Air compressor question

I'm sure you've checked the oil. Right? It may be the motor. About 10 years ago I bought a used Emglo that was puking oil into the air. At that time a rebuild kit which included rings was 27 bucks. In my case the compressor had just been over filled with oil. But if you can find an Emglo dealer in your neck of the woods why not try a rebuild kit? Cheers, Eric

I would suspect a faulty check valve for the condition you described with the first pump. The pulley may be larger on the second pump (since you said it pumps up slower), and the motor's power can overcome the pressure from the tank.

It might be a good time to empty the pressure from the tank and inspect the check valve (when the power has been disconnected). It's possible that check valve(s) may be integral parts of the pump head, but there should be a check valve in place to prevent the tank pressure from applying a continuous load/force on the pump. The check valve is likely to be located in the pump's discharge line, although they're often located in the tank fitting where the pump discharge line enters the tank. Check valves are available from compressor repair shops and numerous commercial suppliers.

The old Emglo pump could be a 2 cylinder single stage piston pump. Emglo produced very good commercial/industrial compressors for decades, and someone recently said they were acquired by DeWalt, I think. If it looks to be about the same shape proportionally, as the other pump, it's most likely a piston pump.

A quality pump of that age may be worthwhile to rebuild when it needs rebuilt.

WB ...............

jim wrote:

Open a door! You have created a partial vacuum in the shop and the pump can't get enough air.

If he can open the door against the suction

Mark Rand RTFM