It seems that it is always the small stuff...
Recently we had a salt water-flow shut-down on our Onan MDKAV. The first thing I checked was the impeller even though I had changed it at the 400 hours interval only a few hours ago. I found nothing wrong with the impeller so I began the process of disconnecting hoses and checking for water flow or blockage...I found no problems.
I removed the salt water pump for the second time and found that the shaft turned freely, but the impeller did not move. The problem was part number 132-0374 which is the shaft key which locks the impeller in place on the shaft. I did not have a key, but did have a spare pump, part number 132-0459 (replaces part number 132-0358).
Hope this helps someone.
s/v BeBe SM2, #387