SIOUX CITY | Some experts expect regular gasoline without ethanol to become more costly and difficult to find in Siouxland as a result in a recent change in the way fuel is distributed to stations.

The trend worries small-engine repair shop owners like Mike Wilmes, who recommend use regular gas in lawn mowers, snow throwers, chain saws, leaf blowers and the like.

In recent years, Wilmes' business has seen a big upswing in repairs from homeowners who instead put ethanol-blended gas in their machines.

"It's a nightmare. These small engines are not made to run on that," said Wilmes, owner of Wilmes Do-It-Best Hardware stores in Sioux City and South Sioux City. "Ninety percent of the repairs that we do in the shop are fuel related. It's frustrating for us. It's even more frustrating for the customer."

Sitting in a small engine tank for weeks and even months, the ethanol blend tends to separate over time, building up a gummy lining that gradually corrodes the carburetor to the point where it no longer starts.

"The ethanol degrades some of the plastic parts in the carburetor. It makes them mushy," Wilmes said. "The more it sits in there, the more it breaks it down, and gums it up."

The fix typically include draining the gas, and cleaning or rebuilding the carburetor. Depending on the extent of the problem, it can cost $20 to $50, he said. With some owners forced to fix machines two to three times a year, the added expenses quickly add up.

Ethanol industry officials argue that gasoline with 10 percent ethanol is compatible not only for vehicles, but small engines. They also point out some newer model machine are made with fuel injectors, rather than carburetors.

The most common regular unleaded gas, 87-octane, is disappearing from pumps in Iowa, Nebraska an South Dakota because refiners are no longer providing the product. The region's largest supplier, Magellan Midstream Partners, in September began shipping a 83 or 84 octane product to terminals in Sioux City and other locations. The transition was scheduled to be complete this month.

The change, driven by a federal mandate that requires America to use more renewable fuels such as corn-based ethanol, has forced stations to either blend the lower octane with ethanol or premium gasoline to reach the minimum 87 octane level in Iowa and other states. The 10-percent ethanol blend is 87-octane, while premium is 91-octane.

Because ethanol sells for less than its petroleum-based counterpart,  the price spread between the two products has widened. Depending on the station, the ethanol-free option costs roughly 10 to 30 cents per gallon more.

Dawn Carlson, president of Petroleum Marketers and Convenience Stores of Iowa, said most retailers continue to offer a non-ethanol option, even with the change.

"A lot of people are asking, 'How am I going to get gas without ethanol?' They want that choice," she said.

The change to lower octane gasoline could pave the way for more stations to switch to a 15 percent ethanol blend, said Delayne Johnson, general manager of Quad County Corn Processors, a Galva, Iowa, ethanol plant. The E15 blend would be a cheaper option to meet the minimum 87 octane, he said.