Which device adjusts fuel during throttle changes?

• A. Barrel Valve
• B. Metering Valve
• C. Bypass Valve
• D. Fuel Filter

Answer: (A)

When the throttle moves, the engine needs more or less fuel to match the change in air entering the cylinders. The device that does this by changing how much fuel can flow in real time is the barrel valve. It slides to open or restrict the fuel passage as throttle position changes, effectively varying fuel delivery to maintain the proper air–fuel mix across the throttle range.

The bypass valve would let fuel skip the metering path and isn’t responsible for throttle‑response metering. The fuel filter only cleans the fuel and doesn’t regulate quantity. While a metering valve sets base fuel flow, the actual adjustment during throttle changes in this system is accomplished by the barrel valve’s variable opening.