Abstract: A throttle body for an internal combustion engine, comprising a suction passage for supplying a suction air to the internal combustion engine; a throttle valve provided in the suction passage and fixed to a rotatable throttle valve shaft so as to adjust a quantity of the suction air; an interconnecting lever rotatably mounted to an interconnecting shaft and adapted to be rotated by pulling an accelerator cable; a throttle valve operating lever mechanically connected to the interconnecting lever and fixed to the throttle valve shaft, the throttle valve operating lever being rotated in predetermined relational association with rotation of the interconnecting lever to open and close the throtle valve; and a tension spring for normally biasing the throttle valve in a valve closing direction, the tension spring having one end or pivotal point fixed to a part fixed to the throttle body and the other end or operation point fixed to the throttle valve operating lever; wherein the pivotal point and the operation point

Abstract: A device for adjusting the degree of opening of the throttle valve of a carburetor comprising a cam pivotally mounted on a pivot. The cam is actuated by a wax valve and rotated in accordance with an increase in the temperature of the cooling water of the engine. The cam has a cam face which is engageable with a lever connected to the throttle valve for retaining the throttle valve at a predetermined fast idling degree during engine warm-up. An auxiliary lever is pivotally mounted on the pivot. The auxiliary lever has an outer circumferential face which is engageable with the lever of the throttle valve for retaining the throttle valve at the predetermined fast idling degree after completion of engine warm-up.