Which type of fuel metering system is most commonly used on small reciprocating engines?

Float-type carburetors are the most commonly used fuel metering systems in small reciprocating engines, primarily due to their simplicity, reliability, and effectiveness in managing the fuel-air mixture. These carburetors operate using a float mechanism to maintain a consistent level of fuel within the carburetor bowl. As the engine draws air through the carburetor, a venturi effect creates a drop in pressure, allowing the fuel to be drawn from the bowl into the air stream in proportion to the amount of air coming in.

This method is particularly efficient for small engines, like those found in general aviation aircraft or small equipment, because float-type carburetors are lightweight and easy to manufacture, maintain, and repair. They provide a sufficient level of control over fuel delivery, adapting to the varying demands of the engine during different phases of operation, such as idle, cruise, and full power.

Other fuel metering systems, while effective in certain applications, are not as commonly employed in small reciprocating engines. Direct fuel injection systems, for instance, are more prevalent in modern automotive engines and larger or high-performance aviation engines due to their complexity and the need for higher fuel delivery precision. Pressure-injection carburetors are typically utilized in more specialized applications where