Another compressor that won't build pressure

by Darren
(Roxana, IL.)

I have a gas powered compressor, like so many that won't build pressure. I have looked all through the pages and not sure what it is so hoping you could help.

It ran just fine until i put it up for the winter. The motor runs continually and never idles down. It builds to 20 psi and that's all. I have checked for leaks and cannot find any. When i shut it off it is quiet with no hissing and hold the 20 psi. I removed the air intakes on all three cylinder heads and no air seems to be coming back out. If i hold my finger tips up to them it sucks my fingers to it and holds them there. All three do this. There is a valve on the back of the compressor behind the cylinder heads, maybe oil valve? It is plastic and has a marble inside it, when the compressor runs it puffs air out. I plugged that just to see if it built pressure and it did not. Any ideas?

Thank you so much,
Darren.

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Bill says...

Darren, to me, the symptoms you describe are often those found when there is an internal leak in the gaskets or seals.

You diagnose the problem well, and do all the obvious checks. Therefore, it has to be something that you cannot check without dis-assembly, and I'm thinking that's what you have to do next.

You might wheel it into a shop for a second opinion.

Cheers, and good luck,

Bill