What should we look for, or look to avoid, when purchasing a USED self powered welder? There is another thread on electric welders so please keep this discussion to only "self powered" welders.

Engines are the biggest variable. The transformer side that makes electricity is similar to a plug-in type - either works or doesn't.

A good thing to know on engine driven rigs that have been sitting a while is that they'll occasionally stick one or more valves. That is usually easy to fix (pull the head and spray with WD40 or similar, cycle and tap down until the springs start returning the valve) so that can be a negotiating point for spending less. I had a Linde that would stick exhaust valves after a month in our humidity. I could pull the head without damaging the gasket and get it running in 30 minutes or so. It was a great machine and ran fine once everything started functioning as designed...:-)

2/19: I just remembered something I was told - don't know if it's true. On a stick machine, set the current to burn a 1/8" rod, then put one in the stinger and short it straight into the work piece. The engine should chug and load up but not stall. I had a pro weldor tell me that's how they tested Lincoln SA-200 machines to see if they had proper operation in the governor and engine.

Watch out that it has not been sitting with an open exhaust pipe aimed skyward. Neighbor had a big 4-cylinder compressor parked longtime, found rainwater had gotten down onto the block. Had to do a ring job. If it runs, try it out with the fattest rod you have at the proper amperage for the rod and see how long a bead it'll make. If it won't run on the spot, or doesn't have leads, a ground clamp, a stinger, I wouldn't buy it. If you know and trust the seller and she knows what she is talking about and she says it just needs a little TLC, that's different.

I agree with the ladder two. Basically, if you know anything about engines and it doesn't run but you know why and are able to get it for quite cheap because of the fact then I, personally, would buy it.

-Get it for cheap because of not running
-Put a little bit of time and effort into it
-Either use it for all you want, or sell it for a good profit and buy a quite a bit better one. :D

Watch out for the electronics on the newer welders. Sometimes they start out welding fine, and after 10 minutes or so they start to get weaker. I've seen the Bobcat at work do this.
Travis