An apparatus for adjusting the air-fuel ratio of a fuel mixture to be supplied to an engine. The apparatus has a pair of needle valve bodies and a pair of receptacles formed in a main body of a carburetor for receiving the needle valve bodies. Each needle valve body has a needle and a head. The needles are axially movable relative to a respective needle orifice. The needles may be axially advanced and retracted by rotating the needle valve bodies within the receptacles to respectively decrease and increase the flow of the fuel mixture around the needles and through the orifices. To prevent tampering with the needle valve body setting, the head of the needle valve body has an unconventional shape requiring a specialized tool to rotatably adjust the needle valve body. To further prevent tampering, the head is recessed with the main body of the carburetor. A retainer is disposed in the main body of the carburetor and receives the needle valve bodies to facilitate maintaining alignment of the needle valve bodies relative to the receptacles. The retainer assures that a constant fuel calibration setting is maintained through the orifices by resisting displacement of the needles due to such factors as external forces applied to the head of the needle valve body or engine vibration.
An apparatus for adjusting the air-fuel ratio of a fuel mixture to be supplied to an engine. The apparatus has a pair of needle valve bodies and a pair of receptacles formed in a main body of a carburetor for receiving the needle valve bodies. Each needle valve body has a needle and a head. The needles are axially movable relative to a respective needle orifice. The needles may be axially advanced and retracted by rotating the needle valve bodies within the receptacles to respectively decrease and increase the flow of the fuel mixture around the needles and through the orifices. To prevent tampering with the needle valve body setting, the head of the needle valve body has an unconventional shape requiring a specialized tool to rotatably adjust the needle valve body. To further prevent tampering, the head is recessed with the main body of the carburetor. A retainer is disposed in the main body of the carburetor and receives the needle valve bodies to facilitate maintaining alignment of the needle valve bodies relative to the receptacles. The retainer assures that a constant fuel calibration setting is maintained through the orifices by resisting displacement of the needles due to such factors as external forces applied to the head of the needle valve body or engine vibration.
An apparatus for adjusting the air-fuel ratio of a fuel mixture to be supplied to an engine. The apparatus has a needle valve body and a receptacle formed in a main body of a carburetor which receives the needle valve body. The needle valve body has a needle and a head. The needle is axially movable relative to a needle orifice. The needle may be axially advanced and retracted by rotating the needle valve body within the receptacle to respectively decrease and increase the flow of the fuel mixture around the needle and through the orifice. To prevent tampering with the needle valve body setting, the head of the needle valve body has an unconventional shape requiring a specialized tool to rotatably adjust the needle valve body. To further prevent tampering, the head is recessed with the main body of the carburetor. A generally annular retainer is disposed concentrically on the needle valve body and laterally biases the needle valve body into engagement with the receptacle to maintain alignment of the needle valve body relative to the receptacle. The retainer assures that a constant fuel calibration setting is maintained through the orifice by resisting needle displacement due to such factors as external forces applied to the head of the needle valve body or engine vibration.