Dryer ouit

when trying to start dryer push the start switch starts running let off switch unit stops running i do have electrical back ground but cant seem to find problem thanks in advance

Here are your parts
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Here is the wiring diagram
https://www.servicematters.com/docs/wiring/Wiring%20Sheet%20-%208528187.pdf

Sounds like a problem with the centrifugal switch on the motor.
Once the motor is running it should disconnect the start winding and hold power to the main winding. It is in parallel with the start switch.