welcome. first, which engine is it, AX, FX, LA or other? second has this plane had a hard hit to the ground? sometimes an impact will make the tnk clunk bend and get kinked. check all bolts on the back of the engine. the LA series backplate is plastic and it does leak air. clean it up good and reseal back plate with some RTV silicone on the backplate. check the carb for leaks. the needle valve can leak also, take out the needle valve, put a short piece, about 3/16" long, fuel hose on the needle valve and screw it back in. after youdo all that, then if your a club member, have your best engine tuner get the mixture right.