Lubricating system for four cycle outboard motor

An outboard motor comprised of a powerhead consisting of a four-cycle internal combustion engine and a surrounding protective cowling, said engine being comprised of a cylinder block having at least two vertically spaced cylinder bores, a crankcase chamber formed at one end of said cylinder bores and containing a crankshaft rotatably journaled about a vertically extending axis, a drive shaft housing and lower unit depending from said powerhead and containing a drive shaft rotatable about a vertically extending axis and driven by said crankshaft, said crankshaft being driven by pistons reciprocating in said cylinder bores, a cylinder head affixed to said cylinder block and in closing relationship to the ends of cylinder bores opposed from said crankcase chamber, said cylinder block and said cylinder head having a cooling jacket through which liquid coolant is circulated, an oil tank for said engine disposed vertically beneath said engine, an oil drain passage for draining lubricant from said cylinder head to said oil tank through said cylinder block, said oil drain passage being disposed vertically above the lowermost portion of said cylinder head cooling jacket, a plurality of ventilating passages extending through said cylinder block from said crankcase chamber to said cylinder head in vertically spaced relationship to each other for conveying ventilating gases between said cylinder block and said cylinder head, and a baffle plate extending across the openings of said ventilating passages for separating lubricant from the ventilating air.