[C320-list] Ethanol Gas and Phase Separation

[Warren Updike]

I was prompted by a conversation with my PHD friend to do some research and
write the following:
   There has been a lot written about E10 and its effects on users. "Phase
separation" are words you hear often associated with ethanol gasoline. It's
something that happens when the E10 or E15 gets exposed to too much water
and it spells bad news when it comes to running the fuel in your car or boat
or lawn mower." 
   Notice the words, ".exposed to too much water."? It turns out that phase
separation is a chemical reaction that occurs when too much water is present
in ethanol gasoline. What does this mean for us? For outboard motors, it
means that if you keep the air vent closed on the tank, and store reserve
fuel in a sealed container, the chance of having water get into the gas is
greatly reduced. Dr Musto tells me he will use ethanol gasoline has been
stored for months if stored in properly sealed containers. 
   So, how does water get into gas tanks and containers? And, this applies
to diesel tanks as well. Well, one way is to buy it with the water already
in there. The other way is from the environment. If there is the ability for
air to get into and out of the storage vessel, there is the ability for
moisture in the air to be carried into the container. As ambient
temperatures fluctuate, air will move into and out of the vessel carrying
moisture. Inside the container, the moisture can condense into water. The
water will sink to the bottom of the tank and when sufficient water is
present, phase separation will begin.
   We diesel users won't experience phase separation; but, other things
happen with water in diesel. Diesel tanks are not sealed like outboard gas
tanks and storage vessels. Air movement in and out of diesel tanks is mostly
a given. Most of the risk may be abated by keeping your diesel tanks as full
as possible. Certainly, never leave a boat for weeks or months with less
than full tanks. When water sits at the bottom of the diesel fuel, small
critters can develop in the boundary between the water and fuel. As they
complete their life cycle, their dead bodies gather on the bottom of the
tank. Eventually, this gook can be stirred-up by boat motion and be sucked
into the fuel line. Hopefully, the gook will be trapped in the fuel filters.
If not, more dire consequences may occur, usually in the middle of your
cruise when the waves are throwing the boat around.
   Bottom line: don't  be reluctant to use ethanol gasoline that has been
properly stored. 

For more information on the subject see
https://www.bellperformance.com/blog/bid/114018/Phase-Separation-Water-E10 

Warren and Pattie Updike
1994 C320 "Warr de Mar" #62
Middle River, Chesapeake Bay