I've had my generator impeller spin 3 times. ( the center bronze separates from the rubber causing an overheat) If you look at the impeller it looks perfect but if you hold the bronze you can turn the rubber. This is a Perko raw water pump with a Perko impeller on the generator, not some cheap replacement. You'd think that they'd know and resolve the problem.

Here we are,,,, I've maintained the generator and WHAM! it overheats, smoke billowing out of the engine room. We shut the thing down hoping it didn't self-destruct. I look at the impeller and it appears perfect but if you take it out it spins on the shaft.

Damn!