Abstract: A four-cycle outboard motor has a lubricating system designed with external gas transfer pipes. Additionally, an internal gas transfer passageway is arranged to encourage the gases contained within the lubrication pan to be expelled through the secondary passageways without substantially blocking a lubrication return line from a camshaft chamber or a crankshaft chamber. The outboard motor features an inline vertically oriented cylinder bank, such that oil introduced at an upper region and drains back to a lubrication pan through the lubrication return passageways arranged at a lower portion of the camshaft chamber and the crankshaft chamber.

Abstract: A four-cycle outboard motor has an oil separator positioned within a head cover assembly. The oil separator is positioned within a recess of a cam cover, which forms a portion of the head cover assembly. A cover plate is interposed between the oil separator and a cam chamber. The oil separator includes a generally u-shaped labyrinth through which exhaust gases with entrained lubricant are sucked. A suction portion extends through the cover plate and facilitates communication between the cam chamber and the oil separator. An exhaust return line is connected to an induction system to draw gases through the oil separator back into the induction system.