Carburetor fuel adjustment assembly

A fuel adjustment assembly of a carburetor for adjusting fuel flow to be supplied to a combustion engine, the assembly comprising:

• a carburetor body;
• two needle valve receptacles formed in the carburetor body, the valve receptacles each having an axis and defining a cavity intersecting a fuel passage formed in the carburetor body;
• a pair of needle valves each supported in a separate one of the needle valve receptacles and each including a distal tip, an enlarged head and an exteriorly threaded shank disposed between the tip and head, the threaded shank being in threaded engagement with the needle valve receptacle, the tip being disposable within an axially-aligned orifice portion of the fuel passage, and being axially advanceable and retractable by rotation of the needle valve within its receptacle, to respectively decrease and increase the area of the orifice open to fuel flow;
• a bore in the carburetor body communicating with the valve receptacles the bore having a centerline disposed at an angle to and generally radially spaced from the axis of the valve receptacles and the bore opening into only one side of each of the valve receptacles;
• and
• a resilient, hollow retainer received in the bore and having an exterior surface projecting into the valve receptacles and engaging and displaced by a portion of and less than the entire circumference of the valve shank to retain and impart a force laterally biasing its tip into one steadfast position relative to the orifice to assure a constant area of fuel flow through the orifice by resisting tip displacement due to such factors as engine vibration and installation of a tamper-resistant limiter cap on the enlarged head.

A fuel adjustment assembly of a carburetor for adjusting fuel flow to be supplied to a combustion engine, the assembly comprising:

• a carburetor body defining at least part of a fuel passage;
• a needle valve receptacle formed in the carburetor body, having an axis and defining a cavity intersecting the fuel passage;
• a needle valve supported in the needle valve receptacle and including a distal tip, an enlarged head and an exteriorly threaded shank disposed between the tip and head, the threaded shank being in threaded engagement with the needle valve receptacle, the tip being disposable within an axially-aligned orifice portion of the fuel passage, and being axially advanceable and retractable by rotation of the needle valve within the receptacle, to respectively decrease and increase the area of the orifice open to fuel flow;
• a bore in the carburetor body communicating with the valve receptacle, the bore having a centerline disposed at an angle to and generally radially spaced from the axis of the valve receptacle and the bore opening into only one side of the valve receptacle;
• and
• a resilient, hollow retainer received in the bore and having an inner surface and an exterior surface defining a wall thickness, and wherein the exterior surface projects into the valve receptacle a radial distance less than the thickness of the wall of the retainer so that the exterior surface of the retainer engages, is displaced by and cooperates with a portion of and less than the entire circumference of the valve shank to retain and laterally bias the tip into one steadfast position relative to the orifice by resisting tip displacement due to such factors as engine vibration and installation of a tamper-resistant limiter cap on the enlarged head.

A fuel adjustment assembly for a carburetor comprising:

• a carburetor body having a threaded needle valve receptacle having a rotation axis;
• a fuel passage defined by the body;
• a cavity defined by the receptacle and communicating with the fuel passage;
• a bore in the body and communicating with the cavity, the bore having a centerline disposed at an angle to and radially spaced from the rotation axis and the bore opening generally radially into only one side of the receptacle;
• a cylindrical retainer of a resilient material fitted into the bore, the retainer having an exterior surface having a portion contacting the carburetor body and a portion projecting a radial distance of 0.008 to 0.020 of an inch into and exposed in the valve receptacle, with the retainer exposed in less than the entire circumference of the valve receptacle;
• and
• a needle valve having an elongated shank engaged threadably to the receptacle and a tip, the needle valve engaging through only a portion of its circumference the resilient retainer and displacing a portion of the resilient retainer in the receptacle to frictionally retain and impart a force laterally biasing the needle valve into a steadfast position of the tip relative to the cavity to inhibit unintentional movement of the tip due to such factors as engine vibration and any installation of an adjustment limiter cap on the valve.