Sounds fuel related to me.......is the fuel in the sight glass staying at the right level........if not needle and seat sticking...seen this many times but it should be flooding out of the carb if this happens....i just usually just whack the top of the needle and seat outside of the carb with a rubber hammer and it unsticks.........if this is not the problem maybe your fuel pressure gauge is out to wack as the needle and seat prssure is usually no higher then 7 psi as it will lift the seat and flood the carb........do you have a power valve in the front or the back as if one screws up it will flood the carb.....not sure if this will help just a few things to check