open the drain screw on the left side of the bowl
Not all NT carbs have a drain screw on the bowl. If your does that makes it simpler but if it doesn't just remove the two phillips head screws and the bowl, dump it and reinstall. If you have to remove the bowl make sure when you reinstall it that the pin that the float swivels on has not moved and blocks the bowl from seating properly against the carburetor body and gasket.
Actually I prefer to remove the bowl even if there is a drain. That way you can see if there is any junk or crud that might have gotten through the needle valve and you can confirm that the needle valve closes properly by gently pushing up against the tang that rides on the float to see it fuel stops flowing. You will also be able to check that the float has no cracks and does in fact, float in gasoline.
Tom