Jim Smart
December 1, 2006

There's no end to the theories regarding carburetion, performance, and fuel efficiency. Just about everyone has a belief they stand by when it comes to carburetors. Fatten the mixture. Lean the mixture. Use this jet. Use that jet. Swap the power valve. Change the boosters. Use this gasket. Use that gasket. Raise the float level. Lower the float level. Use vacuum secondaries. Use mechanical secondaries. Eliminate the power valve. Use an open-element air cleaner. Maybe a more aggressive accelerator pump cam. And choose a carburetor: Holley, Edelbrock, Carter, Stromberg, Weber, Barry Grant, Autolite, or Motorcraft.

Everyone has an angle for carburetor selection and tuning. Our job is to help you make informed decisions when it comes to your carbureted fuel system.

How Do Carburetors Work?
The carburetor was invented in 1893 by Dont Bnki, a Hungarian engineer. It was a pivotal point in the development of the internal combustion engine because it revolutionized the fuel/air management process. The carburetor's function is rooted in the Bernoulli principle that air flow through the throttle bore dictates how much fuel and air enter the combustion chambers. When we open the throttle, air flow increases through the throttle bore which draws on the fuel in the fuel bowl.

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No matter how large or small, the carburetor's job is to mix air and fuel in the proper proportions to support combustion in an internal-combustion engine's chambers. How much power an engine makes is directly proportional to how the carburetor mixes the fuel and air. But the carburetor's job is only the beginning of the power process. Everything has to work together in order to yield precise fuel/air delivery. The proper combination of carburetor, intake manifold, cylinder heads, camshaft/valvetrain system, and exhaust scavenging is necessary to make the most of an engine's potential for power.

To understand how carburetors work, we have to examine each of its systems; floats, accelerator pump, idle/low-speed circuit, cruise/power circuit, and throttle bores/plates.