New to boating.. We have an 88' Four Winns 160 Freedom ( 3.0L OMC outdrive).. Since the wife can't back the trailer down the boat ramp, she stays in the boat, starts it and moves away from the ramp until I return from parking the truck/trailer... I have told her to always make sure the outdrive is down before starting the engine... Well, I should have checked.. I did ask and she said it was down... .(from the captains seat, how can you see?)... Not wanting her to think I was questioning her, I drove off w/ the trailer and returned to a boat that barely had the prop in the water and a pegged water temp guage.. I asked "how long has the temp guage been pegged hon?" as I shut off the engine.... Let it cool for 30min. restarted and temp guage slowly climbed back up so we docked it and took it out of the water.... Impeller is toast.. New impellor and housing kit but now it won't hold a prime.... No bad sounds or smells from the engine itself, oil looks and smells o.k... thermostat housing cleaned out of debris and all hoses too.. Still won't hold a prime.... Now what?...