Abstract: A flange portion formed on an inner periphery of a flywheel is fitted to an end of a crankshaft. A spline piece is fitted to an inner peripheral surface of the flywheel. The flange portion of the flywheel and a flange portion of the spline piece are commonly fastened to the end of the crankshaft by bolts. An upper end of a driving shaft is spline-fitted at a point into a driving shaft coupled portion of the spline piece which is accommodated in an internal hole in the crankshaft. Thus, in coaxially coupling the flywheel and the driving shaft to the end of the crankshaft, it is possible to make such a coupled area compact and to reduce vibration by an accurate centering thereof.

Abstract: A flange portion formed on an inner periphery of a flywheel is facet-fitted to an end of a crankshaft. A spline piece is facet-fitted to an inner peripheral surface of the flywheel. The flange portion of the flywheel and a flange portion of the spline piece are commonly fastened to the end of the crankshaft by bolts. An upper end of a driving shaft is spline-fitted at a point into a driving shaft coupled portion of the spline piece which is accommodated in an internal hole in the crankshaft. Thus, in coaxially coupling the flywheel and the driving shaft to the end of the crankshaft, it is possible to make such a coupled area compact and to reduce vibration by an accurate centering thereof.

Abstract: A flange portion formed on an inner periphery of a flywheel is fitted to an end of a crankshaft. A spline piece is fitted to an inner peripheral surface of the flywheel. The flange portion of the flywheel and a flange portion of the spline piece are commonly fastened to the end of the crankshaft by bolts. An upper end of a driving shaft is spline-fitted at a point into a driving shaft coupled portion of the spline piece which is accommodated in an internal hole in the crankshaft. Thus, in coaxially coupling the flywheel and the driving shaft to the end of the crankshaft, it is possible to make such a coupled area compact and to reduce vibration by an accurate centering thereof.

Abstract: A flange portion formed on an inner periphery of a flywheel is facet-fitted to an end of a crankshaft. A spline piece is facet-fitted to an inner peripheral surface of the flywheel. The flange portion of the flywheel and a flange portion of the spline piece are commonly fastened to the end of the crankshaft by bolts. An upper end of a driving shaft is spline-fitted at a point into a driving shaft coupled portion of the spline piece which is accommodated in an internal hole in the crankshaft. Thus, in coaxially coupling the flywheel and the driving shaft to the end of the crankshaft, it is possible to make such a coupled area compact and to reduce vibration by an accurate centering thereof.

Abstract: A multi-cylinder engine structure includes a multi-cylinder engine body having a plurality of cylinders vertically arranged therein. A fuel feed system has a fuel pump connected to a plurality of carburetors disposed in a vertical arrangement sideways of the engine body in independent correspondence to the cylinders. The fuel pump is disposed below a lowermost one of the plurality of carburetors arranged vertically. An outboard engine includes a case tiltably mounted at a stern. A multi-cylinder engine body is contained in the case. A fuel feed system supplies a fuel to a plurality of carburetors disposed in correspondence with the cylinders. A fuel filter is also provided. The fuel pump is disposed below a lowermost one of the plurality of carburetors arranged vertically and above the fuel filter in a tilted-down state of the case.

Abstract: In an outboard motor, an exhaust pipe coupled to a lower surface of a cylinder head of an engine extends downwardly through an oil case. An exhaust port, defined at a lower end of the exhaust pipe, is opened downwardly into an extension case. An exhaust gas sampling pipe, threadedly inserted into a seat surface formed on a lower surface of the extension case, extends upwardly into the exhaust pipe and has its inner end inserted into the exhaust port in the exhaust pipe. An outer end of the exhaust gas sampling pipe, extending out of the extension case, is closed by a detachable cap. Thus, it is easy to mount the exhaust gas sampling pipe for sampling an exhaust gas from the exhaust pipe for the outboard motor.

Abstract: A multi-cylinder engine structure includes a multi-cylinder engine body having a plurality of cylinders vertically arranged therein. A fuel feed system has a fuel pump connected to a plurality of carburetors disposed in a vertical arrangement sideways of the engine body in independent correspondence to the cylinders. The fuel pump is disposed below a lowermost one of the plurality of carburetors arranged vertically. An outboard engine including a case tiltably mounted at a stern. A multi-cylinder engine body is contained in the case. A fuel feed system supplies a fuel to a plurality of carburetors disposed in correspondence to the cylinders. A fuel filter is also provided. The fuel pump is disposed below a lowermost one of the plurality of carburetors arranged vertically and above the fuel filter in a tilted-down state of the case.

Abstract: Disclosed is a sintered alloy composition and method of manufacturing the same, the sintered alloy composition having a multi-phase structure, comprising: a first phase composed of aluminum and copper; and a second phase being dispersed in the first phase and composed of molybdenum, chromium, silicon and cobalt. This alloy composition has excellent abrasion and corrosion resistance, preferably to be used for making machine parts such as valve seats for engines.

Abstract: An engine for an outboard engine assembly includes a cylinder block with at least one horizontal cylinder defined therein, an oil pan disposed downwardly of the cylinder block, a cylinder head coupled to the cylinder block, and a head cover coupled to the cylinder head. The engine assembly also includes a valve operating mechanism chamber defined jointly between the cylinder head and the head cover, a lubricating oil supply passageway for supplying lubricating oil from the oil pan to at least the valve operating mechanism chamber, and a lubricating oil return passageway for returning lubricating oil from at least the valve operating mechanism chamber to the oil pan. The lubricating oil return passageway has openings for introducing lubricating oil from the valve operating mechanism chamber. The openings are defined in inner surfaces, respectively, of the cylinder head and the head cover which face a bottom of the valve operating mechanism chamber.