Abstract: An intake system in a V-type 4-stroke engine for an outboard engine system is provided. A crankshaft of the engine is disposed vertically, and heads of left and right banks are disposed to face rearwards. The engine is covered with an engine hood. In the intake system, an intake air inlet is provided in an upper portion of a longitudinally flat intake air dispensing box disposed between the left and right banks and a rear wall of the engine hood, and leads to an intake passageway in a throttle body. The inside of the intake air dispensing box is divided by a partition wall into first and second dispensing chambers communicating with the intake air inlet and extending longitudinally. An on-off valve is mounted on the partition wall and is capable of bringing the first and second dispensing chambers into and out of communication with each other. Intake ports are provided in the left and right banks to communicate with the first and second dispensing chambers, respectively.

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 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: An outboard motor is provided which includes, in an engine compartment defined by an engine hood, an engine, an intake manifold including a plurality of intake branch pipes connected to a plurality of intake ports of the engine, and a throttle body connected to an intake inlet of the intake manifold. A negative pressure detection hole that opens within the intake manifold, is provided in the outer wall of the intake manifold, and a negative intake pressure sensor that is fixed to the outer wall is positioned in the negative pressure detection hole.

Abstract: An outboard motor includes an engine, a throttle valve connected to an inlet air silencer, and an intake manifold connected to a downstream portion of the throttle valve. A control valve is provided between a downstream portion of an intake passageway of the throttle valve and an upstream portion of the intake manifold, for controlling air supply in the low-speed driving of the engine. The control valve has a body formed with an intake passageway. The intake passageway of the body communicates in series with the intake passageway of the throttle valve.

Abstract: An outboard motor includes an engine, an induction silencer disposed above the engine, a throttle valve device disposed adjacent the induction silencer, an intake manifold disposed adjacent the throttle valve device, an engine cover for covering the engine, the induction silencer, the throttle valve device, and the intake manifold, and a control cable for opening and closing a throttle valve of the throttle valve device. The induction silencer includes a connecting port communicating with an upstream portion of the throttle valve device. The throttle valve device has a downstream portion communicating with an upstream portion of the intake manifold. The control cable includes a first cable portion extending over an upper surface of the induction silencer.

Abstract: A box-shaped air intake muffler wherein upper and lower separate dish-shaped two halves mated and joined to one another. One of the halves unitarily has an air intake connecting duct to be connected to an air intake passage of a throttle valve unit of an engine. Both of the two halves have concave portions unitarily formed therewith so as to protrude outward, respectively, with respective concave portions being mated with one another to form an outside air intake duct for introducing outside air.

Abstract: A cover structure (50) in an outboard engine (1) having an engine (2) with an engine block (8), a vertical crankshaft (7) and a vertical camshaft (15) having upper end portions projecting upward from the engine block, a timing belt (17) extended between upper ends of the crankshaft and the camshaft, and a flywheel (12a) disposed on the upper end portion of the crankshaft (7). The ventilation cover structure (50) comprises a first cover (60) disposed above the engine block (8) so as to cover at least the flywheel (12a) and opening downward, and a second cover disposed above the engine block (8) so as to cover a space extending over a portion of the engine block (8) including the camshaft (15) and opening downward. The first and the second covers (60, 80) are joined together so that spaces covered with the first and the second covers (60, 80) are united in a single space.

Abstract: An outboard engine system includes a 4-cycle engine. The engine includes an engine block, a cylinder head coupled to the engine block and having an intake port in one side thereof, a carburetor including a carburetor body disposed on one side of the engine block adjacent the intake port and having an intake passageway, and a bypass-type starting device mounted to the carburetor body, and an intake pipe means which connects the intake passageway and the intake port to each other. At least an upper half of the engine including the carburetor is covered with an engine cover. In such outboard engine system, the bypass-type starting device of the carburetor is mounted to the carburetor body between the intake passageway and the engine block.

Abstract: An outboard motor is provided, the motor including a V-multicylinder engine arranged horizontally and an intake silencer arranged above the engine. The V engine has an engine block including cylinder blocks extending in a V configuration, forming an opening to the rear of the outboard motor. The intake silencer is arranged above the engine block to match the shape of the V engine. The intake silencer has two inlets opening rearwards of the outboard motor and one outlet positioned between the inlets for introducing air to combustion chambers of the cylinder heads. The two inlets are positioned above the cylinder blocks in a V configuration, respectively.

Abstract: In an outboard engine system in which a passage defining member having a passage wall defining an exhaust gas passage for guiding an exhaust gas from an engine is provided at its outer wall with a recess and a seal surface surrounding the recess; a fluid passage isolated from the exhaust gas passage is defined between the recess and a lid member which is mounted to the outer wall of the passage defining member with a seal member interposed between the lid member and the seal surface; and an exhaust gas sampling pipe is inserted into the exhaust gas passage through an insertion bore provided in the passage defining member to open into the seal surface, it is arranged that the seal member is formed to surround an opening at an outer end of the insertion bore, and the exhaust gas sampling pipe is gas-tightly fixed in the lid member to extend through the lid member. Thus, the exhaust gas sampling pipe can be inserted into the exhaust gas passage, while avoiding an increase in size of the lid member.

Abstract: In an outboard engine system in which a passage defining member having a passage wall defining an exhaust gas passage for guiding an exhaust gas from an engine is provided at its outer wall with a recess and a seal surface surrounding the recess; a fluid passage isolated from the exhaust gas passage is defined between the recess and a lid member which is mounted to the outer wall of the passage defining member with a seal member interposed between the lid member and the seal surface; and an exhaust gas sampling pipe is inserted into the exhaust gas passage through an insertion bore provided in the passage defining member to open into the seal surface, it is arranged that the seal member is formed to surround an opening at an outer end of the insertion bore, and the exhaust gas sampling pipe is gas-tightly fixed in the lid member to extend through the lid member. Thus, the exhaust gas sampling pipe can be inserted into the exhaust gas passage, while avoiding an increase in size of the lid member.

Abstract: An outboard engine system includes a case member which is disposed below an engine body and integrally provided with an oil pan opening upwards, and a passage wall extending vertically to define an exhaust gas passage through which an exhaust gas flows. A portion of an outer wall of the case member is formed by the passage wall, and a recess is provided in the outer wall of the case member with a portion of the passage wall facing the recess. The recess is covered with a plate member fixed to the outer wall of the case member, and a cooling water passage, through which cooling water flows, is defined between the plate member and the recess. Thus, the passage wall integral with the oil pan is cooled effectively, while avoiding increases in size and weight.

Abstract: A cover structure (50) is incorporated into an outboard engine (1) having an engine (2) placed in an engine room (6) defined by a cowling (5) and an under cover (4) and having an engine block (8), a vertical crankshaft (7) having an upper end portion projecting upward from the engine block (8), a vertical camshaft (15) having an upper end portion projecting upward from the engine block (8), a camshaft driving pulley (11) mounted on the upper end portion of the crankshaft (7), a camshaft pulley (16) mounted on the upper end portion of the camshaft (15), and a timing belt (17) extended between the pulleys (11, 16), and a flywheel (12a) disposed above the camshaft driving pulley (11) on the upper end portion of the crankshaft (7).

Abstract: An outboard engine system includes a 4-cycle engine. The engine includes an engine block, a cylinder head coupled to the engine block and having an intake port in one side thereof, a carburetor including a carburetor body disposed on one side of the engine block adjacent the intake port and having an intake passageway, and a bypass-type starting device mounted to the carburetor body, and an intake pipe means which connects the intake passageway and the intake port to each other. At least an upper half of the engine including the carburetor is covered with an engine cover. In such outboard engine system, the bypass-type starting device of the carburetor is mounted to the carburetor body between the intake passageway and the engine block.

Abstract: A small and light decompression device of a four-stroke-cycle engine which cancels decompression operation surely when the engine rotational speed exceeds a predetermined speed to enable a stable engine starting. The device comprises an axial hole formed in a cam shaft, an oil pressure chamber formed in the axial hole, a decompression shaft reciprocating in accordance with oil pressure in the oil pressure chamber, a decompression pin which drives an exhaust valve to open in the compression stroke when the decompression shaft positions at a first position and stops the opening drive of the exhaust valve when the decompression shaft positions at a second position, a weight rotating in accordance with the engine rotational speed, and an oil pressure control valve interlocked with the weight to open and close a leak hole for controlling oil pressure in the oil pressure chamber.

Abstract: In an outboard marine drive, the engine is received in an under case, and is closed by both a fan cover and an engine cover so that the engine may be entirely covered by the engine cover jointly with the under case for a favorable aesthetic effect. However, the fan cover covers the engine closely in cooperation with the under case so that a narrow air passage is defined around the engine, and cooling air of high velocity can be continuously passed around the engine. Thus, according to the present invention, no part of the engine is exposed, but the fan cover surrounding the engine defines an appropriate gap around the engine for effectively guiding cooling air around the engine.

Abstract: In an outboard marine drive including a vertically oriented engine, a disk member is attached to a lower end of the crankshaft of the engine, and the upper end of the drive shaft is disposed coaxially with respect to the crankshaft and at a prescribed distance from the disk member so that a direct coupling member and an centrifugal clutch device may be interchangeably installed between them. The disk member is provided with axial holes for either pivotally supporting clutch shoes or fixedly attaching the upper end of the direct coupling member. The lower end of the direct coupling member and the clutch drum of the centrifugal clutch device are provided with an identical coupling arrangement for coupling with an upper end of the drive shaft.