Abstract: A controller for a centrifugal clutch with circumferentially spaced actuating weights having radially inwardly projecting actuating arms that pivot rearwardly as the rate of rotation of the clutch accelerates and the weights move to increase actuating pressure in and through the clutch. The controller includes a fluid actuated cylinder and piston unit with a piston rod that carries an arm engages throw-out bearing positioned rearward of the actuating arms. The cylinder is normally charged with a fluid medium that urges the piston and rod forwardly to one end of the cylinder and where the throw-out bearing engages and stops the arms in their normal unactuated position.