Air vent apparatus for auxiliary fuel tank in power unit

摘要

In a power unit such as an outboard motor is provided in which an engine and an auxiliary fuel tank which temporarily stores fuel to be supplied to a fuel injection valve of the engine and to which extra fuel is returned from the injection valve, are housed in an engine room which is defined by a mount case and an engine cover, the upper ends of air vent pipes extend from the auxiliary fuel tank and communicate with an opening portion which opens in an upper outside surface of the engine cover. Fuel vapor occurring in the auxiliary fuel tank, is discharged from the opening portion. Accordingly, the fuel vapor occurring in the auxiliary fuel tank in the power unit is prevented from being sucked into the engine, and the degradation of the exhaust characteristics of the engine can be avoided.