I started up the 67-327-2 barrel and it was running fine. Just letting it warm up and then it started running rough. Got out and opened the hood to see gas just pouring out of the top of the carburetor and down onto the manifold. It was flowing down like a waterfall. I turned it off and soaked it all up with towels. What the heck was that? Should I try to rebuild the carb or just buy a new one?