An electromechanically operated fuel nozzle (1) comprises a solenoid valve for dispensing fuel, an electronic board (7) for operating the solenoid valve (2), electric accumulator means (5) for electrically powering the solenoid valve (2) and the electronic board (7); the solenoid valve (2) comprises an inlet pipe (11) and an outlet pipe (12) connected to the fuel-dispensing pipe (3) to dispense a full flow of fuel for refuelling, and a secondary channel (4) integrated in the solenoid valve (2) for dispensing a lower quantity of fuel for topping up, the inlet pipe (11) and the outlet pipe (12) are opened by an electromagnetic operating device (21), while the secondary channel (4) is opened by another electromagnetic operating device (20).