A little water down the carb can't hurt anything, and it's certainly cheaper than seafoam. I've tried several methods, such as using a spritz pump like the one on a Windex bottle, but the simplest method is just filling a soft drink bottle with hot tap water, hold a thumb over the opening, and dribble the water into the carburetor with the engine running at cruise RPM. The engine will shudder and shake a little, and steam and maybe some carbon will belch out of the tailpipe.
Jerry
