An outboard motor includes a propeller shaft, a lower case, an upper case, and a splash guard. The lower case houses the propeller shaft. The upper case is located above the lower case. The splash guard includes an upper plate that projects forward from the upper case. The splash guard is separate from the upper case and is attached to the upper case.

A marine engine has a powerhead, a crankcase and a crankshaft disposed in the crankcase. A cooling system has a cooling passage that conveys cooling water for cooling the crankcase, a pump that pumps the cooling water from a body of water in which the marine engine is operated through the cooling passage, and a valve that controls discharge of the cooling water from the cooling passage.

Provided herein is a marine propulsion apparatus including a prime mover having a drive shaft, a cowling enclosing the prime mover, first and second struts affixed to the cowling, where each of the struts have a leading portion, an interior belt void, and a trailing portion. The apparatus further includes a lower unit coupled to the distal ends of the struts, a sprocket rotatably disposed within the lower unit, a shaft rotatably coupled to the sprocket, a belt rotatably coupling the drive shaft to the sprocket, such that a first portion of the belt is disposed within the interior belt void of the first strut and a second portion of the belt is disposed within the interior belt void of the second strut. The apparatus further includes a thermal circuit (having a heat transfer fluid) extending from the cowling, through each of the struts, and into the lower unit.

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.

An outboard motor includes a shaft including a second spline that upwardly extends from a housing. The second spline is meshed with a first spline disposed inside either an engine cowl or an upper housing. The second spline includes a distal end and a body. The distal end is provided on an upper end of the shaft. The body is provided below the distal end. In the second spline, a groove width in the circumferential direction at the distal end is larger than a groove width in the circumferential direction at the body.

A marine engine has a powerhead, a crankcase and a crankshaft disposed in the crankcase. A cooling system has a cooling passage that conveys cooling water for cooling the crankcase, a pump that pumps the cooling water from a body of water in which the marine engine is operated through the cooling passage, and a valve that controls discharge of the cooling water from the cooling passage.

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 lower unit for a marine propulsion device includes a gearcase housing defined along a longitudinal center axis between a fore end and an aft end. A propulsor shaft extends through the gearcase housing along the longitudinal axis. A driveshaft extends non-parallel to the propulsor shaft and rotates in a direction of rotation when powered by an engine. The driveshaft is coupled in torque-transmitting relationship with the propulsor shaft. A skeg projects from a bottom surface of the gearcase housing proximate at least the aft end thereof. The skeg or the gearcase housing is cambered such that a moment acting in a direction opposite the driveshaft's direction of rotation is induced on the skeg or the gearcase housing as the lower unit moves through water. A marine propulsion device is also disclosed.

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 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.