I would not reccomend blowing it out, you may damage the carb internally. Instead, get an overhaul kit and dissasemblr the carb. that way you can inspect and clean it more thougholy. Also get a paint gun cleaning kit. These come with an assortment of small brushes(like a mini rifle brush) that can be used to clean the passeges more efficiently. Get a few cans of carb cleaner too, some parts houses and farm stores have it in quart containers as well as spray cans if you need to soak it. It sounds like you may have carbon buikdup in the throttle plate housing, that woud be a good place to start.
