The last thing to do before beginning to weld is adjust the tension on the wire. Cut the wire as close as possible to the end of the torch tip, place it flush against a flat surface (hopefully an ungrounded, nonmetallic surface), and pull the trigger. The wire feed should push the torch tip away from the surface. If it does not, look to see if the rollers are turning but no wire is being fed. That means there's not enough tension on the wire. Tighten the tension adjustment knob until the rollers stop slipping and start feeding the wire. Conversely, too much tension can be hard on the rollers. Back off the adjustment knob until the rollers start to slip, then tighten the adjustment knob about 1/4 turn. The best tension setting is the point just past where the rollers stop slipping.