The Mystery of the "Black Goo" -- Solved? Since the first day a gear-head decided to try running e85 in his carbureted engine the question has been around. What is that black goo that seems to form in my intake after a couple weeks? While it doesn't hurt anything, it has long been a subject of conversation and even argument among us "ethanol heads." The answer to this question isn't a simple one, but here is some information that should help solve the mystery. There are ac