" The problem is this tubing is extremely yellow, and it wipes out the blue dye in the 100LL fuel to the point that it's like water. The easy solution would be to put a little ball of some sort in the tubing, and it would have to be 3/16" or smaller to freely float to the surface."
I'm figuring all those little balls from a batery hydrometer will sink in 100LL. The specific gravity(SG) for 100LL is .72, The SP for electrolyte in a charged battery is 1.265 and 1.1 for a discharged battery at 80 degree F. The bottom line is that electrolyte from a battery is denser that 100LL avgas. I have a few old ball type battery hydrometers setting around the shop, tomorrow I will attempt to float their balls in a container of straight mogas, no alcohol. I'll post the results after work tomorrow. Brant Hollensbe Des Moines, Ia
