Abstract: A cooling structure of a water-cooled two-cycle parallel multicylinder engine includes: an exhaust port in a cylinder block; an air intake port disposed in a crankcase below the exhaust port; a water pump disposed in the crankcase in an opposite side of the exhaust port; a first cooling water passage introducing cooling water discharged from the water pump to a cooling water jacket of a cylinder head; and a second cooling water passage introducing a part of the cooling water discharged from the water pump to a cooling water jacket below the exhaust port, the second cooling water passage being provided in the crankcase.

Abstract: A fuel supply apparatus of an outboard motor for supplyng an air to an engine of the outboard motor comprises a vapor separator for removing bubbles in the a fuel, a float-type bubble discharge valve which is provided for the vapor separator and adapted to be closed when a fuel level in a fuel tank rises, and a negative-pressure-opening type valve connected to a downstream side of the bubble discharge valve so as to be opened upon reception of an intake negative pressure of then engine. A valve opening pressure of the negative-pressure-opening type valve is set to a value lower than a pressure of a squeeze pump, connected to a fuel tank, required for pumping a fuel therefrom.