clark welders

I was having a similar problem,, and found that when the spool of wire was installed,, the label covering the centre hole had not been removed, just crammed over the spindle, and the label was stuck to the inner side hole of the spool and binding.. so the wire would come at sporatic speeds,, check the inside of the spool, clean as nec,, AND never install a spool without removing the nec label..

hope it helps