Central Pneumatic Model 42321 Air Compressor motor keeps running
About the same as most other posts,built up pressure to 40.lbs and motor keeps runing but no more pressure build up.
I installed a new pressure switch, pulled the head off and the two flapper reeds were ok.
replaced head gaskets,i gained 10.lbs pressure 50.lbs,,,motor counties to run but stays at 50.lbs any help here////
That you had a boost in pressure from changing the gaskets was good.
If your intake filter is clean and your unloader valve is not draining air while the compressor is running, I would still suggest that you have a valve or gasket problem. If this were mine I would tear it down and replace the valve plate kit and, unfortunately since you've done it already, a full gasket kt.
I hope you kept your old pressure switch as a spare, as I suspect there was nothing wrong with it.