Abstract: Embodiments of the scavenge passages and the scavenge ports for a two cycle crankcase compression engine wherein the scavenge ports have their side edges tapered outwardly to facilitate the flow into the cylinder block.

Abstract: A number of embodiments of outboard motors powered by four cycle internal combustion engines having a dry sump lubrication system wherein the external oil reservoir is positioned externally of the engine. In some embodiments, the reservoir is contained directly in the power head and in another embodiment, the reservoir is contained externally of the outboard motor. The use of such external positioning of the lubricant reservoirs from the drive shaft housing permits the use of a large expansion chamber for the exhaust system in the drive shaft housing. In one embodiment, a pair of expansion chambers are provided therein.