This is shaping up to be the year of the big, powerful marine engine - if that’s what floats your boat, and if it doesn’t sink your bank account.

Fond du Lac, Wis.-based Mercury Marine Inc. last week unveiled some of the most powerful engines it has ever produced, including a 1,550-horsepower, stern-drive unit that can push a boat at speeds up to about 150 mph.

By changing electronic key fobs, the engine can be powered down to a maximum 1,350-horsepower for more modest activities such as fishing or a pleasure cruise with your family, although it still will run at speeds up to about 140 mph. The system allows a boater to switch from racing fuel, and the extreme top-end power it can provide, to conventional 91-octane gasoline and more moderate performance.

Mercury introduced the $230,240 unit - a price that includes the drive and transom; the engine alone is $163,467 - at the Miami International Boat Show in Miami Beach, Fla.

It’s the largest engine of its kind that Mercury has made for consumer use, and it gives boaters the taste of a race engine without having to use it in that mode all the time.

“So maybe a couple of times a year you will make that investment of buying 600 gallons of racing fuel, put that key in, and have absolute maximum power. But on the other weekends you will use pump gas, put the other key in and still have a boat with the big motor,” said Charles Plueddeman, a contributing writer for Boating Magazine, who lives in Oshkosh, Wis.

The Miami show, which runs through today, features more than 3,000 boats and 2,000 exhibitors. Besides Mercury Marine, several other Wisconsin companies are at the event, including BRP Inc., which has its Evinrude outboard engines headquarters in Sturtevant, and Seven Marine, a Germantown firm that says it has the world’s largest outboard engine.

Seven Marine unveiled a 627-horsepower outboard that’s a supercharged, eight-cylinder, modified General Motors product. It’s well-suited for big boats where the manufacturer would rather have one or two outboard engines on the back than five, said spokesman Dave Kotlan.

An outboard motor is mounted on a boat’s transom outside the hull at the back of the vessel. A stern-drive engine combines the gear case of an outboard with an engine that’s mounted within the hull, under the deck.

Recreational boating is in better shape these days, with modest sales gains, after it experienced one of the worst periods in its history during and after the 2008-09 recession. New boats, including the more expensive ones, are selling as consumers feel more confident about the economy.

In good times, “typically we see a little more risk-taking,” said Christopher Berg, director of marketing and strategic planning for BRP Inc.

In addition to the stern-drive engine, Mercury introduced its largest outboard ever: a 400-horsepower unit priced at $31,530 that can run on 89-octane gasoline.

It’s part of the quest for more power to drive bigger boats. In Miami, a 42-foot boat had five of the new Mercury Verado 400R engines mounted on it, said Kevin Hellman, business development program manager for Mercury’s racing-engine division.

Plueddeman said he took a ride on a boat with four of the 400R engines on it, reaching a top speed of 97 mph. He also hitched a ride on a 30-foot pontoon vessel with twin 300-horsepower outboards.

“You could put 20 people on that boat and still have plenty of elbow room,” he said.

Mercury also introduced a 350-horsepower outboard, with a price of $24,290, that’s a bit less powerful than the 400R but is still aimed at big boats and could replace some twin 200-horsepower engines currently in use.

Both the new Mercury outboards have joystick controls available, for easier steering of the boat, and a gadget called Skyhook that uses GPS to keep a boat in position, without moving, while hanging out at a fishing hole or a diving spot, or waiting for an overhead bridge to open.

“There’s a lot of versatility in these motors. They’re going to find homes on all kinds of boats, even in Wisconsin. I expect to see one of these on Lake Winnebago this summer,” Plueddeman said.

Evinrude E-TEC engines won a National Marine Manufacturers Association product innovation award at the Miami show. BRP says those engines, ranging from 200 to 300 horsepower, have 15 percent better fuel efficiency and 20 percent more torque than leading competitors, and up to 75 percent fewer pollutants.

BRP is using the Miami show to demonstrate a biofuel additive it has spent thousands of hours testing in partnership with the U.S. Department of Energy.

Biobutanol could replace ethanol as an additive blended with gasoline. Unlike ethanol, it isn’t harmful to marine engines when used at higher blends, according to BRP.

With some advancements in microbiology, the production of biobutanol could become more cost-effective, and the fuel could be more widely available in about five years.

“It really is a potential game-changer,” said Jeff Wasil, an engineering manager in engine emissions testing for BRP-Evinrude.