A four cycle outboard engine having a crankshaft substantially vertically oriented when running a cylindrical block supporting the crankshaft. A thrust metal composed of a pair of semi-circlular plates of different thicknesses are mounted in semicircular grooves of different depth formed on the bearing portions of the cylinder block and mounted in such a way that the semicircular plate having the greater thickness contacts the end surface of th semi-circular groove having the shallower depth.
