Abstract: The invention is aimed at providing a dust seal structure for a valve stem in a rotary throttle valve carburetor that does not degrade from the effect of ultraviolet radiation, exhaust emissions, or the like; that is highly durable and requires little maintenance; and that allows further reduction in the vertical mounting dimension.

Abstract: The present invention provides a diaphragm carburetor wherein heat transferred from the engine to the carburetor through the insulator is reduced to lower the temperature of the carburetor unit and reduce the occurrence of bubbles in the fuel. The carburetor of the present invention is a diaphragm carburetor in which a fuel channel that extends from a pump chamber of the carburetor to a constant-pressure fuel chamber is divided into two branches to form one branch as a main fuel channel connected to the constant-pressure fuel chamber, and the other branch as a fuel circulation channel for passing the fuel through the body side surface of the carburetor on the insulator side, or the body side surface of the insulator on the carburetor side, causing the fuel to make a circuit around the carburetor, and returning the fuel to the fuel tank.

Abstract: An articulated arm having a first arm member and a second arm member flexibly coupled mutually by a ball joint. From a plurality of through-holes provided in the first arm member 2 to a plurality of holding holes provided in the second arm member, compression coil springs 8 are inserted. Support shafts are inserted, movably back and forth freely, in the through-holes behind the rear end portion of the compression coil springs. A certain support shaft is moved forward by actuator or the like to push the compression coil spring while other support shaft are moved backward. As a result, the second arm member can be moved to a specified position by the ball joint. Stopping state of the second arm member at the specified position is maintained by the balance of position of support shaft and repulsive force of compression coil spring.

Abstract: The invention comprises a first arm member 2 and a second arm member 3 flexibly coupled mutually by a ball joint 4. From a plurality of through-holes 5 provided in the first arm member 2 to a plurality of holding holes 6 provided in the second arm member 3, compression coil springs 8 are inserted. Support shafts 10 are inserted, movably back and forth freely, in the through-holes 5 behind the rear end portion of the compression coil springs 8. A certain support shaft 10 is moved forward by actuator or the like to push the compression coil spring 8 while other support shaft 10 are moved backward. As a result, the second arm member 3 can be moved to a specified position by the ball joint 4. Stopping state of the second arm member 3 at the specified position is maintained by the balance of position of support shaft 10 and repulsive force of compression coil spring 8.

Abstract: A device in which a needle-shaped valve element of a control valve is inserted into the throttle hole of a fuel channel to adjust the fuel flow rate. Accurate adjustments can be made with a small number of rotations of the control valve. A compensation channel 16 having a metering jet 17 for establishing the minimum required engine flow rate is provided to a valve element 13 of a manual control valve 12 that is inserted in a throttle hole 18 of a primary fuel channel 7. The flow rate is adjusted between the maximum required engine flow rate and the flow rate established by the compensation channel 16 in the gap between the external peripheral surface 13a of the valve element 13 and the entrance edge 18a of the throttle valve 18. Fuel can thereby be adjusted with a small number of rotations of the control valve 12. Accurate fine adjustment can be made with a small number of rotations even when the fine adjustment is achieved by reducing the taper angle of the conical portion 13A.