I've seen that happen a bunch of times (I've been a mechanic for the past 20
years), mostly with metal bowls. I've never seen an official explanation but
my best guess is that the evaporation of the fuel lowers the temp of the
bowl (evaporation uses the heat energy) and the lower temp of the bowl
coming into contact with the moisture in the air causes condensation. On the
bowls I've used I've actually watched the droplets form on the upper exposed
areas and then travel downward, mixing with the gasoline.

Ken


"John Wentworth" wrote in message
...
I observed an interesting thing today while working on a small gasoline
engine. I drained the fuel from the carb bowl into a small metal
container while working on the carb. After about 5 minutes I noticed the
fuel in the container had turned a milky white. I poured a small
quantity of fresh gas into another container and, after about 5-10
minutes it also turned milky white. The fuel is 87 octane unleaded
Getty, I also tried the smae fuel from Mobil. The humidity today was
about 95%. My guess is that the fuel contains alcohol and is absorbing
water from the humid air. Have anyone seen this happen?