Rough idle... only when warm.

Carterbrocks run hot. Use a phenolic/plastic/wood or that 1/4 fiber gasket between the intake an the carb. when choked it changes the fuel circuit. Kinda sounds like your float level may be very low. Choked creates alot more vacuum so it pulls more fuel, if your float level is low, your fuel pressure to the boosters is going to be lower and its gonna run lean. When i starts to run like crap, shut it down and pull the top of the carb off as fast as you can to see what the fuel level is.