just thinking about it, make sure your fuel tank cap is sealing good, i was fooling with my volcano last night, filled the tank and realized it was 10pm so i didnt run it, i took the fuel out and was blowing on the exhaust time and was blowing air from the o ring on the top of the tank, i just ordered a new tank. the engine ran fine the last time i used it but i am almost certain it wasnt leaking like this, when i turned the truck over, fuel was pouring out of the cap. this can make it run lean since its not getting pressure in the tank.