The objective of the present invention is to achieve an engine-driven work machine capable of controlling the rotational frequency of a crankshaft reliably by means of a cooling breeze from a cooling fan. This engine-driven work machine is equipped with: a cylinder in which a piston is capable of moving reciprocally in the up/down directions a crankcase provided below the cylinder a crankshaft that extends perpendicular to the direction of the reciprocal movement of the piston, and that rotates in conjunction with the reciprocal movement of the piston a throttle valve that controls the amount of air taken into the cylinder, and controls the rotational frequency of the crankshaft a throttle shaft that controls the degree of opening of the throttle valve by rotating a cooling fan that is affixed to the crankshaft on the outside of the crankcase, and that rotates in conjunction with the rotation of the crankshaft, thereby generating a cooling breeze that cools the cylinder and a breeze-receiving part that receives the cooling breeze and is moved by the cooling breeze, thereby causing the throttle shaft to rotate. The breeze-receiving part holds the axial direction component of the crankshaft in the movement direction of the breeze-receiving part, and the degree of opening of the throttle valve decreases as the breeze-receiving part moves toward the cylinder in the direction of the crankshaft.La présente invention a pour objet de réaliser une machine de travail entraînée par moteur capable de contrôler la fréquence de rotation dun vilebrequin de manière fiable au moyen dun souffle de refroidissement provenant dun ventilateur de refroidissement. Cette machine de travail entraînée par moteur comprend : un cylindre dans lequel un piston est apte à se déplacer suivant un mouvement de va-et-vient dans les directions haut/bas un carter de vilebrequin disposé en dessous du cylindre un vilebrequin qui sétend perpendiculairement à la direction du mouvement alternatif du piston
