Pacemaker Boats

[merwin10]

Thanks goes out to Associate Editor, Seaworthy Magazine, BoatU.S. for this article -

Mike -


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.

To keep on topic, I'm closing this thread to use as an alert. It may be changed as we learn more. Feel free to start a new thread on ethanol if you want.

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Associate Editor, Seaworthy Magazine, BoatU.S.
http://www.boatus.com/seaworthy/default.asp
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"Best part of Boating -- is the people you meet"