Westerbeke 6.5 Kw Generator - Waterpump Question

[VerBoatin]

Good Afternoon iBoats & Westerbeke Experts,

I have a Westerbeke 6.5 Kw BCG Generator.

Its been working very well!

I changed the impeller over the winter and changed points/plugs, etc...

Generator has been running fine.

I started it up on Saturday and noticed that the exhaust sounded different. Checking the transom exhaust, I noticed it was not pumping out water as normal. I was taking the boat out of the slip and it took a minute or two but I shut it down right away and it was quite warm. I could smell a slight odor of melting rubber and assumed that the intake became blocked (perhaps by debries in the water or something?) and it probably destroyed the impeller within a minute or running, perhaps less! New impeller is on order.

Having said this, I checked the intake and the strainer is allowing free flow of water in bound. I loosened the hose at the pump inlet fitting and sucked water in the hose, no problem at all. Not much effor required to get water up the hose to the pump.

I pulled off the pump, it rotates easily (indicating the impeller is probably bad inside and consistent with the rubber smell I detected, etc - impeller will be replaced soon as stated). The pump bearings are loose and rotate easily, no binding, etc. I"m trying to figure out why it didn't suck up water as it normally did on all previous starts since the impeller was changed. Your speculation on why the pump did not suck up water and circulate it through the heat exchanger, and out through the exhaust etc, would be appreciated. Any thoughts, recommendations, concerns, ideas, suggestions greatly appreciated.

My intention is to ensure I'm not missing some key factor here. I can only speculate that the impeller went bad and it couldn't suck in water (for reasons unknown)?? or there was debries blocking the intake under the boat and by the time I moved the boat and perhaps dislodged it, the impeller was damaged??

I started the generator and it started without hesitation...I shut it down immediately to ensure no further damage, etc.

I will lubricate the new impeller and prime the hose with water prior to tightening in the water pump in again but I'm concerned.

I know it takes mere "seconds" to "burn up" the new impeller if it doesn't start pumping water immediately. Any recommendations on how I can check the pumping ability after I install the new impeller without damaging it would be appreciated as well.

Thanks much,

Verboatin

 

[Don S]

Re: Westerbeke 6.5 Kw Generator - Waterpump Question

Moved your thread here, it's not an electrical problem.

I pulled off the pump, it rotates easily

Replace the impeller, they don't turn easily when the impeller is working. Then start it up and test run it.
Use plenty of dish liquid to lube the new impeller when you install it. The soap bubble out the exhaust will tell if it's pumping or not, and the soap will lubricate the pump for the time needed to start pumping.

 

[UncleWillie]

Re: Westerbeke 6.5 Kw Generator - Waterpump Question

Is the impeller Keyed to the shaft?
Was the Key reinstalled with the new impeller?
The impeller will drag the walls going forward and try to dig in if you turn the shaft in reverse.
Without the Key, it will turn easily either direction because the shaft is just spinning and the impeller isn't.

The burning rubber will be from the over heated Exhaust hoses.
I doubt you will smell a hot impeller.

 

[VerBoatin]

Re: Westerbeke 6.5 Kw Generator - Waterpump Question

Hello Don S.,.
Thanks for your response and as always, your advice is very sound. I'll use the dish soap to ensure the pump is lubricated until it starts pumping water, etc. Also, thank you for moving the thread to the proper forum...I wasn't sure where to post it.
Thanks again,
VB

 

[VerBoatin]

Re: Westerbeke 6.5 Kw Generator - Waterpump Question

Hello Uncle Willie,
Thanks for your response and I appreciate the guidance. The impeller was keyed properly and such but is definetly shot. I have a new one on order. The overheated exhaust hoses, ah yes....thank goodness these generators automatically shutdown so idiots like me don't completely burn things up! Again Sir, thank you! VB

 

[UncleWillie]

Re: Westerbeke 6.5 Kw Generator - Waterpump Question

So if you properly installed a new impeller, what was the failure?
Is the assumption that the intake was mysteriously blocked?

Is the impeller located below the water line?
If not, An air leak in the intake hose would prevent the pump from self priming.

 

[VerBoatin]

Re: Westerbeke 6.5 Kw Generator - Waterpump Question

Hi Again Uncle Willie. New impeller not yet installed but your questions hit the nail on the head as to why I posted the situation and requested guidance. I'm troubled as well as to the cause of the failure in the first place. I also don't want to burn up another impeller trying the pump out after I change the impeller. No Sir, the impeller is about 24 inches above the waterline so it has to suck water up and circulate etc. The Westerneke manual cautions on this point in that It reads that any positive water pressure could bypass the pump and filled the exhaust manifold with water and then the water could get into the engine. Again I am troubled as to why the blockage occurred in the first place. Your point is well taken concerning an air leak in a hose. It never occurred to me that such an air leak might cause the pump to have a problem self priming and perhaps the problem was not a blockage at all but rather a self priming issue. Between now and the time the new impeller arrives I will check the hoses and make sure the fittings are tight and there are no air leaks in the hoses. That was a great piece of insight as well. Thank You and I will get back to you after I investigate further. Again thanks very much for your help. VB

 

[Don S]

Re: Westerbeke 6.5 Kw Generator - Waterpump Question

It may not have been a blockage at all. A seriously worn out impeller will not only not pump water, it's that same impeller that sucks the water up when the pump is above the water line.
If it can't create enough vacuum to suck the water up because it's worn out and the vanes are no longer flexible, your going to have an overheat.

 

[VerBoatin]

Re: Westerbeke 6.5 Kw Generator - Waterpump Question

Hi Don. Thank you for your guidance on this matter. I agree, the pump will not suck up the water if the impeller is worn. The only problem I have with this, is that the impeller was replaced over the winter and had not been used but for about five hours at the most. However it may have gotten dry and become inflexible as it was not run all that much during the winter. I have the new impeller and have installed it in the pump. I will be installing the pump this weekend and should be able to give you feedback as to how it is operating. Again thank you and Uncle Willie very much for your assistance. Verboatin

 

[UncleWillie]

Re: Westerbeke 6.5 Kw Generator - Waterpump Question

A new impeller, less than 6 months old, is not an Old, Dried Out Impeller.
Your Rubber Auto tires "Dry Out" from baking in the UV Light of the Sun, Not because you don't water them enough.
It is rubber, it doesn't dry out. It should be able to last for years.

Unless you find, or accidentally solve the real problem, the new impeller will suffer the same fate.