I have a Century welder model 155GS, it is 11years old but has less than one hour total time welding. In trying to rebuild my office chair, I noticed that the welder was "studdering" or the wire would start and stop very rapidly. I can hear the transformer in the box turning on and off. The frequency increases when the amount of wire sticking out of the nozzle is short, about 1/4" and if you hold the handle further away, say 3/4" or longer the frequency slows with the increase of the lenght of wire. Changing the wire speed and/or the voltage dials do not effect the symtom. I took the sides off and checked all mechanical connections for tightness, nothing was loose. Nothing looked overheated or burned, and there was no smell of something overheating. I am stuck, can you help?
Ole Jack

 

Check your Tip! Sounds like the tip is clogged, or melted, change it, if not change the liner, it could be clogged or kinked. You also want to check the feeder, where the wire enters the rollers, sometimes just one little piece of dirt will cause the wire to jam up. Hope that helps.

 

I did check the tip and replaced it as a precaution. I also cleaned the nozzle and coated the inside with a welding prep that slows down build up. The wire always moved properly when the studdering was present. I am thinking that I am looking at a very expensive ciruit board problem. I can't afford a new circuit board and will have to sell the welder for parts.