After switching to a tuned pipe on my GMS .47, I began to experience problems with the engine shutting off in any high-G maneuver, especially tight loops. After reading this thread, I removed the fuel nipple to discover the brass insert misaligned with the carb body. I was able to remove the insert by heating the carb body with a torch. I drilled the insert larger to match the body, and now it is like a different engine. I have it on a tower kaos and it will easily do unlimited vertical, turning an apc 11-6 at 13500 and doesn't flinch during any maneuver the plane will do. Thanks to those that discovered the problem!