clark welders

What Dave 69 posted. Double check the ground.
Another thing does the wire look deformed coming out of the tip crushed. Tension could be to tight or to loose.
A general way to test if you don't have enough feed pressure is to pull some wire thru bend it slightly then place I against your palm. Pull the trigger. The wire should feed. If not increase tension on rollers if it pushes to fast back off the tension.