Welding and Metalworking - Lincoln 135 won't feed wire

I have a Lincoln SP-135T mig welder that has worked perfectly until today. The drive wheel just spins but won't feed any wire through. I have half a roll of .035 left that has been feeding perfectly. I checked that the groove size is the right size,(the bigger groove). You can feed the wire through by hand very easily. Even when I tighten the thumbscrew down pretty tight, the drive wheel just sits there and spins. Any ideas or thoughts? It has sat for about 2 months without being used, condensation/corrosion of some sort?
Thanks for any ideas.
Joe B

Remove the tip on the gun and see if it will feed wire. If it feeds without the tip in place you probably need a new one (tip).

If that did not work. Release the drive wheel inside the welder and go to the end of the gun and pull out the old wire that is in the gun cable, probably about 10 feet. Re-engage the drive wheel and give it a try.

Make sure that the spool of wire can turn freely. If you store your extra tips and nozzels in there like I do maybe something is jamming the spool from turning.

Those are some great ideas, I will give it a try and see how it goes. Always seems so simple once you stop and think about it.
Are you a pilot too? Fun life isn't it?
Thanks and I will let you know how it works.
Joe B

I took all the tips off, pulled the wire out, fed it through again. It only binds up right at the handle. Works perfectly feeding the wire all the way through, until the wire hits the handle, then the drive wheel starts spinning and the wire stops feeding. Thought of WD-40 but figured that would only be a temporary fix. Any more thoughts? At least I found out where the snag is, now just need to figure out how to fix it.
Anybody? Any more thoughts?
JB

it is probably the liner. you can go to lincoln electric web site and search in parts for a magnum 100 gun and it will show a schematic of the parts.