PURPOSE: To easily mount a steering handle to an outboard engine main unit without changing a constitution of an engine control system by providing a throttle operation restricting mechanism for restricting action of a throttle operating part at neutral time and reverse shift time.

CONSTITUTION: By bringing a neutral opening restricting screw 44 and a reverse opening restricting screw 45 of a control drum 40 into contact with a stopper surface 41A of a stopper 41, rotation of a throttle valve 22 is restricted, and a delivery amount to a side of the control drum 40 can be fine adjusted by these neutral opening restricting screw 44 and reverse opening restricting screw 45. As a result, a steering handle 20 can be mounted on various engines of different restriction of a throttle valve opening at neutral or reverse shift time. Since the control drum 40 and the stopper 41 are housed in the inside of a handle housing 21, no part is delivered into the handle housing 21, to prevent interference with shift operation, and also appearance is improved.