Abstract: An outboard motor cooling system wherein the coolant is circulated through the various cooling jackets so that it first flows into proximity with at least a portion of the exhaust system cooling jacket and then into the cooling jackets of the main engine body that cool the cylinder bore and combustion chamber. Sacrificial anodes are positioned both in the main engine body cooling jacket and in the exhaust system cooling jacket. In addition, a temperature sensor is positioned in a low portion of the cooling jacket and where the water has passed through the exhaust cooling jacket and before it enters the main engine body cooling jacket so as to provide accurate temperature indication while protecting the temperature sensor from excess temperature conditions particularly after engine shut off.

Abstract: An exhaust manifold for an outboard motor that has a vertically extending crankshaft and which exhaust manifold is formed in the cylinder head and cylinder block. The cylinder block forms the exhaust manifold by runner sections that are configured in such a way so as to facilitate the casting process by which they are formed and which provide an effective smooth flow path without requiring complex cores or patterns.

Abstract: An outboard motor having a multi-cylinder four-cycle, internal combustion engine as a power plant. The engine is provided with an oil reservoir in the upper portion of the drive shaft housing and lower unit. Oil is drained back to this oil reservoir by separate drain passages formed in the cylinder head and in the crankcase. In addition, an improved crankcase ventilating system is provided wherein the crankcase ventilating gases follow a circuitous path through the crankcase chamber, camshaft chambers and then to the intake system so as to reduce the emissions of hydrocarbons.

Abstract: An engine of an outboard motor includes an improved engine component layout to minimize the size of the engine and to improve the performance of the components. A separator of a crankcase ventilation system is located on a cam cover outside the cam chamber in order to reduce the size of the cam cover while providing the necessary spacing between the separator and the valve mechanism within the cam chamber. A fuel pump is positioned at about the center of the cam cover, beneath the separator, to generally balance the length of fuel travel to each of the carburetors. A fuel filter also is located on the cam cover, beneath the fuel filter, to generally isolate the fuel filter from the effects of the heated cylinder head and block. The arrangement of these components does not interfere with the hinge-like travel of a top cowling, which surrounds the engine, relative to a lower tray.

Abstract: An outboard motor embodying a twin overhead camshaft, four cycle internal combustion engine as a power plant. The engine has an improved flexible transmitter drive for the camshaft, which permits the drive pulley to overly the end main bearings for the camshafts so as to reduce bending loads on them.

Abstract: An intake manifold for an engine powering a water propulsion device of an outboard motor is disclosed. The engine has first and second combustion chambers and an intake system for delivering a fuel and air charge to each combustion chamber. The intake system includes a first intake passage leading through the engine to the first combustion chamber and a second intake passage leading through the engine to the second combustion chamber, the first intake passage positioned vertically above the second intake passage. The intake manifold is arranged to deliver equal amounts of fuel to the first and second intake passages and includes a main passage extending along a first axis. A first branch defines a passage leading the main passage to the first intake passage, and a second branch defines a passage leading from said main passage to the second intake passage.

Abstract: A vapor separator for an outboard motor is disclosed. The outboard motor has a cowling and a water propulsion device. An internal combustion engine is positioned in the cowling and arranged to propel the water propulsion device. The engine includes a top and a bottom side. The engine also includes an engine block defining at least one cylinder bore therein. A crankshaft is supported for rotation with respect to the engine block and is located in a first chamber. A camshaft is supported for rotation with respect to the engine block and is located in a second chamber. The engine further includes a lubrication system for the lubrication of the crankshaft and the camshaft. A lubrication collection area is located on the bottom side of the engine for the gravitational collection of engine lubrication fluid from the first chamber and the second chamber.

Abstract: An arrangement for an engine positioned in a cowling of an outboard motor and having an output shaft arranged to drive a water propulsion device of the motor is disclosed. The engine has a first end and a second end and a centerline passing through the ends, at least one combustion chamber, an intake system positioned along a first side of the engine for delivering air to the combustion chamber, a lubricating system including an oil filter for delivering lubricant to the engine and an ignition system including an ignition coil for charging an ignition element corresponding to the combustion chamber. The ignition coil and oil filter are positioned along a second side of the engine opposite the intake system and arranged to reduce the transfer of heat from the filter to the coil, with the oil filter having an outermost portion which is positioned outwardly of the engine between the centerline and a second line which extends parallel to the centerline and passes through an outermost portion of the ignition coil.

Abstract: The present invention is an improved oil reservoir for an outboard motor. The oil reservoir is defined by an oil pan portion of an exhaust guide. The exhaust guide includes a support portion which is positioned below an engine powering the motor. The oil pan portion extends downwardly from the support portion. An opening provided in the support portion of the exhaust guide leads to the oil reservoir, serving as an oil return. Preferably, a gasket positioned between the exhaust guide and the engine partially obscures the opening, preventing backflow of oil from the reservoir into the engine when the motor is titled.

Abstract: A gas insulated electrical apparatus in which electric devices for three phases are housed within a common gas-filled vessel includes a first and a second curved wall spaced apart from each other by a first distance and a third and a fourth curved wall connected between the first and second curved walls and spaced apart from each other by a second distance smaller than the first distance to define a substantially oval cross-sectional shape. The electric devices are arranged in a row extending between the first and second walls. The first and second curved walls may have a first radius of curvature and the third and fourth curved walls may have a second radius of curvature larger than the first radius of curvature.

Abstract: An adjustable throttle damper retards closure of associated throttle valves. The throttle damper is positioned between runners of an intake manifold to which the throttle valves communicate. A lever selectively couples the throttle damper to a throttle linkage operating the throttle valves. This arrangement reduces the width of the engine. The throttle damper also operates against a lead throttle lever of the throttle linkage in order minimize the effect play in the linkage has on valve synchronization.

Abstract: An improved cylinder head, cylinder block, and cylinder head gasket arrangement, wherein the gasket and cylinder head are configured in such a way that no water can be trapped in the area between the cylinder head gasket and the cylinder head sealing surfaces in areas where the cylinder head gasket is not engaged by a surface of the cylinder block that faces the surface of the cylinder head engaged by the gasket.

Abstract: An engine of an outboard motor includes an improved engine component layout to minimize the size of the engine and to improve the performance of the components. A separator of a crankcase ventilation system is located on a cam cover outside the cam chamber in order to reduce the size of the cam cover while providing the necessary spacing between the separator and the valve mechanism within the cam chamber. A fuel pump is positioned at about the center of the cam cover, beneath the separator, to generally balance the length of fuel travel to each of the carburetors. A fuel filter also is located on the cam cover, beneath the fuel filter, to generally isolate the fuel filter from the effects of the heated cylinder head and block. The arrangement of these components does not interfere with the hinge-like travel of a top cowling, which surrounds the engine, relative to a lower tray.

Abstract: A drive arrangement for the camshaft of an internal combustion engine employed in an outboard motor that includes a pivoted idler pulley that is disposed within the outer periphery of the flywheel but which has a portion extending beyond the flywheel for adjustment without removing the flywheel.

Abstract: A four-cycle internal combustion engine which has one or more horizontally disposed cylinder bores and a piston supported for horizontal reciprocation in each cylinder bore. Each piston includes a ring structure wherein a plurality of compression rings are fitted in corresponding parallel grooves formed on the outer periphery of each piston. A positioning pin for each compression ring is press fitted into the groove of the associated ring in its end gap for positioning and holding the end gap of each compression ring at a point along the outer periphery of the piston outside of the area under the piston axis.

Abstract: The present invention provides a device for controlling the air/fuel mixture ratio during the starting period for an outboard motor. Specifically, a positive temperature coefficient (PTC) heater controls a fuel flow regulating valve at an engine's charge forming device. A multipolar generator is used as an exclusive power source for the PTC heater. The arrangement of the invention has a relatively simple construction and can be used with propulsion units which do not have batteries.