My 1980 Ski Nautique runs great for approximately an hour & a half - tubing etc...but afterwards it will periodically die and won't run. I let it rest for an half an hour or so and it'll run fine for similar amount of time. This issue started last season (2012) and is re-occurring this season. Marina has tried to reproduce the same result but ofcourse the boat won't act up. This issue does not occur "everytime"...but is somewhat regular.