I agree with sixpackgut. I had the same problem with my 8896-1 Dominator. For the engine to idle it was necessary to open the throttle plates to far and it left the transfer slots completely exposed. I ended up drilling small holes in each throttle plate to correct the concern and increasing ignition timing.

It sounds like your idle mixture is set correctly at this time. Mixture screws 1 1/2 turns out from seated is the correct normal range, Fining tuning can be done later but thats pretty close for now.