The vacuum applied to the bowl and resulting air movement changes with relation to the throttle position and also as the throttle position is changed. The economizer jet plays a role in regulating the pressure/vacuum in the fuel bowl. Screwing the adjustment screw in reduces air and creating a richer mixture. The idle adjustment screw determines how much air is mixed with the fuel. Fuel at idle is drawn out of the main jet area and through the idle jet.

The main jet passageway is also the source of fuel for the idle circuit. Modern carburetors use accelerator pumps for this purpose. The nozzle with holes in the sides allows extra fuel to be stored in the area so that if the throttle is opened quickly the extra fuel stored is available to quickly enrich the increased air volume for quick acceleration while the main jet meters what can continue to enter. The main jet meters the rate at which the fuel flows into the main jet cavity. Fuel in the bowl passes through the main/power jet and fills the chamber where the fuel nozzle is found. When the float drops, the needle valve opens allowing fuel to enter the bowl.

The float controls the amount of fuel that’s allowed to be stored in the float bowl. From there it arrives at the float valve. Fuel enters the carburetor through the elbow strainer. The purpose of the carburetor is to atomize the fuel into the air that is supplied to the motor at the right ratio. Marvel Schebler TSX Carburetor How to rebuild this iconic old Carburetor

Marvel schebler carburetor manual pdf