engine overheating

Speaking of RW pump housings, I replaced the Kohler raw water impeller on my genny. Immediately after doing so I noticed the flow wasn't like in the past somehow I had mistakenly doubled up on the O ring. This cause air to get into the RW pump housing. I took it apart and sure enough one O ring was intact the other couldn't stay lined up causing the loss in pressure. It was an a mistake on my part. I removed the O ring and re-seated the one O ring and everything was fine.
Bill
 
I don't know how the volvo impeller is mounted on the shaft but if the locking mechanism isn't installed, the impeller can very well spin freely and allow water to flow thru the pump.
 
I just dealt with this problem and I did what Sandy suggested and back flushed my coolers. Both my tranny cooler and oil cooler were semi-clogged with crud. Cleaned them both thoroughly and full water is now running thru.
 
quote:
Originally posted by jtybt15

I don't know how the volvo impeller is mounted on the shaft but if the locking mechanism isn't installed, the impeller can very well spin freely and allow water to flow thru the pump.

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Charlie - I thought about that but I believe when I checked a Volvo parts diagram the shaft and impeller hub were splined with no key. I could easily be wrong though.
 
Kinda running outta ideas how the pump ain't pumping. How about what capt bill said.
 
"2. I attached hose from house to output hose from raw water pump to cool the engine. And had clear hose from pump into bucket. Ran engine and no water came out of raw water pump. Also, engine temperature was fine on hose. "

Well then the only answer seems to be the pump is not pumping but the engine is able to flow water through it OK. IMO it's either the pump housing is shot and the pump can't pull a prime or the impeller is not turning. You need the take the cover off the pump and confirm that the impeller can not spin on the shaft and that the shaft is not broken or damaged.
 
Might want to try swapping the impellers between engines to see if the problem follows the impeller. I've heard the Volvo pumps can be particular about using the absolutely correct impeller.
 
problem solved.
bought rebuilt raw water pump on ebay $350.
three bolts hold it to fly wheel. so replacing it was not very difficult.
I'm going to replace bearing seal in old pump and test it on the bench.

Thanks to all that responded.

Hopefully the debris in the Ohio will settle out and we can go for a cruise.
 
That's great you have regained good flow and cooling and that engine is squared away.

Belatedly responding to a previous question, I should think house water pressure of anywhere of say 20-60 psi depending if city or well would be able to make it past the flexible vane impeller of most RW pumps. After all , the vanes don't even touch the housing wear surfaces at elevated boat and engine speeds. I haven't tried that but just strongly suspect that would not be a terribly helpful test. It could have been interesting to try connecting house-pressure water to the new one prior to installation so you would know what to inspect for future tests.
Generally, if the seal has been compromised the pump leaks.

Of course, since the newly-installed pump eliminated the issue, that's a pretty decent clue the old one was more than suspect! Before buying a replacement, I might have swapped out the pumps between engines if I suspected a bad one yet saw no leaks, -but clearly you made a good call.

(I usually keep a spare new & painted RW pump and tools to deal with it onboard in case conditions allow at-sea replacement . I hate waiting to get back to the dock if it's spraying salt water all over the alternator and rest of the front of the engine.)
 
First thing you said was 'replaced impeller...' After that, I pretty much ignored the pump as being the culprit. Goes to show, especially on pumps, replacement of impellers aren't gonna fix a worn housing.
 
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