Full Power with Enrichment
As long as the engine is operating in the mid-rpm range under partial or full throttle load, only the main metering system supplies the fuel. However, as the air velocity in. the induction throat increases with increasing rpm, the vacuum effect in the throat becomes so intense that it begins to draw supplemental fuel from the power enrichment nozzle (q1); the power enrichment system consists of the discharge nozzle ([1) and the metering jet (q2) and draws fuel directly from the float chamber. The enrichment system comes into action when the engine is running under full throttle at high rpm.
The main metering system together with its supplemental enrichment system ensures a well balanced and metered fuel! air mixture required for combustion, realizing the desired fuel economy and, yet, maximum power output on demand.