I know this has been discussed before but here is some additional
information and an additional heads up:

__________________________________________________ __________________________

From http://my.boatus.com/forum/forum_pos...TID=56486&PN=1

First the whys:
Ethanol is being used as a replacement for MTBE, a component of gasoline
that has been banned in many states because of health concerns. The 2005
Energy Bill contained several changes that affect boaters: First, the bill
eliminated the need for oxygenated gas, the main reason MTBE was used
(reformulated gas is still required in high pollution areas, but is not
necessarily oxygenated and is typically used only in winter); second the
bill mandated a certain amount of ethanol in the nation's fuel supply; and
third, the bill did not give liability protection against MTBE lawsuits. The
last reason is why ethanol is spreading quickly - many gas companies are no
longer adding MTBE even if they still can legally, and ethanol is used to
add back the octane that removing MTBE took away. Because of its corrosive
nature and affinity for water, ethanol is added at the tank truck just
before delivery and the same truck that goes to the corner gas station also
goes to the marina.

Because there is a federal mandate for producers to use a certain amount of
ethanol (which increases over the years), there doesn't appear to be any
economical way to keep it out of marinas.

How this affects boaters:
There are two issues - one is a safety issue for those boats equipped with
fiberglass gas tanks, generally those made before the mid-80's. Ethanol
tends to dissolve certain resins, which then find their way through the
engine intake and coat intake valves, which makes them stick causing bent
pushrods or worse. More important is the possibility of a gas tank degrading
to the point of leaking. As anyone knows, gas is the bilge is an explosion
waiting to happen. In addition to boats such as Hatterases, Betrams, and
Chris Crafts made before the mid-80's, some smaller boats, notably Boston
Whaler Montauks, have small above-deck fiberglass gas tanks. Some of these
tanks have been reported leaking as well. Any boat with a fiberglass gas
tank that was not specifically designed for ethanol should be suspect. There
are some resins that are immune to ethanol (some vinylesters, for example)
and are used in underground gasoline storage tanks, but most resins,
including common epoxies are not able to withstand contact with ethanol.
Though it's no comfort to those with fiberglass gas tanks, fortunately, only
a very small percentage of boats have them.

Go to this website and click on the link for results of BoatU.S. sponsored
test done on gas and fiberglass: http://www.boatus.com/seaworthy/default.asp

Ethanol can also affect many plastics and rubber. However, most fuel hoses
made after 1984 and marked with SAE J1527 are designed to withstand ethanol.
Some older fuel filter bowls made of plastic may be affected and some seals,
o-rings, or plastic parts could be damaged.

The other issue is performance and driveability. Ethanol absorbs water
readily and as little as .5% water will cause a phase separation. A
water/ethanol mixture, being heavier than gas, will sink to the bottom of
the gas tank, leaving a lower octane gas on top. This low octane gas can
cause performance issues with 4-stroke engines, but can cause damage with
2-strokes due to a lean condition. In addition, 2-stroke engines can be
damaged if a quantity of water/ethanol is ingested since the proper
lubricating oil won't be present. Keeping water out of the tank is obvisouly
important.

Another problem with the introduction of ethanol copmes from mixing gas with
MTBE and gas with ethanol, especially in the presence of water. This
chemical soup is believed by some manufacturers to create a gel-like
substance that clogs passages in carburetors, most notably in outboards.
Stalled engines and shop bills are the result. Fuel injected engines seem to
suffer much less than carbureted ones.

When ethanol is first introduced, you may experience more frequent fuel
filter replacement as ethanol's superior solvent properties cleans old
varnish and other stuff from the tank.

Note that boats with diesel engines are not affected. At this point ethanol
is not being added to diesel and probably won't be.

Gas with ethanol also typically delivers slightly less fuel economy.

What can you do?
For those with affected fiberglass fuel tanks, the only sure cure is
replacement, usually with aluminum. Ethanol itself does not appear to affect
aluminum, except when mixed with water, where it may contribute to internal
corrosion. Polypropylene gas tanks are unaffected by ethanol, according to
manufacturers. Those with fiberglass gas tanks are urged to install a vapor
detector in the engine space (a good idea anyway) until replacement can be
carried out. And checking for the black substance under the carburetor or in
the intake manifold will alert you to the fact that intake valves are also
being coated.

Keeping water out of your gas tank is important! Keep your tank filled if
you are in an area with large daily temperature swings to prevent
condensation, but remember that gas with ethanol has a shorter shelf life -
use it up. Boats that are going to sit for long periods should store the
tanks empty if possible. Note that gas drying additives are typically simply
ethanol and won't help. The installation of a water separator in the fuel
line can help with small amounts of water. Outboard manufacturers also
recommend adding an injector cleaner to the fuel.

Keep some extra fuel filters on hand, especially during the first season.

Most marinas are not required to post ethanol content on fuel pumps.
Hopefully, marinas will be extra careful to avoid water contamination of
storage tanks. If the lessons of Long Island Sound, where ethanol was
introduced a couple of years ago hold true, problems will begin during the
changeover and should lessen as the season progresses.

The good news:
Nearly all engine manufacturers say that up to 10% ethanol (the current
federal limit) is OK to use. As long as water is kept out of fuel tanks and
fuels are not mixed, aside from boats with fiberglass gas tanks, problems
hopefully will be minimal.
__________________________________________________ __

as little as .5% water will cause a phase separation.

That's a HALF-GALLON in a 100 gallon tank. If there's that much water
getting into the tank on the boat then you've got big problems elsewhere.

Jim, here's some past discussion.

http://groups.google.com/group/rec.b...e7b2046f5b7888

After reading the evidence provided by BoatUS, the thread back in
April is rather "humorous"
to see the one[s] who jsut can't listen to reason....



JimH wrote:
I know this has been discussed before but here is some additional
information and an additional heads up:

__________________________________________________ __________________________

From http://my.boatus.com/forum/forum_pos...TID=56486&PN=1

First the whys:
Ethanol is being used as a replacement for MTBE, a component of gasoline
that has been banned in many states because of health concerns. The 2005
Energy Bill contained several changes that affect boaters: First, the bill
eliminated the need for oxygenated gas, the main reason MTBE was used
(reformulated gas is still required in high pollution areas, but is not
necessarily oxygenated and is typically used only in winter); second the
bill mandated a certain amount of ethanol in the nation's fuel supply; and
third, the bill did not give liability protection against MTBE lawsuits. The
last reason is why ethanol is spreading quickly - many gas companies are no
longer adding MTBE even if they still can legally, and ethanol is used to
add back the octane that removing MTBE took away. Because of its corrosive
nature and affinity for water, ethanol is added at the tank truck just
before delivery and the same truck that goes to the corner gas station also
goes to the marina.

Because there is a federal mandate for producers to use a certain amount of
ethanol (which increases over the years), there doesn't appear to be any
economical way to keep it out of marinas.

How this affects boaters:
There are two issues - one is a safety issue for those boats equipped with
fiberglass gas tanks, generally those made before the mid-80's. Ethanol
tends to dissolve certain resins, which then find their way through the
engine intake and coat intake valves, which makes them stick causing bent
pushrods or worse. More important is the possibility of a gas tank degrading
to the point of leaking. As anyone knows, gas is the bilge is an explosion
waiting to happen. In addition to boats such as Hatterases, Betrams, and
Chris Crafts made before the mid-80's, some smaller boats, notably Boston
Whaler Montauks, have small above-deck fiberglass gas tanks. Some of these
tanks have been reported leaking as well. Any boat with a fiberglass gas
tank that was not specifically designed for ethanol should be suspect. There
are some resins that are immune to ethanol (some vinylesters, for example)
and are used in underground gasoline storage tanks, but most resins,
including common epoxies are not able to withstand contact with ethanol.
Though it's no comfort to those with fiberglass gas tanks, fortunately, only
a very small percentage of boats have them.

Go to this website and click on the link for results of BoatU.S. sponsored
test done on gas and fiberglass: http://www.boatus.com/seaworthy/default.asp

Ethanol can also affect many plastics and rubber. However, most fuel hoses
made after 1984 and marked with SAE J1527 are designed to withstand ethanol.
Some older fuel filter bowls made of plastic may be affected and some seals,
o-rings, or plastic parts could be damaged.

The other issue is performance and driveability. Ethanol absorbs water
readily and as little as .5% water will cause a phase separation. A
water/ethanol mixture, being heavier than gas, will sink to the bottom of
the gas tank, leaving a lower octane gas on top. This low octane gas can
cause performance issues with 4-stroke engines, but can cause damage with
2-strokes due to a lean condition. In addition, 2-stroke engines can be
damaged if a quantity of water/ethanol is ingested since the proper
lubricating oil won't be present. Keeping water out of the tank is obvisouly
important.

Another problem with the introduction of ethanol copmes from mixing gas with
MTBE and gas with ethanol, especially in the presence of water. This
chemical soup is believed by some manufacturers to create a gel-like
substance that clogs passages in carburetors, most notably in outboards.
Stalled engines and shop bills are the result. Fuel injected engines seem to
suffer much less than carbureted ones.

When ethanol is first introduced, you may experience more frequent fuel
filter replacement as ethanol's superior solvent properties cleans old
varnish and other stuff from the tank.

Note that boats with diesel engines are not affected. At this point ethanol
is not being added to diesel and probably won't be.

Gas with ethanol also typically delivers slightly less fuel economy.

What can you do?
For those with affected fiberglass fuel tanks, the only sure cure is
replacement, usually with aluminum. Ethanol itself does not appear to affect
aluminum, except when mixed with water, where it may contribute to internal
corrosion. Polypropylene gas tanks are unaffected by ethanol, according to
manufacturers. Those with fiberglass gas tanks are urged to install a vapor
detector in the engine space (a good idea anyway) until replacement can be
carried out. And checking for the black substance under the carburetor or in
the intake manifold will alert you to the fact that intake valves are also
being coated.

Keeping water out of your gas tank is important! Keep your tank filled if
you are in an area with large daily temperature swings to prevent
condensation, but remember that gas with ethanol has a shorter shelf life -
use it up. Boats that are going to sit for long periods should store the
tanks empty if possible. Note that gas drying additives are typically simply
ethanol and won't help. The installation of a water separator in the fuel
line can help with small amounts of water. Outboard manufacturers also
recommend adding an injector cleaner to the fuel.

Keep some extra fuel filters on hand, especially during the first season.

Most marinas are not required to post ethanol content on fuel pumps.
Hopefully, marinas will be extra careful to avoid water contamination of
storage tanks. If the lessons of Long Island Sound, where ethanol was
introduced a couple of years ago hold true, problems will begin during the
changeover and should lessen as the season progresses.

The good news:
Nearly all engine manufacturers say that up to 10% ethanol (the current
federal limit) is OK to use. As long as water is kept out of fuel tanks and
fuels are not mixed, aside from boats with fiberglass gas tanks, problems
hopefully will be minimal.
__________________________________________________ __