I have a 6hp 33 gal aircomp i builds up to 100 should go to 250 wont shut off because not up to press can you help

indicates reed or poppet valve problems in the head/s
there is a non return valve before the tank but if the head valves springs are broken or damaged , it pumps air in and out or from one cylinder to the other

Try carefully lightning the tubing nut to resale.

Broken reed valves- assuming the regulator is adjusted to maximum air pressure.

These are located on the face of the pistons and require partial disassembly of the compressor head to serivce.

When installing the new ones, add a drop of light duty thread locking compound to the threads to insure the screws do not fall out in use.

i would look at the head gasket

Sounds like the reed valves in the head failed. you need to replace the head (usually cheaper to get a new compressor)

Sounds like part #27 is worn. Replace # 24 24 A 24 B and 24. the cylinder may be worn. Perhaps depending on the age and time and labor replace with new comp. maybe Dewalt.

could be a gaskit or the inlet reed

could buddy put the blue one on there and try this if no difference get back to me i have other options

It sounds like the internal circuit breaker in the motor is heating up and then the breaker trips to shut down the motor. This is the protection so you don't have a fire if the motor burns up. The smell you have is the coils in the motor. Sorry to say that you will need a new motor for this unit. I hope this helps out.

Your compressor is most likely made by Campbell Hausfeld. The oily substance could be leaking from the capacitor on the motor. Remove the cover and examine the capacitor for failure. There is a value printed on the cap. (uf) The cap must measure to within 95% of printed value. A failing capacitor will cause the hum that you are experiencing.