You are correct in assuming its most likely in the carb. They are real basic & simple. The first thing is to pull the top off the carb. There is a tube that runs across the top of the air horn. There is a small plug in one end of it like a tiny freeze plug. Sometimes that blows out of there & causes the very problem you are refering to. If you cant find the plug you can fill it in with JB weld or equivilent. If that is not it remove the idle jet & blow out all the passages. Make sure the float is not full of gas & check the float level.
