Carburetor jets are precision-drilled components responsible for metering fuel flow into the air stream within an engine’s carburetor. Variation in jet diameter is fundamental to regulating the air-fuel mixture. Smaller diameter jets restrict fuel flow, resulting in a leaner mixture, while larger diameter jets permit greater fuel flow, creating a richer mixture. For example, a carburetor intended for high-altitude operation might employ jets with a reduced diameter compared to the same carburetor used at sea level.
The precise regulation of the air-fuel ratio is critical for optimal engine performance, fuel efficiency, and emissions control. An inappropriately rich or lean mixture can lead to issues such as reduced power output, poor fuel economy, engine overheating, or increased pollutant emissions. Historically, jetting changes were a primary means of optimizing engine performance across diverse operating conditions and engine configurations. This adjustability was a key advantage of carburetors before the widespread adoption of electronic fuel injection systems.
