Hi!
Have you tried setting the engine rich? I mean opening the high speed needle when the engine rews at full throttle so the the rpm drops due to too much fuel?!

Forget about removing the carb,just check so that the carbs is securely mounted.

Never ever try to set any screws when the silencer/engine is hot!!! Screws should always be tightened when everything is cold.They will loosen otherwise!

A gasket between the engine and silencer isn't necessary!

Run 5-10% nitro fuel and an OS 8 or ENYA 3 or 4 plug.