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Go Back   SailNet Community > On Board > Gear & Maintenance > Premature impeller failure cause
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Topic Review (Newest First)
07-28-2013 10:10 AM
Re: Premature impeller failure cause

Couple of things after reading this post... Check to see if new impeller doesn't delaminate by trying to pull the vanes at the 9 o'clock and 3o'clock position.

Flip the water pump cover and try the unused side.

Make sure the impeller has seated it self fully on the shaft.

Too much pressure from the cover on a improperly mounted impeller may cause excessive heat which in turn may cause premature failure..
07-28-2013 08:38 AM
Re: Premature impeller failure cause

In my 7.5 Merc. 2 stroke the impeller failed after being test run in a 50 gallon barrel. The first time after being prepped by a repair shop, The second time I did it all by myself. The impeller aparently cannot stand the oil in the exaust. Now I always keep a spare impeller and the tools. They were both OE impellers.
07-27-2013 07:07 AM
Re: Premature impeller failure cause

I agree. We're trying to get Westerbeke to send a new pump to see if that is somehow causing the problem.
07-27-2013 06:48 AM
Re: Premature impeller failure cause

Originally Posted by LinekinBayCD View Post
The blades of the failed impeller were fine, but the brass fitting/bushing and key pin had delaminated from the rubber bushing.
I have seen this condition twice and both times on new, never installed impellers. Judging by the boxes they came in, they had been sitting on the chandlers shelf for many years.
07-27-2013 01:15 AM
Re: Premature impeller failure cause

Am i reading this right, that the same type of failure (rubber off the brass/bronze hub) has been happening over a 3-4 year period? That would be one hell of a big batch of bad impellers to span that many years.
07-27-2013 12:15 AM
Re: Premature impeller failure cause

Is it possible there is a machining bur on the incoming or outlet ports on the pump itself.

I think after using up your new impellers that are being sent, the next option would be to bite the bullet and spring for a new pump.
07-26-2013 11:46 PM
Re: Premature impeller failure cause

If the fellow who works for Westerbeke is suggesting a bad batch of impellers, he has probably heard other stories like yours. I'd give it a try with one of the impellers he sent you before you spend a lot of money changing pumps.
07-26-2013 08:39 PM
Re: Premature impeller failure cause

Roll forward a year. During the winter I had a 1 in. thru hull installed with a new 1 in strainer. Early in the season every thing looked good. Noticed that the engine was running slightly cooler so maybe this was the solution. Unfortunately had another impeller fail right after the 4th of July about a year and a week after the last and about 75 engine hours later. I could tell the impeller was going bad and starting to spin on the bushing by the way the water flow was decreasing and a slight creeping up of the engine temp. Four hour impeller change. Really bad spot for the pump. Regardless of the cause of the problem I think I'm going to try and relocate the pump to make changing the impeller easier. Maybe a crank shaft mount.

My yard is following up with Hansen Marine the Westerbeke dealer as beside my problem they had the same problem on a new boat they were fitting out. Same exact Westerbeke 55 installed. Had the 1 in. thru hulls and 1 in piping right from the start. They are now thinking that the pump might be undersized for the engine or some other design

While the yard is working on Hansen Marine / westerbeke I followed up with Johnson Pump to see if they had any ideas about the causes of the failures. Oddly Johnson Pump had Joe Joyce from Westerbeke email me. He's thinking it is a bad batch of impellers and is sending me a few new ones. I'm there is more to it than that. Anyone have experience with crank mounted pumps? Hard to get a pump that matched the bolt pattern on the crank pulley?
07-12-2012 09:57 PM
Re: Premature impeller failure cause

Originally Posted by Cruisingdad View Post

I don't know if you are right, but that was the best troubleshooting thoughts I have heard in a long time! Great thoughts!

Thanks! My dad started me out troubleshooting electrical when I was just a kid. He'd send me out on jobs with no electrical drawings, only drawings in foreign languages, or where the wires disappeared in holes going who knows where.

My favorite was when I was about 19 and he sent me to a city sewer plant to troubleshoot a boiler. It didn't help that I looked more like 12! I was convinced that the problem had something to to do with two wires that went to the corner of the drawing, which was torn off. The plant manager was giving me a hard time and asking when someone qualified was going to show up. I said I'd be back the next day with my dad. We came back and I went over everything I had found with dad. Suddenly I realized what was on the missing corner of the drawing. I announced that the problem was the thermostat in the office on the other side of the wall. The plant manager said "Yeah right!" I walked over and turned up the thermostat and the boiler immediately misfired and shut down! An unusual set of weather conditions had triggered the problem.

Dad looked at his watch and says to me "Hey you better get going, you have a plane to catch." Then he explains to the plant manager "He has a trouble call to go on for a chemical company in California." The look on his face was priceless. They told me they needed me for a couple of days, I was out there 2 months!

Gary H. Lucas
07-12-2012 06:24 PM
Re: Premature impeller failure cause

Spoke with Westerbeke today confirming the same thing that I was told by Hansen Marine. Every, hose, fitting, etc. needs to have an inside diameter of 1 inch. That includes the pipe ends on the strainer. I'm pretty sure I'm less than that on the thru hull and the strainer.

Going through the installation and operational manuals I was not able to find the Inside diameter requirement. When I spoke with Joe Joyce at Westerbeke he indicated that it is only shown on the installation drawings. The sales info had specs for fuel line size but not water. They didn't make it easy to get info.
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