Ventilation cover structure for outboard engine provided with four-stroke cycle engine

摘要

A cover structure (50) is incorporated into an outboard engine (1) having an engine (2) placed in an engine room (6) defined by a cowling (5) and an under cover (4) and having an engine block (8), a vertical crankshaft (7) having an upper end portion projecting upward from the engine block (8), a vertical camshaft (15) having an upper end portion projecting upward from the engine block (8), a camshaft driving pulley (11) mounted on the upper end portion of the crankshaft (7), a camshaft pulley (16) mounted on the upper end portion of the camshaft (15), and a timing belt (17) extended between the pulleys (11, 16), and a flywheel (12a) disposed above the camshaft driving pulley (11) on the upper end portion of the crankshaft (7). The ventilation cover structure (50) comprises a first cover (60) disposed above the engine block (8) so as to cover at least the flywheel (12a) and opening downward, and a second cover disposed above the engine block (8) so as to cover a space extending over a portion of the engine block (8) on the side of the camshaft (15) and opening downward. The first and the second cover (60, 80) are united together so that spaces covered with the first and the second cover (60, 80) are united in a single space. A discharge duct (90) is formed on at least either the first cover (60) or the second cover (80) so as to lie outside a space occupied by the flywheel (12a) on a level above that of the timing belt (17).