Carburetor Tuning

At a glance, a carburetor may look simpler than a fuel injection system. You simply run a fuel line to one small part that takes care of all the engine’s fuel mixing needs without any external sensors or other complications. A closer look at a carburetor, however, can give you the impression that this one part has squeezed all the complexity of a fuel injection system into a box the size of a paperback Tom Clancy book. The typical carburetor contains an assortment of pumps, valves, moving needles, and tiny tubes running every which way.

The core of a carburetor is the venturi, sometimes called a “barrel.” This is the tube that the incoming air enters, where the carburetor adds fuel. The venturi narrows down in its center, often ...

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