Hello,
I recently purchased an Emglo wheeled portable oil-bath air compressor. It has a 1.5 hp electric motor that powers a K model pump. The unit ran, but produced smoke, and it was starting to bog down, by this I mean start normal, then start to slow then eventually stop. (approximately 15-20 minutes once turned on).

I replaced one of the pistons and its corresponding rings, as well as cleaned the intake and exhaust valves and changed all the gaskets and the oil. I also added unloaders valves to the head assembly (there were no valves, but there were two empty spaces).

I added a check valve and a pressure switch and replaced the pilot valve and a gauge. (all parts purchased from Master Tool Repair)

Once I had this done, the pump ran like a fine, no more smoke and no more bogging down. However, after a few weeks it started to have trouble starting. After turning the switch on the motor would just hum. I would give the wheel a bit of push and it would start to spin; but it would soon bog down. When it finally stops the electric motor would hum, and sound like it wants to work, but the pump stopped pumping. I replaced the start and run capacitors on the electric motor, no change.

I removed the belt and the motor started and ran fine on its own. I reconnected the belt and disconnected the copper tubing that came from the pump head to the tank, and the pump ran fine (pumping air out of the tubing).

I reconnected the copper tubing and opened the two drain cocks, located under the two tanks, and the pump ran, but a bit slower than usual (but it did not stop).

I’m at my wits end… any idea?
Thanks

I don't know exactly how old it is, I can tell you that the guy I got it from had it for 10+ years. It was in his shed, he used for minor stuff like tires and such (because of the smoking issue).

I believe it is a K15A-8P I'll have to get back to you with the serial #.

Yes it was smoking. The smoke was the result of 'blow-by" which was coming out of the head. This went away after I replaced a worn piston, rings and gaskets.

Serial #: A051591098