I use the idle stops on all my six packs that I restore or tune. I set my transfer slot at .040 with the idle set screws and see if I can tune it to idle correctly at that. IfI can get that setting to work, I set the idle stop solenoid at that point. Then you can back off the carb idle screw enough that it can close off the butterflies and then it should stop the after run condition. I don’t know of a solenoid that can overpower the carb and kick it up. The factory ones that I restore can only hold the tension if you crack the throttle. The repops can’t even do that.