Patent ID: 7070173

Claim:
An apparatus for adjusting the air-fuel ratio of a fuel mixture to be supplied to an engine, comprising: a main body having a fuel passage, a needle orifice and a retainer seat; a receptacle constructed in the main body having an interiorly threaded portion, the receptacle communicating with the fuel passage; a needle valve body received within the receptacle and including a tip, an exteriorly threaded portion, a head, and an intermediate portion disposed between the threaded portion and the head, the exteriorly threaded portion being in complementary threaded engagement with the interiorly threaded portion, the tip being axially advanced and retracted relative to the needle orifice when the needle valve body is rotated within the receptacle to respectively decrease and increase the area between the tip and the needle orifice open to fuel flow; and a retainer disposed concentrically about the needle valve body between the intermediate portion and the retainer seat and compressed between the retainer seat and the intermediate portion biasing the threaded portion of the needle valve body into engagement with the interiorly threaded portion of the receptacle to maintain alignment of the tip relative to the needle orifice to maintain a desired position of the needle valve body by inhibiting tip displacement.