1996 60hp outboard starts and runs great, won't re start . We just purchased a used pontoon boat. It has a 1996 Merc 60 hp. The thing starts first attempt. Runs fantastic. We stop to go on the beach or fish, the boat will not restart. It does not spark at all. After about 45 min to an hour it starts up again. This should not happen. Not sure what to do? What should we check first. It has happens on three occasions now.