FAA Powerplant Written Practice Test

What component measures the amount of air delivered to the engine in a carburetor?

1. Throttle Valve

2. Float Chamber

3. Venturi

4. Fuel Discharge Nozzle

The correct answer is: Venturi

The correct answer is the Venturi. In a carburetor, the Venturi is a crucial component that measures and creates a difference in pressure, allowing air to flow into the engine while also mixing with fuel. As air passes through the Venturi, it constricts, causing an increase in velocity and a corresponding drop in pressure. This pressure difference is what allows fuel to be drawn from the fuel discharge nozzle into the air stream. The throttle valve, while it controls the flow of air and fuel to the engine by adjusting engine power output, doesn't measure the air. The float chamber regulates the fuel level in the carburetor to ensure an adequate fuel supply but plays no role in air measurement. The fuel discharge nozzle is responsible for delivering fuel into the air stream but does not measure the amount of air delivered to the engine. Thus, the Venturi is the correct answer because it directly relates to measuring the air intake necessary for proper engine operation.