Internal combustion engine

A main nozzle (38) of a carburetor (10) communicates with a metering chamber (26) through a first fuel feeding passage (44) originally included in the carburetor and a first additional fuel feeding passage (46). The first additional fuel feeding passage (46) includes a flow rate adjusting valve (48). The flow rate adjusting valve (48) is driven by a solenoid actuator (50). The solenoid actuator (50) is controlled on the basis of engine speed.