Some years ago, I bough a really old short hood Lincoln SA200 welder. It might be as old as a '48 model. Before I bought it, it sat, probably for decades. I actually got it running, although not running well. Once it was running I was able to get an electrode to spark but I never struck an arc and welded a bead with it nor did I ever finish the project.
Some time after that, another short hood SA-200 floated by, and I bought it, too. This welder was about a 1958 model. The man I bought it from had the welder in service for a pretty long time. He used it to build barbecue pits and such for people. He sold it because the camshaft cracked in two. The camshaft drive gear just fell off! He pulled the pan and the starter from it but decided to sell it rather than fix it.
So I bought it. Later, on ebay, I bought a Continental F-162 engine. The seller was a machine shop that had rebuilt it but the person abandoned it so the shop sold it for charges.
Now, a few more years later, my tractor mechanic, Gary, has now split the broken engine from the '58 model welder, installed the rebuilt engine on it and gotten it running. The engine runs pretty smoothly but the idle system is probably not hooked up properly and we are not sure how it works, anyway. Gary noticed a couple of wires that run to the idle system but don't seem to be connected to anything. He thinks the wires probably used to be connected to a mercury switch that is now missing. The other welder (the '48) doesn't have this component either. So we can't rob the part from that machine.
The '58 welder (the one we just got running) will not strike a hot arc although it will make sparks - just like what I got out of the '48 welder back when I briefly had it running.
We don't know if the idle system has anything to do with the fact that the armature does not produce enough current to sustain an arc. But regardless of where we dial the rheostats or how high we spin the engine, the machine won't weld although it will spark an electrode. Gary is a very competent equipment mechanic but has no experience with these old Lincoln welders. Needless to say, I have even less.
Gary heard you could put a magnet on the side of the armature and sometimes get it to go hot. We tried that and there seemed to be no improvement. As I said, it will spark an electrode but not induce an arc even with the switches turned "balls to the walls".
We will appreciate hearing all opinions and guidance on what we might try next. In particular, I would appreciate receiving an explanation of how the old idle system worked (a schematic would be great!) as well as some educated opinions on whether the idle system could be why the welder is not hot enough to create a sustainable arc.
Otherwise, any information or guidance on what to do next, and the order in which to do it, would be very much appreciated. I am told that the upgrade idle system costs more than $700. I am not unwilling to incur this expense if necessary but it would be a bummer to spend the money only to discover the armature end is dead or dying.
I look forward to benefiting from the typical eruption of collective wisdom.
Regards and thanks!