Abstract: An outboard motor includes a cowling substantially enclosing an engine therein. The engine has an air induction device for introducing air to a combustion chamber, and an exhaust system for communicating exhaust products away from the combustion chamber. The air induction device has an intake opening near a front end of the engine. The cowling has an air inlet at a rear portion of the cowling. An air guide member is disposed between the cowling air inlet and an engine cover, which is positioned atop the engine. The air guide member and engine cover cooperate to direct air toward a rear and center of the engine.

Abstract: An engine throttle valve linkage includes an improved construction that can be placed in a space around an engine in an internal cavity of a protective cowling so as to control throttle valves under a synchronized condition. In a preferred mode, the engine includes first and second air intake conduits communicating with combustion chambers in the respective cylinder banks of the V-shaped engine and extending generally along side surfaces of the engine body. The first and second intake conduits have first and second throttle valves, respectively, both regulating an amount of air flowing through the respective intake conduits. A manipulator actuates both the first and second throttle valves. The manipulator includes a pair of manipulating members coupled with the first and second throttle valves. The manipulator is disposed generally between the first and second air intake conduits so as to be positioned on the engine body.

Abstract: An outboard motor includes a cowling substantially enclosing an engine therein. The engine has an air induction device for introducing air to a combustion chamber, and an exhaust system for communicating exhaust products away from the combustion chamber. The air induction device has an intake opening near a front end of the engine. The cowling has an air inlet at a rear portion of the cowling. An air guide member is disposed between the cowling air inlet and an engine cover, which is positioned atop the engine. The air guide member and engine cover cooperate to direct air toward a rear and center of the engine.

Abstract: An improved cowling arrangement for an outboard motor powered by an internal combustion engine. The improved arrangement includes a flywheel cover and cowling that incorporate upwardly and downwardly extending ribs which are positioned along an air path between the air vent of the outboard motor and the throttle body of the motor. These ribs act as labyrinth-type seals which prevent water entering the air vent from contacting the throttle body. Also disclosed is an improved cowling arrangement that prevents water pooled on the flywheel cover from draining onto the throttle body when the motor is tilted, such as when the watercraft banks into a turn.

Abstract: An outboard motor throttle and transmission control that employs a bowden wire mechanism for transmitting control signals from the tiller handle to the engine throttle and transmission control. The control handle is pivotally mounted on the front end of a tiller arm and the wire actuators exit the control handle and enter the protective cowling on opposite sides of a longitudinal center plane or on opposite sides of the protective cowling so as to increase the length of the wire actuators in this area so as to facilitate their bending without kinking.

Abstract: A cowling latch for an outboard motor having an upper cowling having a lower surface and a lower cowling having an upper surface is disclosed. The cowling latch comprises a first latching member connected to the upper cowling and a second latching member connected to the lower cowling. The second latching member is moveable between a first position in which it engages the first latching member for connecting the upper and lower cowlings and a second position in which it does not engage the first latching member. The second latching member comprises a first latching member engaging part movably mounted with respect to a support, the support positioned below the upper surface of the lower cowling.

Abstract: A throttle control system for an outboard motor and throttle position sensor therefor that permits a compact assembly by operating the throttle valve via an intermediate throttle valve operating shaft that is disposed closer to the body of the engine and farther from the protective cowling than the throttle valve. A throttle position sensor is associated with this intermediate throttle operating shaft for providing a signal indicative of throttle valve position for engine control.

Abstract: An intake system for an engine arranged to be positioned within a cowling of an outboard motor for powering a water propulsion device of the motor is disclosed. Preferably, the engine is of the "V"-type, having first and second banks defined by first and second cylinder heads connected to a cylinder block, and having a crankcase or second end positioned opposite the heads and facing the watercraft. Each bank contains at least one combustion chamber, and the banks define a valley extending therebetween along a length of the engine. An intake system is positioned at the second end of the engine and comprises a surge tank corresponding to each bank, an intake passage leading from each surge tank to the cylinders of its respective bank, and a throttle body having an air inlet and a branch passage leading to each surge tank. An engine auxiliary component is positioned above or below the throttle body of the intake system.

Abstract: A protective cowling arrangement defining an air inlet opening for an outboard motor that facilitates the ingestion of large amounts of air at low velocity. This aids in the assurance that water is not ingested into the engine. The configuration of the inlet opening is such that the water that is separated by the inlet system can easily flow away from the inlet opening and also the water that collects on the housing surfaces can be easily separated and will drain away from the actual inlet openings into the interior of the cowling.

Abstract: An exhaust system for an outboard motor powered by an internal combustion engine is disclosed. Preferably, the engine is of the "V"-type, having first and second banks defined by first and second cylinder heads connected to a cylinder block. Each bank contains at least one combustion chamber, and the banks define a valley extending therebetween along a length of the engine. A main exhaust passage is defined through each cylinder head generally within the valley, and an exhaust passage extends from each combustion chamber of a bank to the main exhaust passage of that bank. The main exhaust passages of the two banks join into a single passage.

Abstract: A drive arrangement for an engine positioned within a cowling of an outboard motor and powering a water propulsion device of the motor is disclosed. Preferably, the engine is of the "V"-type, having first and second banks and an intake and exhaust camshaft corresponding to each bank. A drive arrangement is provided for driving the camshafts off of a crankshaft of the engine. Preferably, a flexible transmitter is positioned at a bottom end of the engine and directly drives one camshaft of each bank from the crankshaft, with the other camshaft of each bank driven by the driven camshaft.

Abstract: A four-cycle outboard motor having an oil tank that is disposed at least in part in the drive shaft housing of the outboard motor and an oil pump that is driven off of the lower end of the crankshaft. At least a portion of the conduits for transmitting oil from the oil tank to the oil pump and from the oil pump to the engine for its lubrication being formed integrally in a lower face of the cylinder block.

Abstract: A number of embodiments of four-cycle V-type outboard motors embodying an improved and simplified oil filter arrangement wherein the oil filter is easily accessible for servicing is located in close proximity to the oil tank for facilitating pressure relief and is disposed so as to facilitate communication with the main oil gallery of the engine.

Abstract: A crankshaft bearing arrangement for a two cycle crankcase compression internal combustion engine that provides a low frictional resistance and corrosion resistant. Electro galvanic corrosion is precluded by the utilization of an electrical insulating substance and by minimizing the electrical potential differences between the materials of the bearing.

Abstract: An outboard motor having a high-performance V-type twin overhead cam four-cycle internal combustion engine. The oil reservoir for the engine is disposed in a driveshaft housing below the engine and an oil pump is driven off the lower end of the engine crankshaft for circulating the oil from the oil tank to the engine. The oil supply system for the engine includes a vertically extending main gallery and a drain passage which extend in parallel side-by-side relationship and which are disposed over the oil tank for ease of oil return. The exhaust and cooling system for the engine is configured so as to minimize heat transfer between the exhaust system and the lubricating system and to maintain a compact assembly.

Abstract: A catalytic exhaust system for an outboard motor wherein the catalyst is positioned in the drive shaft housing to remove the source of heat from the power head. However, the catalyst is contained within a sealed compartment in the drive shaft housing lower unit. In order to protect the catalyst from water, a trap section is positioned in the power head and this is water cooled by a source of water which has not passed through the engine for its cooling prior to delivery to the trap section. In addition, the guide plate that separates the power head from the drive shaft housing and through which the exhaust gases pass is also water cooled. An arrangement is incorporated for permitting replacement and servicing of the catalytic converter. Although above the water and below the water exhaust gas discharges are employed, all gases flowing to the atmosphere through either exist pass through the catalytic converter.

Abstract: An exhaust system for a marine propulsion outboard drive wherein the exhaust gases are normally discharged to the atmosphere at a point below the level of the body of water in which the watercraft is operating. A catalyst bed is provided in the exhaust system and the catalyst bed is protected from damage by precluding the flow of water in the exhaust conduit to the catalyst bed in response to certain conditions. These conditions may be either rapid deceleration of the engine or watercraft, stopping of the engine, or any of a combination of sensed factors. The water is precluded either by purging it through air pressure or from generating heat in the exhaust conduit, by providing a heat source in the exhaust conduit that will cause water to vaporize and increase the pressure or by a valve in the exhaust conduit positioned below the catalytic bed. The preclusion of water is initiated for only a predetermined time or until the sensed condition no longer is existent.

Abstract: A number of embodiments of exhaust systems for outboard motors wherein the exhaust ports of the engine discharge the exhaust gases to the atmosphere through an underwater high speed exhaust gas discharge. A trap device is provided for precluding the water from the underwater exhaust gas discharge entering the engine through its exhaust ports. This trap device includes a section that extends above the highest exhaust port of the engine for this purpose.

Abstract: An exhaust cleaning system for a marine propulsion engine that includes a catalyst positioned within a tube that communicates with an expansion chamber. A cooling jacket extends around at least a portion of the exhaust system and the liquid coolant is discharged into the exhaust system for flow with the exhaust gases. A number of different arrangements are shown for precluding the coolant from flowing back into the exhaust system and contacting the catalyst bed either when the watercraft is inverted and righted or in the event the engine is stopped and restarted.

Abstract: An exhaust gas purifying arrangement is provided for an outboard motor for a watercraft. At least one exhaust port is provided which opens into a first exhaust passage having a first catalyst member lining at least a portion of its inner wall. The first exhaust passage then opens into an exhaust expansion chamber. Next, a second exhaust passage originates just beyond the expansion chamber. A second catalyst member is mounted within and across a section of exhaust passage beyond the first exhaust passage and at a location above the water line within which the outboard motor operates. A first passageway is provided which leads from the second exhaust passage, from a position beyond the second catalyst member, to an exhaust outlet located at a position below a body of water in which the watercraft operates.