weird cutting out problem

Couple of quick thoughts. Vapor lock maybe, if you have a metal line running from fuel pump to carb make sure
Its not contacting anything hot. Also be sure where its routed along frame its away from exhaust. Secondly if you have a tach unhook it, had a sunpro years ago that was shorting and killing ignition. Even though your getting a fuel shot from accelerator nozzles you could still be dealing with fuel percolation, there may be enough fuel in the accelerator pump to do so.