Onan Generator not sucking water or spitting out exhaust

hipo

New Member
Aug 8, 2017
25
Kent Narrows, MD
Boat Info
2005 420 Sedan Bridge
Engines
Cummins 6CTA
So just fired it up for season--with new impeller installed--it ran for about a minute and stalled--no water coming out exhaust--
I think its airlocked from new impeller install--
I loosened the cap off strainer and tried to run it--got same result
Any suggestions?

thanks
 
Is the seacock completely open? Is the strainer clean and getting water?
 
Has your diver checked the strainer inlet on the bottom?

Did you lube up the impeller?

Is it possible that you heat exchanger is clogged up?

Those would be my top 3 in addition to the ideas above.

I just replaced my impeller on the generator. I used a large amount of glycerine as lube, and I had a strong flow of water in about 15 seconds. I ran my pump dry and it shredded the old impeller after about 45 seconds dry.
 
Yes, the seacock is open and water coming in when I removed the strainer cap--impeller was properly installed with lube--I guess maybe not enough water coming in through strainer, boat in the water all winter--I am having a diver come next week
Thanks!
 
Last year I had a similar situation, but I think it was a combination of a blockage with an air lock. I took lots of thing apart until I got to the bottom of it.

To save you trouble, the most effective exercise I did was flushing the system both ways. I used two points, one from the water pump (after the impeller, as I knew 100% that impeller was fine) and the other the hose going in to mixing exhaust elbow.
 
I just had this last week. First they thought the wear plate had to much wear. ( was already reversed.) IT is such a bitch to replace i purchased a new water pump. Problem solved . So it was either the wear plate or worn seal on the drive shaft letting air in . Mind u generator worked like a champ at end of season ( impeller was wasted ). At 12 years old she doesn't owe me anything .

( we had already made sure no obstructions and hooked a hose up at the intake so it was def pump related )

Rob
 
I had the exact same problem last year and my tru-hull was stopped up completely. I took off my intake hose and nothing came out at all. Stuck a phillips screwdriver in the tru-hull and trash and leaves started coming out slowly then after about 3-4 jabs it started pouring out, problem solved......
 
I had the exact same problem last year and my tru-hull was stopped up completely. I took off my intake hose and nothing came out at all. Stuck a phillips screwdriver in the tru-hull and trash and leaves started coming out slowly then after about 3-4 jabs it started pouring out, problem solved......
I replaced impeller last year before putting boat away for the winter. Generator ran great before new impeller. After new impeller installation generator kept shutting down. After checking all the usual problems and removing plate to check impeller it still would not run. I had another impeller and decided to swap it out and it instantly began pumping water. Appears impeller has spun the hub, however wasn’t noticeable unless under pressure.
 
I have one other thing to check. Is the belt tension correct and is the pulley working correctly?
 
So the Genny is running perfect! turns out, it was airlocked--had to take off hoses and fill system with water--from the top--ALL is good--Does anyone know if there is a ZINC in the Onan?
 
Zinc_and_Coolant_Drain_Location1.jpg
 
Good luck getting to the zinc . Sound enclosure is soo in the way ....

Zinc Part number 23-6401 replaces Onan part # 130-4434

Never been replaced sadly..

: (

Rob
 

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