Just picked up my first MIG, a Millermatic 250. Guy bought it a few years back, not working, with plans to fix it and he never did. I paid $150 for it including a Tweco torch, regulator, and even a nearly full spool of wire. I plugged it all in and tried running some wire, and it seems to work...sort of.


1) There's a relay, CR1, and it has a couple wires that jumper between pins. Or at least they used to, now that those wires are burned through. I'm assuming that I'll need to replace those wires, but I know enough not to replace burnt wires without knowing what caused the problem in the first place. Any ideas? Should I just replace the wires and not worry about it, or is it a sign that something else may have gone wrong/is broken?

2) The bottom feed roller, attached to the motor, is not aligned properly with the wire. I can change the alignment of the top roller with the adjustment screw, but I don't see any obvious ways to align the bottom one. It's off by maybe 1/16th of an inch. Is there any way to adjust it, perhaps by pulling the roller off the motor and shimming it, or should I not even bother?

3) There's a ton of spatter/BBs. I'm guessing this very likely be caused by issue 1, above, but is there anything else to check? One thing I don't know how to do is verify the gas is flowing correctly. When I pull the trigger I hear and see a SLIGHT flow of gas, if I put my hand right at the end of the gun, and the flow meter reads 15 CFH when I do this, too. Since I have no other MIG machine to reference against, however, I have no idea what is "normal"

Settings I used (came from a Miller guide I found): 1/8 material, ~200 IPM feed (switch on low, dial at 60%), 19V, 15 CFH gas, 0.035 wire

Thanks is advance for any help!
- Ian