Which part of the carburetor regulates the amount of air-fuel mixture entering the combustion chamber?

The throttle is the component of the carburetor responsible for regulating the amount of air-fuel mixture that enters the combustion chamber. It controls the engine's power output by managing the airflow and subsequently adjusting the fuel flow to match the engine's demand for power at various speeds and loads. When the throttle is opened, more air is allowed to enter the engine, and subsequently, more fuel is drawn in, which enhances combustion and increases engine performance.

The float, meanwhile, serves a different function as part of the carburetor's fuel delivery system, maintaining the proper fuel level within the float chamber to ensure an adequate supply for atomization. The choke primarily assists with cold starting the engine by restricting airflow, enriching the fuel mix temporarily until the engine warms up. On the other hand, the jet is the component through which fuel is metered and delivered into the air stream but does not directly control the overall air-fuel mixture entering the combustion chamber.