Assuming it hasnt been beat how many hours should a 502 mpi with procharger last? Also its been run in saltwater but supposedly flushed and not left in water? 500 hours? 1000? thanks

You will want to follow the regular scheduled maintenance from Mercury and do the valves at 250. If you are not running strainers and are on an impeller than it will need changing every year as the procharger will be running it hot all the time. Depending on the blower install the motor should last as long as you keep it up. Did you do compression and a leak down before you made the purchase?

I didnt buy it yet it was one I was considering. It has 350 hours on it in salt water. I'd be using it in fresh water only its a 95 baja outlaw.

I think the bes tyou ocould expect would be 500 hours and that is under the asumption the valve springs, lifter, and other components were upgraded. If it is ALL STOCK I would say its on borrowed time already. Not meaning its going to blow apart, but more HP wears all the parts faster it only takes one part to fail to be expensive day.