An outboard motor includes a cylinder block, a cylinder head unit, a delivery pipe, a plurality of injectors, a fuel pump, and a fuel pipe. The cylinder block includes a plurality of cylinders. The cylinder head unit is connected to the cylinder block. The delivery pipe is attached to the cylinder head unit. The injectors are attached to the delivery pipe. The fuel pump is attached to the cylinder head unit. The fuel pipe is attached to the delivery pipe and the fuel pump. A first attachment direction of attaching the fuel pump to the cylinder head unit is parallel or substantially parallel to a second attachment direction of attaching the fuel pipe to the delivery pipe.

A method for preserving electrical power in a marine vessel having a marine propulsion device. The method includes operating a variable operating device according to an original setting, measuring an actual system voltage for the marine propulsion device, and comparing the actual system voltage measured to a target system voltage. The method further includes adjusting the operation of the variable operating device from the original setting based on the comparison of the actual system voltage to the target system voltage, where adjusting the operation changes the electrical power usage in the marine propulsion device.

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.

There are included: a motor contained in a top cover; a vertical shaft that is rotationally driven by the motor, the vertical shaft being contained in an extension casing; and a propeller that is rotationally driven by the vertical shaft, the propeller being provided at a gear casing, wherein a heat exchanging part is provided inside a front portion of the gear casing, and inside the heat exchanging part, there are formed an inflow-side oil channel and an outflow-side oil channel that cooling oil for cooling the motor flows through.

A method for preserving electrical power in a marine vessel. The method includes operating a variable operating device according to an original setting, measuring an actual system voltage for the marine vessel, and comparing the actual system voltage measured to a target system voltage. The method further includes adjusting the operation of the variable operating device from the original setting based on the comparison of the actual system voltage to the target system voltage, where adjusting the operation changes the electrical power usage in the marine vessel.

An objective of the disclosure is to provide a simulation method for a two-stage plunger pressurized common rail fuel system of a marine low-speed engine. The method includes: first setting initial status parameters, such as a control step of a system model, a total time of a calculation process, and structure parameters and pressures of components; and then establishing a mathematical model of a fuel booster unit, a mathematical model of a high-pressure fuel pipe and a mathematical model of a fuel injector based on a MATLAB simulation platform, and connecting input and output parameters of the models to realize data transfer between the models. By considering one-dimensional (1D) spatial fluctuations in the high-pressure fuel pipe, the disclosure establishes a high-precision model of the fuel system, which provides an effective method for designing and calculating detailed pressures in the common rail fuel system.

An apparatus is for operably connecting a marine drive to a marine vessel. A transom bracket is configured for fixed attachment to the marine vessel and for attachment to the marine drive such that the marine drive is trimmable up and down relative to the marine vessel about a trim axis. The transom bracket has a sidewall with a rigging opening through which at least one elongated rigging member extends for operably connecting the marine drive to the marine vessel, wherein the rigging opening is located along the trim axis. The rigging device has an elbow conduit with an inlet end and an outlet end, wherein the outlet end is positionable into a plurality of clock positions relative to the inlet end.

An engine oil receiving structure comprises a vertically disposed crank shaft, a laterally movable piston, a connecting rod connecting the crank shaft and the piston, a cylinder barrel housing the crank shaft and the piston, a crank case containing the crank shaft together with the cylinder barrel, a cylinder head forming a combustion chamber, the combustion chamber connecting to a piston movable part end face of the cylinder barrel, an oil filter filtering engine lubricant, and an oil case storing oil flowing out when the oil filter is removed from a mounted position, and the oil case is fixed to an engine under the oil filter, and comprises a discharge path to discharge the stored oil.

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 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.