Thanks to Dean Z, Nick@NY casecollectorsc,Don Rudolph Bobl1958 for your wisdom and experience. I was able to get the DC running off of the 20# lp cylinder. It idled along very well. I could not rev it up, it would sound as if it was not getting fuel. Since this was a conversion and not a Case factory lp. It had the Century H vaporizer/regulator. I replaced with same. I've since ordered a book that was primarily directed at John Deere lp tractors which also used this regulator. Also I now know that after 1975 something changed about this regulator so I have a conversion directive coming also. Really made me happy to get this tractor which has not been started for 10+ years barking again. Will update when next step is accomplished. thanks to all gobble