Internal combustion engine and outboard motor provided with the same

Abstract

An internal combustion engine installed in an engine compartmentcovered with an engine cover C is provided with an intake air passage P. The intake air passage P extends continuously from an intake air inlet Pi to intake air outlets Pe in the engine compartmentand has a first down passage, a reversing passage, an up passageand a second down passagearranged in the order in the flowing direction of combustion air. The combustion air taken through the intake air inlet Pi into the intake air passage P flows down through the first down passage, the reversing passagereverses the flowing direction of the combustion air that has flowed down through the first down passagesuch that the combustion air flows up, flows up through the up passageto a position at a level higher than that of an uppermost intake air outlet Pe. Then, the combustion air flows down through the second down passageand flows through the intake air outlets Pe into combustion chambers. Thus, an effect on preventing the flow of water into the combustion chamberof the engine is improved.