Watching the float pin can tell you a lot. If the needle drops at the higher speed, then the restriction is in the tank and the fuel line to the carburetor. It could even be the air vent in the gas cap is plugged. If it comes up when the fuel is turned on and stays up at the higher settings, the fault is in the carburetor. I had one come into the shop that lost a screw that plugged the end of a fuel passage. The leak was immediately noticed, however the hardware store screw the owner replaced it with was too long. It stopped the leak, but shut off the fuel.
Good Luck . . . 😉
