Quincy Won't build PSI above 50

by Jerry
(Zion,, IL)

I have a Quincy. When the compressor is running, air comes out of the crankcase vent and won't build past 50 PSI. I took apart valve plate assembly and cleaned. Didn't solve the issue. Any suggestions

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Feb 10, 2015
Gasket leaking on compressor
by: Bill

I haven't taken your pump apart, but usually there is a gasket between the high pressure side and the low pressure side. It may be part of the whole gasket.

If there is an opening developing in this seal, sometimes it doesn't let go until the back pressure reaches a certain pressure level, like 50 PSI for example, and then it opens enough that air flows back and forth between the high and low pressure side rather than being forced into the tank.

That is what I think is happening on your compressor. When you disassembled and reassembled, if you did not replace the gasket, you may have modified it a bit so that the former leak and somewhat self sealed, and then, as the pump was used further, eventually that same leak developed, and the pressure going into the tank plateaus as whatever point the gasket opens allowing air to flow back and forth.

B.

Feb 10, 2015
Gaskets?
by: Anonymous

Oh. Forgot to say I checked it with soapy water after initial change. No leaks then. I'll check again later.

Feb 10, 2015
Gaskets?
by: Anonymous

Are you referring to the "head" gasket between the upper and lower section? If that was leaking wouldn't I get a strong wind or blowing air out the side? I don't find anything that seems to be leaking.

Feb 10, 2015
Repaired valves
by: Bill

What you are experiencing now sounds like it could be a gasket failure.

Did you, when you re & re the pump, replace the gaskets too?

Bill

Feb 10, 2015
Model 216-19 with same issue
by: Anonymous

I have the same issue on a 216-19. Put in new rings on both cylinders. Took the 4 valves apart, replaced the "pucks" and springs. Cleaned everything I could see and feel. Reassembled the unit and it pumped up to 110 and shut off like normal. Worked great for two days. One day three it was back to the old problem. It gets near 50 lbs and you can hear a change in the sound, like it's not sucking air anymore. It sounds like a car that is "missing" on a cylinder. There is no bypass setup (can't think of the right term - where the motor continues to run, but not pump air). This one shuts off completely at each cycle. However, since it won't reach pressure, it keeps running and gets VERY hot, VERY quickly. The unit holds pressure for days with no trouble, so it's not leaking back through the pump. If I rotate the pump manually, I don't hear any air leaks as the parts cycle through their actions. If I remove the oil cap while the unit is running, I get some splash, but no pressure, so it should not be the rings. Not sure what else to check.

Oct 06, 2014
Quincy Won't build PSI above 50
by: Bill

Bit hard to help you when you don't indicate the model number Jerry.

Add that below and someone will help, I'm sure.

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