow water in the sea water strainer. Running for sixty seconds at cruise speed without water in the pump, is enough to destroy the impeller.
I hope that helps.
I'm on the way to check my sea water strainer...............

 

Attachments
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Image icon IMG_0713S.JPG105.59 KB
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Bill Dolan 1990 Catalina C-36 MKI - Hull #1041  'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Port Charlotte, FL
'You are never out of work if you own a boat'

 
LeslieTroyer's picture
LeslieTroyer
Last seen: 1 day 3 hours ago
Joined: 3/13/16
Posts: 456

Thanks Joel - lots of good info.

Les

--
Les & Trish Troyer
Mahalo 
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 
alfricke's picture
alfricke
Last seen: 4 weeks 1 day ago
Joined: 4/14/09
Posts: 38

Folks...I have been following the Sherwood/Oberdorfer issue for several years. Like most, I would love to have a pump that has easy access from the front. I am about to make the jump and get the kit form (I have the 35B). What is making me nervous is the number of owners who have experienced weep hole "dripping" with new Oberdorders with what appears to be not very much usage. This has led to discussions of rebuild kits, returns to factory etc. On the other side of it, my Sherwood just keeps on pumping with no need for rebuild or anything other than prophylactic impeller replacement every 200 hrs. I've put on about 1000 hrs on the present pump in 7 years with no problem so far. So, I'm knocking myself on the head with the old "If it ain't broke, don't fix it" adage. Thoughts or different experiences?

 

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Al Fricke
S/V Jubilee
Catalina 36' MkII  #1867
pkeyser's picture
pkeyser
Last seen: 23 hours 45 min ago
Joined: 5/18/13
Posts: 397

About a 100 hours on my Oberdorfer replacement- no issues/weeping up to this point. Had a similar one on our M25 (C30). It needed a rebuild (seals) at about 650 hours. It did run dry a few times with clogged intake.

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Paul & Wendy Keyser
"First Light"
Newburyport MA/Rye NH
2005 C36 MKII #2257
Wing, M35B

Gsmith's picture
Gsmith
Last seen: 4 hours 41 min ago
Joined: 11/25/10
Posts: 108

400 hrs over 4 seasons with no leaks, ran dry once from clogged intake and burned up impeller.

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Gary Smith
93 MK I, Hull #1231
Std rig; wing keel
M35A Oberdorfer conversion
 

William Miller
Last seen: 1 month 2 weeks ago
Joined: 10/4/08
Posts: 291

I have had my pump for 2.5 years and about 250 hours and today was the first time I changed the impeller.I could not get the snap ring on and had to pull the shaft out and put the ring on .With the shaft in the grove for the snap ring was not far enough out .Has anyone else had this problem? Also one of the impellers would not fit on the shaft too tight but the other fit fine ,called oberdorfer and he said it must have been the 1% that are bad

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Bill Miller
S/V Lorraine
Pacific Northwest,Sound Sound
Grapeview,Wa
1990 Mk1

LeslieTroyer's picture
LeslieTroyer
Last seen: 1 day 3 hours ago
Joined: 3/13/16
Posts: 456

You can leave the snap ring off. It serves no useful purpose once pump is mounted on the engine.  It is there to prevent loosing the shaft while on the shelf. 

Les

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Les & Trish Troyer
Mahalo 
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 
William Miller
Last seen: 1 month 2 weeks ago
Joined: 10/4/08
Posts: 291

I like that idea ,but does it rub against the cover to do any damage?

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Bill Miller
S/V Lorraine
Pacific Northwest,Sound Sound
Grapeview,Wa
1990 Mk1

William Miller
Last seen: 1 month 2 weeks ago
Joined: 10/4/08
Posts: 291

Thanks Less for your answer,I called oberdorfer and they know of this and said some people pull the shaft out a little,I do not know how you keep it out as you put snap ring on or you just leave snap ring off like you do which I like

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Bill Miller
S/V Lorraine
Pacific Northwest,Sound Sound
Grapeview,Wa
1990 Mk1

LeslieTroyer's picture
LeslieTroyer
Last seen: 1 day 3 hours ago
Joined: 3/13/16
Posts: 456

Bill I've had the boat a year. It did not have a snap ring when I changed the impeller this year.  I saw no shaft gouging of the cover. There was minor wear from the impeller but that would be there regardless of the snap ring.  I read in another forum that the reason for the ring was to keep the shaft with the pump while on the stocking shelf. 

Les

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Les & Trish Troyer
Mahalo 
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 
bakerha's picture
bakerha
Last seen: 3 hours 29 min ago
Joined: 7/23/10
Posts: 265

So there are issues with these pumps that we seem to be willing to overlook because it is so much more convenient to change the impeller.  I had issues installing mine early this month.  Had to grind the base to allow it to line up with the bolt holes like on the M35's.  Modified the nipples so they could be screwed into the pump.  These were acceptable and easy to fix.  But I have two issues that I feel are more significant. 
First, the lower nipple (output) is so tight to the engine the hose is barely on the fitting and crimped more than I want it to be. Has anyone extended the fittings to get the hoses in a less prone to failure position?
Second - the snap ring issue mentioned above. If leaving the snap ring off is the right answer, I'm good with that. But having it there and possibly coming off and damaging the pump face is not acceptable.
Would be good to hear from Oberdorfer if that is an acceptable solution.

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_____________
Harold Baker
S/V Lucky Duck
Sandusky Ohio, Great Lakes
1989 C-36 mkI TR/WK M25XP

William Miller
Last seen: 1 month 2 weeks ago
Joined: 10/4/08
Posts: 291

If you used the N202M-908 it mounts just like the sherwood no grinding  easy install.I called oberdorfer and the snapring is to keep the shaft in when the pump is off of engine like Les wrote in his post

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Bill Miller
S/V Lorraine
Pacific Northwest,Sound Sound
Grapeview,Wa
1990 Mk1

Haro's picture
Haro
Last seen: 7 hours 48 min ago
Joined: 11/7/14
Posts: 240

 

I purchased N202M-16 version which has larger water flow volume. I used one of the original 5/8" "L" elbow and for the inlet side I purchased brass 2 piece elbow from the hardware store.
It must be noted that the gasket must be as thin as possible as the mating area will be reduced if thick gasket is used.
My Oberdorfer is 4 years old, no leaks yet.
I found that the pump seals fail if they are run in low tide where the propeller stirred up mud which is sucked in by the water and circulated around the seals. The fine mud particles quickly wear out the seals.
I run dry for 10 minutes, No damage was done. Yes - I forgot to open the through hull.
EDITED--06-21-2019
Since my original post above I designed and installed a warning system to remind me to open the raw water through hull valve before starting the engine. The system simply is a magnet installed on the tip of the valve handle and a reed relay mounted on the hull. The magnetic switch contacts are closed if the magned it closeby - the handle is closed - and this sounds a new soanalert installed in the captain's panel at the binnacle. When the ignition key is rotated the soanalert will sound if the handle is in the closed position. When the handle is rotated away from the closed position, the magnetic switche's contacts are open and the soanalert does not sound. In addition I have installed a bright flashing LED panel mount light on the control panel that blinks if valve is not opened.

 

 

 

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bakerha's picture
bakerha
Last seen: 3 hours 29 min ago
Joined: 7/23/10
Posts: 265

Bill - unfortunately I purchased the pump 4 years ago from CD and that is the only one they had for my engine. Since my Sherwood was still working fine, I just had it on board as a spare - that I assumed ( yea I know) would fit when the need arose.  I was not happy this spring when the Sherwood failed and the spare would not fit without modification. I had not followed these pump threads so I was unaware of the issues.
Haro - thanks for the pics.  I will definitely be re-routing / replacing the hoses as it's a struggle to even check my oil with the hoses the way they are and chaffing is beginning to be an issue in several spots.
All - thanks for the info on issues and the resolutions. Nine years and I'm still learning stuff from you guys!

Another issue that came up during the install ( again - my fault) was that in the nearly 4 year old (new) spare pump - the impeller had taken on a serious set. I doubt that it would have worked very efficiently, so I replaced it with my spare and ordered a new one from the Pumpsandparts place. Will remove the impeller from the next one I buy as a spare and store it separately.

 

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_____________
Harold Baker
S/V Lucky Duck
Sandusky Ohio, Great Lakes
1989 C-36 mkI TR/WK M25XP

VermontSailor's picture
VermontSailor
Last seen: 1 week 1 day ago
Joined: 11/15/08
Posts: 97

1. Solving the clearance problem with the original fittings, see attached image.
3. I never have had to "prime" the pump.

I have around 2000 hours on a number of Oberdorfer pumps.  I have rebuild these units, seals will eventually leak. Barely noticeable on fresh water, but messy on salt water.

Attachments
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Nile Schneider
Mañana C36 #1798
Lake Champlain, VT

ROAM's picture
ROAM
Last seen: 1 month 1 week ago
Joined: 5/24/17
Posts: 29

With a number of different model Oberdorfer replacement pumps, I'm trying to sort out the best fit/price for my 2001 M35BC ?
If a gasket is not provided, the best source for that or material used to make one

Thx, Greg

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Greg 
ROAM 
C36 MkII 2001
SF Bay
Catboat Willy's picture
Catboat Willy
Last seen: 22 hours 31 min ago
Joined: 12/22/14
Posts: 234


Greg; Give these guys a call and discuss it with them.The gaskets are available and vary depending on what pump you are installing.We put the kit on our M-35
https://www.pumpsandpartsonline.com/shop/oberdorfer-pumps/rubber-impelle... (link is external).
Tel; 314-628-0100
Mention the Catalina Association and receive free shipping.
Replacement Impellers are $28.00 each.
 

--
Bill Dolan 1990 Catalina C-36 MKI - Hull #1041  'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Port Charlotte, FL
'You are never out of work if you own a boat'

 
Sajanim's picture
Sajanim
Last seen: 3 weeks 2 days ago
Joined: 5/19/18
Posts: 6

I just received the new Oberdorfer pump from Cardinal Pump/Pumps & Parts. I purchased the N202-908. I debated buying the kit but after discussions with Scott at Pumps & Parts the only difference between the kit and the 908 was the elbows and a gasket in the kit. I decided I could get the elbows locally and make a gasket myself. I happened to be looking at my Universal manual and noticed the gasket to mount the water pump to the engine listed. I looked up the part number on the web and found the gaskets Universal P/N 302678 at marinepumpdirect for $1.30 each. I figured that for $2.60 and postage it was worth a try. They fit the new Oberdorfer perfectly and saved me the trouble of making them. I will be installing the new pump this weekend.  Hope this helps if someone else is looking for the gaskets. 
 

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Troy
S/V Xena
2002 Catalina 36 MK II
Hull #2103
Seward, Alaska
Dinoburb
Last seen: 2 months 5 days ago
Joined: 8/3/19
Posts: 1

I am mounting the -908 pump on my M3-20b and I have seen that two gaskets are recommended. I have also found the kubota p/n for that gasket (16264-88130) that is available locally.  The Kubota gasket is a nicely formed gasked with a crush ring circling the round opening.  What is the reason that two gaskets are listed as necessary?  Does the Universal gasket have the crush ring or is it flat?  Do I really need two or is one enough?

Catboat Willy's picture
Catboat Willy
Last seen: 22 hours 31 min ago
Joined: 12/22/14
Posts: 234

Thanks for the heads up on that Troy. I'll be ordering a few.
One other comment, that kit that I bought containing all the Oberdorfer parts (elbows etc. ) contained the bronze mounting ears as well. When I took the old pump off, I found that one of these bronze mounting ears had a severe crack in it. I just mention it as it probably something to keep an eye on.
Bill

Attachments
--
Bill Dolan 1990 Catalina C-36 MKI - Hull #1041  'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Port Charlotte, FL
'You are never out of work if you own a boat'

 
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