check the throttle shaft bushings for wear. that is common problem. the throttle shafts bind because the butterfly valves never end up in the same place twice. thery also leak vacuum so it is hard to adjust the idle mixture. also check all the rest of the linkages and pull offs on the carb. some are affected by the choke so if the choke is still on a little that part of the linkage isn't operative. like the 4bbl lockout won't owrk if the choke is active. grab some carb cleaner/lubricant spray at the parts store and do a little clean up of all the rods etc. if you have a little extra cashola, get a new aftermarket carb and some new distributor weights and springs (recurve the distributor) at the same time. that will perk it up. have to spend a couple hundred though.