If you go to the Sears parts site they have actual part breakdown diagrams.
They sell the parts here but they are easier to look uo part numbers at Sears.
Sears does not share the part breakdown diagrams with other vendors.

See the attachment for the tech sheet.

Sounds like it could be a problem with the centrifugal switch on the motor.

The motor has two centrifugal switches whicj activate when the motor gets close to operating speed.
One of them switches in the heat.

The other has two functions.
1. It provides an alternate/parallel circuit path for Neutral around the start switch. This lets you release the switch and the unit stays running.

2. It switches out the start winding because if it is left in circuit the motor will trip it's internal thermal protect. It then shuts off and you have to wait for the motor to cool down (protect reset) before you can start the motor again.

Check that the motor is clean and not clogged up with lint which could impede the switches.

If all Ok you may need a new motor.