Help Me Fix An Air Compressor

[D45]

Today picked up this little 120V, oil lubricated, portable air compressor

When I try to turn it on, there is just a loud humming/buzzing noise

The motor does not seem to turn on

The compressor is probably 5-8 years old and appears to visually be in good working order

What can I check to try to get it to fire up?

Alton
6 HP
2.5 HP
AT01204-6

Similar to this:

https://www.aircompressorscenter.or...6-gallon-hotdog-tank-oil-lube-air-compressor/

 

[The Cobbler]

first check to see if the motor /compressor spins freely by hand. under the shroud will be a fan you can see if it turns. next is check the start capacitor

 

[rlitman]

first check to see if the motor /compressor spins freely by hand. under the shroud will be a fan you can see if it turns. next is check the start capacitor

Yep. There's a good chance that once you turn the fan a bit by hand, you may be able to plug it in and watch it work.

I'm assuming that there's no pressure in the tank and it's an unloader issue, right? Or (dotting all the i's and crossing all the t's) the check valve could be stuck shut, so the pump can't push any air, stalling the motor.

My portable is just like that (could be the same exact one). I got it in a similar state for chump change at a thrift store in the same condition (hummed, but didn't run), and I found it tight and grinding as I turned the fan (these are direct drive, so you can't just take the belt off to check the motor). In my case, I had to take the pump apart and use a stone to remove some burrs from the cam. It's been working great for the past 15+ years since.

 

[D45]

Took the plastic cover off...........6 screws

The motor fan blade would move and rotate somewhat easy

I added a few ounces of oil to the fill port

Shot some WD40 on the motor shaft bushing/bearing area

The compressor fired right and ran SMOOTH

I am glad I took the time to save it from being thrown out

There was a decent amount of brown rust water I drained out of the tank

All is good. Hope it runs this good a for a few more years

 

[nadogail]

You may now add Compressor Repair to your resume.

 

[rlitman]

You may now add Compressor Repair to your resume.

Yep. Nice save.