Good day to all, and thanks for all your help in the past.
I have a quick issue I would like to validate. My raw water pump (Sherwood) is leaking through the weeping hole, and a rebuild kit is like $300. A new Sherwood pump is like $400-500. However, I have read an article in an older archive of Mainsheet that shows a Oberdorfer N202M-16 pump retrofitted to replace the Sherwood. I can also find this "O" pump for about $230.
The early articles and forums discussing this says the O pump is good to go. (I'm glad I have a M35A.) I just wanted to get an update and see if there are any changes to this idea. Using the "O" pump instead of a Sherwood. Has anyone seen any issues using the "O" pump, like temperature ranges, waterflow, etc? What is expected life span of the O pump and the Sherwood?
Also, what is best way to prime the pump once replaced before starting the engine? Is it as simple as opening the through hull and letting it sit for a few minutes before starting the engine?
Thanks again for all your help.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
I installed the Oberdorfer pump on my M35A and its worked great ever since, and impeller change is a snap. The mod to cut a small notch in the flange took about 5 minutes with a dremel tool.
Gary Smith
93 MK I, Hull #1231
Std rig; wing keel
M35A Oberdorfer conversion
David S. Power
Two If By Sea #1687
Burnt Store Marina
Punta Gorda, FL
Thanks for the info. I suspect I can use the same fittings and mounting bolts off the Sherwood? I plan on ordering the pump tomorrow.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Does the O pump need priming to operate? Can you just start the engine and self primes?
Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
When you operate it the 1st time, probably a good idea to prime because it will run dry for a short time until it draws in the water.
Yes- it is self priming otherwise.
Also- the article on the Catalina Association technical site suggested using a sawzall for modifications to the casting. I used a dremel with a cut off wheel. The dremel may take a little more time, but it gives you better control on the cut. It also gives a smoother cut with fewer burs to clean up. The bronze casting needs modifications for the M35B. I can't remember if it needs modifications for the M35A.
Lastly, the Oberdorfer mounts at an angle on the M35B. This places the weep hole higher and should the pump seal ever fail, sea water could gain access to the engine. Not sure about the M35A- you might want to check....and if it's the same- drill a new weep hole on the bottom of the pump.
The rubber impeller on Oberdorfer, over a long time, will wear the face plate and you will loose suction. The pump is designed to reverse the face plate (flip it over) if and when that happens. You can also sand/polish the face plate level again, or simply install a new one. I had experienced that at about 500 hours on our Catalina 30.
It's a much simpler/less expensive to maintain pump than the Sherwood. Glad I made the change.
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
I use dish washing liquid soap to prime the pump.
Sail La Vie 1999 Catalina 36 MKII, M35B-17031, Coyote Point, San Mateo, CA
About Sail La Vie
I have had an Oberdorfer N202M-16 on our M35B for over 4 years. The original article in the Mainsheet was based on my experience making this pump fit. I had around 800 hours (600 in saltwater) on the pump before I replaced it with a new one last year. My wife and I traveled from Vermont to the Bahamas down the ICW. I brought a spare pump and on the return trip I swapped in the new pump, because of some minor leakage on the seal. I may have been a little anal and premature on replacing it. The second pump had been modified using a 4 inch abrasive cutting wheel, easier and faster than the Sawzall.
I found a very good article from the Catalina 34 website by Ron Hill (http://www.c34.org/wiki/index.php?title=Raw_water_pump,_impellers_and_cooling_system) on replacing seals on these pumps. I bought the replacement seals and did the replacement. The cover plate did have wear, but the plate was actually slightly bowed out, so flipping it over and using the backside probably would not work well. I will have the cover ground flat before reusing.
I bought the seals from San Diego Marine Exchange, SKU = 40121, Description = OBE 5463 Lip Seal for $15.75 each. (http://www.downwindmarine.com/Oberdorfer-Model-202M-Rubber-Impeller-Pumps-Universal-Engines-p-91002307.html)
The engine always runs at 162 degrees F, once warmed up. I have never had to prime the pump.
Nile Schneider
Mañana C36 #1798
Lake Champlain, VT
Well the O-pump project went like a dream. Probably the easiest mod I've made. To prime, I filled the hoses with water, then opened the vent plug on the top of the pump and added some water there as well. Started right up, and no leaky-leaky. I also found putting a thin film of Vaseline on the barbs made the hoses go on easier.
I'll keep the Sherwood pump in the spare parts bin for emergency use.
Thanks again for the information and validation.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
What is the benefit of the O pump over the S pump?
Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
The Oberdorfer is much less expensive, and it has a forward-facing plate for removal and changing of the impeller. The Sherwood is very inconvenient to work on. The Oberdorfer is also a much simpler design, having about one fourth of the parts of the Sherwood.
Search this site for much more information on your raw water pump choices.
Nick Tonkin
*Former* Website Administrator, C36/375IA
*Former* owner, C36 tr/fk #255, Santa Barbara, CA
The Oberdorfer has a one piece all bronze body. The main body of the Sherwood is cast iron, which does make a great leak indicator, when it starts rusting.
Nile Schneider
Mañana C36 #1798
Lake Champlain, VT
I just left a phone conversation with Oberdorfer Pumps in Syracuse, NY. and they are now offering a complete kit to replace the Sherwood pumps. Although it is not listed on their website as yet, the new part number for the kit is N202M-837 for the M-35 engine. The kit is supposed to fully replace the Sherwood G908 pump. The kit contains not only the pump, but all necessary parts for mounting the new pump to include new 90 degree nipples, gasket sets and mounting ears. We ordered the pump kit after a discussion and at the suggestion of the technical service department at Depco Pump in Tampa, FL.
We'll be installing the kit next Thursday and we'll will keep the FORUM members on the progress of the installation.
Bill Dolan, Punta Gorda, FL
#1041, 1990 C-36
M-35, wing keel,
A special thanks to Mr. David Power for his assistance.
Bill Dolan 1990 Catalina C-36 MKI - Hull #1041 'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Charlotte Harbor & The Gulf Islands of Florida
'You are never out of work if you own a boat'
David S. Power
Two If By Sea #1687
Burnt Store Marina
Punta Gorda, FL
Today I installed the new Oberdorfer Pump Part Number N202M-837 on my M-35 engine in a late 1990 C-36. In talking with my parts/pump distributor; DEPCO PUMPS in Tampa, FL. they steered me toward the forgoing Oberdorfer number and stated that is supposed to be a new kit designed to directly replace the Sherwood Pump, that is to say, without any grinding or further fitting.The kit came with new 90 degree elbows and all needed gaskets.
I am happy to report that was the case for me, as the pump was a direct replacement without any alteration or grinding of the pump housing. The new pump housing appears to have a modified collar making it more like the Sherwood.
Whether all of this will work (without grinding) on the M-35 A, B, BC engines is something we'll investigate - but it supposed to be a new item. A call to Oberdorfer in Syracuse, NY would certainly confirm whether it would work with your engine.
Only one word of caution; Be sure you understand which hose and pump fitting - is the input and which is the output of the pump before re-attaching. The job took less than one hour.
Bill Dolan
1990 C-36 #1041
M-35, Punta Gorda, FL
Bill Dolan 1990 Catalina C-36 MKI - Hull #1041 'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Charlotte Harbor & The Gulf Islands of Florida
'You are never out of work if you own a boat'
Bill
Thank you, I'm ordering one of these pumps on Monday!
I noticed my water temp at about 180-185 deg this last week on a week-long cruise to Catalina Island, and looked up when I last replaced my Sherwood impeller...4 years had passed. So, I looked on our C36IA website (first time ever since the email list went virtually inactive) and found your post.
So thanks, I am ordering one of these new Oberdorfer Pump Part Number N202M-837. My local Long Beach CA marine parts store pulled out their Oberdorfer catalog, said there is not such part listed. So I showed them your post. THey were impressed!!!
Steven Jones
C36 2164 Maléna
Seal Beach CA
Steven Jones
C36/375IA FaceBook group administrator
C36/375IA Jib Sheet Editor 2012
Seal Beach, CA, USA
C36 #2164 Maléna 2003 Mk-II SRig/FullK, Long Beach, CA
stevenjones21@gmail.com
Steven,
Please be sure that the model of Oderdorfer pump you order is the correct one for your engine as there are several different styles of the pump base that are offered for the type 202 pump.. Some are square and would require grinding (as outlined in the tech notes section).
The Oberdorfer pump that came with kit number N202M-837 was pump part number N202M-908 DKE and has a round pump base that easily fit to the M 35 engine without grinding (as shown in the picture in my post)
Again, whether it will directly fit your engine is a discussion you should have with Oberdorfer (call Oberdorfer in Syracuse, NY 800-448-1668)
I believe the N202M-908 pump should fit all Universal/Kubota 35 engines without grinding, however, it would be best to check.
Keep your cool....LOL
Bill Dolan
Punta Gorda, FL
C-36 (Late) MK-I #1041 SR, WK, WT, M-35
PS; When this engine was rebuilt several hours ago, the re-builder re-sprayed it Universal Gold rather than the new Blue color
Bill Dolan 1990 Catalina C-36 MKI - Hull #1041 'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Charlotte Harbor & The Gulf Islands of Florida
'You are never out of work if you own a boat'
Bill
What was the cost of this "new" pump from Oberdorfer, Syracuse ?
Three years ago I tried to get Oberdorfer (parent company Gardner Denver) interested in making this G908 replacement from their existing casting for the N202M-16. I even created CAD drawings to show them. No interest at the time. Maybe they just move slowly.
Nile Schneider
Mañana C36 #1798
Lake Champlain, VT
[quote=VermontSailor]Bill
What was the cost of this "new" pump from Oberdorfer, Syracuse ?
Three years ago I tried to get Oberdorfer (parent company Gardner Denver) interested in making this G908 replacement from their existing casting for the N202M-16. I even created CAD drawings to show them. No interest at the time. Maybe they just move slowly.[/quote]
hmmmm, royalties??
---- Howard & Linda Matwick ----
--- S/V "Silhouette" - Nanaimo, BC ----
--- 1999 C36 MkII #1776 M35BC ---
Will this pump work for the 25xp engines also?
Bill Miller
S/V Lorraine
Pacific Northwest,Sound Sound
Grapeview,Wa
1990 Mk1
Bill-
I had a C30 with an M25. It had an Oberdorfer raw water pump since new....but not the same pump as can be used on the C36 M35 Universal series. I would connect with a Universal/Westerbeke dealer to get the correct info. The dealer I use in the North East is Hansen Marine in Marblehead Mass ( a very good source for Westerbeke parts) if you can't find a local one..
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
Thanks Paul ,that is what I will do
Bill Miller
S/V Lorraine
Pacific Northwest,Sound Sound
Grapeview,Wa
1990 Mk1
Over the years ('94 Cat) in changing the impeller two of the three holes holding the front on have become stripped. The yard drilled holes all the way through so that machine screws from the front and rear bolts hold the cover on. This was supposed to be a temporary solution many years ago but seems to be working. This weekend, however, I fried my impeller by not opening the thru hull. Temporarily I replace the impeller with a spare used one and a used paper gasket. Water seem to be pumping fine, but there is a slight drip around the front seal. I will be buying a new impeller kit. I may also have the paper gasket in the wrong place. Does it go in front or behind the backing plate that is behind the impeller? My memory is failing me. Looking for comments. Thanks.
Richard
Richard
1994 C36 Tall Rig M1.5
Waukegan Harbor
Lake Michigan
I replaced my Sherwood G908 pump with the Oberdorfer N202M-908 pump a few weeks ago because the Sherwood pump was leaking again. I also had my heat exchanger boiled out and I installed all new hoses. My Universal 35 BC engine has traditionally run at about 180 degrees at 2500 RPM. Now the engine is running at about 200 degrees at 2500 RPM. Does the Oberdorfer pump push less water than the Sherwood. Is there a high capacity impeller I could install in the Orberdorfer pump.
That might be the case as I noticed my engine which ran at a cool 160F (indicated) with the leaking Sherwood pump - is now running some 15 degrees warmer at 175F (measured) with the Oberdorfer N202M-908. (2500 RPM at 5.9 Kts SOG) Never thought much about it because since it's still with in the operational range. But now that you mention it..........
It did prompt me to go out and buy an infer-red thermometer .
As to whether the Oberdorfer pushes less water through is a discussion for the spec sheets, but I suspect that must be the case, otherwise what what would account for the higher temperature?
One could always change the thermostat to compensate for a lower temperature.
As to whether there is a high capacity impeller available is a discussion you could have with Oberdorfer in Syracuse or your local distributor.
Bill Dolan 1990 Catalina C-36 MKI - Hull #1041 'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Charlotte Harbor & The Gulf Islands of Florida
'You are never out of work if you own a boat'
Bill
It is not unusual to see higher engine raw water temperatures at this time of the year because our sea water is as much as 15-20 degrees warmer now then in the winter. Today it is 84 in the Gulf and slightly warmer in our Harbor.
__/)__/)__/)__Capt Mike__/)__/)__/)__
Punta Gorda Florida
1990 Std WK M35 Hull #1050
There are 2 sizes of inlets for Oberdorfer. For my M35B I userd N202M-16. This has 1/2" water inlet. There is also M15 version which is 3/8 water inlet. This difference may be the reason for higher water temperature. For my engine it runs at 162F at any RPM.
Sail La Vie 1999 Catalina 36 MKII, M35B-17031, Coyote Point, San Mateo, CA
About Sail La Vie
That's good to know about the different size inlets......had not heard that before..........
Thanks,
Bill
Bill Dolan 1990 Catalina C-36 MKI - Hull #1041 'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Charlotte Harbor & The Gulf Islands of Florida
'You are never out of work if you own a boat'
Great feedback to the questions concerning the Oberdorfer N202m - 908 vs the Sherwood 908. As stated earlier I was running quite a bit hotter after installing the Oberdorfer and boiling my heat exchanger. I called Oberdorfer and spoke to a tech. He related that the two pumps, pump the same amount of water. I then went back to the boat and started at the sea water intake and checked along the line. When I pulled the hose running from the pump to the exchanger I was able to see that during my installation I had partially crimped the intake nipple on the exchanger. After straightening the nipple and reattaching all hoses I ran the engine up to 2500 rpm under load and the temp never climbed over about 170 degrees. I then enjoyed a well deserved ice cold one!
I'm guessing that begets the question; What is everyone's typical cruising RPM ? (I'd sure like to know) for various engines ?
What temperature is normal ?
What speed/RPM are you at - and fuel consumption ?
I'm running a M-35 with a three blade prop
2300-2400 RPM
5.6Kts. SOG
160 F
.56 Gallons per hour
Engine has 360 hours since re-manufacture.
Bill Dolan 1990 Catalina C-36 MKI - Hull #1041 'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Charlotte Harbor & The Gulf Islands of Florida
'You are never out of work if you own a boat'
For me
M35B
3 blade original propeller
2100 RPM
7.1 MPH or 6.12 knots Land speed
.75 Gallons per hour
162 F ( temperature never changes at any RPM)
980 Hours on the engine
Oberdorfer M16
Sail La Vie 1999 Catalina 36 MKII, M35B-17031, Coyote Point, San Mateo, CA
About Sail La Vie
M35B
Wing keel
3 blade original propeller
2400 RPM
6.5 knots SOG with clean bottom and calm conditions
0.8 GPH
165 F
Nick Caballero
Retired C36/375IA Mk II Technical Editor
M35A
Wing keel
2 blade propeller
2500 RPM
160° -162° F
.7 GPH
approx 1800 engine hours
Gary Smith
93 MK I, Hull #1231
Std rig; wing keel
M35A Oberdorfer conversion
M35BC fin keel
3 blade Autoprop
2150 rpm = 6.2 kts calm conditions = 2.5 liters per hour
Always approx. 162 deg.
---- Howard & Linda Matwick ----
--- S/V "Silhouette" - Nanaimo, BC ----
--- 1999 C36 MkII #1776 M35BC ---