I'm not saying that it couldn't be a problem with the carb; I'm just saying that it could also be the timing. I spent a lot of time on the carb because I was certain that it had to be a carb problem, afterall it was somewhat cured by leaving the choke partially out. Ignition and carb problems can have very similar symptoms, so don't count out a problem with the ignition system is all I'm saying.
