Gasoline Fuel Systems: Carburetor operation

Carburation	A light vehicle under normal conditions needs an air-fuel ratio, by mass, of about 15 to 1. By volume, that's 11000 to 1.
Carburetor system components	The main components in most carbureted systems are a float chamber, a venturi, the throttle, idle circuit, main circuit, a choke and an accelerator pump.
Carburetor systems	Low speed and idling ports allow the engine to operate with a low throttle opening before the main system is operating fully.
Metering jets	The main jet size is selected to provide the best mixture for fuel economy. An extra jet supplies additional fuel for maximum power.
Accelerating	For acceleration, suddenly depressing the accelerator delivers extra fuel into the airstream.
Carburetor barrels	A two-stage carburetor has a primary throttle open only from idle to medium speeds. At higher speeds, the secondary throttle opens to admit more air-fuel mixture.

Topic	Summary