Like several others on this sight, I replaced/upgraded my original raw water pump with the Oberdofer model three years ago. This unit was highly recommended over the one it replaced. I just returned from a month long cruise to the Keys and on the return trip we noticed a substantial accumulation of salt water kept building up in the engine sump. When I searched for the source of this water the only entry I found was a slow drip coming from the raw water pump, the little weep hole in the side. Does this mean that my relatively new pump is shot? Can I have it rebuilt? I had two occaisions on this trip when my engine overheated due to grass accumulating in the raw water intake. Could the engine over heat or running the pump with insufficient water incoming, cause this leaking? I also realized when recently hauling the boat that there is no grating or any kind of guard over the intake on its exterior. Just the screen on the inside of the boat. I've been advised by others to add such a grating. Anyone else done this.
Any help appreciated.
Thanks, Sam
Capt. Sam Murphy
1994 Catalina 36, Hull 1327
Shoal draft, two cabin model.
Panama City, Florida
yes they can be rebuilt - yes running them without water can destroy the rear seal which keeps raw water out of the engine. yes the weeping is an indication that the rear seal has failed. NO please dont add a guard/grating over the intake - unless you like to swim to remove the grass from the external grating, rather than pull from the seperator.
Les & Trish Troyer
Mahalo
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor.
Commodore
[quote=Capt. Sam]Can I have it rebuilt? I had two occaisions on this trip when my engine overheated due to grass accumulating in the raw water intake. Could the engine over heat or running the pump with insufficient water incoming, cause this leaking? I also realized when recently hauling the boat that there is no grating or any kind of guard over the intake on its exterior. Just the screen on the inside of the boat. I've been advised by others to add such a grating. Anyone else done this.
Any help appreciated.
Thanks, Sam[/quote]
There is a rebuild kit for the Oberdorfer. And if you check through the C36 "Technotes" CD, there was a well-written article from the May 2008 issue by a former tech editor on how to rebuild it yourself. Its not that hard a job.
I ordered a new pump and rebuilt the old one as a spare. I've found I get about 3-4 years out of the Oberdorfer before it needs to be rebuilt (others' mileage may vary).
I have no idea whether running it dry would have damaged that seal; generally my understanding is that the more frequent damage is to the impeller blades, not the seal.
As to adding a screen, I would think that's not going to be as effective as just checking and cleaning the strainer basket more often.
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
David S. Power
Two If By Sea #1687
Burnt Store Marina
Punta Gorda, FL
I'm always grateful for the good and timely responses I get on this site. Thank you. I'll probably go for the rebuilt kit. I had hoped to get more out of the pump than the three years of light usage that I've got so far.
But that's how it goes. As to just relying on the internal screen to catch the grass, it should be noted that both times that my engine overheated on this trip, the internal screen was clear. All the grass was stuck hard in the exterior intake hole and never made it to the internal screen. The first time I removed it when the boat was our of the water, the second time, working inside the boat I removed the entire screen housing, opened the through-hull valve and pushed a big screw driver through the intake to clear the grass out.
Capt. Sam Murphy
1994 Catalina 36, Hull 1327
Shoal draft, two cabin model.
Panama City, Florida
The Oberdorfers can leak. I just ordered a brand new one that started leaking from the shaft seal after the first 10 min. of use. Sent it back and after many months Oberdorfer said it tested out just fine. I will put it back on the boat this weekend and see. I do have a rebuild kit for it, but I hate to have to use it on a brand new pump.
Paul Cyr
C36 "At Last"
1984 hull# 369
Oriental, NC
I talked to Oberdorfer tech support yesterday and was told that if water is coming out of the weep hole then the lip seal is failing and must be replaced to avoid salt water getting into the engine. There are two lip seals, the first one must fail to allow water to get out of the hole which is your notice to replace it. There's a second one closer to the flange that mates the engine block and is the last thing to stop water from going in the engine. If they both start to fail, then water is defnitely going where you don't want it. I ordered both of them (same part number 5463 $20 each) from the distributor in Clearwater, Fl.
I've got about three years on the pump, a little over 300 hours and the guy I talked to at Oberdorfer said that's about normal life expectancy for the seals. That was a surprise to me and I wonder what others' experience has been. I'm going to put the seals on my list of required on-board spares.
Sam
Capt. Sam Murphy
1994 Catalina 36, Hull 1327
Shoal draft, two cabin model.
Panama City, Florida
Yes that does sound a little bit early to show signs of failing to me too... guess things just aren't made to last anymore.
Great, another regular maintenance item! (I put on about 150 hrs a year so I need to check my 3 yr old one a little closer...
---- Howard & Linda Matwick ----
--- S/V "Silhouette" - Nanaimo, BC ----
--- 1999 C36 MkII #1776 M35BC ---
I have had a lot of variation on the seal wear out time on the Oberdorfer. We are currently returning from the Bahamas, our second time, to the fresh waters of Lake Champlain. I have been using the Oberdorfer pumps for 6 years now. Our first trip south I replaced the pump mid trip after probably 600 hours on it. This trip south (two years later) I replaced that pump with a rebuilt and it started leaking with less than a 100 hours. I replaced that one with a brand new one and that one has been leaking from the start, not a lot and I will wait to change it after we get home.
When you rebuild a pump I would recommend replacing the shaft also. My rebuilt pump that leaked was probably due to wear on the shaft where the seal made contact.
Nile Schneider
Mañana C36 #1798
Lake Champlain, VT
I feel like a fool just dropping ~$280 on the 3/8" NTP Oberdorer from CD today. I overlooked the rebuild idea. Should have tackled this over the winter. The seal had a running trickle leak first launch last spring but the seal tightened up after a few minutes of operation down to a slow drip. Do the seals have a tendency to dry out on the hard? Yes the seawater cooling was flushed with pink antifreeze sucking from a 5 gal bucket when winterized.
Russell Green
S/V "GoodwiII" #759
1987 C36 MKI TR/WK M25XP
Moored: Deale, MD
I bought a new Oberdorfer at the end of last year to replace my old Sherwood, since I had heard that the Oberdorfer was a much better pump. I installed it and all looked good. Lots of water flow at the exhaust. Then after about 10 min. the pump started dripping at the weep hole.
I removed the pump, sent it back to Catalina Direct, who sent it back to Oberdorfer. Oberdorfer checked it out and said a pressure test showed no leaks. I finally got the pump back after almost 6 months. I installed it about a week ago and it still leaked. I let it run a little longer this time and eventually the water seal stopped leaking. I don't feel real good about the quality of the Oberdorfers right now. I do have a rebuild kit for it, but I might rebuild my old Sherwood first to have a ready to go spare. Mainesails website has a good tutorial on pump rebuilding.
Paul Cyr
C36 "At Last"
1984 hull# 369
Oriental, NC
Here's a follow up on my original post. I ordered the two lip seals and an O-ring from Depco in Clearwater and successfully rebuilt my pump on my bench vise. this was before I knew there was a repair kit available that included those items plus a new carbon bushing and snap ring at a price equal to or less than what I paid for just the seals on O-ring, plus tax and shipping. Plus trying to remove the seals without removing or damaging the carbon bushing required some creativity. And scored the inside of the pump body a little, hopefully not in a place that is critical. For now the pump is working fine with no weeping and the engine is running nice and cool. I've also gone ahead and ordered a brand new pump and another rebuild kit to have in the spare parts locker. I shopped around a bit and found much better prices than I've seen quoted on this site. I bought the new pump (N202M-16) for $225 including shipping, no tax from Amazon. I got the repair kit (OB11691) from www.pumpsandpartsonline.com for $51.12, no tax, free shipping compared to other sellers at $75 plus tx and shipping. I hope this helps others save a few $.
Sam
Capt. Sam Murphy
1994 Catalina 36, Hull 1327
Shoal draft, two cabin model.
Panama City, Florida