FAA Powerplant Written Practice Test

Which component is responsible for maintaining the appropriate air-fuel mixture at high power settings?

1. Fuel pump

2. Float chamber

3. Throttle body

4. Economizer system

The correct answer is: Economizer system

The economizer system is critical in managing the air-fuel mixture at high power settings. This system helps to ensure that the engine receives the correct proportion of fuel relative to the amount of air entering the combustion chamber, aiming to maintain optimal performance and efficiency during demanding operational conditions. When an engine operates at high power settings, the air demand increases significantly. The economizer enriches the fuel mixture as it responds to the higher airflow, preventing the engine from running too lean, which could lead to overheating or detonation. This adjustment is necessary because a lean mixture at high power could impair engine performance and compromise safety. While other components mentioned play roles in engine operation, they do not directly control the air-fuel mixture specifically at high power settings. The fuel pump supplies fuel but does not regulate the mixture, the float chamber primarily manages fuel levels in carbureted systems, and the throttle body regulates airflow but does not adjust the fuel mixture in response to engine demands as effectively as the economizer system does.