A mechanic has determined that no fuel squirts into the carburetor when the throttle is opened quickly. What could be the cause?

The scenario describes a situation where fuel is not being delivered to the carburetor when the throttle is opened quickly, which is crucial for maintaining engine performance during rapid acceleration. Each potential cause is valid and could independently lead to this problem.

A disconnected linkage would prevent the accelerator pump from functioning properly, as the throttle opening is what activates the pump to deliver a squirt of fuel into the carburetor. If the linkage is not connected, there will be no movement to engage the accelerator pump when the throttle is pressed.

A hardened accelerator pump plunger would also lead to issues. The accelerator pump's function is to provide an extra squirt of fuel during rapid throttle opening. If the plunger has hardened, it loses its ability to create the necessary pressure to push fuel through the system effectively. This would directly result in a lack of fuel being delivered under these conditions.

A plugged pump nozzle can inhibit the flow of fuel from the accelerator pump to the carburetor. If the nozzle is blocked, no fuel will be able to exit the pump and enter the carburetor when the throttle is actuated, leading to a lean fuel condition during quick acceleration.

Considering all these points, it is clear that any one of these factors—or a combination of