Been having the same problem and took apart the carb 3 times, cleaned it, you name it, checked everything. Then a buddy told me he had the same problem and it was the needle in the carb sticking. It allows the carb bowl to fill up and then empty but then doesnt drop to allow refill. He said to just buy a new carb, they are about $30 cnd if you can find one. Don't quote me tho, I havent tried that yet. Im gonna try cleaning the needle 1st, then buy a new one if I have to.
Good luck & keep us posted