The nationwide transition to gasoline with a 10 percent ethanol mix, known as E10, is striking fear in the hearts of boat owners.

Some marinas say they're busy rebuilding carburetors and replacing filters and hoses as the new gas mixture damages older boat engines.

In addition to damaging older hoses, water in the gas tank can mix with ethanol, causing fuel separation and creating problems, according to the Associated Press.

And ethanol can loosen gunk that has accumulated in older fuel tanks and deposit it in filters and carburetors, choking off the fuel supply or impeding smooth operations.

Owners of boat manufactured after the early 1980s don't have much to worry about. They were built with E10 in mind and the fuel is covered by manufacturers' warranties, according to the American Coalition for Ethanol.

Most problems in older boats can be resolved by replacing a clogged fuel filter – or installing a filter if there isn't one – and simply keeping the gas cap tight to keep out water, the AP said.

BoatU.S. offers a tipsheet for dealing with ethanol. Check it out.