The invention relates to a mechanism, intended for assembly on an irrigation emitter, which includes a cylindrical housing (2) in which the pressure of the water flowing through the emitter moves a first disc-shaped part (3), thus rotating a tubular body (7) which in turn rotates a cylindrical part (9) which is connected to a second disc-shaped part (12), to which end screws (15) are connected, the extent to which said screws are tightened defining in the displacement and rotation of the parts the operation of the emitter during either one of the possible time periods relative to the total time commanded by the irrigation controller.
