im sure that if you have been having this problem a while you have tried replacing the plug but if not that would also be something to try, after that just completely change the fuel tank to one of your other plane's tanks that you know works if you have it mounted in the correct spot and none of that corrects the problem then send her in and tell evolution what it is doing and what you have done to try and remedy the situation and most likely they wont charge you for repair or replacement!