If you don't have a vacuum leek causing it to run lean. Then try the old trick of revving the engine up with the air cleaner off. Then you put a waded up shop rag over the carb choking it. Then you pull it off and repeat a couple of times. This will flush fuel through every hole in the carb. So if there was some chunk of crap plugging something it will just suck it clean. Also try a new fuel filter just for fun.