Abstract: Several embodiments of V-type outboard motors having direct cylinder injection using electronic fuel injectors driven by a solenoid driver. The solenoid driver is mounted in the otherwise void area between the cylinder banks of the engine. The solenoid driver is also cooled so as to provide long life and good operation. The cooling can be either by air or water or both. Mounting the solenoid driver in the valley between the cylinder banks also permits shortening of the conduits from the solenoid driver to the solenoids of the injector valves for their operation.

Abstract: A number of embodiments of outboard motors employing direct fuel injection systems having high pressure fuel pumps that are mechanically driven off of the engine crankshaft. A wide variety of driving arrangements are disclosed which include direct and indirect drives and drive that employs flexible transmitters and other types of driving arrangements. Furthermore, the pump operating mechanisms are also provided with lubricating systems that will permit servicing of the lubricant even though the drive arrangement may be positioned outside of the crankcase of the engine. Furthermore, arrangements for mounting various components including the fuel pump and other engine-driven accessories in an outboard motor are shown.

Abstract: A cowling arrangement for an outboard motor for use in powering a watercraft is disclosed. The motor has an engine and a water propulsion device, the engine having an output shaft arranged to drive the water propulsion device. The cowling defines an engine compartment in which the engine is positioned and an air chamber having an inlet. The cowling comprises a cover and an air chamber base. The air chamber base is connected to the cover in a sealed manner and divides the engine compartment from the air chamber and includes a duct which extends upwardly into the air chamber. The air chamber base which defines an air passage leading from the chamber to the engine compartment. The air chamber base defines a surface sloping in a direction of a drain through the air chamber, whereby water drawn through the inlet is drained therefrom.

Abstract: A cylinder block is coupled to a cylinder block/cylinder head coupling surface of a cylinder head by ten bolts which are disposed to surround outer peripheries of combustion chambers. In order to enhance sealability of an opening of a cooling water passage defined radially outside the bolts as viewed from the combustion chambers, the cylinder block and the cylinder head are further fastened to each other by a bolt disposed in the vicinity of the opening. Thus, the fastening force of the cylinder block/cylinder head coupling surface can be increased to increase the degree of freedom in design of the opening of the cooling water passage defined in the coupling surface.

Abstract: An outboard motor body case supported on a swivel shaft through a connecting member. The swivel shaft is vertically swingable about a tilting shaft. An engine is mounted at an upper portion of the outboard motor body case, with a crankshaft thereof being oriented vertically, and a flywheel is mounted at a lower end of the crankshaft and disposed between an engine block and the connecting member. A dynamo is mounted within the flywheel, and a starter motor is engaged with a ring gear which is formed around an outer periphery of the flywheel. Thus, since the flywheel having a large weight is mounted at the lower end of the crankshaft, the position of the center of gravity of the outboard motor is lowered. Therefore, it is possible to easily perform a tilting-up about the tilting shaft with a small force. Moreover, since the flywheel is mounted on a power taking-off side of the crankshaft, the torsional vibration of the crankshaft can be reduced.

Abstract: An outboard motor embodying a four-cycle internal combustion engine having a decompression device for automatically reducing the compression ratio to assist in pull starting. The decompression device is mounted and operated through one end of the cam shaft and thus facilitates modification of engines so as to incorporate this feature or not incorporate the feature. The construction also facilitates lubrication of a centrifugal mechanism that actuates the decompression device.

Abstract: An outboard motor having a direct cylinder fuel injection system with a high-pressure pump that is driven directly from the engine crankshaft. This drive is positioned on the crankshaft above the flywheel at the upper portion of the engine, with other accessories being driven from the crankshaft below the flywheel, while still at the top of the engine. This facilitates servicing of the components and places them all in easily accessed locations.

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: In an outboard motor, a simple drain structure is provided which can drain the water that has entered the engine compartment while effectively preventing water from entering the engine compartment through the drain structure itself. A drain passage is formed in a peripheral portion of an engine mount member which, together with a part of an engine cover, constitutes a bottom of the engine compartment. A reed valve unit made of a resilient material and having a base portion and a valve portion is fittingly received by the side wall defining the drain passage of the mount member so that the valve portion normally closes the opening of the drain passage due to its own resiliency and bend to drain water when water accumulates in the drain passage.

Abstract: An outboard motor exhaust system and control for insuring good running and effective exhaust gas silencing and treatment. The system includes a very compact exhaust system that includes an expansion chamber formed beneath the exhaust guide plate and to which the exhaust gases are delivered and removed at optimal locations. Furthermore, a feedback control employing a combustion condition sensor is employed along with a catalyst in the exhaust. Sensors are provided upstream and downstream of the catalyst to ensure that it is operating at optimum conditions.

Abstract: A marine outboard drive that is equipped with integrated splash plates and a baffle plate that prevent water splash-up along the drive shaft housing. The baffle plate protrudes from the drive shaft housing to interact with plates on the lower bracket to create a labyrinth effect. The labyrinth created by the splash and baffle plates impedes the path of any water impinging upon the lower bracket and the drive shaft housing. This minimizes the amount of water travelling up the drive shaft housing. A splash plate may also be included on the lower bracket to minimize water flow above the lower bracket.

Abstract: A number of the embodiments of exhaust systems and oil tank arrangements for four-cycle internal combustion engine powered outboard motors. In all of the embodiments, idle exhaust gases are discharged to the atmosphere through a path that extends above the oil tank. A cooling jacket is formed around an exhaust pipe that depends through a cavity in the oil tank and coolant from this cooling jacket is discharged to the exterior surface of the exhaust pipe so as to cool it. Cooling water from the engine and from the exhaust pipe cooling jacket is isolated from the idle exhaust gas discharge so as to ensure that this cooling water cannot enter the engine through the idle exhaust gas discharge path.

Abstract: A heat-discharging electronic component is mounted in an unused space on the side of an engine of an outboard motor without unnecessarily restricting the layout of parts in the outboard motor, or increasing the number of parts or assembly steps. The unused space is a cavity between a side of the engine, an exhaust manifold, and an electronics box spaced apart from the exhaust manifold to form the cavity. The cavity is further defined by a perpendicular projection of a cover member covering the upper portion of the engine. Fixing bolts remain accessible below the cover member when a removable cover is removed, thereby improving accessibility of the heat-generating electronic component. Locating the cavity under the perpendicular projection of the fixed cover member improves protection against the entry of moisture into the heat-generating electronic component.

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: 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: A cowling arrangement for an outboard motor for use in powering a watercraft is disclosed. The motor has an engine and a water propulsion device, the engine having an output shaft arranged to drive the water propulsion device. The engine has a body with a top end and a bottom end, the output shaft extending above the top end. A flywheel is connected to the output shaft at the top end of the engine, and a flywheel cover is positioned over the flywheel and supported by the engine body. The cowling defines an engine compartment in which the engine is positioned and has an opening therein. A starter panel is connected to the flywheel and supported solely thereby, the starter panel cooperating with the cowling to close the opening therein, the starter panel supporting at least one component of a starter for the engine.

Abstract: A cover for an outboard motor is provided to protect an operator from a flywheel. The cover is disposed under the cowl of the outboard motor. The cover is made of a generally rigid material, such as plastic, with first and second sheets being associated together to form conduits with openings extending therefrom. In one particular embodiment, one of the openings is shaped to receive an inlet of a compressor and this provides a positioning aid in attaching the cover to the engine. This device eliminates the need for flexible hoses and accomplishes two tasks with one component. It provides air conduits for the air passing through the cover and it provides a generally rigid means for locating the proper location of the cover.

Abstract: An outboard motor includes an engine holder, an engine disposed above the engine holder in an installed state of the outboard motor, a flywheel magnet device disposed above the engine, an oil filter disposed on a side portion of the engine, an electric equipment box, an air suction device, an exhaust device and a fuel supply device, these electric equipment box, suction device, exhaust device and fuel supply device being arranged around the engine, and an engine cover covering the engine. The air suction device is composed of a throttle body, a surge tank and an intake manifold including a plurality of branch members extending from the surge tank, the intake manifold is disposed vertically, in the installed state, on one side of the engine so that the intake manifold is located between the flywheel magnet device and the oil filter as viewed from a side portion thereof and the intake manifold has at least a portion superposed on the flywheel magnet device and the oil filter as viewed in a plan view.

Abstract: An engine includes first exhaust passages formed in a cylinder head, a second exhaust passage formed in a cylinder block and communicating with the first exhaust passages, and a cooling water passage having water jacket portions formed around combustion chambers. The cooling water passage includes a first water jacket and a second water jacket. The cylinder head and the cylinder block are fixedly connected together by bolts. The second exhaust passage opens at a joining surface of the cylinder block along cylinders, which opening is surrounded by the bolts. The cooling water passage has water jacket portions formed between the bolts in the joining surface of the cylinder block such that they surround the opening of the block exhaust passage.

Abstract: An outboard motor body case supported on a swivel shaft through a connecting member. The swivel shaft is vertically swingable about a tilting shaft. An engine is mounted at an upper portion of the outboard motor body case, with a crankshaft thereof being oriented vertically, and a flywheel is mounted at a lower end of the crankshaft and disposed between an engine block and the connecting member. A dynamo is mounted within the flywheel, and a starter motor is engaged with a ring gear which is formed around an outer periphery of the flywheel. Thus, since the flywheel having a large weight is mounted at the lower end of the crankshaft, the position of the center of gravity of the outboard motor is lowered. Therefore, it is possible to easily perform a tilting-up about the tilting shaft with a small force. Moreover, since the flywheel is mounted on a power taking-off side of the crankshaft, the torsional vibration of the crankshaft can be reduced.

Abstract: A cylinder head is coupled to a cylinder block/cylinder head coupling surface of a cylinder block by ten bolts which are disposed to surround outer peripheries of cylinders. In order to enhance sealability of an opening of an oil passage defined radially outside the bolts as viewed from the cylinders, the cylinder block and the cylinder head are further fastened to each other by two bolts disposed in the vicinity of the opening. Thus, the fastening force of the cylinder block/cylinder head coupling surface can be increased to increase the degree of freedom in design of the opening of the oil passage defined in the coupling surface.

Abstract: A four cycle outboard motors that have water cooled engines and an oil pan that is formed in the upper portion of the drive shaft housing. An exhaust pipe collects exhaust gases from an exhaust guide and delivers to a cavity that is formed in the oil pan by an interior wall thereof. The exhaust pipe does not terminate below the lower surface of the oil pan and idle exhaust gases are delivered to the area between the exterior of the exhaust pipe and the interior surface of the oil pan that defines the cavity. These idle exhaust gases are discharged to the atmosphere through and above the water exhaust gas discharge. The oil pan lower surface has a drain opening that is aligned with a vertical drain opening in the drive shaft housing. At least a pair of elastomeric members are clamped between the drive shaft housing and the oil pan to provide stiffness and sound damping.

Abstract: A number of embodiments of direct injected V-type outboard motors. In each embodiment, a high pressure pump is driven off of the upper end of the crankshaft and is disposed at a high level in the protective cowling. The drive for the high pressure pump is disposed in the path of air flow from an opening in the protective cowling to the engine induction system. On the other hand, the high pressure pump is out of this air flow to avoid corrosion. Various alternative locations for the components of the engine including specifically the high pressure pump, an alternator, a fuel vapor separator, an ECU control unit and a fuel injector solenoid driver are disclosed.

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 outboard motor includes an engine bottom cover member which is disposed in a space between a front portion of an under cover and an upper portion of an outboard motor attachment mechanism and conceals a bottom end portion of an engine from view at least in a lateral direction of the outboard motor. The outboard motor having such concealed engine bottom portion is sightly in appearance. The engine bottom cover member is formed integrally with an under cover and, hence, it can be assembled automatically when the under cover is attached to the under case.

Abstract: This invention is an outboard motor exhaust device compatible with a small, lightweight cylinder block, which simplifies the exhaust manifold assembly and allows greater precision of assembly. The engine of an outboard motor is located above an engine holder, and comprises a horizontally assembled cylinder head, cylinder block, and crank case. An air intake device is located on one side of the cylinder block, and the exhaust manifold comprising the exhaust device is located on the opposite side of the cylinder block from the air intake device. A side surface of the cylinder head and a side surface of the engine holder are coplanar and form a support for the exhaust manifold.

Abstract: An electrical system is disclosed for a watercraft powered by an outboard motor with an internal combustion engine having a block defining a crankcase at one side and having a cylinder head generally positioned on an opposite side thereof, the engine oriented such that an output shaft thereof extends vertically. The electrical system includes a starter and generator mounted generally alongside the crankcase of the engine and between the ends thereof, the generator driven by a flexible belt extending in engagement with the output shaft, and the starter motor positioned for engagement with a flywheel positioned on the output shaft of the engine.

Abstract: An induction system for an outboard motor of the type having a water propulsion device powered by an internal combustion engine positioned within an engine compartment defined by a cowling, is disclosed. The induction system includes a cover extending over a top end of the engine. The cover defines an air duct leading from an intake chamber defined by the cowling to an intake pipe of the air intake system of the engine. The cover also defines an air duct in communication with the engine compartment and leading to an exhaust chamber defined by the cowling. A pair of intake ports lead through a cover of the cowling from the intake chamber, and an exhaust port leads through the cover from the exhaust chamber. The intake ports are positioned forward of the exhaust port when considering the forward movement of a watercraft which is powered by the motor.

Abstract: A fuel injection system for an internal combustion engine of the type utilized to power an outboard motor of a watercraft is disclosed. The engine is oriented with its crankshaft vertically extending, such that the engine has a top and a bottom, a first end and a second end, and a side between the ends. An air delivery passage extends generally from the first end along said side to an intake passage leading through the engine to a combustion chamber therein. A fuel injector is positioned along the side of the engine and arranged to deliver fuel into air flowing through the passage. In one arrangement, the fuel injector is connected to an intake manifold defining at least a part of the air delivery passage and is adapted to deliver fuel opposite the flow of air through the passage at the point of delivery. In a second embodiment, the fuel injector is positioned between the air delivery passage and the side of the engine.

Abstract: A fuel injection system for an internal combustion engine of the type utilized to power an outboard motor of a watercraft is disclosed. The engine is oriented with its crankshaft vertically extending, such that the engine has a top and a bottom, a first end and a second end, and a side between the ends. An air delivery passage extends generally from the first end along said side to an intake passage leading through the engine to a combustion chamber therein. A fuel injector is positioned along the side of the engine and arranged to deliver fuel into air flowing through the passage. In one arrangement, the fuel injector is connected to an intake manifold defining at least a part of the air delivery passage and is adapted to deliver fuel opposite the flow of air through the passage at the point of delivery. In a second embodiment, the fuel injector is positioned between the air delivery passage and the side of the engine.

Abstract: A coolant system for a vertically oriented engine of an outboard motor is disclosed. Coolant flows through the coolant system from a coolant pump into a coolant jacket surrounding an exhaust manifold of the engine, down to a bottom of a cylinder head of the engine, through the cylinder head an engine block, through a thermostat, and then to a jacket positioned along an exhaust pipe leading from the exhaust manifold, to a coolant discharge.

Abstract: An air intake system for an internal combustion engine has a vertical crankshaft and a pair of substantially horizontally disposed cylinders that extend outward from a crankcase to form a V-space therebetween. The air intake system includes an air inlet through a blower housing on top of the engine, an air cleaner housing that is disposed substantially directly above the V-space and that receives air from the air inlet, an air-fuel mixing device disposed substantially directly below the air cleaner, and an intake manifold adapted to deliver a combustible mixture from the air-fuel device to each cylinder. The air cleaner includes a filter supported such that air received from the air inlet flows through the filter in a substantially upward direction. The air cleaner housing and the blower housing are integrated into a single housing.

Abstract: An outboard motor having an upper unit containing an internal combustion engine and a lower unit containing an exhaust guide is disclosed. The engine has a vertically oriented crankshaft having an end extending from the bottom end of the engine. A flywheel is positioned on the crankshaft at the bottom end of the engine within a recess defined by the exhaust guide. A starter motor is positioned at the bottom end of the engine and is positioned at least partially within the exhaust guide, the motor having a gear for engaging the flywheel to start the engine.

Abstract: A latching assembly for engaging and disengaging an upper cover portion and lower tray portion of a cowling of an outboard engine. The lower tray portion includes a recess in which part of the latching assembly is located. The latching assembly includes a shaft mounted to the lower tray portion. A latch is rotatably secured to the shaft and movable between an engaged and a disengaged position. The latch is disposed within the recess when engaged so that is is flush with the exterior of the cowling. A catch is mounted to the upper cover portion and is engageable by the latch hook. A mechanism for biasing the latch to the engaged or disengaged position is provided for preventing the latch from moving from the engaged or disengaged position.

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 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: In an outboard motor, an engine is mounted to an upper portion of an engine holder. A crank shaft is vertically disposed in a crank case of the engine. A plurality of cylinders are arranged in a cylinder block of the engine in parallel with each other in a vertical direction. An oil pan is disposed in the engine holder, and a balancing device is mounted to a bottom surface of the cylinder block facing the oil pan. The cylinder block is disposed between the crank case and a cylinder head. The bottom surface of the cylinder block is recessed. In this recessed portion, a balancing device is disposed.

Abstract: A high-performance outboard motor embodying a V-type four overhead camshaft four-cycle internal combustion engine. A compact cam driving arrangement is provided for driving the camshafts from the crankshaft of the engine at the upper end. A flywheel is mounted to the lower end of the crankshaft and is driven by a starter motor for starting of the engine. Another engine accessory is driven off the upper end of the crankshaft so as to maintain a compact and yet highly serviceable arrangement.

Abstract: A camshaft drive for the engine of an outboard motor includes a drive sprocket mounted to the crankshaft of the engine, a sprocket mounted to each of first and second camshafts, and a drive belt engaging the sprockets, whereby the crankshaft drives the camshafts. A cover extends over the camshaft drive, the cover having an air inlet and air outlet and defining a first cooling air flow path from said air inlet across a first portion of the drive belt pathway for cooling a first portion of the belt, and a second flow path across a second portion of the drive belt pathway to the air outlet for cooling a second portion of the belt.

Abstract: Embodiments of four-cycle outboard motors having an improved exhaust system. The exhaust system includes an expansion chamber that is formed in the drive shaft housing of the outboard motor below an oil tank for the engine which is positioned therein. A water chamber is formed around the expansion chamber and the lower portion of the oil tank for cooling them. An above-the-water exhaust gas discharge is provided that communicates with the area above the water jacket.

Abstract: An intermediate drive mechanism allows an alternator to be mounted beneath an engine flywheel on the side of the engine. This location reduces both the girth and height of the engine, thereby reducing the size of the power head of an outboard motor. The intermediate drive mechanism includes a first intermediate pulley, which lies generally at the same level as a drive pulley attached to the engine output shaft. A second intermediate pulley lies beneath the first intermediate pulley and generally at the same level as a driven pulley of the generator. Belts couple the pulleys of the intermediate drive mechanism to the respective drive and driven pulleys. The intermediate pulleys also can move relative to the corresponding pulleys so as to function as a belt tensioner.

Abstract: A disclosed engine assembly comprises an engine; a crank shaft having an end extending outward from inside the engine; a rotating body mounted at the end of the crank shaft; a cover body mounted on the engine so as to cover the rotating body; the cover body comprising a lower cover that covers at least lower part of the rotating body and an upper cover connected to the lower cover so as to cover at least upper part of the rotating body; the lower cover having at least one ventilating intake port for sucking hot air located around the engine under the intake port; the upper cover having a ventilating exhaust duct for discharging the sucked hot air; the rotating body including a timing belt located near one side of the engine, a tensioner located near one side of the engine and having a mounting position adjustment bolt for adjusting a tension on the timing belt, and a manually starting pulley located on one side of the engine outside the timing belt; and the starting pulley having at least one opening located

Abstract: Cooling water pumped by a cooling-water pump is passed via a cooling-water supply passage, a cooling-water dispensing chamber, two upper and lower through-holes and a water jacket, a thermo-valve and discharged via a cooling-water discharge passage. When the amount of cooling water supplied from the cooling-water pump is excessive, or when the thermo-valve has been closed, a relief valve mounted in a bypass passage which connects the cooling-water supply passage and the cooling-water discharge passage is opened, thereby permitting the cooling water to be diverted. The bypass passage diverges from the cooling-water supply passage upstream of the cooling-water dispensing chamber. Therefore, even if the relief valve is opened, the flow pattern of the cooling water flowing within the cooling-water dispensing chamber is not influenced, and the flow rates of the cooling water passed through the two through-holes cannot be unbalanced.

Abstract: A number of embodiments of four-cycle internal combustion engines having belt-driven overhead cam shafts. The power head of the outboard motor includes a protective cowling that has an atmospheric air inlet and the air drawn through this atmospheric air inlet is directed over a timing belt that drives the cam shaft from the engine crankshaft for its cooling. The air flow is controlled either by utilization of fans, baffles and/or utilizing the flow of air caused by the induction system.

Abstract: In an outboard engine, an electric device is attached, utilizing a cooling water passage cover for closing a recessed part constituting part of a cooling water jacket, to the cover via a boss part, thus providing a compact electric device mounting structure with no such parts projecting from a side of an engine as in a conventional box member. An engine starting apparatus of the outboard engine is provided with an ignition device and a starter motor connected to a battery, and an AC generator is connected to the battery via an electric device having voltage restricting and rectifying functions. When it is cranked by the starter motor or a starter pulley, the engine is started by the ignition device operated by the battery. As it is cranked by the starter pulley while the battery is discharging, the ignition device is actuated by a current generated by the AC generator and rectified by the electric device to thereby start the engine.

Abstract: A four-cycle outboard motor embodying an improved lubricating system. The lubricating system drains oil from the cylinder head back to the oil tank, in a manner so as to not add to the length of the engine. In addition, an improved crankcase ventilating system is employed that incorporates a simple baffle arrangement for ensuring that oil thrown by the crankshaft rotation will not pass through the ventilating passage into the cylinder head or escape from the ventilating system.

Abstract: A V-shaped multi-cylinder engine is mounted in such a manner that a crankshaft is mounted in a vertical attitude and cylinders are opened into a V-shape in a rearward direction. An intake silencer is mounted above a throttle body which is disposed in front of a crankcase portion of the engine. The intake silencer includes an intake silencing chamber defined by a belt cover which covers a belt of a valve operating mechanism and by a lower wall member. Two left and right air intake pipes extend downwardly from the intake silencing chamber and open into an engine compartment. A single intake-air introducing pipe extends downwardly from the intake silencing chamber and is connected to an upper end of the throttle body. Thus, it is possible to reduce the intake noise of the engine for an outboard engine system.

Abstract: An exhaust pipe for guiding an exhaust gas from an engine into an exhaust gas expansion chamber defined within an extension case is connected to a protrusion of an oil pan which is mounted on a lower surface of a mount case that supports the engine at its upper portion. A breathing bore is formed in an upper portion of the exhaust pipe, and an outer side of the breathing bore is covered with a shield plate. Therefore, water cannot enter the exhaust pipe through the breathing bore. A cooling-water supply pipe for introducing cooling water from a cooling-water pump into the engine is formed with a cooling-water ejection bore which is located at a position in which it is not opposed to the breathing bore. Therefore, even if cooling water is ejected through the cooling-water ejection bore to the exhaust pipe to cool the latter, the cooling water cannot enter the exhaust pipe.

Abstract: An upper intake pipe and a lower intake pipe interconnecting a left bank and a throttle body are disposed along a left side of a V-shaped multi-cylinder engine having a vertically placed crankshaft. The lower intake pipe is disposed by utilizing a waste space which is defined between a starter motor and an oil filter, while the oil filter is disposed by utilizing a waste space which is defined between the upper and lower intake pipes. Thus, it is possible to rationally dispose the intake pipes and other auxiliaries on a side of an engine block to reduce the size of the engine for the outboard engine system.

Abstract: A four-cycle engine including a magnetic detection sensor mounted on a non-magnetic cam shaft pulley which is rotated in operative association with a crank pulley for detecting a plurality of detecting portions formed on the magnetic detection member by coils mounted in the cylinder head. The magnetic detection member is integrally formed with the plurality of detection portions for different uses such that distances from the center of rotation of the cam shaft pulley to the plurality of detection portions are different, and wherein the coils are separately mounted in correspondence to the detection portions. Thus, it is possible not only to take out timing signals for different uses from a single cam shaft pulley, but also to eliminate interference between the discrete coils.