FOUR-CYCLE ENGINE OF OUTBOARD MOTOR

摘要

PROBLEM TO BE SOLVED: To provide a four-cycle engine for outboard motor capable of enhancing a durability of variable valve timing mechanism by preventing a deposition of water on the variable valve timing mechanism. SOLUTION: In the four-cycle engine 10 for outboard motor, a suction/exhaust cam shaft disposed in parallel to a crank shaft vertically disposed is rotated and driven by the crank shaft. A VVT(variable valve timing mechanism) 40 is provided on an upper end of the suction cam shaft. An open/close timing of a suction valve is varied by changing an oil pressure fed to the VVT 40 by an OCV(oil control valve) 43. An air duct 52a opened to an upper portion in a cowling 7 is disposed in offset at an exhaust side in a right/left direction. According to the present invention, a distance between the VVT 40 and the air duct 52a is extended in a right/left direction and a deposition of water contained in an external air introduced from the air duct 52a into the cowling 7 on the VVT 40 is prevented to enhance a durability of the VVT 40.