Skip to main content

In the engine room: I/Os and inboards

Technology in the diesel and gasoline inboard and sterndrive segments truly surged in 2012 with lighter, more efficient, quieter and cleaner power plants. Cummins, Mercury, Volvo Penta and Yanmar have been touting new engines and/or drives.

Mercury now offers a 4.2-liter, 350-hp diesel, and Cummins has a new 6.7-liter diesel ( Yanmar America’s 370-hp 8LV diesel showed exceptional acceleration and power when I sea-trialed it last year ( Same goes for Volvo Penta’s next generation of gas engines ( The company’s V8-380 gasoline sterndrive improves acceleration and fuel economy in a package that’s lighter and more durable than its predecessor.

Volvo Penta V8-360 gas sterndrive

“We did not stick with the same old, same old,” Volvo Penta manager of engine engineering Mel Cahoon says. “We didn’t just update what we already had. We chose to go forward. This is a new generation of our highest-horsepower sterndrive.”

The V8-380 uses the engine that powers the Chevy Silverado 2500 pickup truck. Technological advances enable the engine to generate the same horsepower as its predecessor — the 8.1-liter engine General Motors no longer makes — to more than make up for its lower displacement of 6 liters, or 364 cubic inches, Cahoon says.

The engine manufacturer last year also unveiled the V8-225 EVC, a 5.7-liter gas sterndrive that delivers power and torque and lower emissions through the use of computer-controlled fuel management and catalytic exhaust treatment systems, according to the company.

At a press event for its V8-380 gasoline engine, Volvo Penta announced a new feature called Joystick Driving, which allows the skipper to use the joystick at high speeds. This option is just being introduced to the U.S. market.

Cummins says its new QSB6.7 — a 6.7-liter diesel — packs more power and runs cleaner and more quietly than the 5.9-liter engine it replaces. It can be used for conventional inboard and Zeus pod installations.

The first Cummins engine to meet Tier 3 emissions standards, the QSB6.7 is about the same size as the QSB5.9, but it has a greater displacement and weighs 2 pounds less.

The QSB6.7 will be available in 380-, 425- and 480-hp ratings — same as the QSB5.9. Pricing was unavailable. Cummins will be pumping up the engine’s horsepower so it can power performance boats, says Andy Kelly, marketing communications manager for Cummins Recreational and Light Commercial Marine.

Mercury’s 350-hp TDI 4.2-liter diesel debuted under the Cummins MerCruiser name, but is now a Mercury Marine product. Volkswagen manufactures the V-8 engine for Mercury. In return, Volkswagen gets penetration into the U.S. market, Mercury says. The engine can be installed in boats to 40 feet, including express cruisers and sportfishing boats, according to Mercury, and is a nice fit for large runabouts. Pricing was unavailable.

Mercury 350-hp 4.2-liter TDI diesel

Volkswagen also makes and marinizes 1.9-, 2.5- and 3.0-liter diesels for Mercury at its plant in Salzgitter, Germany. The 1.9-liter is an inline 4-cylinder engine with a 40- to 75-hp rating. The 2.5-liter, an inline 5-cylinder engine, has a rating of 55 to 165 hp. The 3.0-liter V-6 is rated at 225 to 265 hp.

See related article:

- Power for Play

March 2013 issue


The updated F350 is lighter and Yamaha covers it with a 5-year warranty.

Power to play: new outboards, sterndrives, pods and more

After several years of high-horsepower introductions, outboard manufacturers have shifted their focus to the midrange, with Yamaha debuting a much lighter 90-hp 4-stroke and Evinrude pushing out 2-strokes from 150 to 200 hp with its G2 technology.