sp 135 sputtering arc

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I have an out of warranty sp 135 mig that started acting up last night.  It does not maintain a constant arc but stops and starts intermittently (once or twice per second.)   You can feel the wire pushing back at you until it fires.  Of course, it is playing heck with the breaker, but that is because it is constantly starting and stopping the arc.  I put a new feed tube in and checked the wire speed, it seems to be working properly as is the amp settings.  Also, cleaned the grounding clamp.  Used it on several different setting and was the same on all settings.   Instead of the normal HISSSSSSS, it is pop - pop-pop.  The welds of course look like the machine sounds.  I will get the owners manual tomorrow from the Lincoln site, but thought I would put this out there just in case it rings a bell with anybody.  I am using gas, not flux core, when I shut the tank off and fire up the gun the guage drops so it appears to be getting shielding gas.   I cleaned up everything this morning thinking it was a feed problem, but I think it is an electrical problem.  Of course a three day weekend, and I had plans for the welder this weekend.  Oh well, I'll find another project to do.  Thanks!
Reply:The wire tensioner comes to mind, clean everything out with compressed air. Is the whip kinked anywhere? A kink in the liner is bad. I like using a wiper with solvent on it to keep from gunking up the liner with dust. The drive rolls need to be the correct size and clean and smooth. A full spool of clean wire helps a lot. Try the block of wood test, hold the gun close to a block of wood and pull the trigger. Wire should curl out from between the gun and block smoothly. That can be adjusted to some degree by adjusting the wire tensioning knob. When it doesn't feed smoothly, find an equipment repair shop, or start trouble-shooting if you feel confident.Welcome to the shop floor. City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:While I am not intimately familiar with that type of welder, may I suggest you check the tightness of the allen screw that holds the liner at the gun end.  If this is loose  or corroded it can cause that sputtering problem.  Hope that may help.Good luckEd
Reply:Thanks for the thoughts, but I pretty much looked at all of the things that you have suggested.  The wire actually contacts the work without an arc and drives the gun away from the work until the arc starts.  Maybe I can try cleaning the ground cable.  When this started it was welding  normally and then the arc grew visibly smaller and weaker and then started this sporadic stuff.  I think it probably needs to go into the shop for an experts opinion.  Thanks for your help!
Reply:PROBLEM SOLVED!  The positive connection inside of the case had been arcing and had finally corroded the connection so bad that it could not maintain a constant arc.  I cleaned up that connection (abrasive paper) and tightened the negative connection which had worked loose as well and it is back to humming away.  I am going to apply some dielectric grease to help with the electrical connection and keep from arcing so bad.  The wing nut was tight, but the underside was all eaten up by the arcing.  I also cleaned up the ground clamp which was looking a little moth eaten as well.  This would probably hold for any welder, you should probably check the connections periodically anyhow, but as we all know, there isn't a problem until there is a problem so preventative maintainance gets a back seat.  Thanks to all.
Reply:Damaged polarity studs are not covered under warranty on any make of welder.When the damage is caused by a loose connection on the customers side of the panel.It is owners responsibility to kept them clean and tight.