Call the Airgas distributor in Salt Lake or Ogden. Get in touch with a guy named Phil Bowden. If Airgas can't fix you up, then Phil might be able to put you in touch with another local repair shop that can do a good job.
Praxair welder repair in SLC. Address is 1900 S. and 300 W. the phone number i have is 801-924-0164. they have done work for me in the past on a classic and a 305D. i think they do a better job then Airgas especially on engine drives. Airgas bought out the shop in ogden. that would be closer to you. address is 3050 S. 1235 W. in ogden west off the 31st. street exit. phone number is 801-334-0060.