A marine propulsion system includes an internal combustion engine; a fuel reservoir; a pump that pumps fuel from the fuel reservoir to the internal combustion engine; and a fuel filter that filters the fuel. The fuel filter includes a canister and a fuel inlet that conveys the fuel adjacent to cylindrical sidewalls of the canister so that the fuel immediately spirally flows around and down the cylindrical sidewalls under centrifugal force and under force of gravity, and then is drawn radially inwardly through a filter element by the pump. A fuel outlet extends at least partially along a center axis of the canister and discharges the fuel from the canister. A drain is located at the bottom of the canister and configured to drain water that separates from the fuel as the fuel flows around and down the cylindrical sidewalls.

An engine includes a crankshaft. A driveshaft is connected to the crankshaft, and extends in an up-and-down direction of an outboard motor. A propeller shaft is connected to the driveshaft, and extends in a back-and-forth direction of the outboard motor. An intake pipe is connected to the engine. The intake pipe includes a first pipe portion and a second pipe portion that are provided separately from each other. A seal member is disposed between the first and second pipe portions, and couples the first and second pipe portions therethrough.

An outboard motor having an idling stop function, which includes a starter motor configured to start up an engine, a capacitor configured to serve as a power source of the starter motor, a restarting circuit that includes a restart switch configured to activate the starter motor by electric power supplied from the capacitor in conjunction with a shift lever directly operated by a ship operator at a time of restarting after idling stop, a changeover switch configured to switch to an idling stop mode that enables the restarting circuit, and an engine control device configured to control shifting to the idling stop in the idling stop mode. The capacitor is disposed in an engine compartment of the outboard motor.

An outboard motor 10 includes an engine 16, a fuel tank 25, a propeller 17 which is configured to be driven by the engine 16, a case member 18 which rotatably supports the propeller 17, a recoil starter 29 which is configured to cause the engine 16 to start by manually rotating a crankshaft of the engine 16, and a cover member 16 which is mounted on the case member 18 so as to cover the engine 16, the fuel tank 25, and the recoil starter 29. The recoil starter 29 includes a recoil cover 34, which is formed with an air passage hole 34c.

A directional control system of a marine vessel includes a steering control member manually operated by a user and operationally connected to a direction-variation member acting on or in the water, such as at least one rudder blade or at least one outboard engine, the direction-variation member having an angular position that is controlled by the steering control member; and a locking system locking the free variation of the angular position of the direction-variation member, which can be activated and deactivated to allow the variation of angular position and carry out a directional change, the locking system including a hydraulic cylinder having a piston dividing the cylinder into two chambers, which are connected by a bypass circuit that can be opened and closed by a switching member.

A boat hull cooling and marine-drive system intended for use in a primary shallow water bottom environment includes a boat hull with an integrated internal engine heat exchanger, marine drive system and steering assembly. The steering assembly incorporates a ring-within-a-ring steering mechanism and an obstacle resistant shoe plate. Stabilizer fins positioned above the shoe plate at a position forward of the spinning propeller allow air and water to exit from the rear of the stabilizer fins away from the spinning propeller.

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.

An outboard motor 10 includes an engine 16, a fuel tank 25, a propeller 17 which is configured to be driven by the engine 16, a case member 18 which rotatably supports the propeller 17, a recoil starter 29 which is configured to cause the engine 16 to start by manually rotating a crankshaft of the engine 16, and a cover member 16 which is mounted on the case member 18 so as to cover the engine 16, the fuel tank 25, and the recoil starter 29. The recoil starter 29 includes a recoil cover 34, which is formed with an air passage hole 34c.

An outboard motor includes an engine, a fuel pump to draw fuel into an outboard motor body from a fuel tank installed on a hull, a temporary storage tank to temporarily store the fuel drawn into the outboard motor body by the fuel pump, a fuel injector to inject the fuel stored in the temporary storage tank into the engine, a temperature sensor on the temporary storage tank to detect a temperature of the fuel stored in the temporary storage tank, and a controller configured or programmed to perform a control to limit an engine speed to no more than a predetermined upper limit rotation speed based on a detection result of the temperature sensor while the engine is running.

A directional control system of a marine vessel includes a steering control member manually operated by a user and operationally connected to a direction-variation member acting on or in the water, such as at least one rudder blade or at least one outboard engine, the direction-variation member having an angular position that is controlled by the steering control member; and a locking system locking the free variation of the angular position of the direction-variation member, which can be activated and deactivated to allow the variation of angular position and carry out a directional change, the locking system including a hydraulic cylinder having a piston dividing the cylinder into two chambers, which are connected by a bypass circuit that can be opened and closed by a switching member. According to the invention, the fluid in the hydraulic circuit is a magnetorheological fluid, and a magnetic field generator, which can be activated and deactivated by the switching member, is combined with the bypass circuit, the magnetorheological fluid changing viscosity depending on the generated magnetic field, switching from a fluid condition to a substantially solid condition or viscosity that prevents flow in the bypass circuit.