FAA Powerplant Written Practice Test

Which part of the carburetor is responsible for creating a low pressure area that draws fuel into the airflow?

1. Throttle Plate

2. Venturi

3. Float Bowl

4. Mixture Control

The correct answer is: Venturi

The correct answer is the Venturi, which plays a crucial role in the carburetor's operation. The Venturi is a narrow passage that has a shape designed to accelerate the airflow as it passes through. According to Bernoulli's principle, as the airflow speeds up in this constricted area, the pressure within that area decreases, creating a low-pressure zone. This low pressure draws fuel from the float bowl through the fuel jets and into the airflow, allowing for the proper mixing of air and fuel for combustion in the engine. Understanding the Venturi's function is key to grasping how carburetors work. Other components, such as the throttle plate, regulate the amount of airflow entering the engine, but they do not create the low-pressure area necessary for fuel flow. The float bowl serves as a reservoir to supply fuel, while the mixture control adjusts the fuel-to-air ratio but is not directly responsible for creating the low pressure that draws fuel into the airstream.