I was given a firepower fp120 mig welder with the bottle/regulator but have a few problems with it performance. Short story welder was in fire at one time and got water in it from the sprinklers and then was told didn't work, I got it free took it home clean up connections with wire brush and got it working. I am wondering if I sholud put new liner in it maybe new gun cause trigger sucks compare to hobart 140 and trying to figure out best way to clean pulleys and keep the rust build up off, and could I use a electrical contact clean then use die electrial grease on all connections? welder seems to need some TLC and hey it was free and works ok but not like it fully should. Aslo little popping going on while welding but believe that might be adjustments not set right or surface not being perfectly clean for it. Any help guys? Brandon