Idle System

Fuel for idle and off idle operation flows from the bowl through the primary main metering jet into the main well. Fuel then flows through an idle fuel restriction and is mixed with air entering through the primary idle air bleed. This air/fuel mixture travels past the idle transfer holes which serve as additional air bleeds during curb idle. The air/fuel mixture then moves past the idle mixture screw tip which controls the amount of mixture discharged into the engine from below the throttle plate. At speeds slightly above idle, the idle transfer holes begin discharging additional air/fuel mixture. This occurs because the increased opening of the throttle plates exposes the idle transfer holes to intake manifold vacuum. As the throttle opening and engine speed increase, airflow through the carburetor is increased. This creates a vacuum in the venturi causing the main metering system to begin operation.