Re: Oops I messed up!!!
This from The USCG Boating Safety Circular #85
http://www.uscgboating.org/recalls/pdfs/BSC85_1.pdf
Ethanol, being alcohol based, absorbs water very
well. This is a bit of a double-edged sword for the
marine industry. Marine fuel systems are very
susceptible to water intrusion. E10 has the ability to
absorb a certain amount of water into solution and
simply allow it to be burned by the engine. As an
improvement over MTBE gasoline, which can hold
about 600 ppm in solution, E10 can hold 6,000 to
7,000 ppm in solution. Meaning, if you have a 100-
gallon (378.5 l) tank it could hold up to .6 ? .7 gallons
(2.3?2.6 l) of water in solution.
The problem for the
ethanol alternative comes with ?phase separation.?
That?s what happens when the fuel is saturated beyond
its capacity to hold water in solution. The water and
gasoline actually separate, and the gasoline floats on
top of the water. With MTBE you could simply pump
the water out from under the gasoline, or let your
filters remove the water, and burn any gasoline that
remained. With E10, ethanol blends more easily with
water than it does with gasoline. When phase
separation occurs in E10, the ethanol is pulled out of
the gas and stays with the water. This result is two
solutions, neither of which is good for engine or fuel
system. The gasoline left behind now has no
oxygenate; it shouldn?t be burned in the engine and
must be disposed of. The water left behind now
contains a high concentration of ethanol; this solution
is highly corrosive and damaging to any materials it
may be in contact with in the fuel system. The only
solution to dealing with E10 that has phase separated
is to dispose of the whole load of fuel, clean the tank,
and start fresh with a new load of E10.
Every precaution must be taken to keep water out
of fuel in storage tanks and on board. Checking fill
caps and fittings for proper gaskets, and insuring that
vent systems are up to spec, are two ways of being
certain your fuel system is sound.
E10?s ability to absorb water has yet another
drawback: it can absorb water directly from the
atmosphere through the vent while simply sitting in
the tank. In just 100 days at 70% humidity, E10 can
absorb enough water to phase separate. The shelf life
of E10 is only 60?90 days if left without treatment.
Gasoline ?oxidizes? when exposed to air. That is, it
loses its volatility over time. A good nonalcohol fuel
stabilizer (we don?t want to add even more alcohol to
the mix) is highly recommended at all times in your
fuel. There are several products on the market that
will do a great job. But the key for any boatyard or
boater is to not leave a boat for long periods of time
with a large load of fuel aboard. If the yard or owner
knows there will be an extended delay between trips
out, then leave the tank low and refill just before the
next trip out. In general, the more the boat is used,
the better off it will be.
When it comes to winter storage, a boatyard should
run the tank down as low as possible at the end of the
season and treat what is left for the winter. That of
course goes against traditional thinking in terms of
condensation, but: better a small amount of water from
condensation than a tank full of bad gas.
Looks like I need to update my keep it full all winter theory
