Rick Kitchings has been a small-engine mechanic for about 30 years, and he’s been busier than ever lately.
Recently, a customer came into his shop in Savannah, Ga., with a string trimmer that had barely been used. “It looked like it just came off the showroom floor, but the motor was absolutely shot, absolutely worn out,” Kitchings said.
The owner had fueled the trimmer with an gasoline-ethanol blend, which is becoming increasingly common thanks to a federal mandate to convert to biofuels.
Although the Web is rife with complaints from car owners who say ethanol damaged their engines, ethanol producers and automakers say it’s safe to use in cars. But smaller engines — the two-cycle utility engines in lawnmowers, chain saws and outboard boat motors — are another story.
Benjamin Mallisham, owner of a lawnmower repair shop in Tuscaloosa, Ala., said at least 40 percent of the lawnmower engines he repairs these days have been damaged by ethanol.
“When you put that ethanol in here, it eats up the insides or rusts them out,” Mallisham said. “All the rubber gaskets and parts - it eats those up.”
Auto mechanics say the same thing takes place in car engines, where debris dislodged by ethanol in gas station fuel tanks can gum things up. But car engines are highly sophisticated; especially in later models, they're equipped to comfortably handle the fallout of ethanol-blended gas, mechanics said.
The Renewable Fuels Association, a trade group for ethanol producers based in Washington, says there's no evidence that ethanol can damage smaller engines, either.
"Tests completed on lawnmowers, chainsaws, weed trimmers and blower vacs with ethanol fuels showed no engine failures, no unscheduled maintenance and good performance," the association said.
But mechanics across the country insist that as gasoline blended with ethanol takes over in more gas stations, lawnmowers and boat motors everywhere are choking.
"They’re starving for gas, because the little needle holes in them are stopped up with the gel that happens when that stuff breaks down," Mallisham said. "It stops them up so it can't run."
Here’s what happens: In smaller engines, ethanol can create a chain reaction of events that end up clogging valves and rusting out small metal parts — including, crucially, carburetors.
"When you mix ethanol with your fuel, you've now put a chemical substance in there that’s going to attract moisture, which is going to promote a quicker deterioration of the fuel that you have," said Bob Magnotti, owner of Magnotti's Small Engine Service in Roanoke, Va.
In effect, said Doug Ryms, a mechanic at Como Mower Service in Columbus, Ohio, "the alcohol actually dissipates the oil. So on a two-cycle engine, you're lubricating the engine, but the oil is being pushed away, so it's actually not lubricating the engine."
That creates a gummy residue, called shellack, that clogs filters and hoses. And it does no good to follow the rocking-chair wisdom that says you’ll be fine if you drain the tank before you gas it back up.
"People will tell you you can take the gas out of them and it won’t happen, but it’s the residue that does the damage,” Mallisham said.
Most gasoline sold in the United States is now mixed with up to 10 percent ethanol, according to industry estimates. Use of the blended fuel, often called E10, has grown with a federal mandate designed to boost the levels of renewable fuels at the pump. In many areas, it’s the only gasoline widely sold.
The fuel blend has been the focus of debate in recent months as analysts and some farmers say the diversion of corn to ethanol production has led to higher prices for corn in its use as a food crop. The Environmental Protection Agency is considering a request for a temporary 50 percent cut in new mandates for ethanol production because of concern that they are helping drive up food costs.
In a study released this week, researchers at Purdue University in Indiana found that corn prices had risen to $4 a bushel, the highest in a decade, largely because of the higher prices farmers can demand from fuel producers.
"Three dollars was just because the price of oil went up and the market demanded more ethanol to substitute for gasoline," said Wallace E. Tyner, co-director of Purdue's Center for Global Trade Analysis.
David Summers, a biofuels researcher at Missouri University of Science and Technology in Rolla, said that while ethanol was cheaper to produce than pure gasoline because it is subsidized, vehicles may also get fewer miles to the gallon.
"It was the wonder fuel to get us out of trouble ' and it won't," he said.
When you add in its tendency to damage some engines, many mechanics and green fuel advocates are asking whether ethanol is worth it.
"There is no massive PR machine working to point out the downsides of ethanol, like there is on the other side," said Christa Westerberg, a lawyer in Stoughton, Wis., who has represented opponents of ethanol plants in Wisconsin.
Rick Kitchings, the mechanic in Georgia, said consumers simply should insist on pure gasoline for their small utility engines.
"Theoretically, avoid ethanol," he said. "Avoid ethanol."