Patent ID: 6508223
Filing Date: 2003-01-21
Classification: F02B

Abstract:
A four cycle outboard internal combustion engine for driving a watercraft with a cylinder housing having cylinders arranged in at least two rows, wherein a piston is reciprocating in each cylinder, said pistons driving an approximately horizontally accommodated propeller drive shaft by way of an approximately vertically oriented crankshaft, each cylinder bank being provided with cylinder head sealing surfaces for a cylinder head housing receiving gas shuttle valves and wherein the cylinder head sealing surfaces of all of the cylinders are arranged in one single cylinder head sealing plane and an exhaust main manifold for all of the cylinders is arranged approximately parallel to the crankshaft in the cylinder head housing in the area of a central plane of the motor which is configured parallel to the crankshaft, including one crankshaft for each cylinder bank, the crankshafts having a stable relative speed ratio and acting upon the propeller drive shaft through a common jackshaft, and including means for causing said crankshafts to rotate in opposite directions.