ive just aquired a mig welder got the wire to run freely which involved untangling a big not and clearing it from the tube it goes into. when i strike the welder it works but it seems to spit as you try and weld, or what i mean is rather than it doing a consistent line it justs sputters along and doesnt seem to penetrate. i have only just been given it from an old garage it hasnt been used for a year. i have turned the ampage up full cleaned the metal and earth clamp is good. could you please recommend things to do to test the welder and clean it up any little tips and tricks to get an old welder to work would be much appreciated