It could also be that your low speed mixture screw is terribly out of wack. Applying the choke is essentially just creating a super rich fuel/air mixture so for in order for it to only run that way after it cranks means it is starving for fuel.

If it is a clogged jet, it could be from ethanol residue but could also be from particles from an old, deteriorating fuel line or junk from your gas tank. Do you have a fuel filter anywhere? If not get a cheap inline FRAM filter from an auto parts store or Walmart and put it in between the fuel pump and the carb.