If it were me, I would want to get a handle on the problem before tearing down the carburetor. If you rebuild it and end up with more problems you won't be able to tell what caused the original problem. The choke should be closed when you go to start it and if it is an automatic choke, it should imediately be pulled open a few degrees as soon as it starts. The choke is very critical to the starting process. If is backfires because of being too lean, it can send "white smoke" out of the top of the carb.
