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Is fuel with an increased level of ethanol a problem for small gas engines?

Consumer Reports News: June 24, 2009 12:30 PM

During our testing of mowers and tractors in Fort Myers, Florida, this past winter, project leader Peter Sawchuk took us to a local power-equipment dealer who had an intriguing story to tell.

Employees at the shop regularly rebuilt carburetors gummed up from the so-called "varnish" that builds up from unstabilized gas left sitting in engines. But since ethanol started being added to fuel sold in Florida in 2007, the power-equipment pros were seeing something new: metal parts crusted up, plastic parts stiffened and cracked, and everything rubber, including the tips of needle valves, deteriorated. (The photo shows how ethanol could impact the carburetor of a small gas engine; the white, crusty film is apparently caused by the ethanol.)

Ethanol has been mixed with gasoline at the pumps for decades and is used in about half the country. The typical ratio is about 10 percent ethanol to 90 percent gasoline, known as E10. There are other blends, including E85, a mixture with 85 percent ethanol. (Learn more about ethanol.)

A political storm over ethanol is brewing, and it revolves around adding more ethanol to gasoline.

It began this past March, when a coalition of ethanol producers formally asked the U.S. Environmental Protection Agency to approve the use of E15, a blend containing 15 percent ethanol. The lobbying group Growth Energy filed for the waiver to the Clean Air Act, claiming that increasing the blend to E15 would create jobs and inject billions of dollars annually into the economy. Granting the waiver request, the group also said, wouldn't impact small engines since gas stations would still be able to sell E10.

The EPA has until December 1 to make a decision. Many members of Congress, most notably from states most involved in ethanol production, support the waiver, with other Congress members from other states voicing opposition. But the Outdoor Power Equipment Institute (OPEI), a trade group of power-equipment manufacturers, and numerous other parties are calling timeout in a big way.

While it supports the use of E10, the OPEI is calling for a formal waiver process that considers the full effects of higher levels of ethanol on small engines. This means not only nonroad equipment such as lawn gear but also generators, marine engines, snowmobiles, and motorcycles. The group moreover expresses concern about fostering confusion at the pump, when a homeowner goes to refill a mower and sees multiple blends of ethanol. Choose too rich an ethanol blend, and the results could prove harmful to the engine and dangerous to the user.

Among studies Growth Energy cites to support its filing is one from the U.S. Department of Energy (PDF) that tested the effects of various blends on engines. But the study itself, predating Growth Energy's application, acknowledges the need for further tests. It also includes numerous findings that should warrant hesitation on the EPA's part, according to analysis by a consultant to the OPEI (PDF):

• Engine-exhaust temperatures are significantly higher when E15 fuel is used compared with E10, which affects product longevity.
• Operators face increased safety risks, including some unintentional engagement of the clutch because of high idle speeds.
• Two power blowers failed completely after running on E15 fuel for 25 or less hours.
• Operational problems resulted, including erratic equipment operation, "missing" and stalling of engines, and power reduction.

Two other groups have called the waiver request premature. The Union of Concerned Scientists charges the petitioners with "trying to subvert the science with its request . . . before the studies are completed." The Washington, D.C.-based Environmental Working Group says the ethanol industry is "misrepresenting scientific facts in efforts to dupe the [EPA] into waiving critical public-health protections for the sake of boosting ethanol sales." The EWG further claims that all the studies (besides the DOE's) that Growth Energy cites contain evidence "that undermines the case for E15 and above."

Currently, the use of gasoline blends with any higher a percentage of ethanol than E10 voids the warranty of outdoor power equipment and other engines, including those in cars. But among comments to the requested waiver are those from boating associations such as the National Marine Manufacturers Association, a trade group representing the recreational-marine industry. It's concerned that Growth Energy's petition for a waiver makes no mention of marine engines and the potential impact, supported by studies, of intermediate ethanol blends on boating consumers or marine equipment.

At least for boaters, ethanol blends aren't a new problem. A July 2006 article in BoatU.S. magazine (PDF) warned of dissolving fiberglass gas tanks, ruined carburetors and intake valves, and—worst—the threat of engine failure while miles out at sea. "Affected engines may run rough, stall or bog down under load," the article stated.

Comments to the EPA on the proposed waiver, with details here, will be accepted until September 25.—Ed Perratore | | Twitter | Forums | Facebook

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