A Carburetor , or a “Carb”, is a specific device in your vehicle that mixes air & fuel for something called an internal combustion engine. If you didn’t know, the word "Carburetor" comes from the French word “Cabure”, which means “Carbide”. The word “Carburer” means to combine with carbon. If you know about fuel chemistry, you know that the term has a much more specific meaning to it; it has the much more distinct meaning of increasing the carbon content of a fuel by combining it with a volatile hydrocarbon.

The very first carburetors were surface carburetors; the volatility of the petrol was used in these ones. As of now, all carburetors work on the Bernoulli’s principle : the faster the air moves, the lower the static pressure is, and therefore, the dynamic pressure is higher. The accelerator linkage doesn’t exactly have control over the gas in your car. Instead, it actuates the same carburetor mechanisms that monitor the flow of the air being pulled into the engine. The pressure of this flow determines the amount of fuel drawn into the air stream.

If you ever see a carburetor used in an airplane with piston engines, you’ll most likely take notice that there are special designs & special features that are needed to prevent something called “Fuel Starvation” during a flight. The newer engines use an early form of fuel injection also known as a “Pressure Carburetor”.

In the beginning of the 1930s, the downdraft carburetors were the most popular type of carburetor for cars in the United States & you can get them at any Carburetor Shop . In Europe, there were something called sidedraft carburetors that replaced downdraft as free space in the engine bay dwindled & the use of the SU-type carburetors increased. There are some aircrafts that are propeller driven & those crafts still use the updraft carburetor design.

Let’s get to some of the basics that I understand, in your typical Carburetor, there’s an open pipe & a barrel where the air passes into the inlet manifold of the engine. The pipe that’s in the carb is in the form of a venturi: it tends to narrow in certain sections and then it widens again in different sections. This causes the airflow to increase in speed in the narrowest parts of the pipe. Below the venturi, there’s something called a butterfly valve .. which is also known as the throttle valve. This is a rotating disc that can be turned end-on to the air flow. This valve also controls the flow of air that goes through the carburetor throat, so it regulates the engine power & speed.

The throttle is connected through a cable or some sort of mechanical linkage of specific rods & joints; or sometimes, it’s connected by something called a pneumatic link. This is linked to the accelerator pedal on the car, but is very rare to see.

When the throttle starts to open slightly from the closed position, the throttle plate begins to uncover additional fuel delivery holes behind that same throttle plate where there is a low pressure area that has been created by the throttle plate that has been blocking the air flow; which allows more fuel to flow.

When there’s too much fuel in the fuel-air combination, this is known as being too “Rich”; and when you don’t have enough fuel, it’s called being too “Lean.” To be completely honest, I’m not a car-type-of-girl so all this kind of makes sense to me. If you get it, I’m so happy I wrote it right. If you need any Carburetors , a Carburetor Shop , or a Rebuilt Carburetor , just go ahead & visit us at .