Campbell Boat Owners Website

Ethanol

Article by Campbell Boat Owner Ron Fasola, owner of "Strange Brew"

The following information came from paraphrasing from an article on this subject in the West Marine catalog, various internet articles, and some personal opinions.  The bottom line is that ethanol in gasoline presents a host of problems for us boat motor owners.

FROM WEST MARINE (MOSTLY)

Ethanol is an alcohol, made from grains or corn, added to gasoline to oxygenate, (add oxygen), to gasoline.  Most states have mandated replacement of a former gasoline component or additive called MTBE, (methyl tertiary butyl ether), with ethanol.  MTBE  was used to oxygenate gasoline and to raise its octane, but it fell out of favor when it became known that MBTE contaminated underground water tables when gasoline containing it was spilled, and it was also suspected of being a carcinogen. Ethanol, made from Midwestern corn, replaces MTBE and is being gradually added to the nation's supply of gasoline.  Because it reduces our country's dependence on imported oil, (and enriches corn farmers), ethanol is politically popular, and is not likely to go away. 

The current blend of ethanol-modified gasoline at your local fuel dock or land station is called E-10, and contains up to 10% ethanol.  There is a push by corn farmers and ACE, (American Coalition for Ethanol), to require E-15, which is 15% ethanol.  Not one current single engine manufacturer approves of gasoline with over 10% ethanol for use in their engines.  Mercury approves and warranties the use of E-10 fuels in their products.  A few states now have E-85 fuel, (85% ethanol), for use in late model flex-fuel cars.  Don't even think about using this gasoline in a boat motor.       

Every state currently sells SOME E-10 gas at public pumps.  Several states do not label gas pumps when ethanol is added to gasoline, others states label only when alcohol added exceeds 1-2%.  Pumps which have no ethanol today, will likely switch over to E-10 in the very near future.

California DOES require a label on the pump for ethanol presence.  Arizona SOMETIMES requires labeling, depending on the percentage of ethanol added.  Most marinas are required to post the ethanol content in their fuel.

The problems with ethanol containing gasoline, even just 10% like E-10, are serious for boat owners:

Ethanol acts as a detergent

It loosens rust, debris and other gunk inside your tank and fuel lines.  This crud, when loosened, then can clog fuel filters, restrict fuel flow, and cause stalling and hard starting.

Ethanol is hygroscopic

It absorbs water, and will mix more easily with water than with gasoline.  Up to 10% of your fuel could become a water-ethanol mix, and the liquid may undergo "cooling-induced phase separation", forming a top layer of pure low-octane gasoline and a bottom layer of water-saturated ethanol.  Since the fuel pickups are located just above the tank bottom, the water contaminated fuel will be picked up first and can cause your engine to run badly, or not run at all.  This low-octane fuel causes problems with performance in four stroke engines, and can cause damage in two stroke outboards from lean fuel and lack of the in-fuel lubricating oil, (due to the presence of the water).

Octane loss

Ethanol has a short six-week shelf life, and the octane begins to decrease after that time period.  This is a minor concern in a car, but this rapid octane deterioration is a more substantial problem in infrequently used boats or during winter haulouts.  The word is that E-10 gasoline has a shelf life of about 90 days MAX, under ideal conditions. The shelf life of gasoline without ethanol in it used to have a shelf life of up to several years! 

Damage to fuel tanks

Ethanol's corrosive solvent-like characteristics can also damage some plastic and rubber materials, (like some O-rings).  Most significantly, it harms the resins in fiberglass fuel tanks, with documented cases where tanks have slowly softened and begun leaking.  Black sludge is also created that builds up on intake valves, (which can cause them to stick), and on fuel injectors; clogging their orifices, with the potential for major engine damage.

What Can You Do?

Use a fuel stabilizing additive. 

Although treatments like StarTron and Sta-bil do not remove water from fuel, they contain detergents to battle ethanol dissolved gunk, help to prevent a loss of octane, and delay water phase-separation.  West Marine stores and Home Depots carry Sta-bil.

Don't mix ethanol-enhanced fuel with old gas that contains MTBE. 

A gell-like material could be formed.  There's probably not much old MTBE gas out there anymore.

Install a fuel/water separator filter. 

Then carry a replacement filter, and the tools needed to replace a filter element on board to deal with a clogged filter while on the water. 

Watch your tank levels. 

Avoid storing full tanks of gas for long periods of time.  The argument FOR keeping full tanks is that full tanks prevent water from condensing on their walls.  Since Havasu is usually dry, it appears keeping low tank levels may be wiser for those of us who keep our boats in Havasu.

It might be prudent to simply add stabilizing additive every time fuel is taken onboard, to avoid having to keep track of when it was added, when is the next time the boat will be used, cancelled boating trips, etc.

Notes:

Before MTBE, lead, (tetra-ethyl lead or TEL), was used as the most economical way to increase octane.  TEL fell out of use because of the toxic effect lead has, and also because it poisoned catalytic converters.  TEL is still used in aviation gasoline to achieve the required high octane required for airplanes.

There have been many technical arguments that indicate that ethanol use for gasoline makes little sense when the total environmental picture of the water, energy, land, etc. used in producing ethanol from corn is considered.  Also, the actual energy in ethanol, in BTU's per any volume unit, is far less than gasoline, so the total energy content of a gallon of gasoline with ethanol in it is reduced.  This means less mileage, directly proportional to the amount of ethanol in the gasoline, is derived from ethanol-containing gasoline.  Some feel ethanol is just a "green cover" for subsidizing corn growers, because it appears growing and harvesting corn for fuel is not currently economically possible without federal subsides.