If you really want to clean the carbon out of your engine follow these simple steps. Fill an empty soda bottle with water. Remove your air cleaner. Start your engine. While using one hand to control the throttle, trickle the water into the carb or throttle body with the other while holding your thumb over the bottle opening. Keep the engine rpm's up so that the engine doesn't die. Make sure that you don't pour the water in too fast! Water doesn't compress and if you pour too much water in, severe engine damage can result! White smoke from the exhaust is normal.
Try it and report back how it works for you.....