G'day Tommy, have you tried adjusting it mate by loosening the set screw in the section that the jet is screwed in (and in a darkish room) pulled the burner in an out till you get those little dancing blue devil flames and then tighten up the set screw?
Yes Jim, I tried adjusting the jet assembly in the tube. I had in all the way and slowly worked it out
looking for those devils. The flame never changed. Wrong jet? It's a #5.