A control mechanism for a spreader incorporating a movable material control gate comprises a first limit switch having a fixed position, a linear actuator having a positional member which moves in response to operation of the linear actuator. Movement of the positional member in a first direction causes the positional member to contact the first limit switch to define a closed position of the control gate. The control mechanism also includes a second limit switch mounted to the positional member and an adjustment system comprising a user adjustment device engaged with a linear adjustment member adjustable through a positional linear range. Movement of the adjustment device by a user causes the adjustment member to move within the linear range. Additionally, movement of the positional member in a second direction causes the second limit switch to contact the adjustment member to define an adjustably open position of the control gate.
