Small Engine Carburetors

Carburetors are a component of internal combustion engines that generate a combustible mixture of gasoline and air. Carburetors were used in cars in earlier days, but presently, they have been replaced by the electronic fuel injection technology and are being used in smaller machinery like lawn mowers, chain saws, motorbikes, small boats, and light aircraft. Even though electronic fuel injection technology has more advantages like flexibility, reliability and complexity, its higher cost makes carburetors a better choice for small engines.

The basic function of a carburetor is to ensure the right mix of air and gasoline into the engine. The carburetor comprises of a tube with an adjustable plate called the throttle placed across it. This throttle controls the amount of air that flows through the tube. The carburetor tube narrows down at a place called the venture, where a vacuum is created.

There is a hole in this narrowing called the jet that allows the fuel to be drawn in because of the vacuum. There are several parts in a carburetor that allow for smooth functioning. The parts are the pilot, pilot airscrew, throttle valve, jet needle, needle jet, air jet, and main jet. Other important parts are the choke, accelerator pump, float chamber, and barrels that help to create the ideal mixture of gas and air in the engine.

Carburetors have improved over the years in terms of efficiency and effectiveness. Their emissions standards have are much better and adhere to environmental standards. This is also another reason for the increased use of carburetors in smaller machinery.

There are many kinds of small engine carburetors. The complexity of the modern machines demand greater sophistication in the carburetor design. Float-type and suction-type are the two main categories of carburetors and there are two kinds of float-type carburetors including one-piece and two-piece. Suction-type carburetors have a built-in fuel pump.

The major manufacturers of carburetors are Amal Ltd., Autolite, Carter, Holley, Pierburg, Rochester, Solex, Stromberg, SU, Walbro and Tillotson (small engines), Briggs and Stratton, Villiers, Weber and Zenith. Rebuilt or remanufactured carburetors can also be used in small engines.