The __________ adjusts fuel during changes in throttle.

• A. Metering Valve
• B. Fuel Filter
• C. Barrel Valve
• D. Shut-off Valve

Answer: (C)

Fuel delivery must respond to throttle input, adjusting how much fuel is sent with each pump cycle. The barrel valve inside the fuel injection pump is what directly does this metering. As the throttle opens and demand rises, the barrel valve shifts to increase the metering opening, delivering more fuel. When the throttle closes and demand drops, the valve narrows the opening to reduce fuel. This dynamic control keeps the engine responding smoothly from idle to higher power. Other components listed have different roles—filters clean fuel, shut-off valves stop flow, and while other metering elements exist in various systems, the device that actually adjusts fuel with throttle changes in this setup is the barrel valve.