Abstract: A lubricating oil supply device for an internal combustion engine in which a lubricating oil pump is provided to one end of a balancer shaft, but an oil conduit is not required to be provided to the balancer shaft. The lubricating oil pump is connected to one end of the balancer shaft. An intake oil conduit for directing lubricating oil to the lubricating oil pump is disposed inside a wall thickness of a crankcase. A discharge oil conduit for directing lubricating oil pressurized in the lubricating oil pump to the in-shaft oil conduit is disposed within the wall thickness of the crankcase.

Abstract: In an engine operated machine system including a hollow support rod connected at one end to an engine through a vibration insulator, an auxiliary weight is mounted at the other end of a crankshaft for generating a centrifugal force in the same direction as an inertia force of a piston, when the piston reaches top and bottom dead centers. Thus, it is possible to bring a center of gravity of the engine closer to the position of the vibration insulator, thereby suppressing the application of the vibration from the engine to the support rod to the utmost.

Abstract: An oil pan-coupled surface 115 formed on a lower surface of an engine block 11 having a crankshaft 15 supported to be directed vertically is extended below a cylinder head 12 beyond a line L extending downwards from a cylinder head-coupled surface 114 formed on a rear surface of the engine block 11. Thus, it is possible to increase the area of the oil pan-coupled surface 115 without interference with the cylinder head-coupled surface 114 and to increase the volume of an oil pan 411 coupled to the oil pan-coupled surface 115. Moreover, the cylinder head-coupled surface 114 and the oil pan-coupled surface 115 are not continuous with each other and hence, there is no possibility that the sealing of the coupled surfaces 114 and 115 may be impeded.

Abstract: In an engine, a cover member closing an opening in an engine block is integrally formed with supporting arms extending radially outwards beyond an outer periphery of a flywheel mounted on a crankshaft supported at its one end on the cover member, and a recoil starter located axially outside the flywheel is supported on the supporting arms. Thus, the recoils starter can be supported easily and reliably without provision of a special mounting bracket and a stay and while preventing the interference with the flywheel. Moreover, the coaxiality of the recoil starter and the crankshaft can be ensured.

Abstract: An oil-cooled engine assembly is provided for cooling lubricating oil, which has lubricated movable parts of an engine and subsequently recirculating cooled lubricating oil to the movable parts. The engine assembly includes a lubricating oil pump contained in the engine, and a hollow frame body which supports the engine. The hollow frame body has an oil passage through which lubricating oil flows. The lubricating oil pump is connected to the oil passage. Lubricating oil, which has lubricated the movable parts of the engine is air cooled with the frame body. Cooled lubricating oil is circulated again to the movable parts of the engine.

Abstract: In an engine operated machine system including a hollow support rod connected at one end to an engine through a vibration insulator, an auxiliary weight is mounted at the other end of a crankshaft for generating a centrifugal force in the same direction as an inertia force of a piston, when the piston reaches top and bottom dead centers. Thus, it is possible to bring a center of gravity of the engine closer to the position of the vibration insulator, thereby suppressing the application of the vibration from the engine to the support rod to the utmost.

Abstract: An oil-cooled engine assembly is provided for cooling lubricating oil, which has lubricated movable parts of an engine and subsequently recirculating cooled lubricating oil to the movable parts. The engine assembly includes a lubricating oil pump contained in the engine, and a hollow frame body which supports the engine. The hollow frame body has an oil passage through which lubricating oil flows. The lubricating oil pump is connected to the oil passage. Lubricating oil, which has lubricated the movable parts of the engine is air cooled with the frame body. Cooled lubricating oil is circulated again to the movable parts of the engine.

Abstract: A breather device for an engine comprises a gas-liquid separation chamber communicating with the crankcase chamber through the one-way valve, a breather passage opening the gas-liquid separation chamber into an air cleaner, first and second oil suction holes arranged below and above an inner end of the breather passage opening to the gas-liquid separation chamber, and an oil passage communicating the first and second oil suction holes to an oil reservoir chamber having a pressure lower than that of the gas-liquid separation chamber. This construction enables the oil separated from the blow-by gas and liquefied in the gas-liquid separation chamber to be returned quickly to the oil reservoir chamber through the first or second oil suction holes, irrespective of whether the engine is in an normal upright position or an inverted position.