In a lubricating device of an internal combustion engine having a crank chamber and a transmission chamber, which is arranged in the rear of the crank chamber so as to accommodate therein a gear transmission provided with a main shaft and a pump shaft. The pump shaft is shared by a scavenging pump and a feed pump for feeding oil to a part to be lubricated and to which motive power from the crank shaft is transmittable. An axis of the pump shaft is arranged below an axis of the main shaft. A pump gear located on the pump shaft meshes directly with a primary driven gear, which meshes with a primary drive gear located on the crank shaft so as to form a primary gear reduction mechanism in cooperation with the primary drive gear.

A torsion spring for an oil pump chain tensioner for use in an engine. The torsion spring has: a second end; a leg connected to the second end through a hook bend; an outer coil connected to the leg having an outer coil outer circumference and an outer coil inner circumference; a first inner coil connected to the outer coil, the first inner coil having a first inner coil outer circumference and a first inner coil inner circumference, the outer coil inner circumference being adjacent to the first inner coil outer circumference; and a second inner c-shaped coil connected to the first inner coil through a bend back loop, the second inner coil having a second inner coil outer circumference and a second inner coil inner coil circumference and terminating in a first end, where the second inner coil outer circumference and the first coil inner circumference define a gap.

A variable displacement pump includes: a pump constituting section; a movable member; a first control hydraulic chamber; a second control hydraulic chamber; a control mechanism arranged to be actuated by receiving a control hydraulic pressure which is the discharge pressure on a downstream side of the discharge portion, through a single control passage formed within the engine, and to control a supply and a discharge of the discharge pressure with respect to the second control hydraulic chamber; and a switching mechanism arranged to switch a connection and a disconnection between the control passage and the control mechanism.

A first check valve of a hydraulic control system allows oil to flow in only a direction from a first oil pump toward an oil receiving portion. A second check valve allows oil to flow in only a direction from a second oil pump toward the oil receiving portion. A third oil passage is configured to provide communication between a merging point of a first oil passage and a second oil passage, and the second oil pump by bypassing the second check valve. The third oil passage includes a throttle mechanism. The third oil passage is configured to restrict a flow rate of oil that is discharged from the second oil pump.

A oil supply structure of an internal combustion engine, includes: an oil flowing path which is formed to extend along a camshaft vertically above at least one of intake and exhaust camshafts (3a, 3b) of the internal combustion engine, and in which oil flows; an oil supply portion provided on one end side of the oil flowing path, and supplying oil to the oil flowing path; and oil ejection holes aligned along the oil flowing path, provided to be opened vertically downward, and through which the oil of the oil flowing path is ejected toward the camshaft, wherein, in the oil flowing path, a partitioning portion, which extends along the oil ejection holes toward the other end side opposite to the oil supply portion from one end side, and partitions the inside of the oil flowing path, is provided.

An internal combustion engine which can be miniaturized, even where it includes an oil filter between a hydraulic clutch and an oil pump, without significantly increasing the length of an oil passage for the hydraulic clutch, the oil pump and a hydraulic pressure adjustment apparatus. A second oil filter is provided on an oil pan at a lower portion of the internal combustion engine so as to be disposed at a position at which the second oil filter does not overlap with any of a controlling oil pump and a hydraulic pressure adjustment apparatus as viewed in side elevation and which is lower than those of the oil pump and the hydraulic pressure adjustment apparatus.

An outboard marine engine comprises an internal combustion engine; a lower gearcase, a set of gears disposed in the lower gearcase, the set of gears being configured to transfer power from the internal combustion engine to drive a propulsor to generate a thrust on the outboard marine engine, and a dipstick that extends into the lower gearcase. The dipstick is removable from the lower gearcase and configured to indicate a level of lubrication in the lower gearcase.

An engine includes a crank shaft inside a crankcase and an oil pan and penetrates the crankcase and the oil pan in an up-down direction. An oil pump and an oil strainer are provided inside the oil pan. The oil pump is coaxial with the crank shaft and is driven by the crank shaft. The crank shaft includes a first region and a second region respectively supported pivotably by a plate-shaped support and the crankcase. The support is provided in the crankcase such a that both surfaces of the support are covered by the crankcase and the oil pan and allows communication between the crankcase and the oil pan.

A first fitting portion is coupled to a protruding end of the crankshaft to be rotatable about a crankshaft rotational axis. An intermediate member includes a first hole wall slidably supporting the first fitting portion in a first direction orthogonal to the crankshaft rotational axis so that the intermediate member rotates together with the crankshaft. An inner rotor includes a second hole wall slidably supporting the second fitting portion in a second direction orthogonal to the first direction and the crankshaft rotational axis so that the inner rotor rotates together with the intermediate member. One of the first direction and the second direction is in parallel with a line segment joining the crankshaft rotational axis and an axis of a crankpin of the internal combustion engine which is closest to the protruding end of the crankshaft.

A two-stroke engine comprises a first oiling system and a second oiling system. The first oiling system includes a low-pressure pump that distributes oil from a first oil tank to the two-stroke engine. The second oiling system includes a pump mechanically coupled to a crankshaft of the two-stroke engine, wherein the pump distributes oil from a second oil tank to an accessory at a pressure greater than the first oil pressure, wherein oil distributed to the accessory is returned to the second oil tank.