low compression

I have a speedaire compressor that runs until it turns off but it only has about 20psi. the pressure is factory preset. what can i do?

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Bill says...

A bit more info, please.

It runs and shuts off at 20 PSI? Did it always do this or is this new?

When it shuts off, does the pressure switch trip the motor off, or is power still flowing to the motor through the switch?

Please post info as a comment here so I can follow our conversation.

Cheers,

Bill