Fuel flow automatic modulating and economizing carburetor jet assembly

In a carburetor of the type including an air and fuel mixture passage extending therethrough, a throttle plate shiftable between open and closed positions, an idle fuel port opening into said passage immediately downstream from said throttle plate and a vacuum port opening into a venturi portion of said passage upstream from said throttle plate and subject to increases in vacuum as the speed of said air flow through said passage increases, said idle fuel port including a first end opening into said passage, a second end opening outwardly of said carburetor and an intermediate portion opening into a chamber of said carburetor having liquid fuel therein;

• the improvement comprising a combined idle fuel adjustment, idle fuel aeration and high speed engine fuel consumption reduction valve assembly, said valve assembly including a tubular needle valve body defining a central passage extending therethrough and threaded in said idle port second end, said tubular needle valve body including a hollow externally tapered inner end tip adjustable axially of said first end of said idle fuel port, said tubular needle valve body including at least one lateral port means formed therein outwardly of said inner end tip opening outwardly into the intermediate portion of said idle fuel port and an outer open end, a needle valve loosely reciprocal in said central passage and including a first tapered end axially shiftable past said lateral port means toward and away from said inner end tip, and force means operatively associated with said needle valve for biasing said needle valve inwardly toward an inner limit position and to progressively shift said needle valve outwardly from said inner limit position responsive to increases in engine speed of operation as sensed at said venturi vacuum port while said throttle plate is in an open position.