Koehler 8KW Impeller Change Problem

[Sadey]

Just changed out the impeller on my 8KW generator which was working properly the last time I used it. I’m using the right impeller, correct part number and it matches up with the old one, it sits properly on the shaft and I verified with the cap off that it rotates. I get some water splashing out with the cap off. When I put the cap back on, no leaks out of the cap and I can see the pump shaft rotating. However, there is no water coming from the exhaust out of the exhaust thru hull. There is exhaust coming out and the hose in and out of the lift are warm. I know that the thru hull is open and not plugged because I took the cap off the strainer, opened the valve and water flows freely out of the strainer basket. This is a first in many impeller replacements, any suggestions?

 

[Cricket]

Pull the pump discharge hose either at the pump or where it connects to the HE to see if there's any flow.
If poor flow you could be pulling some air between the seacock and pump or inside of pump could be worn.
If there's good flow then maybe there's a blockage in the HE, also could be blockage in the exhaust elbow, etc.

 

[Captain Ralph]

The last time it ran and flower water?
All old impeller bits accounted for?
Pre-lube on the new impeller?

 

[Sadey]

Checked all of the above but it turns out it might be the paper gasket not sealing properly. Ordered a new one and if worse comes to worse, I’ll use Permetex to get me through. Scott to the rescue, I’ll order a new pump and swap out the old one to rebuild as a spare.

blew air through the discharge hose and I can hear the water bubbling in the heat exchanger to the lift exhaust. The new impeller rotates freely and the old impeller was completely intact. FYI.

 

[bostonhatteras]

what about the pump cam?

 

[Sadey]

Scott and Cricket were correct. Scott sent a new pump from Depco which I swapped out with the old one and we’re back in business. It must be the cover plate or the inside of the pump is worn enough that it’s sucking air. Thanks again Sams!