Clean the orfice, and adjust the air until you get a nice flame. The adjustment changes with altitude, and a very small movement can get things burning nicely. Just a matter of taking your time to get it right!! I soak the orfice in alcohol for a few minutes and then blow out with air. A plastic bristle from a tooth brush works well. Don't use anything metal to clean it.
2012 GMC 2500 HD Duramax Denali
1994 Excella 34' 1987 Limited 34'
1976 31', 1976 Argosy 22' Gone to new homes