A manual choke is a carburetor control for cold starts, using a pull-cable to enrich the fuel-air mix by restricting air, but it's discontinued in modern cars, replaced by electronic fuel injection (EFI) for better efficiency, reliability, and emissions. Drivers manually pull the choke lever to help a cold engine start, then gradually push it in as the engine warms, a process often requiring finesse to avoid stalling or over-enriching.

How it Works

Cold Start: A cold engine needs a richer fuel mixture (more fuel, less air) to run because fuel doesn't vaporize well in cold conditions.

The Choke Plate: The choke is a butterfly valve in the carburetor that closes partially when pulled, reducing airflow.

The Cable: A cable connects the choke plate to a knob or lever inside the car, allowing the driver to operate it.

Operation: Depress the accelerator fully (this sets the choke and prevents friction). Pull the choke knob/lever out. Turn the key to start the engine. As the engine warms, slowly push the choke in until the engine idles smoothly, then turn it off completely.

Why it's Discontinued

Electronic Fuel Injection (EFI): EFI systems use sensors and an Engine Control Unit (ECU) to precisely manage fuel delivery automatically, making manual adjustments unnecessary.

Improved Efficiency & Reliability: EFI offers better fuel economy, smoother operation, and easier starting in all conditions compared to carburetors.

Emissions: EFI provides more accurate fuel control, helping vehicles meet stricter emissions standards.