Make sure that the idle shutoff solenoids are receiving power. There are two mounted low on the carb pointing forward. Could just be a fuse problem.
As far as your secondaries, they will only open under high load where the vacuum is low. Sticking secondaries are quite often signs of over-torquing which warps the carb. You may be lucking and it might however just be gummed up. Not likely causing your idle problem.