Main Metering

As engine speed increases, air velocity through the booster venturi creates a vacuum in the venturi.

Fuel begins to flow through the main metering system due to high pressure in the bowl and low pressure at the main discharge nozzle.

Fuel flows from the fuel bowl through the main jet and into the main well. Then the fuel travels up the main well tube where it is mixed with air.

Air, supplied through the high speed air bleed, mixes with the fuel through small holes in the sides of the main well tubes.

The proper air fuel ratio is maintained because the high speed air bleed meters an increased amount of air whenever venturi vacuum increases.

As the air/fuel mixture moves to the discharge port, it is discharged into the booster venturi.