Hi I have a 1990 Bombarder. It runs great for about 20 mins then dies and will not start again. If I wait about two hours it will fire up and run great again for 20 mins. What do think might be the issue? Things that I have checked-Fuel vacuum issue overheat (Water flows through fine. I did notice air bubbles in the fuel line bubbling back from the carb to the tank. Any help would be appreciated.