The simple but dirty two-stroke engine, the primary source of power for recreational watercraft for decades, is being phased out to help clean up the nation’s air and water.

The engines, known for their smelly trail of blue smoke, not only pollute the air, but are a major source of oil pollution in the nation’s waters.

Although the EPA is requiring that the engines no longer be sold starting in 2006, states around the nation are working with the marine industry to promote an even faster phase-out of the engines.

In June, Maryland Department of Natural Resources Secretary Chuck Fox signed a memorandum of understanding with the National Marine Manufacturers Association, the Marine Retailers of American and the Marine Trade Association of Maryland to speed the transition by jointly promote the use of the cleaner, but slightly more costly, engines.

“This memorandum demonstrates our determination to not just talk about cleaning up the environment, but taking actions necessary at the state level to make it happen,” Fox said. “Less air pollution means less nitrogen going into the Chesapeake Bay, which advances Maryland’s goals in the multistate Chesapeake 2000 agreement.”

The industry groups will work with members to promote the sales of the cleaner engines, by doing such things as having sales representatives make sure they tout the benefits of the cleaner engines to customers. It will also develop fact sheets and other public information materials.

“I believe the best way to promote boating in Maryland is to have clean water,” said Hamilton Chaney, president of the Marine Trade Association of Maryland. “The Chesapeake Bay is the golden goose of Maryland, and we have to protect it in any way that we can.”
Fox also said that the Maryland Natural Resource Police will begin phasing out older engines and incorporating the newer engines into its existing fleet.

Right now, about 75 percent of all engine sales are made up of conventional two-stroke engines, according the the Bluewater Network, an environmental organization that has advocated the use of “eco-labels” to promote cleaner engines, a program that has been adopted by California and New York.

The conventional two-stroke engines generally used in personal watercraft such as jet skis and outboard motors on recreational boats are among the dirtiest engines manufactured. According to the EPA, only the small gasoline engines used in lawn mowers and garden equipment typically emit higher levels of hydrocarbons.

In carbureted two-stroke engines, fuel enters the combustion chamber at the same time the exhaust is leaving. The mixing of the intake and exhaust gases causes raw fuel to pass directly out of the engine — some studies suggest that as much as 30 percent of the fuel leaves a two-stroke engine unburned.

Also, because two-stroke engines burn a mixture of gasoline and oil, much of the exhaust ends up as oil in the water. A recent National Academy of Sciences report estimated that about 1.6 million gallons of oil and gasoline enter the nation’s coastal waters each year from two-stroke engines.

Newer, fuel-injected, two-stroke engines and cleaner, four-stroke engines reduce air emissions by up to 75 percent, burn 35 percent to 50 percent less gasoline, and use up to 50 percent less lubricating oil.

They cost about 10-20 percent more than the old carbureted two-stroke engines.

But replacing the engine on an existing boat with new, cleaner, engine is not always a straightforward issue, according to John Page Williams, of the Chesapeake Bay Foundation, which has switched its entire fleet to the cleaner engines.

A four-stroke engine with the same horsepower as a conventional two-stoke would be heavier, potentially throwing the boat off balance. In selecting the right engine, buyers have to pay attention not only to horsepower, but also to selecting the right propeller and gear case.

“When you get it right, the result is just stunning,” Williams said. “They are clean, they are quiet, and they are smooth. One of the things that is fun with them is going places slowly, because they are so quiet and so smooth, where a two-stroke is hacking and spitting.”

Further, he said, the fuel bill for his own 17-foot whaler has fallen by 50 percent.