Thanks for the reply and for all the help provided. After doing a lot of research and watching several videos on these old Quincy compressors I feel like I got a great deal when I purchased it. These old machines were well made back in the day to last 50+ years.
You ain't kidding! I picked up a Quincy 325 on Marketplace about a year ago. It's from the 50s. 70+ years old now. Runs well. I fell down a rabbit hole to get it running in my home garage. You can see the VFD on the wall (3PH motor). Had to get a new tank as I found weld repairs on the bottom of the one it came with. The plumbing is 'temporary' just to get it up and running. I'll plumb it better one of these days.
After further reflection, if that's the only hole on the unloader tower it wouldn't make sense for it to be fully plugged. The air would have nowhere to go... If it leaks while the compressor is off it usually means the diaphragm is no good. (in your case an o-ring is likely leaking) OR a leaky HP discharge valve could be the cause.Joel, got to work on my air compressor this weekend and did as you suggested. Drained the oil which was pretty black. Opened the side cover and cleaned out all the sludge that was in the bottom (found quite a bit in there) removed and cleaned the oil screen. Was also able to get to the brass crank shaft plug and remove it and the oil spill valve and clean it as well. Reassemble everything, refilled the compressor with 30W Non-Detergent oil, started it up and “WOW” oil pressure back up to 18-20 psi. Happy, Happy, Happy!!!
Oh yea almost forgot, I add the Solberg air filter you recommended and it made a world of difference to the noise of the intake as you said it would.
Have another question, on my cylinder unloader valve there is a 1/8” NPT socket head pipe plug what is this plug for? How tight should it be? Mine was only finger tight which allowed it to leak air. See pics below.
Thanks and Happy Saint Patrick Day everyone!
DandyDon
