On Fri, 19 Mar 2010 18:03:07 -0500, "Karl Townsend"
wrote:

"The kid" was trying to weld irrigation pipe today. My Century 500 (private
label Sears made by Lincoln) Mig welder was giving him fits. The wire will
hang up just 1/2 a second every now and then. Changes the arc length on him.

We've replaced the liner and feed rolls, no joy. Any other suggestions?

It can't be both a Century and a Lincoln, they're competitors.

Check the condition of the wire. My little Lincoln SP125+ exhibits
the behaviour you describe with wire that is dirty or even mildly
rusty as in corroded or tarnished. I never leave wire in that
machine, always bag it after use and backfill the baggie with dry
argon from the TIG. No problems since I adopted that practice.

Mr. Miller (Millermatic 210) does not require such TLC. The little
Linc works superbly with thin metal like autobody so I tolerate its
fussiness about wire condition.