Variable venturi carburetor

A carburetor, comprising:

• a main body defining a bore extending along an axis;
• a main passage defined within the bore;
• a venturi defined within the bore;
• a fuel nozzle carried by the main body and including a fuel nozzle outlet in fluid communication with the venturi;
• a valve member translatable with respect to the axis of the bore of the main body to control an open area of the bore, such that in a closed state, the valve member closes the main passage but maintains the venturi at least partially open to allow an amount of air for engine idling to flow therethrough;
• and
• the valve member includes a wall portion disposed so as to move in slidable contact with end surfaces of the venturi defining openings of the venturi.

A carburetor, comprising:

• a main body defining a bore extending along an axis;
• a main passage defined within the bore;
• a venturi defined within the bore;
• a fuel nozzle carried by the main body and including a fuel nozzle outlet in fluid communication with the venturi;
• a valve member translatable with respect to the axis of the bore of the main body to control an open area of the bore, such that in a closed state, the valve member closes the main passage but maintains the venturi at least partially open to allow an amount of air for engine idling to flow therethrough;
• and
• a valve member guide block carried by the main body across the bore to support the valve member and defining the main passage and the venturi.

A carburetor, comprising:

• a main body defining a bore extending along an axis;
• a main passage defined within the bore;
• a venturi defined within the bore;
• a fuel nozzle carried by the main body and including a fuel nozzle outlet in fluid communication with the venturi;
• a valve member translatable with respect to the axis of the bore of the main body to control an open area of the bore, such that in a closed state, the valve member closes the main passage but maintains the venturi at least partially open to allow an amount of air for engine idling to flow therethrough;
• and
• a valve member transmission, including:
• a shaft extending through the main body;
• a throttle lever coupled to the shaft external of the main body;
• an arm coupled to the shaft;
• and
• a connecting rod coupled to the arm and to the valve member, wherein throttle operation moves the throttle lever to rotate the shaft, which rotates the arm and moves the valve member via the connecting rod.

A carburetor, comprising:

• a main body defining a bore extending along an axis;
• a main passage defined within the bore;
• a venturi defined within the bore;
• a fuel nozzle carried by the main body and including a fuel nozzle outlet in fluid communication with the venturi;
• a valve member translatable with respect to the axis of the bore of the main body to control an open area of the bore, such that in a closed state, the valve member closes the main passage but maintains the venturi at least partially open to allow an amount of air for engine idling to flow therethrough;
• a throttle shaft carried by the main body;
• a fuel bowl carried by the main body and at least partially defining a fuel reservoir;
• a needle valve disposed at a fuel nozzle inlet of the fuel nozzle to variably control flow of fuel through the fuel nozzle inlet;
• and
• a needle valve transmission for converting rotation of the throttle shaft to translation of the needle valve to adjust an amount of fuel supply according to movement of the valve member.

A sliding throttle valve carburetor, comprising:

• a carburetor main body defining an intake bore;
• a valve member movable in a direction of a diameter of the intake bore to increase and decrease an open area of the intake bore;
• a venturi disposed in the intake bore and having a flow passage narrower than the intake bore;
• and
• a fuel discharge port that opens into the flow passage of the venturi;
• wherein the valve member is integrally provided with a wall portion such that the wall portion moves with the valve member to open and close openings of the venturi, and wherein the wall portion is disposed so as to move in slidable contact with end surfaces of the venturi defining the openings.