I am having trouble with my 1980 fl250. Sometimes it runs like a champ for awhile, then it will die. If I hold the throttle wide open it will idle, but if I let go, it dies. Cant ever find any dirt in jets, bowl is clean and about 3/4 full of fuel. After I put the carb back on, it will fire right up and run great again for an hour or two, then do it again. could I be looking in the wrong place? Getting tired of towing it back to camp with my quad. Please help.