[Masteryota]

If it is on the very bottom of the carb, that is a fuel bowl drain, and drains the fuel out of the carb for extended storage. It would explain why it won't start if it is still open and draining. The pilot screw is near the intake hose leading to the engine, I would not mess with the screw settings till you double check the pilot and main jets are cleared. Even then, screw it in taking note now many turns it takes to seat, and put it back in the same setting during reassembly.