The way I was taught to adjust the wire spool tension is to angle the gun and hold it against a slick surface (against the welder). Pull the trigger and the wire should curl. If the wire pushes on the gun and does not curl then you have too much tension. You want the spool to spin with ease, but you don't want the spool to spin freely. In other words when you let off the trigger the spool stops and does NOT continue to spin.

Also how do you have wing nut, spring, and washer in place? I put on the spool with the plate that goes in the center and align. Put the spring on the shaft it will go against the metal plate. Put the washer against the (outside) spring, and tighten the wing against the washer. I've played with it but this works the best.

What is the brand name wire?