The invention discloses an engine transmission apparatus, comprising: a base; a pulley having a receiving space provided with a circular protrusion inside; a rocker having a body that is provided with a terrace, with the axis of the terrace separate from and parallel to the axis of the body, the terrace rotationally nested in the circular protrusion, the body provided with a hollow portion, and the hollow portion provided with an inner protrusion inside; a pivot penetrating the rocker and the base, rotationally fitting the rocker and fixed to the base; a locking structure arranged in the hollow portion, wherein the locking structure provides resistance to stop the rocker rotating when the rocker rotates around the axis of the body, and the direction and magnitude of the resistance are adjusted according to the rotating direction and rotating distance of the rocker. The locking structure provides resistance to stop the rocker rotating according to the rotation of the rocker; the direction and magnitude of the resistance may be changed according to the rotating direction and distance of the rocker, and dynamic adjustment of the resistance is achieved; adjusting can be made in real time according to working conditions, so that timing effect is improved.