A method for checking the oil level in a marine drive unit, where the drive unit is provided with an external oil filter, an oil level sensor adapted to determine an oil level in the drive unit, and an electronically controlled tilt means, comprising the steps of, initiating an oil level check, controlling the tilt means to tilt the drive unit to a plurality of different tilt angle positions, for each tilt angle position, determining if the oil level sensor detects the oil level in the drive unit, for each tilt angle position, registering the tilt angle of the drive unit and the signal from the oil level sensor, determining at which tilt angles the sensor detects the oil level, and in dependence of the determined tilt angle of the drive unit, determining if the oil level of the drive unit is within a predefined range.

The lubrication mechanism 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, and an oil filter installation member in which the oil filter is vertically installed, and the oil filter installation member includes a lubricant detour structure.

Engine includes: crankcase housing crankshaft extending in vertical direction; cylinder block mounted on side of crankcase and formed with cylinder; cylinder head mounted on side of cylinder block and provided with air inlet port and air outlet port communicating with cylinder; cylinder head cover mounted on side of cylinder head and covering air inlet port and air outlet port; mount case including: supporting portion provided below crankcase and cylinder block and supporting crankcase and cylinder block; and extending portion extending from supporting portion below cylinder head and cylinder head cover; oil pan provided below mount case and storing lubricating oil; and communication tube communicating first space formed between cylinder head and cylinder head cover and second space formed between mount case and oil pan. Communication tube is provided between cylinder head cover and extending portion.

An outboard engine includes a steering mechanism having a pod propulsion device disposed in water outside a hull; a propulsive drive mechanism that is disposed in the hull and gives a propulsive drive force to the pod propulsion device; and a circulation cooling circuit which has an outward flow path that supplies a cooling oil to the steering mechanism and the propulsive drive mechanism, and an inward flow path which recovers the cooling oil from the steering mechanism and the propulsive drive mechanism, in which the inward flow path and the outward flow path of the circulation cooling circuit communicate with each other inside a case body of the pod propulsion device.

A marine propulsion device includes a first gear, a second gear, a third gear, a case, a partition wall, and a first flow path. The case includes an internal space in which the first gear, the second gear, and the third gear are located. The partition wall is located between the second gear and the third gear in the internal space. The partition wall partitions the internal space into a first space and a second space. The second gear is located in the first space. The third gear is located in the second space. The first flow path communicates the first space with the second space. The first flow path is located on a same side as the first gear with respect to a center line of the second gear and the third gear.

A port insert for a marine lower unit includes a hollow body having a first end and a second end, the second end having a first exterior thread configured to couple with a cap and one or more apertures formed in the body adjacent the first end. The port insert also includes a spring mechanism disposed within the hollow body. The port insert further includes a sealing member coupled to the spring mechanism, the sealing member being biased toward the second end in a non-use state.

There is provided an outboard motor. A first oil passage is provided in a lower case, extends upward from a front lower portion, and reaches a first connection position which is positioned above a height position of an anti-ventilation plate or at a front portion of a boundary portion between a middle case and the lower case. A second oil passage is provided in the lower case or at the boundary portion, extends rearward from the first connection position, and reaches a second connection position which is positioned at a rear upper portion or at the rear portion of the boundary portion. A first oil supply/discharge port is opened on a side surface of the rear upper portion of the lower case or on a side surface of the rear portion of the boundary portion, and communicates with the second oil passage at the second connection position.

There is provided a breather chamber structure. An inner wall partitions a breather space surrounded by outer walls into a plurality of chambers including a first chamber, a second chamber, and a third chamber. An inlet allows the gas to flow into the first chamber. A first communication path communicates between the first chamber and the second chamber. A second communication path communicates between the second chamber and the third chamber. An outlet allows the gas in the third chamber to flow out of the breather space. An oil discharge port is configured to return oil separated from gas in the breather space to an oil reservoir. The third chamber has a volume equal to or greater than half of a volume of the breather space. The first chamber has a volume larger than a volume of any of the chambers except for the first and third chambers.

A marine engine comprises a powerhead having an engine block, a cylinder head and a crankcase containing a crankshaft. Operation of the marine engine causes rotation of the crankshaft. A crankcase cover encloses the crankshaft in the crankcase. A supercharger is on the crankcase cover, the supercharger being configured to provide charge air for combustion in the powerhead. The supercharger comprises a charge air outlet for conveying charge air from the supercharger for combustion in the powerhead, the charge air outlet being oriented so as to discharge the charge air towards the powerhead.

Example apparatus and methods for filling the lower units of boat engines with lubricating fluid through their top/vent holes are disclosed. A disclosed fill fitting for filling a compartment of a boat engine with a fluid includes a body, a fluid passageway and a pressure relief passageway. The body having a shaped portion, the shaped portion configured to secure the body in an opening in the compartment. The fluid passageway being defined in the body configured to direct a fluid into the compartment. The pressure relief passageway being defined in the body configured to allow gasses and fluids to escape from the compartment as a fluid is flowed into the compartment via the fluid passageway.