Raw water pump.
- Thread starter PlaneTom
- Start date
2001 Catalina 310, Universal M-25 XPB
Last week, letting the diesel warm up while I removed covers, I looked down and it was hotter than normal. Looked over the stern, and less water coming out of the exhaust than usual.
Realizing I had not changed the impeller when I had planned a while back, I ordered a kit and replaced it, even though the old impeller looked OK, cleaning out the heat exchanger at the same time. Started it up, same problem. I pulled the pump cover off again and bumped the starter, and no rotation!
I removed the pump housing complete, to find the drive end twisted, and unable to turn the shaft in the pump even with a wrench on it. Frozen bearings or whatever, time for a complete pump.
The end of the shaft where this engages in the engine looks good and undamaged, luckily.
Lesson for me- don't assume the impeller is the whole problem, make sure the pump is turning!
Last week, letting the diesel warm up while I removed covers, I looked down and it was hotter than normal. Looked over the stern, and less water coming out of the exhaust than usual.
Realizing I had not changed the impeller when I had planned a while back, I ordered a kit and replaced it, even though the old impeller looked OK, cleaning out the heat exchanger at the same time. Started it up, same problem. I pulled the pump cover off again and bumped the starter, and no rotation!
I removed the pump housing complete, to find the drive end twisted, and unable to turn the shaft in the pump even with a wrench on it. Frozen bearings or whatever, time for a complete pump.
The end of the shaft where this engages in the engine looks good and undamaged, luckily.
Lesson for me- don't assume the impeller is the whole problem, make sure the pump is turning!
You bet!
I messed up the first post, meant to include the text but hit a wrong key.
Yeah. That's had it. Appears to have seized and sheared off the pulley that the belt goes on. So, why do you think that happened? Did you make some kind of mistake installing it?
That is the drive end, it fits into a shaft in the engine, no drive belt on this pump. The fresh water coolant pump is belt driven, this one is the raw water pump.
This picture is the other side of the pump, no belt drive.
Based on the corrosion on the rest of the housing, it would not surprise me if it was the original pump, with just impeller changes over it's life. All I have done to it was impeller changes since I've owned the boat from 2014. I never disturbed the drive end, so no installation issues.
Since the engine started life as a Kubota, other parts like the fresh water pump, injector pump, etc, can be acquired from Kubota suppliers. This raw water pump is not part of the Kubota build, so it is a marine part, costing more.
Times like this I REALLY appreciate the easy engine access on the 310! I'll probably take another 10 minutes and change the engine oil while I'm there.
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If I had to guess what happened, I will guess that you have not used the engine for a long time, like 6 months. The salty water evaporates and the salt corroded the inside and the shaft will not turn. You are lucky that the engine driver did not break. I suspect that the round gasket used was thicker than it was designed for and as a result the 2 pieces did not mate deeper, so it jumped out of the groove.
This would be a good time to replace the pump with OBERDORFER pump. The impeller can be replaced from the front.
Visit Sail La Vie | 1999 Catalina 36 MK II for more content and visit the album. The seals can be replaced for $60.00.
This would be a good time to replace the pump with OBERDORFER pump. The impeller can be replaced from the front.
Visit Sail La Vie | 1999 Catalina 36 MK II for more content and visit the album. The seals can be replaced for $60.00.
Interesting idea. I do intend to measure the engagement of the drive tang with the new pump.
Having that drive tang twist far enough to slip does protect the shaft in the engine to some extent. If the pump seized and the drive end didn't slip go it could damage the engine internals. On the airplanes I work on, many if not most of the accessories ( starter, generator, hydraulic pump, etc) driven by the gearbox use frangible drive connections to protect engine internals
The old one is too far gone for a reasonable rebuild, the shaft won't turn even with considerable force. Really seized up.
Pretty much all the internals would need replacing, and that's if the housing was reusable after forcing everything apart, it's not going to give up easily.
Maybe I'll soak it in rust remover for a long while and then experiment, but a new pump is on the way.
Definitely go with the Oberdorfer. Much cheaper than the Sherwood, more reliable, easier to rebuild, and, as Joe said, easy to change the impeller. Lots of threads in the C310 forum on doing the conversion.Oberdorfer already on the way.
Not at all uncommon with the Sherwood pumps. Replace it with an Oberdorfer!. You're very lucky it was the pump end that failed or you would likely be looking at a new engine..
New Oberdorfer raw water pump arrived and installed. I had to fuss with the inlet fitting, it's pretty long and the spacing on the ports is closer than on the Sherwood. A small delay, the old inlet fitting is in two parts, just needed to be persuaded to separate then reassemble.
You may notice that the injector pump is a different color. It failed about 3 years ago, and a local industrial diesel shop that works on Kubotas had the parts to rebuild it in stock and did it for about 1/3 of what the Universal/Westerbeke supply chain wanted for a rebuilt.
You may notice that the injector pump is a different color. It failed about 3 years ago, and a local industrial diesel shop that works on Kubotas had the parts to rebuild it in stock and did it for about 1/3 of what the Universal/Westerbeke supply chain wanted for a rebuilt.
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Yes, Oberdorfer. I had a leaky Sherwood and completely rebuilt it. Definitely not fun..many parts, some very hard to remove and replace. Vastly overcomplicated. It worked perfect for about 50 hours then started dripping raw water. I replaced with an Oberdorfer and could not be happier. I did replace seals in the Sherwood and, like you, I keep it onboard as a backup. I also found that the Oberdorfer is not quit a "drop in", but with a little effort you can make work. One of the best things is ease of annual impeller replacement. Sherwood rebuild below.
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Update.
I installed the new Oberdorfer, it worked well until yesterday. I hadn't used the boat much since Feb, busy with work, but now retired and looking forward to more sailing.
I was at the dock Wednesday, taking care of a few things and preparing to clean the topsides and remove the mainsail, new sails arriving Monday!! I started the engine, checked for water flow at the exhaust and had plenty. Fiddling around with the main when I heard the temp alarm. Temp gauge showed 200+ and no water flow in the exhaust.
I pulled the cover on the pump, impeller looked to be intact. I turned the engine by hand and the shaft rotated but not the impeller vanes. I removed the impeller, and the rubber vanes were loose, not bonded to the brass center.
This only has maybe 10 hours at most on the pump since new.
I'm sure any warranty expires once it's installed, but I'll call Oberdorfer and see what they might do for me, but not expecting much.
I ordered a new impeller kit, I may try some heavy adhesive to reattach these vanes to the core, and keep it as an emergency spare.
I installed the new Oberdorfer, it worked well until yesterday. I hadn't used the boat much since Feb, busy with work, but now retired and looking forward to more sailing.
I was at the dock Wednesday, taking care of a few things and preparing to clean the topsides and remove the mainsail, new sails arriving Monday!! I started the engine, checked for water flow at the exhaust and had plenty. Fiddling around with the main when I heard the temp alarm. Temp gauge showed 200+ and no water flow in the exhaust.
I pulled the cover on the pump, impeller looked to be intact. I turned the engine by hand and the shaft rotated but not the impeller vanes. I removed the impeller, and the rubber vanes were loose, not bonded to the brass center.
This only has maybe 10 hours at most on the pump since new.
I'm sure any warranty expires once it's installed, but I'll call Oberdorfer and see what they might do for me, but not expecting much.
I ordered a new impeller kit, I may try some heavy adhesive to reattach these vanes to the core, and keep it as an emergency spare.
"I pulled the cover on the pump, impeller looked to be intact. I turned the engine by hand and the shaft rotated but not the impeller vanes. I removed the impeller, and the rubber vanes were loose, not bonded to the brass center.
This only has maybe 10 hours at most on the pump since new."
I had this happen to me last year with a brand new oberdoerfer pump I ordered from CD. The impeller was bad after about 1 hour of running. Same thing, the rubber was not attached to the brass ring in the center. I called CD about it and they sent me a new one after I shipped back the broken one (at my expense). So I ordered another impeller off of amazon in the meantime and that one was fine, better than the one supplied by manufacturer apparently.
This only has maybe 10 hours at most on the pump since new."
I had this happen to me last year with a brand new oberdoerfer pump I ordered from CD. The impeller was bad after about 1 hour of running. Same thing, the rubber was not attached to the brass ring in the center. I called CD about it and they sent me a new one after I shipped back the broken one (at my expense). So I ordered another impeller off of amazon in the meantime and that one was fine, better than the one supplied by manufacturer apparently.
When I needed my pump, CD was out of stock, I got it from BoatBuildersSupply. I called them and they are in the middle of a move and all stock is in containers and not available. I ordered an impeller from CD, should be here late tomorrow. I contacted Oberdorfer by email, never found a phone number, explained it to them and waiting for a reply.
I will likely get one from Amazon as you did, just to have another spare.
In case I need to move the boat before I get a new impeller, I glued the impeller vanes to the brass ring with some heavy structural adhesive, and I'll keep it as an "emergency use only" spare.