Carburetors perform a variety of engine-related duties that enable a vehicle to run at peak performance. Although not as common now thanks to the emerging popularity of fuel injection systems, carburetors are still widely used as a reliable alternative to more costly fuel delivery systems.
An automotive carburetor is basically nothing more than a large, vacuum-operated suction device. One of the main functions of a carburetor is to suck in outside air and inject it directly into a car's engine. A typical, gas-operated engine requires both air and fuel (gasoline) in order to function. A carburetor provides this.
In addition to injecting air into a car's engine, a carburetor is responsible for supplying a steady flow of fuel (gasoline) to a car's engine. Connected to a car's gas tank by a long fuel line and a fuel pump, a carburetor is supplied with an ongoing source of fuel, which it meters out in specific dosages directly to a car's engine.
One of the most important functions of a carburetor is its creation of a car engine's air/fuel mixture. An air/fuel mixture is a specific ratio of air and fuel (gasoline) that a car's engine needs in order to function. For an engine to run and operate, it's air/fuel mixture has to be constantly adjusted, metered out and restricted depending on engine operating conditions. A carburetor performs all of these functions.
A carburetor speeds up a vehicle's warm-up by elevating the vehicle's idle speed for a few minutes and by altering its air/fuel ratio. A carburetor has a small vacuum-operated choke that increases the ratio of fuel to air in a cold vehicle's air/fuel mixture and also increases its idle speed, both of which help a cold vehicle to start and warm-up.
When a vehicle's accelerator is pressed to the floor, a sudden rush of power is generated by the transmission passing gear, a special vacuum-operated gear that is triggered by the passing gear assembly, an assembly located directly within the carburetor. This passing gear, which is simply the downshifting of the transmission from drive into second gear, enables a car to speed up quickly or, as it's name implies, pass another vehicle in a hurry.
