An air intake passage structure includes an outer cover forming an outer wall of an outboard motor, an inner cover disposed inside the outer cover, a first intake port formed in the outer cover, a second intake port formed in the inner cover, an air introduction chamber formed between the outer cover and the inner cover; and an air passage formed inside the outer cover. The air passage includes a first passage part on an upper side of the air introduction chamber, and a second passage part extending downward from the first passage part. The air introduction chamber includes a side portion communicating with the first intake port, and a top portion communicating with the first passage part through an opening formed in the partition wall.

This outboard machine has: a V-type engine (engine) in which a plurality of cylinders are arranged in a V-shape when viewed in a plan view; and a cover that covers the engine. The engine has a plurality of intake ports that form pairs in a V-shape inside the plurality of cylinders in a plan view and a concave space is formed between the plurality of intake ports. The cover has therein an intake path that guides air to the intake port, and is also provided with, at a position that is adjacent to the intake path and enters the concave space, a silencer that attenuates the sound during intake.

An outboard motor, including an engine having a cylinder containing a combustion chamber, an intake pathway connected to the combustion chamber, a piston disposed in the cylinder, a crankshaft connected to the piston, a fuel injection device connected to the intake pathway, and an ignition device connected to the combustion chamber. The outboard motor further includes a controller that is configured to receive a signal indicating an engine speed from a sensor, control the fuel injection device to suspend fuel supply and control the ignition device to suspend ignition, upon determining that the engine is in an over-revolution state, control the fuel injection device to release the suspension of the fuel supply upon determining that the engine has recovered from the over-revolution state, and control the ignition device to release the suspension of the ignition after lapse of a number of cycles of the engine since the release of the suspension of the fuel supply.

A marine engine has a crankcase containing lubricant; an intake plenum for conveying intake air for combustion in the marine engine; and a cooling apparatus located between the crankcase and the intake plenum. The cooling apparatus is configured to cool both the lubricant in the crankcase and the intake air in the intake plenum.

A marine outboard motor is provided with an internal combustion engine comprising an engine block defining at least one cylinder, an air intake configured to deliver a flow of air to the at least one cylinder; and an air intake duct forming part of an air intake path for delivering the flow of air to the air intake. The engine further includes a flow sensing arrangement located in the air intake duct and comprising a flow meter configured to generate a signal indicative of a flow rate of the flow of air through the air intake duct, and a bluff body located in the air intake duct upstream of the flow meter, wherein the flow meter is a vortex shedding flow meter.

An outboard motor, including an engine having a cylinder containing a combustion chamber, an intake pathway connected to the combustion chamber, a piston disposed in the cylinder, a crankshaft connected to the piston, a fuel injection device connected to the intake pathway, and an ignition device connected to the combustion chamber. The outboard motor further includes a controller that is configured to receive a signal indicating an engine speed from a sensor, control the fuel injection device to suspend fuel supply and control the ignition device to suspend ignition, upon determining that the engine is in an over-revolution state, control the fuel injection device to release the suspension of the fuel supply upon determining that the engine has recovered from the over-revolution state, and control the ignition device to release the suspension of the ignition after lapse of a number of cycles of the engine since the release of the suspension of the fuel supply.

An intake manifold is connected to a cylinder head, and extends backward therefrom. An injector is attached to either the cylinder head or the intake manifold. At least one of the cylinder head and the intake manifold includes a curve pipe portion shaped to curve backward from a lateral surface of the cylinder head. An injector is attached to the cylinder head at either an outer lateral surface of the curve pipe portion in a right-and-left direction of an outboard motor or a position located forward of the curve pipe potion.

An intake manifold is connected to a cylinder of an engine, and extends backward from the cylinder. A throttle body is attached to the intake manifold. As seen in a plan view of an outboard motor, the throttle body is disposed backward of a head cover, while being disposed inward of a lateral end of the intake manifold in a right-and-left direction of the outboard motor.

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).

A marine outboard motor is provided with an internal combustion engine comprising an engine block defining at least one cylinder, an air intake configured to deliver a flow of air to the at least one cylinder; and an air intake duct forming part of an air intake path for delivering the flow of air to the air intake. The engine further includes a flow sensing arrangement located in the air intake duct and comprising a flow meter configured to generate a signal indicative of a flow rate of the flow of air through the air intake duct, and a bluff body located in the air intake duct upstream of the flow meter, wherein the flow meter is a vortex shedding flow meter.