Private Pilot Private Exam

What happens to the fuel/air mixture when carburetor heat is applied?

1. The mixture becomes leaner

2. The mixture remains unchanged

3. The mixture becomes richer

4. The mixture evaporates

The correct answer is: The mixture becomes richer

When carburetor heat is applied, the fuel/air mixture becomes richer. Carburetor heat works by allowing warmer air from around the engine to enter the carburetor instead of the colder outside air. Cold air is denser and carries more oxygen, which results in a leaner mixture when combined with fuel. Conversely, warmer air is less dense and contains less oxygen, leading to an increased amount of fuel in the mixture relative to the air. This adjustment helps to prevent carburetor icing, ensuring the engine runs more smoothly, particularly in colder weather conditions where ice can form in the carburetor and disrupt the fuel flow.