A fuel supply system includes a sub fuel tank, a booster pump, a fuel pipe, a fuel pressure sensor and a controller. The sub fuel tank stores a fuel supplied thereto from a main fuel tank. The booster pump is disposed inside the sub fuel tank. The fuel pipe has a returnless structure and supplies the fuel with a pressure increased by the booster pump to a fuel injection device of an engine. The fuel pressure sensor detects the pressure of the fuel inside the fuel pipe. The controller is configured or programmed to perform a feedback control of the booster pump based on a value of the pressure of the fuel detected by the fuel pressure sensor such that the pressure of the fuel inside the fuel pipe becomes greater than or equal to a first threshold.

An outboard motor includes an outboard motor body, a mount mounted on a boat body, and a support member that supports the outboard motor body so as to be steerable with respect to the mount. The support member includes an upper support that surrounds a drive shaft and supports the outboard motor body, a lower support that is spaced below the upper support, surrounds the drive shaft, and supports the outboard motor body, and a coupler that couples the upper support to the lower support.

An engine for an outboard motor is provided with an engine body, an intake system configured to supply combustion air to the engine body, an exhaust passage formed by connecting the engine body and the middle and lower units thereunder, a catalyst provided in the exhaust passage, and an air pump configured to supply secondary air to the upstream side of the catalyst. The air pump is driven by an electric motor.

A breather apparatus for an engine includes a breather chamber, one side portion and other side portion of the breather chamber, and a bottom face of the other side portion. The breather chamber is formed, along substantially half a circumference of a cylinder bore, in a cylinder block. The one side portion of the breather chamber is provided with a blow-by gas introduction hole leading blow-by gas in the crank chamber to the breather chamber and a one-way valve opening and closing the blow-by gas introduction hole. The other side portion of the breather chamber has a pipe connection hole connecting a breather pipe to the breather chamber and with a breather oil return passage. The bottom face of the other side portion projects into the crank chamber to a level lower than a bottom face of the one side portion.

A fuel supply system includes a sub fuel tank, a booster pump, a fuel pipe, a fuel pressure sensor and a controller. The sub fuel tank stores a fuel supplied thereto from a main fuel tank. The booster pump is disposed inside the sub fuel tank. The fuel pipe has a returnless structure and supplies the fuel with a pressure increased by the booster pump to a fuel injection device of an engine. The fuel pressure sensor detects the pressure of the fuel inside the fuel pipe. The controller is configured or programmed to perform a feedback control of the booster pump based on a value of the pressure of the fuel detected by the fuel pressure sensor such that the pressure of the fuel inside the fuel pipe becomes greater than or equal to a first threshold.

A fuel supply device that supplies fuel from an external tank to an engine includes a fuel injection, an internal tank, a first pipe, a second pipe, a first pump, a fuel supply quantity detection device, and a control device. The internal tank stores fuel to be delivered to the fuel injection device. The first pipe is linked to the internal tank and delivers fuel from the external tank to the internal tank. The second pipe is linked to the fuel injection device and delivers fuel from the internal tank to the fuel injection device. The fuel supply quantity detection device is attached to the first pipe and detects a quantity of fuel supplied from the external tank via the first pipe to the internal tank. The control device implements a predetermined control when the quantity of fuel detected by the fuel supply quantity detection device is below a threshold.

An intake structure of an outboard motor supplying intake air to an internal combustion engine for the outboard motor has an engine cover covering the internal combustion engine for the outboard motor, an inner cover disposed on an outside of the engine cover, and a top cover covering the inner cover. The inner cover and the top cover form an intake duct supplying intake air to the internal combustion engine for the outboard motor.

A vessel propulsion apparatus includes an engine that rotates a crankshaft in a forward rotation direction, a rotation speed detector that detects a rotation speed of the crankshaft, a propeller shaft coupled to a propeller, a shift switch that switches between a shift-in state and a neutral state, a shift state detector, an intake passage, a throttle valve, an intake pressure sensor, and a controller. The controller determines that the crankshaft is reversely rotating by an external force input from the propeller shaft when a predetermined reverse rotation recording condition is satisfied, and stores reverse rotation information. The reverse rotation recording condition includes a condition that an intake pressure after the shift switch switches from a neutral state to a shift-in state while the crankshaft rotates in the forward rotation direction is larger than a value equal to or higher than atmospheric pressure.

An air intake structure for an outboard engine wherein air which is taken in from an air intake opening provided in an engine cover for covering the upper part of the outboard engine is supplied to and sucked into a throttle body. The engine cover has an air intake opening which is open at the front of the outboard engine in the forward movement direction and a lid member which can open and close the air intake opening. A space which connects the air intake opening and the throttle body is provided separated from an engine room.

There is provided an intake apparatus of an engine for an outboard motor. An intake manifold, a throttle body and an intake silencer box are arranged at one of right and left sides of an engine block which is configured such that an axial direction of a cylinder coincides with a front and rear direction of the outboard motor. An intake duct communicating with an intake introduction port provided at an upper part of an engine cover is coupled to an upstream end of the intake silencer box. A first water separation part is arranged between the intake introduction port and the intake duct. A second water separation part is provided below a duct part of the intake duct. The second water separation part is formed by providing a drain hole at a bottom part of a resonator chamber part communicating with the duct part to reduce an intake noise.