We will need a lot more information... what type of fuel, running rpm, running temp...I had a problem similar with my .55ax. never really could find any problem, but after rebuilding the fuel tank, plumbing and cleaning the carb(where I never found a problem with any of it) it started running like it was supposed to. I would suggest back flushing the carb out and ensure that there is nothing on the needle valve or in the needle valve housing(its easy with that needle valve remote, just hook up the fuel pump to the side closest to the carb and pump it a couple of times). Keep us posted with specs if you have any results.
dan