An outboard motor engine has a cylinder block including vertically stacked cylinders divided into two cylinder banks arranged in a V-shape. Two cylinder heads define intake passages, each intake passage corresponding to a respective cylinder. Air intake manifolds include air intake runners that extend from an opposite end of the engine, around outer sides of the cylinder block, and respectively connect to the intake passages. Two vertically extending fuel rails are respectively located between the first cylinder head and the first air intake manifold and between the second cylinder head and the second air intake manifold. The fuel rails are integral with either the respective cylinder heads, or the respective air intake manifolds. Fuel injectors are coupled to the fuel rails and vertically spaced from one another with respect to each fuel rail such that each fuel injector is associated with a respective cylinder.

A personal watercraft includes a rider operation member operated by a rider to be movable to an acceleration position for providing a forward movement command, a deceleration position for providing a rearward movement command, and a neutral position for providing an idling command, the neutral position being set to a position between the acceleration position and the deceleration position. The first operation section protrudes forward of an axis of the grip and the second operation section protrudes rearward of the axis of the grip. The first operation section and the second operation section are provided on an inner side of the grip, and the tip end of the second operation section is located inward of the tip end of the first operation section in a rightward and leftward direction. The upper end of an operation surface of the second operation section is located below the grip.

An outboard motor including an internal combustion engine for propelling a ship is equipped with an air-guiding system using a covering hood surrounding surfaces of the internal combustion engine and auxiliary units. The covering hood is provided with airflow inlet and outlet openings in its interior, and a fan driven by the internal combustion engine influences airflows in the covering hood. An air-guiding system includes channeling devices for partial air flows. First partial air flows are fed as intake air to an engine intake system, and second partial air flows act, with the aid of the fan, on surfaces of the internal combustion engine and the auxiliary units heated by operation of the internal combustion engine. The heated airflows are conveyed by the fan and a third channeling device as exhaust air via an outlet opening in the covering hood outside of the covering hood or into the atmosphere.

A personal watercraft includes a rider operation member operated by a rider to be movable to an acceleration position for providing a forward movement command, a deceleration position for providing a rearward movement command, and a neutral position for providing an idling command, the neutral position being set to a position between the acceleration position and the deceleration position. The first operation section protrudes forward of an axis of the grip and the second operation section protrudes rearward of the axis of the grip. The first operation section and the second operation section are provided on an inner side of the grip, and the tip end of the second operation section is located inward of the tip end of the first operation section in a rightward and leftward direction. The upper end of an operation surface of the second operation section is located below the grip.

An outboard motor includes an internal combustion engine and a cowl covering the engine. An air vent allows intake air into the cowl, an air intake duct routes the intake air from the air vent to the engine, and a throttle body meters flow of the intake air from the air intake duct into the engine. A sound enhancement device is located proximate the throttle body. A sound duct is provided, and has an inlet end located proximate the sound enhancement device and an outlet end located proximate an outer surface of the cowl. The sound enhancement device is tuned to amplify a first subset of sounds having a desired frequency that are emitted from the throttle body, and the sound duct transmits the amplified sounds to an area outside the cowl. A method for modifying sounds produced by an air intake system of an outboard motor is also provided.

A jet propelled watercraft includes a watercraft body, an engine mounted on the watercraft body, an air intake box configured to supply air to the engine, and a mounting portion provided on the air intake box. The air intake box is disposed opposite to the engine. An electrical device is mounted on a front surface and a right surface of the air intake box, which are different from the surfaces of the air intake box that oppose the engine. The electrical device is removably mounted on the mounting portions without using an implement such as a tool.

An outboard motor includes: an upper case supported on a hull; a lower case pivotably supported on the upper case; a first drive source disposed within the upper case; a planetary gear mechanism connected to the first drive source via an upper drive shaft; a propeller shaft connected to the planetary gear mechanism via a lower drive shaft; and a second drive source that provides the lower case with a torque. The planetary gear mechanism includes a sun gear, a planetary carrier supporting planetary gears and connected to an upper end of the lower drive shaft, and an internal gear. One of the sun gear and the internal gear is connected to the lower end of the upper drive shaft, and the other is connected to the lower case to provide the lower case with a torque in a direction opposite to a rotation direction of the lower drive shaft.

An intake manifold includes: a surge tank, die-molded to temporarily store intake air; and branch pipes, in communication with the surge tank. The surge tank includes, on an outer wall thereof, a flange part and a reinforcement rib, a sensor unit configured to detect an intake air state quantity being installed to the a part. The flange part includes: a fitting hole, having an axis as a center to be fit with a detection part of the sensor unit; and boss parts, provided on a periphery of the fitting hole, and the flange part is formed to be rotationally symmetric with the axis as a center. The reinforcement rib includes a limitation piece interfering with a portion of the sensor unit to limit assembling at a time when the sensor unit is assembled erroneously for being deviated from a normal orientation.

An intake manifold 2 suitable for an engine includes: a surge tank 100, die-molded to temporarily store intake air; and a plurality of branch pipes 211, 212, 213, 311, 312, 313, in communication with the surge tank. The surge tank 100 includes: a boss part 111, having a cylindrical shape; and boss reinforcement ribs 114, extending in a direction toward a center S of the boss part and connected with the boss part, the boss part and the boss reinforcement ribs being integrally formed on an outer wall of the surge tank.

To provide a compact intake manifold which can easily and reliably hold the flame arrester (25) to the base member, the base member (21) having the flame arrester (25) incorporated therein has the recessed body portion (31) and the annular fitting holding portion (32) for fitting the flame arrester (25) in the axial direction. The fitting holding portion (32) includes an abutment surface (32a) and a fitting inner wall peripheral surface (32b). The flame arrester (25) includes a flame suppressing structure (26), an outer cylinder body (27) surrounding the flame suppression structure (26), and an elastic holder member (51) which covers the outer peripheral surface and both end faces of the outer cylindrical body (27). The elastic holder member (51) has an outer peripheral fitting portion (52) fitted to the fitting holding portion (32) while being held in close contact with the outer cylindrical body (27).