Walbro says in their technical literature that the idle has to be richer than optimum for good throttle transition, and I have found this to be slightly more pronounced when running Gas/Glow. It likes a richer idle than normal. However, you should be able to work it out.

Try using one of those intake horns they sell. (You could make one.) Most all two strokes have what is called "stand off". It is a mist of fuel that is expelled out of the carb when the piston goes back down to close the intake port. With an air filter, or an intake horn, (velocity stack), the mist is drawn back into the engine. Without, that mist is blown away by the propellor, effectively leaning out the mixture.

So try that, and if that doesn't work, I would try a different carb. Also, if the carb is too big you will have this same problem.

Good luck,
AV8TOR