Boating with Alcohol Laced Fuels

A lot has been written in the last few years concerning the addition of alcohol to gasoline (gasohol). Although the history of gasohol reaches all the way back to 1907, recent interest has surrounded the mandate that Ethanol has largely replaced another fuel additive, MTBE, a potential carcinogen which was banned in 25 states after it was discovered in ground water.

MTBE is made primarily from natural gas or petroleum products and has been used in gasoline since 1979. MTBE was used to replace lead as an octane enhancer and to help prevent detonation. In 1992, MTBE began to be used at higher concentrations to fulfill the oxygenate requirements required by the Clean Air Act Amendments of 1990 (CAA). Oxygen helps gasoline burn more completely and reduces exhaust emissions. The CAA required regions with poor air quality to use gasoline reformulated with an oxygenate. Most refiners chose MTBE over other oxygenates for financial reasons and for its blending characteristics. As early as 1907, alcohol was suggested as a safer alternative to tetra-ethyl lead (TEL), but was rejected for reasons that have lately made themselves clear.

After MTBE was proven to be a carcinogenic groundwater pollutant, many states banned it and caused the accelerated use of ethanol as the only economically feasible fuel additive for states with air quality problems. The Energy Policy Act of 2005 further accelerated the demise of MTBE in that gasoline marketers were no longer required to use an oxygenate, but they also did not receive the MTBE liability protection that they had petitioned for. This put refiners at a liability risk if they continued to use MTBE after an oxygenate was no longer required by law. Predictably, the demand for ethanol increased at unprecedented rates as most refiners replaced MTBE with ethanol.

Even though refiners were not obligated to use an oxygenate after May 6, 2006, most of them switched from MTBE to ethanol primarily for the following reasons:

1. There still exists EPA emissions control requirements. Adding oxygen to gasoline allows for more complete combustion of the fuel, which reduces exhaust emissions of CO (carbon monoxide), which can result in lower levels of toxic, ozone-forming pollutants and greenhouse gases, especially if higher-level ethanol blends are used.
2. Ethanol has the advantages of MTBE without the same dangers, and it contains 35 percent oxygen by weight, twice the oxygen content of MTBE. Ethanol is the highest-octane fuel in the market. Because it doesn't leave gummy deposits, it helps to keep the vehicle's fuel system clean for optimal performance.
3. Ethanol extends gasoline supplies. Because its production is encouraged by a federal tax credit of 51 cents per gallon, ethanol is economically attractive. Without this credit, it would not be as competitive.

So what is so wrong with ethanol? Well, for a very new automobile that is a daily driver and has never used anything but E10.... probably not much. However, this is about boats, not automobiles so..... here is what is wrong with alcohol.....

A Solvent

Simply put, ethanol is an excellent solvent (it dissolves plastic, rubber, fiberglass and more). The ethanol that you are putting into your tank has previously served duty literally cleaning the entire fuel-supply line, from its point of introduction into the gasoline (likely the tank delivery truck), through the in-ground storage tank, to your boat's entire fuel system. You just inherited everybody else's gunk, including your own. Additionally, it may be dissolving your hoses, fuel system components, and, yes, even your boat, if you have a integral fiberglass fuel tank! (Especially if made prior to 1991)

A Hygroscopic Agent

Unlike MTBE, ethanol will attract and absorb water. This water will cause corrosion, phase separation, loss of octane, and in the case of two-cycle engines, separation of fuel and lubricating oil.

Phase Separation

Ethanol has a great affinity for water, and will attract moisture from the atmosphere through the fuel tank vent. The water molecules form a bond with the ethanol that is stronger than the fuel’s original bond with the ethanol and since water is heavier than gasoline, the water/ethanol molecule is dragged to the bottom of the tank and separates from the more buoyant fuel molecules. This is referred to as phase separation and occurs when the water content in the fuel reaches roughly .5%. (That is only 8 oz. of water in 12.5 gallons, folks!) Ethanol provides a significant boost to the octane rating of the fuel, so when phase separation occurs you end up with a corrosive water/ethanol layer on the bottom of the tank, and fuel that no longer is adequate for most engines with respect to sufficient octane, vapor pressure, oxygenation, etc. In addition, if your 2-cycle oil is mixed in the fuel tank that, too, will join all of the rest of the goo at the bottom of the tank. Your engine will receive little or no lubrication!

Corrosion

This pretty much speaks for itself. Anything that attracts water and carries it into the most inaccessible recesses of your fuel system (e.q., fuel injection or carburetor) is nothing but expen$ive trouble you don't need out on the water.

Fuel Mileage

Ethanol has a heat potential of 76,000 BTU per gallon, which is approximately 30 percent less than gasoline's heating value (which is approximately 109,000 to 119,000 BTU/gal). The result is E-10 gasoline which should yield slightly lower mileage... a decrease of approximately 3%-5%. Fuels containing higher levels of ethanol will have a corresponding reduction in mileage. E85 fuels, for example, produce mileage approximately 30% less than gasoline.

A Realization

With good intentions, I had set about writing an exhaustive evaluation of all the things wrong with alcohol as a fuel in boats. As I approached this point in the treatise, I asked myself, "How much more gloom and doom must I enumerate before I have made my point?" I concluded that anybody reading this far, without an overwhelming conviction that there are some major operational and safety issues, is a victim of cognitive dissonance and isn't really interested in letting the facts interfere with their position.

What to do?

I don't really have the answer... I'm not a chemist, so I can't evaluate a lot of the "snake oil" claims, but I do know enough about chemistry and physical science to understand that the mechanical longevity of my fuel system and boat engines are in jeopardy. (And I have aluminum tanks, not fiberglass.) Mercury marine states that: There is no practical additive that can prevent phase separation from occurring. The only practical solution is to keep water from accumulating in the tank in the first place." and they add, "[That] there [are no] additives that can allow the phase-separated mixture to remix when added to the fuel tank; the only way to avoid further problems is to remove the water, dispose of the depleted fuel, clean the tank and start with a fresh, dry load of fuel."

1. If it's possible in your area, avoid E-10 fuel like the plague. In some states, a pump dispensing E-10 is required by law to be labeled. However, some states are legislating that those fuels containing alcohol not be labeled, feeling that it drives consumers away! Duh! See this list:
2. Install a 10-micron, water-separating fuel filter on your boat, or switch from the standard 30-micron element to a 10-micron element if you've already got a canister-type filter between your fuel tank and your engine. Suzuki (www.suzuki.com) has required a 10-micron filter for all of its OEM installations for several years, and Yamaha now offers two 10-micron filters, including one designed for the tight transoms of smaller boats. Mercury Precision Parts (www.mercurymarine.com) offers three different Racor 10-micron filter elements.
3. Carry a spare filter on board, and check the filter often for water.
4. Try to keep your boat's fuel tank filled. This will reduce the volume of the air-void space above the fuel in the tank, and reduce the flow of air in and out of the tank through the vent line that happens with changes in temperature (from cool nights to warm days, for example).
5. Add a fuel stabilizer to the fuel tank if you are not going to use the boat for more than a few weeks. This will inhibit oxidation of the fuel, which leads to the formation of deposits, commonly called varnish, gum, or gunk, in the fuel system. Follow the directions on the stabilizer, and then run the outboard for about 10 minutes to get the stabilized fuel all the way through the fuel system.
6. If you have a fishing boat with a kicker, make sure it's also protected with stabilizer and a 10-micron fuel filter.