An air choke is a device used in engines, particularly in internal combustion engines, to restrict airflow during the starting process. By limiting the amount of air entering the engine, it creates a richer fuel mixture, which helps the engine start more easily in cold conditions. Once the engine warms up, the air choke automatically opens to allow more air in, optimizing the fuel mixture for efficient operation. This process is crucial for maintaining engine performance and reducing emissions, making air chokes an important component in many automobiles and small engines.