exavid· Postpubescent member
I used to test gasoline for alcohol when I was using it for aircraft fuel. The old Marvel carburetors rubber parts don't like ethanol or at least didn't when alcohol was first added. A lot of folks who had aircraft engines that could be STC'd for auto gas saved money by using it when 80/87 avgas disappeared due to lead. I used to test gas by dumping equal measures of gasoline and water into a tall narrow jar shaped somewhat like a test tube. If you mark the jar with two measures of water, make a mark where the first measure fills the bottle then another mark with two measures of water. Dump out the water and dry the bottle. Then put one measure of water in the bottle add one measure of gasoline, shake it a bit and let it settle. If there's alcohol in the bottle there will be less than two full measures in the bottle once it's settled.