Carver Owners Forum

Kohler 7.5 r gas generator not pumping water and shuts down in 30 seconds . checked impeller looked great but went ahead and replaced it anyway still not pumping water . any help would be appreciated

I have a 11 KW Kohler on my Carver 396 and experienced the same problem. Mine problem was due the pump bearing was seizing and burnt the belt off. I replaced the pump and reconnected the supply and hose to the heat exchanger and had no flow. First check the thru hull valve to make sure it is open, my was not. The thru hull screen can also be clogged with algae or in my case zebra mussels and make sure supply hose is clear which mine was clogged with mussels. I had a fellow skipper tell me to burp the heat exchanger which I did, buy still had no water flow. After all else failed, I disconnected the supply and heat exchanger hose at the new pump and reversed their connection. Even though I had taken a picture prior to old pump removal and reconnected hoses to new pump exactly like the old pump was connected. Reversing the hoses worked???? Still don't know why, but my Genset runs fine now. Best of luck in your endeavor!

Start with the simple stuff; I assume the seacock is open? If there is a strainer, ensure it is clean and filled with water. Remove the raw water line from the pump, lay it low in the bilge and see if you have free water flow. You should get something because the strainer if applicable should be below the waterline. If you have free flow, hook back up tot he pump and remove the hose from the output side of the pump, run the engine and see if there is water pumping out. If there isn't, the issue is from the pump to the hull intake. Could also be a loose hose clamp letting in air, or a hole in the hose.

It could be that your pump needs to be primed however I have very rarely run into this with a generator. There may be a reason why it isn't priming on its own.

If the new impeller ran for 30 seconds dry, it may be toast now if you didn't lubricate it at installation. If the wear plate is scored, the pump won't work efficiently. This should have been checked when the old impeller was removed. That and other issues will cause the same sympton.

thanks for the input finally found out my exhaust was stopped up so we took it apart and flushed even the muffler out and has run perfect since

Darn, it wasn't the in, it was the out. Good to know, if we can remember it when it happens to us! LOL-Mike