I've got a B&S 08P502-0047-F1, I've replaced the carb and air filter(ebay parts), but I don't think that's the problem, it has a rough idle with the air filter on, but when I take the air filter off, and sort of block the air passage with my fingers, it'll smooth out perfectly, what I'm thinking is it's getting too much air or maybe not enough gas, I say that because when I block the air passage with my finger it is around idle rpm, so if you add more gas to it, wouldn't it rev up higher than idle? Anyway is there a way to adjust this or do I try and jimmy rig it?