Patent ID: 7647901

Claim:
An engine for a planing-type boat, the engine including an engine cooling jacket and being configured to be mounted in the planing-type boat such that including an engine cooling jacket provided on an upper side of an engine body to cool the engine with water, the engine being a four stroke engine, the engine comprising: a crankcase with a crankshaft housed within the crankcase; a cylinder block including at least first and second cylinders, first and second pistons disposed in the first and second cylinders, respectively, the cylinder block including first and second apertures at upper ends of the first and second cylinders, respectively; a one-piece cylinder head having a surface facing toward the first and second cylinders and covering the first and second openings, thereby forming first and second combustion chambers with the first and second cylinders, the crankcase, the cylinder block, and the cylinder head including respective outer surfaces forming respective parts of an outer surface of the engine body, the cylinder head including at least first and second exhaust ports extending from the first and second combustion chambers to first and second exhaust port openings on the outer surface of the cylinder head, respectively, the cylinder head further comprising at least first and second intake ports extending from the first and second combustion chambers to first and second intake port openings disposed on the outer surface of the cylinder head, the cylinder head further comprising at least first and second ignition plug mounting holes extending from the first and second combustion chambers, respectively; the engine water jacket extending through the cylinder head into thermal communication with at least the first and second intake ports, the first and second ignition plug mounting holes, and the first and second combustion chambers, the engine water jacket also comprising a ceiling having a frontward portion and a rearward portion, a highest portion of the rearward portion of the ceiling being higher than a highest portion of the frontward portion, and a water drain provided adjacent to the highest portion of the water jacket to discharge the cooling water out of the water jacket.