RE: engine shutting down on take off
I have a GMS .47 that was given to me because it ran like that. It was one of the older ones that had the mis-drilled fuel inlet bushing on the carb, and also had air leaks all over. Re-drilling the inlet via the fuel nipple and sealing everything with a healthy coat of make-a-gasket made for a great running engine. The partially blocked inlet lets it run fine at low throttle settings, or even rich, but leans it out more and more as the throttle is advanced. Remove the nipple off the carb and look at the bushing. If the hole your looking at is partially blocked at the bottom, this could be your answer.