A propulsion apparatus includes a screw, a unit case, an anti-cavitation plate, a heat generation portion, and a cooling liquid passage. The screw is submerged in outside water and generates a propulsion force. The unit case accommodates at least a power transmission mechanism which transmits power from a drive source to the screw. The anti-cavitation plate is arranged on the unit case at a higher position than the screw, and at least part of the anti-cavitation plate is submerged in outside water. The heat generation portion is arranged at an inside or an outside of the unit case. The cooling liquid passage causes a cooling liquid to flow to the heat generation portion. Part of the cooling liquid passage is arranged within the anti-cavitation plate.

A marine propulsion apparatus including a first strut and a second strut, each extending from a proximal end to a distal end, wherein the proximal ends of the first and second struts are coupled to an anti-ventilation plate, a lower unit coupled to the distal ends of the first strut and the second strut, the lower unit the lower unit housing a sprocket, a shaft rotatably coupled to the sprocket, a propeller coupled to the shaft proximate the tail portion of the lower unit, the propeller configured to rotate with the shaft, a belt rotatably coupling the drive shaft to the sprocket, wherein the belt is disposed within the interior belt voids of the first and second struts; and at least one thermal circuit channel extending through a portion of the anti-ventilation plate, the at least one thermal circuit configured to channel a coolant to flow therethrough.

An outboard motor having an internal combustion engine that rotates a driveshaft disposed in a driveshaft housing, a transmission that is operatively connected to the driveshaft and is disposed in a transmission housing located below the driveshaft housing, a set of angle gears that operatively connect the transmission to a propulsor for imparting a propulsive force in a body of water, wherein the set of angle gears are located in a lower gearcase located below the transmission housing, and a lubrication system that circulates lubricant to and from the transmission.

In one embodiment, an electric outboard motor includes a motor casing in which an electric motor and a propeller shaft are accommodated; a shaft configured to connect the motor casing to an operation handle; a fixing member configured to fix the shaft to a hull; and a shaft adjuster provided on the shaft and configured to adjust distance between the motor casing and the fixing member.

An outboard motor and methods of use thereof in general, includes a powerhead removeably affixed to the transom of a boat, and a gear case rotationally connected to a propeller shaft, the outboard motor including a telescopic drive shaft, the telescopic drive shaft having a first drive shaft section rotationally connected to the motor and a second drive shaft section rotationally connected to the gear case, and a telescopic drive shaft housing, the telescopic drive shaft housing configured to support the telescopic drive shaft internally therethrough, whereby the telescopic drive shaft and the telescopic drive shaft housing are configured to provide depth adjustment for the gear case and the propeller shaft, and thus enable the propeller to be raised and lowered during propulsion to improve propulsion efficiency.

A method is for making a marine drive for propelling a marine vessel in water. The method includes providing a gearcase; installing a propeller shaft assembly that extends forwardly from the gearcase; coupling front and rear propellers to the propeller shaft assembly, forwardly of the gearcase, such that rotation of the propeller shaft assembly causes rotation of the front and rear propellers, respectively, which thereby propels the marine vessel in the water; and reducing deleterious effects of cavitation on the gearcase by the combination of forming the gearcase with a wide trailing end portion, in particular to maintain pressure alongside the gearcase, and configuring the front and rear propellers so that the front propeller absorbs more torque/thrust load than the rear propeller during said rotation.

A cowling for an outboard motor has port and starboard intake ports that direct flow of intake air into the cowling and extend downwardly along the aftward side of the cowling and face laterally outwardly. A duct system receives and conveys intake air intake ports to an intake conduit for the outboard motor. The duct system includes port and starboard intake troughs that extend alongside the intake ports and redirect the intake air from a generally lateral flow into the intake ports to a generally vertically downward flow and then to a generally forward flow towards the intake conduit. Port and starboard baffles that extend alongside the intake ports and direct flow of water into port and starboard channels located alongside the baffles, respectively. The channels drain the water by gravity depending on tilt and trim orientation of the outboard motor.

An outboard motor includes a shift rod including a first rod, a second rod, and a joint. The first rod extends in a vertical direction. The second rod extends in the vertical direction and is located below the first rod. The second rod is disposed eccentrically with respect to the first rod. When viewed in a plan view, the second rod overlaps with at least a portion of the first rod or is in contact with the first rod. The joint connects the first rod to the second rod.

An outboard motor includes a mount on which an engine is mounted, an engine cover, and a sealing structure. The engine cover is divisible into a top portion, a front bottom portion, and a side bottom portion. A first seal in the sealing structure integrally includes a first portion, a second portion, and a third portion. The first portion seals the boundary between the top portion, the front bottom portion, and the side bottom portion. The second portion seals the boundary between the front bottom portion, the mount, and the side bottom portion. The third portion seals the boundary between the front bottom portion and the side bottom portion.

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.