Final answer:
Small reciprocating engines commonly use a carburetor or a fuel injection system for fuel metering, each having different advantages in terms of complexity, cost, and efficiency.
Step-by-step explanation:
The most common types of fuel metering systems used on small reciprocating engines are carburetors and fuel injection systems. Carburetors mix the air and fuel by drawing the air through a venturi and using the resulting vacuum to draw in fuel. This type of system is simple and cost-effective, making it suitable for many small engines. Fuel injection systems, on the other hand, use pressurized nozzles to inject fuel directly into the air stream or combustion chamber. This allows for more precise control of the air-fuel mixture and can result in better fuel efficiency and performance. Both systems have their advantages and are widely used in small engines across various applications.