Running on two

[Quigley1930]

My coupe which was running great last Nov. when I stored it now is really running rough. I have timed it to be spot on and get a nice blue spark from the coil wire to a head nut. I have tried three different carbs. I am using ethanol free gas. After starting with great difficulty it appears to be firing on 1 & 3 only. it backfires and belches black smoke from the carb. I do have a nice spark at the points. I'm stumped and any help will be most appreciated.

Sewall