From OpenContent Curriculum
Carburetor: a device used to mix fuel and air before delivering it into an internal combustion engine.
A carburetor (or carb) works by using air pressure differences to "draw" fuel through various passages and jets as an engine pulls air through it. Moving air has less pressure than still air. The fuel reservoir (float bowl) on these carburetors is vented to the atmosphere, so it has pressure similar to the outside. Atmospheric air pulled (sucked) rapidly through the carburetor creates lower pressures as it passes the fuel jets. Fuel in the reservoir is pushed up through the passageways and jets toward the lower pressure of the moving air, where it is broken up into small droplets (mist) and vaporized.