Which device is commonly used to aid a cold engine start by restricting air flow?

Which device is commonly used to aid a cold engine start by restricting air flow?

• A. Spark plug
• B. Fuel pump
• C. Choke
• D. Oxygen sensor

Answer: (C)

When starting a cold engine, it helps to have a richer fuel-to-air mixture because fuel doesn’t vaporize well at low temperatures. The choke is a device that partially blocks the air intake, which reduces the amount of air entering the carburetor and forces more fuel into the mixture. This richer mixture makes ignition easier and helps prevent stalling until the engine warms up. Once started and warmed, the choke is opened to restore normal air flow. The spark plug provides the ignition spark, the fuel pump supplies fuel, and the oxygen sensor monitors exhaust to adjust the mixture for emissions—not to aid initial cold starts by restricting air.

When starting a cold engine, it helps to have a richer fuel-to-air mixture because fuel doesn’t vaporize well at low temperatures. The choke is a device that partially blocks the air intake, which reduces the amount of air entering the carburetor and forces more fuel into the mixture. This richer mixture makes ignition easier and helps prevent stalling until the engine warms up. Once started and warmed, the choke is opened to restore normal air flow. The spark plug provides the ignition spark, the fuel pump supplies fuel, and the oxygen sensor monitors exhaust to adjust the mixture for emissions—not to aid initial cold starts by restricting air.