Private Pilot Private Exam

Generally, how does the use of carburetor heat affect engine performance?

1. It increases engine performance

2. It stabilizes engine performance

3. It decreases engine performance

4. It has no impact on performance

The correct answer is: It decreases engine performance

The use of carburetor heat generally decreases engine performance due to the nature of how it operates. Carburetor heat is utilized primarily to prevent carburetor icing, which can occur when moisture in the air freezes in the carburetor, disrupting the proper mixture of fuel and air. When carburetor heat is applied, it introduces warmer air into the carburetor. While this warm air can help to melt any ice that may have formed, it also reduces the density of the air being fed into the engine. The introduction of warmer air means that there is less oxygen available for combustion, leading to a richer mixture. This rich mixture can result in a decrease in overall engine efficiency and power production, as the engine may not be operating at its optimal mixture ratio. Generally, pilots should be mindful of using carburetor heat only when necessary for safety regarding icing and be aware that it can lead to a decrease in performance during use.