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Adding fuel to the fire?

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By FRANK SARGEANT

Tribune correspondent

Published: April 26, 2009

The Environmental Protection Agency, at the urging of some segments of the agricultural industry, is considering a proposal to allow an increase of ethanol in gasoline to 15 percent, from the current 10 percent maximum allowed nationwide.

The public comment period began Tuesday and will continue for 30 days.

While ethanol appears to cause no harm in cars, there have been reports of issues when it is used in marine engines. Martin Peters, spokesman for Yamaha Marine, the world's largest outboard manufacturer, said the change could be troublesome for boaters.

"All modern outboards are designed to live with 10 percent ethanol. It's not the best fuel and it can cause problems, but the motor parts can stand up to it so long as you use fresh fuel that's not contaminated with water or dissolved plastics from an older fuel tank," Peters said. "That may not be the case with 15 percent ethanol. This is increasing the ethanol content by 50 percent, remember, and it's sure to cause more problems with water attraction if it becomes standard issue fuel."

Ethanol is an alcohol made from corn or other plant products, and is used in gasoline as an oxygenator that reduces toxic emissions when the fuel is burned. It's also being pushed as a way to reduce dependence on foreign oil, though there's some argument regarding the amount of tractor fuel required to produce grain ethanol. The net benefit appears to be small.

The big issue when ethanol-mix fuels are used in boats is that the fuel often sits in the tank for months before it is used. Unlike in a car, where the turnover is often weekly, some boats are stored for long periods before they burn off a tank of gasoline.

"When a boat sits with the tank partially full, the heating and cooling causes condensation inside the tank," Peters said. "And ethanol fuels attract that moisture and mix with it; pure gasoline does not."

Peters said the water can cause the oil to be washed off cylinder walls and rings in two-stroke outboards, resulting in serious engine damage.

"We have also seen some cases in four strokes where residue that is dissolved by ethanol in the fuel tank collects on the valve edges and stems," he said, "and this not only causes rough running but in extreme cases it can cause the piston to hit the valves, and again you've got a major repair."

To assure you won't have problems with the current 10 percent mix, Peters suggested the following:

•Use a 10-micron filter on the fuel line. This will get rid of most "gunk," and it also pulls water out of the fuel. (These filters must be sized to the engine or they can cause fuel starvation.)

•Buy your fuel at high-volume stations where the fuel does not sit long in storage tanks. This reduces the risk of water buildup due to condensation.

•Add a fuel stabilizer to your marine gas, especially if you don't expect to run through the tank of fuel immediately.

•Keep your tank just short of full. Allow room for expansion, but keep the level at about seven-eighths to reduce the space where condensation occurs.

•Use a fuel test kit to check ethanol levels in gasoline you buy. Some stations sell blends that have higher than the recommended 10 percent; avoid these stations. (The reusable test kits cost about $25 and are offered by numerous makers on the Internet.)

Peters said the fuel filter is probably the biggest single protective measure boaters can take, but boaters must change the element frequently.

"A filter lasts about 50 hours on most boats," he said. "If you start getting poor performance on the hole shot or top end, it's telling you that you need a new element."

Boaters can give their opinion to the EPA regarding the addition of ethanol to the fuel supply. Call (202) 343-9303 or e-mail caldwell.jim@epa.gov.

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