Dryer motors don't normally have a centrifugal start switch built in them. To start a dryer, you set the timer then push a 'cycle start' switch. Just a momentary contact switch that does the job of the built in centrifugal switch used in most motors. It is part of the safety system, to keep the drum from turning with the door open.
Try putting a switch between the two terminals where the red wires go. Don't leave the switch on after motor starts, or the start winding could burn out.