This old unit was just given to me and I have no idea of it's history. It has a 120V plug on the end of it so I plugged it in to see what happens. It runs and pumps air. The pressure gauge doesn't work so not sure how much before the motor started stuttering and shut down. Let it sit a few minutes and plugged it back in - still stutters and shuts down almost immediately. Purged the pressure, restarted the motor and it ran for a couple minutes before shutting off.  The motor did not get hot within the 2 minutes or so it runs before it shuts down.

From what I can tell - the numbering and specs between CH and HD and other brands is very confusing to me - this should have a single cylinder pump (or maybe 2 side by side cylinders?? can't tell from pictures). But, it looks like it may have had the Harbor Freight "V"2 cylinder 5 HP pump installed on it. The pump is not marked but looks identical to the HF photos. The motor is an Emerson 240V 2.98KW Model 163xWBSS1486, Cust PN MC015403AJ (again the numbers seem hard to find and pin down to this particular compressor).

My big question is about the 240V motor being run off 120V. I can't tell from the terminal block inside the motor if the connections in it are correct. Is there an actual option to run this motor on 120V?? I wouldn't think so considering the information on the data plate - seems like it would say 120/240 if it were designed for that.  All I know for absolute sure is that the hot and neutral wires from the power cord are run to the LINE terminals in the power switch assembly.
The label on the compressor tank says it is set up for 240V/15A but I have no idea what the previous owners may have done (in addition to replacing the pump).

I would prefer to run this off 240V but I hate to just run 240V to it and turn it on without knowing if the motor is wired correctly for it.....
Does anyone know where I can find a reference to the connection terminals under the motor cover plate??

My thinking is this -- the 240V motor is running off 120V and as such, once the pressure builds up to a certain point, it no longer has the umph to push the pump and stalls out.... I would confirm - or disprove!!  - if I knew that the motor was wired correctly to run off 240V but again, I can't find any information regarding the terminal wiring inside the motor.

Any help, suggestions, or thoughts would be most appreciated.

Thanks.
Note: Accidently put this in Suggestions originally. Deleted it from there and put it here in Compressors.

Well, looking at the history of answers to questions on this forum (or lack thereof) I guess I won't hold my breath for a reply.  

To follow up.... went and bought a 220v plug that matches my welder outlet. Turned it to Auto and came inside (it's outside under cover) and plugged it in. Plugged it in and it immediately started running much "stronger". Watched the Guage and it got to 150 psi and popped the safety valve but didn't shut off! Did a little reading and looked at new pressure switches online. Was gonna pull the switch off when I noticed a pressure adjustment! Adjusted it lower a couple times and now it shuts off at about 135 and back on at 90. Think I'll do a little maintenance on it and get new fresh air filters and put it into service! Nice compressor for the price of a new power plug!