Thanks for your reply. Yes, the tubes are nearly equally down inside the collars, but not exactly. I positioned the assemblies next to each other in such a way so that the tops of the tubes that are inside the collars are even with each other, for a good tube length comparison. It's the tubes themselves that are different lengths, and not so much the collars. I realize I could knock the new tube down further inside the collar to get an overall length closer to the original, and even knock the collar deeper into the hole in the carb body, so the tube hangs deeper down in the hole. Just wondering if it matters. Could the fuel ever get so low that a 1/8" shorter tube couldn't reach it?