Engine Fuel and Fuel Metering Systems Oral Practice Test

The carburetor economizer adds fuel specifically when high power is requested to keep the engine cooler and prevent detonation. As power needs rise, a separate path allows extra fuel to enter the mixture, enriching it just at the moment when the engine is most prone to knocking. The cooling effect comes from the fuel vaporizing in the intake and combustion charge, which absorbs heat and lowers peak cylinder temperatures, helping maintain safe operation under heavy load. This enrichment isn’t applied at idle or light power and isn’t a constant increase in fuel flow. It’s a feature found in carbureted engines to manage detonation risk at high power, not limited to two-stroke designs.