I have a heritage softail with a S&S 113 with a G carb it also has a zipper ignition module. It will idle with some back fire out of exhaust if I move the throttle it just dies this has all begun after I changed the plugs, once I noticed it I changed the plugs to the old ones still doing it. I have also put a new stronger battery in it, I have the mixture screw set and idle set I have changed the gas and cleaned the bowl on carb(not that dirty) I could really use some help. Thanks