Also I have read in FSM, a 1976 one I believe, about those electrical assist systems where they had a hot assist side and a cold assist side. Nut shell if this assist was above a certain temp it would heat up the choke faster IE already hot engine compartment or hot day. And it also had how to adjust the ohms I believe on them to regulate the speed at which they opened them. I guess it kinda sounds like your ballast deal your refering too.