Abstract: In order to avoid overfilling of fuel to small internal combustion engines a nozzle is presented which automatically closes the flow when the tank is almost full. The nozzle is put on the fuel container which communicates with the surroundings by an air conduit through the nozzle, constituted of two sleeves, an outer one (13) and an inner one (14) and a bushing (11). The fuel passes the inner sleeve, whose outer end has a valve body (15). At rest the outer sleeve presses against the body and then the nozzle is closed. When the nozzle is put into a filling hole, the spring-biased outer sleeve is pushed back and allows the fuel to pass through the inner sleeve to the tank. When the fuel reaches the outer end of the nozzle the air inlet to the container is closed and the flow stops. When the nozzle is pulled out of the hole it is automatically reset into the rest position.