Secondary Power Enrichment System

Fig. 4 Carburetor secondary power enrichment system:

The secondary system is provided with an air velocity operated power system for fuel enrichment, Fig 4. As the secondary throttle plate nears wide open position, air velocity through the secondary venturi creates a low pressure area at the discharge opening in the air horn. Fuel flows from the bowl through a vertical channel. During this time, air enters through a calibrated air bleed and mixes with the fuel, and this mixture is discharged through the opening.