When the choke on a carburetor is closed, it provides:

When the choke on a carburetor is closed, it restricts the amount of air entering the engine. This creates a higher fuel-to-air ratio, resulting in a rich air-fuel mixture. A rich mixture is beneficial during cold starts, as it helps the engine to ignite more easily and run smoothly until it warms up.

In this state, the engine receives more fuel than it typically would with an open choke, enhancing combustion in conditions where the engine needs more assistance to start. As the engine warms up, the choke can gradually be opened, allowing more air in and achieving a more balanced mixture for regular operation.