Thanks for the post!

IMC/BelAire doesn't make a 319VL unit that I'm aware of, could it be the 318VL that you have? You can find a full breakdown of this unit on our website by clicking on the below link:

www.mastertoolrepair.com/stationary-two-...-318vn-p-785776.html

As long as your electric motor has been checked and ruled out and your breaker is large enough to run the unit, I would test the motor's Capacitors. If you don't have a motor capacitor tester, you can use a voltometer to test the capacitors. There's a chance the start or run capacitor is defective, so as to not give the unit enough "juice" to start up and stay running.
You can find out how to test the capacitors watching the below video:



Also, make sure your Drive Belt(s) aren't too tight, there should be no more than 1/2" deflection when pressing in the center of the Belt(s).

Also, make sure the motor pulley and pump flywheel are properly aligned.

Take the cover off of the Pressure Switch (unplug the unit first!) and check the copper contacts; are they in good shape? Are they burnt or corroded? Are the motor wires and power cord wires connected securely and are they in good shape?

Do you have the proper gauge power cord plugged into the wall outlet? It's probably a 14 gauge cord; try increasing the size to a 12 gauge cord.

These are a few starting points, let me know what you find and we'll go from there.

- MTR