Did you check the trap door on the outside of the house where the vent goes outside. If the door is stuck or the end of the vent is blocked you will get excessive dry time like you are having. Also possibly a thermostat inside starting to go bad and sticking.
Dryer motors do not require start capacitors. Their is multiple windings in the motor and a centrifugal switch. When the start button is pushed all of them windings are on and when the motor gets up to speed start winding drops out. If you need further help, reach me via phone at https://www.6ya.com/expert/dan_73bbd84fe1d95b61
It should not be on sounds to me like the cent switch inthe motor needs replacement. Common on amana dryer motors, not too hard to fix. See if it slides easy by hand and oil it cleaning out any lint that may have accumulated in the swtich. The job of the switch is to power on the heating element ONLY when the motor gets up to speed and centrifugal force slides out wrights on the switch allowing for power to go to the heater element . Switch stuck most likely, let me know. If you need further help, reach me via phone at https://www.6ya.com/expert/dan_73bbd84fe1d95b61
