You problem is a plugged idle circuit in the carb. These carbs idle circuit plugs easily when water gets into the carb or gasoline is let go stale. The idle circuit is also VERY hard to clean. I have never had any luck with any type of carb cleaner. I cut one carb apart to see how the idle circuit worked. There is a SMALL hole above the threaded area where the main jet adjuster/bowl retentions screw go in that is plugged. It is also VERY HARD to to clean with a small wire which is the ONLY way to open this hole. I have heard some people have had luck using CLR. I have not try this.