JobSmart 2 HP 4 GAL air compressor-motor hums when lever placed in auto position-will not start. Has no Motor will not start when lever is placed in auto position. It only makes a humming sound. Can not locate a RESET button. Purchased from Tractor Supply- I am told JobSmart=Clarke

The start capacitor has gone bad. Needs to be replaced. That's what's inside that bump on the side of the motor.

I need the diaphram in the On/Off pressure switch on a Black Bull- 4 Gal., 2 HP, 5.0 cfm @ 90 PSI 120 v /13.8 amp . Batch # 0911. These are the only # I can find

It sounds like it is a capacity start motor and the capacity has gone bad.

Could be a seized compressor, a bad start relay, or a problem with the pressure switch or a bad motor.

I would check the capacitor since it appears that the motor is not locked up. Here is a how to on testing capacitors;


how-to-check-capacitor

it is either locked up or most likely it needs a new start capacitor for the motor

Are you a mechanical type person? There is a fast and easy way to test the motor but it is not recommended for anyone who doesn't do this for a living. I have replaced 4 shaded pole motors in the last 3 years that did the same thing and never had a problem with a capacitor start or capacitor start/run motor. If the motor hums, it is trying to run. Try giving the stator help getting started while the motor is humming. Use a small piece of wood or soft plastic. Any non-conductor will do. Look inside the rear of the motor and you will see the field coils around the outside surface and the stator is the round thing in the middle of the motor that rotates. Use the non-conductor to start it turning in the direction it would normally run while the motor is humming. If the motor starts and runs ontill the pressure switch shuts it off, the motor is bad. If it has a capacitor on it, try replacing that first. Please let me know how this works out for you.

1. While the compressor is unplugged, see if you can turn the motor freely with a screwdriver or something to determine that the motor is not jammed 2. If there is a removable cover, check to see if the brushes are worn, (replace if needed). 3. There is also a relay that tells the motor to start located near the pressure adjustment. If this relay is defective or the contacts are burnt, you may need to replace the relay. Good Luck!

SOME TIME THESE MANUALS CAN BE CONFUSING. THE OFF POSISTION MEANS OFF THE AUTO/ON POSISTION IS THE ON THE COMPRESSOR WILL NOT RUN IN THE OFF POSISTION

brushes or bearings but i would test your windings first just to make sure you dont have a bad set you need a continuity meter and isolate you windings this is all done in the wiring conection box on motor let me know if you need more help i can give you a step by step explination