I put a stock carb on it today. I can't see a size number on it, but it's 13mm at the throttle butterfly. Engine runs good, but still not enough power.

17-8 Zinger--6100RPM

I'm going to just run it and try to put some more fuel through it. Still haven't even put a gallon through it yet. I should have cut weeds with this thing for a season before I slapped it in a plane.