Abstract: The present invention is to provide a synthetic weld body which sectional shape of a passage to a bore can be an ideal shape by welding two synthetic members. The edge at the passage side of the rising boundary line 78a-1, 78a-2, 78b-1, 78b-2, 78c-1, 78c-2, 78d-1, 78d-2 which is the boundary between the top end connecting face and the mount connecting face of the middle member 70 is disposed at or in the vicinity of a contact point of the tangent line of the ridge line 84 of the mount connecting face at the passage side with the inner edge of the top end connecting face 74a, 74b, 74c, 74d at the bore 50a, 50b, 50c, 50d side. The rising boundary line 78a-1, 78a-2, 78b-1, 78b-2, 78c-1, 78c-2, 78d-1, 78d-2 including the edge at the passage side is parallel to the standard direction for vibration.

Abstract: The present invention is to provide a synthetic weld body which sectional shape of a passage to a bore can be an ideal shape by welding two synthetic members. The edge at the passage side of the rising boundary line 78a-1, 78a-2, 78b-1, 78b-2, 78c-1, 78c-2, 78d-1, 78d-2 which is the boundary between the top end connecting face and the mount connecting face of the middle member 70 is disposed at or in the vicinity of a contact point of the tangent line of the ridge line 84 of the mount connecting face at the passage side with the inner edge of the top end connecting face 74a, 74b, 74c, 74d at the bore 50a, 50b, 50c, 50d side. The rising boundary line 78a-1, 78a-2, 78b-1, 78b-2, 78c-1, 78c-2, 78d-1, 78d-2 including the edge at the passage side is parallel to the standard direction for vibration.

Abstract: An intake manifold is provided that comprises a plurality of intake ducts, a surge tank, a vacuum chamber, and a negative pressure check valve. The negative pressure check valve enables negative pressure induced in the surge tank to flow into the vacuum chamber. Each upstream end of the intake ducts protrudes into the inside of the surge tank. Further, a pressure inlet formed inside the surge tank, to lead the negative pressure induced inside the surge tank to the negative pressure check valve, is positioned on a side closer to an engine than the respective upstream ends of the intake ducts.

Abstract: An outboard engine has an internal combustion engine as a prime mover, a throttle valve device including a valve element and a valve shaft supporting the valve element, and combined with the internal combustion engine, a driven unit combined with the throttle valve device, and a drive unit for driving the driven unit. The drive unit is capable of smoothly transmitting an external throttle-operating force to the driven unit regardless of its position. A throttle valve operating mechanism connects an operating lever included in the driven unit, and a throttle-operating Bowden cable included in the drive unit. The throttle valve operating mechanism is a linkage including plural links. Joints joining the adjacent joining parts of those links are ball-and-socket joints, respectively. The valve shaft has one end connected to the operating lever and the other end connected to a throttle position sensor. The valve shaft is inclined to a horizontal plane.

Abstract: The intake manifold assembly comprises three blocks each molded from a plastic material by injection molding, the three blocks consisting of a first block defining a half of the surge tank, a second block defining a half of the individual intake pipes and a third block defining a remaining half of the surge tank and a remaining half of the individual intake pipes. Thereby, the intake manifold assembly may be provided with various features for defining a pair of intake pipe sections arranged in a mutually parallel relationship while being made to be suitable for an injection molding process. Because the surge tank are defined by the first and third blocks while the individual intake pipes are defined by the second and third blocks, the intake manifold assembly essentially consisting of three blocks can internally define essential features required for a dual port intake device without requiring additional component members.

Abstract: A decompressing mechanism (D) for an internal combustion engine (E) is incorporated into a camshaft (15) provided with a bore (54) extending in the direction of the arrow (A) along the axis (L1) of rotation of the camshaft (15). The decompressing mechanism (D) includes a decompression member (80) formed by metal injection and integrally having a flyweight (81), a decompression cam (82) for exerting a valve-opening force through an exhaust rocker arm (48) on an exhaust valve, and an arm (83) connecting the flyweight (81) and the decompression cam (82). The flyweight (81) is supported for swing motion by a pin (71) on the camshaft (15). The axis (L2) of swing motion of the flyweight (81) is included in a plane (P4) substantially perpendicular to the axis (L1) of rotation, and does not intersect the axis (L1) of rotation and the bore (54) of the camshaft (15). The fully expanded decompression member (80) revolves in a cylindrical space of a small diameter around the camshaft (15).

Abstract: A decompressing mechanism included in an internal combustion engine has a flyweight supported for swinging motion by a pin on the camshaft of the internal combustion engine, a decompression cam and an arm connecting the flyweight and the decompression cam and having the shape of a plate. The flyweight has a weight body and projections projecting from the weight body and engaged with the pin. The weight body is a block of a width along the axis of swinging motion and a thickness, along a radial direction, which are greater than the thickness, along the axis, of swinging motion of the arm. The weight body overlaps the camshaft as viewed from a direction perpendicular to a reference plane. The decompressing mechanism is small, lightweight and is capable of concentrating most of its mass on the flyweight.

Abstract: A split face of an exhaust passage-defining member is coupled to a split face provided at a rear portion of an oil case interposed between an engine block and an extension case. A main exhaust gas expansion chamber and a subsidiary exhaust gas expansion chamber are defined between the exhaust passage-defining member and the oil case, so that an exhaust gas supplied from a first exhaust passage in the oil case is discharged into a second exhaust passage in the oil case via the main exhaust gas expansion chamber. A portion of the exhaust gas in the main exhaust gas expansion chamber is passed through a communication bore and the subsidiary exhaust gas expansion chamber and discharged from an exhaust outlet into the air.

Abstract: In the dual port intake device of the present invention, the intake manifold assembly comprises three blocks each molded from a plastic material by injection molding, the three blocks consisting of a first block defining a half of the surge tank, a second block defining a half of the individual intake pipes and a third block defining a remaining half of the surge tank and a remaining half of the individual intake pipes. Thereby, the intake manifold assembly may be provided with various features for defining a pair of intake pipe sections arranged in a mutually parallel relationship while being made to be suitable for an injection molding process.

Abstract: In fuel supply system for an engine in which a discharge port in a fuel pump driven by the engine to draw up fuel in a fuel tank is connected to an inlet port which is provided in a fuel reservoir and which is controlled in opening and closing by a float valve so that the fuel in the fuel reservoir is supplied to the engine, a second discharge port is provided in the fuel pump, and a second inlet port without a float valve is provided in the fuel reservoir. The second discharge port and the second inlet port are connected to each other through a control valve opened during starting of the engine. Thus, when the engine is started, fuel vapor generated in a pump chamber in the fuel pump can be discharged to the fuel reservoir having an air vent, to normalize the function of the fuel pump, leading to an enhancement in hot startability of the engine.

Abstract: An outboard engine has an internal combustion engine as a prime mover, a throttle valve device including a valve element and a valve shaft supporting the valve element, and combined with the internal combustion engine, a driven unit combined with the throttle valve device, and a drive unit for driving the driven unit. The drive unit is capable of smoothly transmitting an external throttle-operating force to the driven unit regardless of its position. A throttle valve operating mechanism connects an operating lever included in the driven unit, and a throttle-operating Bowden cable included in the drive unit. The throttle valve operating mechanism is a linkage including plural links. Joints joining the adjacent joining parts of those links are ball-and-socket joints, respectively. The valve shaft has one end connected to the operating lever and the other end connected to a throttle position sensor. The valve shaft is inclined to a horizontal plane.

Abstract: An intake manifold is provided that comprises a plurality of intake ducts, a surge tank, a vacuum chamber, and a negative pressure check valve. The negative pressure check valve enables negative pressure induced in the surge tank to flow into the vacuum chamber. Each upstream end of the intake ducts protrudes into the inside of the surge tank. Further, a pressure inlet formed inside the surge tank, to lead the negative pressure induced inside the surge tank to the negative pressure check valve, is positioned on a side closer to an engine than the respective upstream ends of the intake ducts.

Abstract: An outboard motor having an intake silencing box provided above a cylinder block in communication with combustion chambers is provided. The intake silencing box has left and right air induction passages located forwardly of exhaust passages and extending vertically downwardly between the exhaust passages and a skirt of a crankcase in a suspended fashion. The lower ends of the air induction passages open downwardly.

Abstract: In an intake system of a variable air-intake characteristic type for a multi-cylinder engine, an intake air-dispensing box is comprised of a dispensing box body which includes an intake air inlet, first and second intake branch pipes and one of halves of a partition wall and which has an opening provided in its outer wall opposite from the first and second intake branch pipes to extend between first and second dispensing chambers, and a lid detachably coupled to the dispensing box body to close the opening and having the other half of the partition wall. The lid is made of a light alloy by casting, and a valve bore and bearing bores for supporting a valve shaft of the on-off valve are defined in the other half of the partition wall. Thus, it is possible to carry out the maintenance of the on-off valve only by removing the lid disposed outside the intake air-dispensing box from the box, leading to an enhancement in maintenance property.

Abstract: To improve a freedom of layout within a narrow cowling of the outboard engine, achieve a reduction of manufacturing cost and an improvement of a maintenance performance of a filter member, a fuel supply apparatus in an outboard engine is structured such that fuel within a fuel tank is supplied into a vapor separator (V) via a low pressure fuel pump, the fuel stored within the vapor separator (V) is pressurized by a high pressure fuel pump (P) and is supplied to a fuel injection valve via a filter, a pump case (10) receiving the high pressure fuel pump (P) is arranged in a side portion of the vapor separator (10), an upper opening thereof is fixed by a cover member (14), a fuel discharge passage (15) connected to a pump discharge passage (PB) of the high pressure fuel pump (P) and a filter receiving recess portion (16) connected to the fuel discharge passage (15) are formed in the cover member (14), and a filter member (17) is detachably arranged in the filter receiving recess portion (16).

Abstract: In fuel rail/fuel conduit connecting structure in an engine for an outboard engine system, a first connecting bore opens into an end face of a fuel rail, and a second connecting bore opens into an end face of a terminal member having a connecting pipe portion which is projectingly provided on one side thereof and to which an end of the fuel conduit is connected. One of halves of a joint collar is fitted to an inner peripheral surface of the first connecting bore with a first seal member interposed therebetween, and the other half of the joint collar is fitted to an inner peripheral surface of the second connecting bore with a second seal member interposed therebetween. Thus, it is possible to connect the fuel rails and the fuel conduits to each other, while providing reduction in number of parts and number of assembling steps for the connecting structure and moreover, the connecting structure is excellent in corrosion resistance.

Abstract: An air intake muffler has an enclosure having a longitudinal axis, a first portion, and a second portion defining with the first portion an interior space of the enclosure. An air intake connecting duct is formed unitarily with the first portion of the enclosure and extends outwardly from the interior space of the enclosure. A pair of outside air intake ducts for introducting outside air into the interior space of the enclosure diverge in a V-shaped configuration from the longitudinal axis of the enclosure. Each of the outside air intake ducts has a pair of mating concave portions each formed unitarily with a respective one of the first and second portions of the enclosure and extending outwardly from the interior space of the enclosure.

Abstract: An engine intake manifold is provided that can prevent fuel loss by promptly supplying to an engine the fuel that has collected on the base within an intake air distribution box. The engine intake manifold includes an intake air distribution box having an intake inlet, and a plurality of intake branch pipes made of a synthetic resin that are provided in a vertical arrangement connected to a side wall of the intake air distribution box with downstream ends connected to a plurality of corresponding intake ports of the engine. A funnel is formed at the upstream end of each of the intake branch pipes disposed within the intake air distribution box. A fuel collector recess is formed on the base of the intake air distribution box. A fuel draw-up hole communicating with the recess, is provided in a side wall of the lowest funnel.

Abstract: In an intake manifold of an internal combustion chamber comprising a surge tank assembly and intake pipe assembly, a seal member is interposed between the end surface of the intake pipe assembly and the mating surface of the surge tank assembly so as to seal off the intake passage and mounting holes individually. Thus, the seal member, combined with the use of the blind threaded holes for the threaded bolts joining the two parts, ensures the sealing of both the intake passages and mounting holes at the interface between the end surface of the intake pipe and the mating surface of the surge tank assembly in a both reliable and simple manner. Preferably, the seal member comprises an O-ring made of elastomeric material, and at least one of the mating surface and end surface is provided with a groove for receiving the seal member.

Abstract: An outboard motor auxiliary fuel tank/fuel pump assembly includes an auxiliary fuel tank disposed in an engine compartment and a fuel pump joined to one side of the auxiliary fuel tank for supplying fuel stored within the auxiliary fuel tank to fuel injection valves of an engine. A float of a float valve provided within the auxiliary fuel tank is supported in the auxiliary fuel tank via a pivot shaft that is parallel to a tilt shaft of an outboard motor. First and second mounting bosses on which the fuel pump can be mounted are formed on the right side face and the front end face of the auxiliary fuel tank.