[Rev]

I'm not convinced that it's necessarily a "too rich" situation. A too large carb often gives a weaker signal causing an overly lean situation. But that situation usually occurs higher in rpm range when the main jets are functioning. I'm thinking that it may actually be a "not enough accelerator pump shot" rather than too much.

Is there any black smoke when you nail it from a stand still? That would mean an overly rich situation (too much pump shot). If that's not the case, I think the hesitation means not enough shot.

Rev