Buying gasoline used to be a simple transaction. Then came the choice of different octane ratings, followed by leaded versus unleaded. Now gas is changing again. The gas you buy this season at the fuel dock or gas station may not be the same as the gas you bought last year. Gasoline refineries are phasing out the use of MTBE, a toxic additive that helps oxygenate gas and reduces emissions, and replacing it with ethanol. Your car or truck will never notice the change. Your boat, however, may well.

If you boat in an area where MTBE is being removed and a reformulated gasoline blend called E10 (because it contains 10% ethanol) is substituted, it may be necessary to take steps to protect your engine from the effects of the switchover.

As of mid-April of this year, E10 was sold at around 40% of all gas stations in the U.S. but is not being introduced universally or on a set time schedule. Diesel fuel will not be affected.

Most oil refineries are removing MTBE from their products because federal legislation passed in 2005 did not provide limits on liability for refiners that used MTBE, which was required by the EPA. As a result, while using MTBE is still legal in many states, the refineries are treating it as a banned substance. The result is more and more regions of the country receiving E10 gas at the pumps, exposing more boaters to the potential problems.

Ethanol has been linked to the weakening of fiberglass gas tanks, clogged fuel filters and carburetors. E10 has a shorter shelf-life than gasoline and also attracts water, causing yet another set of problems. But most alarming is the deterioration of certain gas tanks.

The majority of gas tanks on boats are made from either aluminum or plastic. However, some older boats, mostly high-end sportfishers, were built with fiberglass gas tanks as are some smaller, portable, and under-the-seat gas tanks in newer boats. Custom and semi-custom yachts may also have fiberglass tanks, but typically are diesel powered and therefore remain unaffected.

BoatU.S. Magazine reported in January that the ethanol in E10 gas was dissolving a limited number of older fiberglass tanks with potentially disastrous consequences. Independent laboratory tests sponsored by BoatU.S. Marine Insurance have now confirmed that the resins used in some fiberglass tanks are leaching from the tank walls, weakening the tanks.

The resin released by ethanol makes its way through the fuel system where it sticks to valves and other internal engine parts. The buildup of this sticky black substance has bent pushrods, clogged intake valves and ruined some engines. Affected engines may run rough, stall or bog down under load.

The fiberglass tank of any boat whose engine experiences these symptoms/damage needs to be inspected immediately and replaced if necessary. If your boat contains fiberglass gas tanks, consider it a prime candidate for tank replacement. Consult the manufacturer, if possible, to determine what type of resin was used to construct the tank. Tanks built with vinylester resins may resist degradation. Again, diesel powered vessels are not affected.

But even if you don’t have a boat with fiberglass tanks, the properties of ethanol could still cause problems, particularly in older boats. Ethanol is a solvent and attracts water. These two properties can lead to clogged filters, inadequate lubrication in two-strokes, and low octane conditions that can damage engines.

There is also anecdotal evidence that the mixing of MBTE gas and E10 gas may be responsible for producing a gel-like substance that clogs carburetors and fuel injection passages. Boatyards in the Long Island, NY, area reported rebuilding hundreds of carburetors at the beginning of the 2005 season instead of the usual dozens. New York state phased out MTBE well ahead of much of the country.

The simplest precaution you can take is to burn as much of the gas that is left in your tank from last season as possible before refueling this year. If you haven’t already topped off your tanks this season, don’t.

But even if every drop of MTBE gas is out of your tank, ethanol’s properties as a solvent will still loosen deposits in fuel tanks and lines leading to clogged filters, carburetor jets, or fuel injectors. If you have an older boat, expect to change filters much more frequently this season. Keep spares aboard so a clogged filter doesn’t leave you stranded when it starves your engine for gas.

The other concern with E10 is ethanol’s affinity for water. Ethanol absorbs water — for years ethanol was sold as “dry gas,” an additive to remove water from gas tanks. And it works — to a point. E10 gas will phase separate, or spontaneously divide out into its component parts in the presence of as little as one half of one percent water. This means that if a boater with a 100-gallon tank has as little as half a gallon of water in the bottom of the tank and adds E10 gas, the ethanol in that gas will separate out and could render the gas unusable in many cases.

Without ethanol blended in gasoline, it reverts to low octane base stock. Typical 87 octane E10 that phase separates would become 83 or 84 octane fuel, which would cause knocking in most engines, or not run them at all. Premium grades of E10 that were sold as 93 octane at the pump would become 89 octane if separated, which would still run most engines, but could void the warranties of some high performance engines.

In addition, there is concern that introducing E10 fuel into warm, high humidity climates could speed up the corrosion of metal tanks. Unlike gas tanks on automobiles which are closed, marine fuel tanks vent directly to outside air. Ethanol will draw moisture from the air through tank vents. The more water drawn in, particularly from salty air, the faster a tank will corrode. As of now, it is unclear how much faster this process will take place.

Keeping tanks full, common wisdom for avoiding moisture accumulation during winter storage, would minimize the “breathing” of the fuel tank, but E10’s shelf life has been estimated to be as low as 60-90 days. After that the gas may begin to degrade, which could gum up carburetors or fuel injectors.

So What Can Be Done?

Preventative maintenance may alleviate some of the potential problems. Additional fuel-water separators will help with small amounts of water. BoatU.S. Magazine’s Technical Editor, Chuck Husick, recommends sumping an older boat’s gas tanks.

“Ask your boatyard to find a way to get a tube to the bottom of the tank and get the water out with a hand pump,” says Husick. The goal is to prevent large amounts of water/ethanol mixture from being drawn into the carburetor or fuel injection system. Four-stroke engines may burn small amounts of water/ethanol mixture without damage. But two-strokes, particularly older models that do not feature oil injection, will not fare as well, as the water/ethanol mixture will not contain the lubricating oil that two-strokes require.

Expect to change fuel filters more frequently as the ethanol loosens deposits in the gas tank that may have built up over time. Don’t let gas sit in tanks unused for long periods of time. The longer it sits, the more time it will have to absorb water.

Above all, pay more attention to your engine(s) this season. Pay attention to a knocking or rough running engine, signs that your gas may have separated. If it has, the tank must be drained or you risk considerable engine damage.

Is E20 Next?

America’s corn belt agribusinesses produce more than nine billion bushels of corn each year. Canada adds another 350 million bushels. With the production of all this corn comes the need for an ever expanding market. Using the surplus corn to produce ethanol is an attractive option for America’s agricultural interests, especially with the 51 cents per gallon federal subsidy that keeps the cost of adding ethanol to gas artificially low.

While ethanol producers hope to wean the U.S. economy off of petroleum-based products, they have a long way to go, even though more than 30 new ethanol production plants are currently under construction along with eight major plant expansions.

Current production levels of ethanol — around four to four-and-a-half billion gallons a year — simply don’t match our nation’s thirst for fuel. In 2004, motor vehicles in the U.S., including cars, trucks, boats, and other off-road vehicles, consumed 141 billion gallons of gasoline. Accordingly, it would take 14 billion gallons of ethanol to produce enough E10 for the entire country. Even if the 30-plus new ethanol plants being built today were to come up to 100% production this year, the total capacity of U.S. producers would add up to just over six billion gallons a year. Imported ethanol will have to make up the difference between U.S. ethanol demand and capacity this year, roughly one to one-and-a-half billion gallons, much of which will come from Caribbean basin countries and Brazil.

The number one ethanol producing country in the world, Brazil, produces ethanol cheaply and efficiently from sugar cane and sugar cane waste products. The ethanol produced by this process yields about eight times the amount of energy that goes in to it. In contrast, American producers’ use of corn kernels as the basis for ethanol production yields just as much energy as it takes to produce, or possibly slightly more, depending on whose study you believe. When you add to this equation the reduction in fuel economy that accompanies adding ethanol to gasoline and the fact that producing all that corn in the Midwest uses vast amounts of fertilizer which runs off into the Mississippi River and creates a huge “dead zone” in the Gulf of Mexico each summer, corn-based ethanol production may not be the perfect solution to our energy problems.

It took Brazil, which began promoting ethanol as a fuel in 1975, over 30 years to develop the processes and agricultural infrastructure necessary so that now around 40% of their fuel needs are met by ethanol. Most gasoline in Brazil is E25. A large number of Brazilian cars can also run on 100% ethanol. In 2004 ethanol represented just 2% of U.S. fuel consumption.

Despite the fact that U.S. oil refineries will end up having to import ethanol this year to meet demand for E10, the ethanol lobby is pushing for higher and higher amounts of ethanol to be required in fuels. Minnesota is currently considering mandating E20, a blend of 20% ethanol and 80% gasoline.

In order to proceed, Minnesota must apply for a federal waiver from the EPA to be able to mandate E20. As part of that waiver process, the state must prove that the use of E20 will have no negative impacts on the drivability and durability of both automobile and marine engines, as well as small hand-held tools powered with gasoline, such as chainsaws and leaf blowers.

If marine manufacturers have anything to say about it, the backers of E20 will have to overcome research conducted by Orbital Engine Company on behalf of Environment Australia, a governmental organization similar in mission to the EPA. Orbital’s research has shown that outboards operated on E20 will suffer significant performance problems, including stalling when pushed to wide open throttle.

Other research conducted on small hand-held gas powered tools has shown that E20 will damage these engines in as little as 25 hours of light-duty use. E20 makes engines, particularly carbureted, air-cooled engines, run lean, because they provide more oxygen during combustion than gas alone. This increases exhaust temperatures as much as 100 degrees Fahrenheit leading to burned head gaskets, burned exhaust valves, scored cylinders and loss of compression. Some engines tested lost 20% of their rated power in just 25 hours use. In addition the higher levels of ethanol attacked rubber gaskets and seals, in some cases causing them to fail in as little as one week.

Based on this preliminary research, Minnesota will have to overcome a number of hurdles in its quest to expand the use of ethanol. In the meantime, BoatU.S. is working with the National Marine Manufacturers Association to alert lawmakers to the potentially dangerous effects of adding ethanol to marine fuel systems.

— By Michael Vatalaro

©BOATU.S. MAGAZINE July 2006



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