What component in a pressure-type carburetor aids in fuel supply during idling?

In a pressure-type carburetor, the component that aids in fuel supply during idling is the spring in the unmetered fuel chamber. This spring serves to maintain a specific pressure in the fuel system, which is crucial for delivering the right amount of fuel to the engine when it is idling.

At idle, the engine requires a precise and stable fuel flow, which can be facilitated by the spring's action in adjusting the fuel delivery based on the engine's demand. The spring helps to regulate the pressure of the fuel in the unmetered chamber, ensuring that the engine receives sufficient fuel to maintain a steady idle without excessive enrichment or lean conditions.

This mechanism is particularly vital, as the carburetor must compensate for varying engine speeds and loads, and the spring provides the necessary support in maintaining optimal fuel delivery during the idling phase.