I've had a problem like this when I got a small piece of junk in the fuel line. At idle, it would run fine, and run up to full throttle, but then very quickly cut out. I cleaned and blew out both the remote needle valve, and the inlet at the carb, and it worked just fine after.

My theory was that after the engine died, the junk would fall back out of the needle valve, and at the lower pressures around idle, would stay out. But as soon as I throttled up, it would get sucked back into place and block the fuel line, and the engine would quit again. I run fuel filters on most of my planes now, and haven't had it happen in a long while.