An outboard motor includes an engine and a plurality of fuel supply mechanisms each including a suction pump to suck in liquid fuel stored in a fuel tank in a hull, a vapor separator tank to store liquid fuel sucked in by the suction pump and separate the liquid fuel and vapor, and a supply pump to supply the liquid fuel stored in the vapor separator tank to the engine.

The present invention relates to a drive system for outboard motors. The drive system comprises a combustion engine having a crankshaft adapted to rotate about a substantially vertical axis. The combustion engine further comprises a camshaft extending parallel to the vertical crankshaft. A high pressure fuel pump is provided for supplying high pressure fuels to the combustion cylinders. The high pressure fuel pump is directly driven by the camshaft.

An outboard motor unit includes a first outboard motor including a supercharger that is located inside a first cowling and supplies compressed air to a first engine, a second outboard motor including a second cowling and a second engine housed in the second cowling, and an air passage through which the air compressed by the supercharger of the first outboard motor is supplied to the second engine of the second outboard motor.

An outboard motor includes a vapor separator tank, a downstream fuel supply path, a fuel pump that discharges a fuel in the vapor separator tank into the downstream fuel supply path, a downstream bypass path, and a downstream relief valve provided in the downstream bypass path. A first end of the downstream bypass path is connected to a downstream portion that is closer to the fuel injector than is the downstream check valve in the downstream fuel supply path, and a second end of the downstream bypass path is connected to an upstream portion between the downstream check valve and the vapor separator tank in the downstream fuel supply path. The downstream relief valve opens the downstream bypass path when a fuel pressure in a downstream region that is closer to the fuel injector than is the downstream check valve in the downstream fuel supply path exceeds a first predetermined value.

A marine propulsion unit is described. The marine propulsion unit allows for shallow, obstructed, or otherwise impeded operation of a vessel through a novel marine propulsion transfer unit that is, or can be, mechanically coupled to an outboard motor or other similar marine motor. A mount for raising and lowering the marine propulsion unit in a generally vertical direction allows for adjustment of operating depth of the marine propulsion unit to accommodate a wide range of operating conditions from shallow and obstructed water to traditional deep water operation.

An outboard motor includes an engine, a fuel tank, a fuel pathway, a fuel pump, and a controller. The engine includes a fuel injector. The fuel tank includes an internal space in which fuel is stored. The fuel pathway is connected to the fuel injector and the fuel tank. The fuel pump is disposed in the fuel pathway, and supplies the fuel from the fuel tank to the fuel injector. The controller controls the fuel pump. The controller determines whether or not a start condition, indicating that air has entered the fuel pathway, is satisfied. The controller is configured or programmed to execute an air releasing control to open the fuel injector and drive the fuel pump when the start condition is satisfied.

An outboard motor includes a shift switch including a shift shaft and a rotary drive provided on an axis of the shift shaft and that rotates the shift shaft, and that switches a rotation direction of a propeller shaft. An entirety of the rotary drive is disposed below a mount, and at least a portion of the rotary drive is disposed above a lower case.

A trim-tilt device includes a first electric motor electrically connected to a power source and tilts an outboard motor body in an up-and-down direction. A steering device includes a second electric motor electrically connected to the power source. The steering device turns the outboard motor body in a right-and-left direction. A fuel pump is electrically connected to the power source, and supplies fuel to an engine. A controller limits an inrush current into the first electric motor using a PWM control for a predetermined period of time from a starting time point of an input current into the first electric motor.

Provided is an outboard motor raising and lowering apparatus that is capable of automatically changing the speed of raising/lowering of an outboard motor according to the status of the outboard motor. An outboard motor raising and lowering apparatus (1) includes: a first fluid passage that connects a pump (42) and a lower chamber(s) of one or more tilt cylinders (14); a second fluid passage that connects the first fluid passage and a lower chamber(s) of one or more trim cylinders (12); a switching valve (60) provided at the second fluid passage; and a control section (100) configured to control the switching valve (60) with reference to a watercraft status signal.

A valve for a marine propulsion unit comprises a valve body (11) having an end face (13) and a wall (14) extending from the end face. An aperture (15) is defined in the end face. A valve stem (12) is moveable within and with respect to the valve body, such that, in the closed state of the valve, the valve stem closes the aperture. A maximum width (d.sub.1) of the valve stem is greater than the width (d.sub.2) of the aperture in the end face of the valveso that, if the valve stem should fracture, the detached portion(s) of the valve stem will be retained in the valve body. The valve may for example be used as a cylinder drain valve in a marine propulsion unit.