Impeller Westerbeke 44a

[Ashanty]

I have two 44a on my catameran (yes, I feel sorry too...) and beside many other problems I have to change the impellers about every 100 h. Is this a normal 'Wester brakes' behaviour???? Thnaks for any ideas!

[Pblais]

Not sure but I have a Westerbeke too (63b). They usually use Shurwood raw water pumps on all I've ever seen. The water pump has never been made by Westerbeke. They are an engine company only.

Something is going on that isn't right. I'm not sure how you could be screwing it up yourself though. If the bearings were bad on the pump it might lead to premature impeller demise. Just what type of impellers are you using. Mine is a spline shaft impeller?

[Ashanty]

I'm using the original Westerbeke impellers part No. 034440 . Bearing seems ok, no leaking! And I have the problem on both (!!!) engines starbord and portside!

[Chief Engineer]

My first supposition is the belts are too tight.

What do the impellers look like when you replace them?

[Ashanty]

Belts are ok! Again: This happens on both engines! Dents are broken away. Last impeller was cracked completly...

[Chief Engineer]

What is a broken "Dent"?

[Ashanty]

Sorry I#m not English motherlinguage its a 'Zahn' from the impeller....

[Chief Engineer]

I translated "zahn" to be a tooth or a cog.

Do you mean the blades of the impeller are torn away?

If that is the case, you might have air getting sucked into the pump.
This could be from a bad pump seal, loose intake hoses, loose gaskets on strainers or obstructed hoses. Are your intake hoses wire reinforced?

[Ashanty]

Thanks!!! This may helps. I guess it was a loose hose that leaks very little...Its fixed now and we will see how long it works now.

[mikefossl]

From what I understand the impellers can crack very quickly if there is any restriction in waterflow; even if it doesn't result in engine overheating. I replaced the impleller on my 44a and after 40 hrs of running, I checked the impeller after noticing reduced waterflow in the exhaust. One of the vanes had already broken off and another was cracked. I then found another three broken vanes jammed in the pump outlet restricting flow. I suggest you check the raw water cooling circuit including heat exchanger for broken vanes or bits of zinc from the sacrificial anode.

Mike

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