An outboard motor is for propelling a marine vessel in water and can be trimmed about a trim axis into and between a raised position in which the outboard motor is fully trimmed up out of the water and a lowered position in which the outboard motor is fully trimmed down into the water. The outboard motor has a hydraulic steering actuator for steering the outboard motor about steering axis and a reservoir mounted on the outboard motor and containing hydraulic fluid for the hydraulic steering actuator. A vent opening vents the reservoir to atmosphere and is located on top of the reservoir and closer to the back of the outboard motor than the front of the outboard motor so that the vent opening does not become covered by the hydraulic fluid when the outboard motor is trimmed into and out of the raised and lowered positions.

An outboard motor comprises an engine; an input driveshaft that is caused to rotate by the engine; an output driveshaft that extends parallel to and is laterally spaced apart from the input driveshaft; and a transmission that operatively connects the input driveshaft to the output driveshaft such that rotation of the input driveshaft causes rotation of the output driveshaft. The transmission is positionable into a forward gear in which forward rotation of the input driveshaft causes forward rotation of the output driveshaft, a reverse gear in which forward rotation of the input driveshaft causes reverse rotation of the output driveshaft, and neutral wherein forward rotation of the driveshaft does not cause rotation of the output driveshaft.

An outboard motor includes an electric motor, a drive shaft, a propeller, a propeller shaft, a cooling water flow path, a water pump including an impeller and a pump shaft, a first gear mechanism, and a second gear mechanism. The first gear mechanism includes a first gear to rotate together with the drive shaft and a second gear to mesh with the first gear and rotate together with the propeller shaft. The second gear mechanism includes a third gear, different from the first gear, to rotate together with the drive shaft, and a fourth gear to mesh with the third gear and rotate together with the pump shaft.

An outboard motor includes an upper case, a lower case including an oil reservoir chamber, an oil flow passage, and an oil flow passage shutoff valve. When the lower case is detached from the upper case, the oil flow passage is separated into an upper oil flow passage in the upper case and a lower oil flow passage in the lower case and connected to the oil reservoir chamber. The oil flow passage shutoff valve opens the lower oil flow passage in a state in which the lower case has been attached to the upper case. The oil flow passage shutoff valve closes the lower oil flow passage in a state in which the lower case has been detached from the upper case.

An outboard motor for a marine vessel application, transmission devices for such an outboard motor, and related methods of making, operating, and modifying attributes of same, are disclosed herein. In at least one embodiment, the motor includes a horizontal-crankshaft engine in an upper portion of the motor, positioned substantially above a trimming axis of the motor. In at least another embodiment, first, second and third transmission devices are employed to transmit rotational power from the engine to propeller(s). In at least a further embodiment, the motor is made to include a rigid interior assembly formed by the engine, multiple transmission devices, and a further structural component. In further embodiments, the motor includes numerous cooling, exhaust, and/or oil system components, and/or other transmission features. In at least some additional embodiments, a transmission device of the motor is configured to facilitate gear ratio variation and/or includes an integrated oil pump.

An outboard motor has an adapter plate with an upper surface supporting an engine, a lower surface spaced therefrom, and fore and aft sides connecting the upper and lower surfaces. A first pocket is defined in the adapter plate's fore side and a second pocket is defined in its aft side. A midsection housing is coupled to the adapter plate's lower surface and suspends a propulsion unit therebelow. A driveshaft coupling the engine's output shaft to the propulsion unit's propeller shaft extends through the adapter plate. A steering arm, which extends into the first pocket, has a hole through which the driveshaft extends. A mount in the second pocket is located aft of the driveshaft, and the mount's fore side is coupled to the steering arm's aft end by way of connectors. A cover plate attached to the adapter plate's aft side secures the mount within the second pocket.

The invention provides an internal combustion engine comprising a piston mounted for reciprocating linear motion within a cylinder along a cylinder axis. The piston is coupled to an output shaft by a power transfer assembly arranged to convert linear motion of the piston to rotary motion of the output shaft. The piston has a first head moveable within a first chamber and a second head opposite the first head and moveable within a second chamber. The power transfer assembly has a lubrication system for lubricating moving components of the power transfer assembly. The lubrication system is sealed from the first chamber and the second chamber to prevent the passage of fluid from the lubrication system into the first chamber and the second chamber.

An outboard motor having an internal combustion engine that causes rotation of a driveshaft, a planetary transmission that operatively connects the driveshaft to a transmission output shaft, a band brake configured to shift the planetary transmission amongst a forward gear, neutral gear and reverse gear, a hydraulic actuator is configured to actuate the band brake, and a cooling water circuit that extends adjacent to the hydraulic actuator so that the hydraulic actuator exchanges heat with cooling water in the cooling water circuit.

An outboard motor includes: a driveshaft housing configured to accommodate a driveshaft; and a gear case bulging laterally below the driveshaft housing and configured to accommodate a gear device, wherein an inside of the driveshaft housing communicates with an inside of the gear case, an introduction port for introducing lubricating oil into the gear case is opened on the driveshaft housing, and a confirmation port for causing the lubricating oil introduced into the gear case to flow out is opened on a front end side of the gear case.

An electric shift actuator is provided in an engine cover in which an engine of an upper unit is accommodated, a forward/reverse shift mechanism is provided in a lower unit, and a shift transmission mechanism including a clutch rod is provided to transmit driving force of the electric shift actuator to the forward/reverse shift mechanism by connecting the electric shift actuator with the forward/reverse shift mechanism, in which the clutch rod is disposed vertically in an intermediate unit on the rear side of a drive shaft that transmits driving force of the engine.