Hobart Hefty CC/CV rat nest problem

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I have a Hobart Hefty CC/CV powered by Bobcat 250. I just got the hobart back from the shop, bought it used and didnt work so sent it in to get fixed. Im using .30 flux core  using a .35 tip(because of the flux core) and it keeps getting a rat nest in the machine just after the motor wheel that is feeding the wire into the lining. It will run for a little bit, but most of the time it will nest as soon as I get the wire out of the gun. Anyone have any suggestions? The lining in the hose was replaced so it isnt that. Thanks,Trent
Reply:I would look at the liner first.  is it the right size? if the liner is a .035/.045 then that is the problem.  the .030 wire is snaking inside the liner. also I would use the .030 tip if i am running .030 wire.  Just curious, Why are you running .030 fluxcore?  your machine will push larger wire.  Finally, back off on your tension.  if you are crushing the wire it will birdnest more easily.  oh one last thing.  on the output of the drive roll, how close is your contact?  sometimes it is too far and the wire has travel unsupported before entering the liner.Last edited by Scott Young; 03-03-2010 at 12:27 AM.
Reply:agree with above. also adjust the tension by starting with it too soft and gradually tighten so you can just stop the wire with your hand. flux cored wire that small will be very sensitive to kinking and nesting
Reply:The liner was just replaced but Ill have to check the work order to see what size was put in. It was suggested to use the .035 tip for the garless flukcore .30. dont know why, but took their advise. Ill change that back to a .030 tip. Im running the smaller wire because I use it mainly for fence and lighter material. The contact from the drive roll to the start of the liner was a concern to me, its probably about an inch or so (Ill have to check tomorrow) away. Ill take it back to the shop and have them take a look at all these things before I take it off their hands again. Thanks for the input.
Reply:the smaller fluxcore is more finicky to push.  Don't use an over size liner if you can help it.  use the right tip, and try and get as much support on the outfeed wire  as you can.  I would be curious why they recommend the oversized tip.  I have used over sized tips when i have burned up all the right sized tips.  can you take any pictures?
Reply:Thanks for the suggestions, I took it back to the shop and found out that between the drive roll and the lining it is missing a guide. And the drive roll is the wrong size. I ordered the drive roll and the guide plus I traded the .30 for some .35 flux and stuck with a .35 tip. we will see how that works. Thanks again for the help. The reasoning behind using an oversized tip is because the fluxcore expands or something. but Ill try the right tip first and go from there.
Reply:aluminium wire will expand to the point of needing a tip size bigger, but i don't know that steel wire does the same
Reply:speaking of alminum wire, Idoes anyone know if it easy to run through this machine without a spoolgun?
Reply:Originally Posted by Trentmcspeaking of alminum wire, Idoes anyone know if it easy to run through this machine without a spoolgun?