My 12 gal. comp wont turn on. When i flick the switch,it buzzes like it wants to turn on but doesn’t?

by steve
(kirkville ny)


Craftsman 12 gallon air compressor

Steve, first, please shut the compressor off, dump all the air from the tank, plug it in and turn it back on.

Any change?

If so, it may be your unloader valve that’s not unloading properly. Not sure what that is? See the unloader valve on this site for a complete explanation.

If it does not start after that experiment, please add a comment to let us know, will you?

919.167310 Motor running – blows breaker

by Robert

Craftsman 919.167310 Motor running (But sounds different), Piston moving, but no compression and blows breaker

Craftsman 919.167310 air compressor
Craftsman 919.167310 air compressor

I have a Craftsman 6hp 30 gallon Air compressor. I have had it for 8 years. Never any problems till now. I plugged it in and started the compressor. It ran like normal for 1 minute then blew breaker. When restarted, the motor was very quiet and will flip breaker after 15 seconds of running. I took the cover off and replaced the compression ring with a new one, then reassembled. Same issue. The tank has 0 pressure, and I even tried starting with the drain valve open for kicks, but no good. Motor seems to spin fine, moving piston as it should but no pressure and substantially quieter. Help!


Robert, when you replaced the piston ring, did you examine the valve plates and the gaskets?

A blown gasket would make a change in sound, as would a valve failing.

The popping the breaker is electrically related, of course, and that may or not be connected to the noise change.

An overload motor will pop the breaker, and that could be the result of back pressure, mechanical issues, intake filter being plugged, check valve not operating properly, capacitor weakening, or the motor itself failing, among others.

Humming and Capacitor

by: David

I had same issue as others with humming noise. Replaced capacitor with something similar. It started and I thought I fixed the problem. Second time it hummed again and a smell of burnt wiring was noticed. I can turn the mechanism by hand so I eliminated the idea it was seized. I’m about ready to order another capacitor rated for more power to the motor. Any ideas?

The the original capacitor had a rating of 60uf….whatever that means…the replacement one had a rating of 40uf so I am thinking it burned out.


David, please see: