taking that nut off will drop the float bowl ,under there is a float, a needle shut off pin, small and easy to loose, sounds more like your carb is gummed up, take it completly off , and clean, use sea foam a stronger better product, blow things out with air, DO NOT bend or twist things, at one time the carb worked good just where there at, soak in sea foam over night ,blow things out ,reinstall. this is not a hard job , look up the hole where the needle valve is, if it looks like a screw slot? un screw pull out clean those little holes thats the clog.
