Which circuit uses a mechanically actuated squirter that activates with a sudden or aggressive movement of the throttle linkage?

• A. Transition circuit
• B. Accelerator pump circuit
• C. Bucket lifter
• D. Valve spring

Answer: (B)

When you move the throttle quickly, the engine needs a quick burst of fuel to prevent a lean stumble. The accelerator pump circuit is built for that exact purpose: a pump linked to the throttle squirts a small amount of fuel into the intake as soon as the throttle is opened, giving a momentary rich mixture until the air flow stabilizes. This mechanical actuation by the throttle linkage creates that sudden fuel spray through the squirter.

The other options don’t fit this description. A transition circuit is involved in adjusting the fuel-air mixture during throttle changes but doesn’t rely on a dedicated squirter spray. Bucket lifter and valve spring are parts of the valve-train, not the fuel delivery system, so they don’t involve a squirter activated by throttle movement.