Outboard engine structure

摘要

An outboard engine structure including an extension case having a hollow portion formed therein and extending downwardly, the extension case being coupled with the lower surface of a crankcase of a vertical type engine, and including a driving shaft contained in the hollow portion of the extension case for transmitting power from the crankshaft of the engine to a propeller shaft. A cylinder block is connected at the rear of the engine with a cylinder head and slidably receives a piston on its cylinder bore, an exhaust passage block is interposed between the cylinder head and an extension section projecting rearwardly at the top of the extension case, and an exhaust port in the cylinder head communicates through an exhaust passage formed in the block with the hollow portion of the extension case. A water jacket is provided to surrounds the combustion chamber in the cylinder head and extends axially of the cylinder bore to an intermediate portion thereof, and the inlet and outlet passages for the water jacket are formed in the cylinder head.