Kohler 7.3e will not pump raw water

[Great Cornholio]

Few weeks ago my Kohler 7.3e shut down on its own while out on a cruise after about 45 mins or so. I managed to restart it and then it shut down again after a minute or two. I was thinking this was an overheat issue so the first thing I did was clean the sea strainer. After cleaning the sea strainer we noticed that the raw water pump wasn't pumping water. Checked the impeller and it was still in tact. Did notice that the shaft the impeller fits onto spun freely like it wasn't hooked up to anything at all. Just as more trouble shooting we left the cover plate off the impeller to see if it spun with the gen running. Started the gen up and the impeller did not spin at all. I've looked around and can't find any info on this. Does anyone have an idea of what part needs to be checked/replaced next?

Thanks.