An outboard motor stabilizer of unitary construction has a cylindrical body and an axially oriented cylindrical orifice with an opening at the bottom end of the body. The orifice has a diameter sized to fit onto a tilt rod of an outboard motor and is of a length that is longer than the tilt rod of the outboard motor.

An outboard motor includes an engine, a pressure charger, an intercooler, a bypass air passage, and an air bypass valve to open and close the bypass air passage. The engine includes a cylinder block and an air intake passage and an exhaust passage both of which are connected to the cylinder block. The pressure charger is located in the air intake passage. The intercooler is located in the air intake passage between the cylinder block and the pressure charger. A first end of the bypass air passage is connected to a region of the air intake passage upstream of the pressure charger. A second end of the bypass air passage is connected to a region of the air intake passage downstream of the pressure charger. The air bypass valve is directly attached to the intercooler.

A cowling for an outboard motor extends from port side to starboard side in a lateral direction. The cowling includes port and starboard inlets that direct flow of intake air into the cowling and face outwardly in the lateral direction. The cowling further comprises port and starboard duct systems. Each duct system is configured to receive and convey intake air from one of the port and starboard intake ports to an intake conduit for the outboard motor. Each duct system defines a first separation region that receives and conveys the intake air laterally outward to separate a first portion of water from the intake air. Each duct system further defines a second separation region that receives and conveys the intake air from the first separation region laterally inward to separate a second portion of water from the intake air.

A watercraft propulsion system includes a propulsion unit to be driven by an engine. The engine includes a cylinder block, an air intake channel, an exhaust channel, a supercharging device, and a fuel injector. The watercraft propulsion system includes the engine, the propulsion unit to be driven by the engine, a rotation speed sensor to detect a rotation speed of the engine, an air intake pressure sensor to detect an air intake pressure of the engine, and a controller. The controller is configured or programmed to compute a command fuel injection amount so that the engine performs a combustion operation at an air/fuel ratio in a lean-burn range (lean-combustion range) according to the rotation speed detected by the rotation speed sensor and the air intake pressure detected by the air intake pressure sensor, and to drive the fuel injector based on the computed command fuel injection amount.

A system for flushing a cooling water pathway of a marine propulsion device with water supplied from a water source includes a water control device and a controller. The water control device is connected to the water source and the cooling water pathway of the marine propulsion device. The controller controls and causes the water control device to supply the water from the water source to the cooling water pathway so as to perform the flushing. The controller obtains propulsion device data including at least one of a pressure of the water, a flow rate of the water and a concentration of salt contained in the water in the cooling water pathway. The controller determines whether or not to stop a supply of the water by the water control device based on the propulsion device data.

An intake manifold which can ensure a pressure resistance strength, a mechanical strength, and the like and also reduce a passage resistance and an outboard motor which can be made smaller and thinner in a width direction. A resinous intake manifold made of a resin and configured to be applied to an engine of an outboard motor includes: a surge tank which forms a flat contour and includes an intake inlet; and a plurality of branch pipes which defines intake passages communicating with an internal space of the surge tank, wherein a contour wall of the surge tank includes a plurality of ridge portions which protrudes toward the internal space and is oriented toward the intake passage side.

A cooling system for an outboard motor of a marine vessel is provided. The cooling system includes an oil sump housing having an inner housing wall and an outer housing wall. The inner housing wall defines a transmission mounting cavity, and the inner housing wall and the outer housing wall defines an oil containment cavity that at least partially surrounds the transmission mounting cavity. The cooling system further includes a first sprayer nozzle and a second sprayer nozzle. Both the first sprayer nozzle and the second sprayer nozzle are coupled to the oil sump housing and configured to spray cooling fluid within the transmission mounting cavity onto an inner surface of the inner housing wall.

An intake plenum is for a marine engine, the marine engine having first and second throttle devices for controlling flow of intake air to the marine engine. The intake plenum has an airbox providing an expansion volume, first and second inlets that convey the intake air in parallel to the expansion volume, first and second outlets that convey the intake air in parallel from the expansion volume to the first and second throttle devices, and first and second Helmholtz-style attenuator devices located at the first and second outlets, respectively. Together the first and second inlets, expansion volume, and first and second Helmholtz-style attenuator devices are configured to attenuate different frequencies of sound emanating from the marine engine via the first and second outlets.

An outboard motor is provided with: an engine cover in which a first outside air inlet port, an exhaust port, and second outside air inlet ports are formed; and a lower housing that is disposed below the engine cover. The engine cover is provided with a front guide and a rear guide that guide outside air, introduced respectively from the first outside air inlet port and the second outside air inlet ports into the engine cover, downward in the gravity direction.

A variable pitch propeller assembly operatively coupled with an engine and methods for controlling the pitch of a plurality of propeller blades thereof is provided. In one example aspect, the variable pitch propeller assembly includes features for combining overspeed, feathering, and reverse functionality in a single secondary control valve. The secondary control valve is operable to selectively allow a controlled amount of hydraulic fluid to flow to or from a pitch actuation assembly such that the pitch of the propeller blades can be adjusted to operate the variable pitch propeller assembly in one of a constant speed mode, a feather mode, and a reverse mode.