Raw Water Pump Leaking Advice

[dhandzy]

Hi -- this weekend, I found that the raw water pump has a slow leak (less than 1 drop/second) but it's been going on long enough to have corroded some of the parts beneath it. I have an Oberdorfer impeller (N202M) on a Westerbeke M-25XPB engine. It looks like the water is leaking from the holes on the engine-side of the impeller housing unit. I'm pretty sure the leak is from the back of the impeller housing (the side closer to the engine) and I suspect it may be the seals and bearings around the water-pump shaft. This is based on the Raw Water Pump diagram on page 49 of the April 2013 Parts List edition.

At idle, from a cold start, the leaking is about 1 drop per seconds. After the engine warms up at I increase speed, the leak diminishes to about 1 drop every 10 seconds.

Any advise on how to address / diagnose further?

 

[Davidasailor26]

Yes, that does look like the area that water drips from when the seals go bad. It should be possible to replace the seals if the shaft isn’t damaged.

 

[dlochner]

Some Westerbeke models have this issue, unfortunately I can't remember which models. Call Hansen Marine they were the Westerbeke dealer and still have parts.

 

[colemj]

If it isn't a latent defect particular to a specific Westerbeke model, then it looks like a common lip seal maintenance thing. Happens all the time. Just take the pump off and change the seals. I'm pretty sure Oberdorfer uses a bushing instead of bearings, but it can be changed also. It is unusual for the shaft to be bad.

Looks like Fisheries sells a replacement kit with impeller: Oberdorfer Pumps 5463 | Fisheries Supply

Or contact Depco Pump, who usually have the best prices.

DON'T buy this from a Westerbeke or Universal dealer. They will charge 3-4x the price. There is nothing special about these common lip seals, and the prices being charged by places like Fisheries are already egregious.

Mark

 

[kloudie1]

Check out this article from forum member Mainesail..

Rebuilding A Raw Water Pump - Marine How To

Pump Removed This article is going to assume you have the skills to safely and easily remove your own water pump from the engine. This one is easy and uses four bolts and a gasket to mount to the timing gear

marinehowto.com

Not exactly the same pump, but very similar

 

[JoeWhite]

I can easily claim to be the expert when it comes to replacing Oberdorfer seal replacement.
There are no ball bearing in your version of Oberdorfer. Just replace 1 carbon bearing and 2 seals. Before you remove the seals observe which way the seals are facing. And the carbon bearing must be inserted until it is flush in the impeller housing.
The leaking could cause salt water to enter into the engine oil. Replace the seals as soon as possible.
Visit my website here, includes where to order the repair kit. The pricing may have changed.
Give me a feed back of your success.

Oberdorfer Seals Replacement | Sail La Vie

mei1970.org

View these albums, specially the one using steering wheel puller.

Oberdorfer-Seals-Replacement | Catalina 36 MKII Album | Sail La Vie Home

mei1970.org

 

[colemj]

Good info. A bit of googling finds a small price break: Pardon Our Interruption...

If you don't need the carbon bushing, the kit I linked to Fisheries is half the price (that's an expensive bushing).

Mark

 

[Straycat22296]

On my C36 with a 35B engine with 650hrs. I also had a leak like yours. My pump was the type that you had to remove the whole front face to replace the impeller but the same mount, I do not remember the model off hand.
My pump was leaking like yours but unfortunately the inner seal failed also allowing a small amount of sea water into the engine.
I found the water issue right away by checking the oil level before the next trip. It ruined that trip.
I replaced the whole pump with a new pump like yours with the front plate. I am now able to replace the impeller easier.
After pump replacement I drained the oil, removed the filter and then replaced the oil and filter. I ran the engine to operating temperature and shut her down.
I once again repeated the process of draining the oil and replacing the filter and found no evidence of water.
I have had no further issues or signs of engine problems.
I HIGHLY RECOMMEND that you check your oil and rebuild/replace the pump as soon as possible.
I love my Sailboat but am not always fond of my engine.
Good luck with your repair.

 

[Stu Jackson]

Oberdorfer Pump Rebuild 101 - Mysteries of the Oberdorfer - Seal Replacement - REBUILDING A PUMP w/Flix