on a dual carb, front carb, the curb idle screw has to turned all way out so, carb will not idle,, also, screw idle mixture screws all way in, the rear carb is only one for driving, the front carb is for wide open throttle, after that then turn rear idle screws out about a half turn or so, also use a vac gauge to set idles. vac advance goes to rear carb. i've ran all dual carbs this way. just food for thought.
