Inspiration is a funny thing. At one time boatbuilders looked to on-road engine designs for the newest technologies. Then, as the popularity of boating exploded, they discovered powerplants designed just for marine applications, whether hanging off the transom or rumbling under the deck of an inboard cruiser. But as many of us know, everything works in cycles, and for 2007 a number of engine manufacturers are again looking to the on-road industry for new, cleaner-burning powerplants.
Two of these offerings come from Germany. The Japanese company Yanmar will introduce a line of six-cylinder diesel based on BMW's. Volkswagen debuts a line of five- and six- cylinder diesels to be distributed through Florida-based Ring Power. Both lines feature common-rail technology. And outboards haven't been left out, as Honda has marinized its automotive-based 1.4-liter powerplant for its smaller outboards.
While many of the engines and gensets featured in the following pages are among the cleanest-burning engine manufacturers have ever produced, there's still plenty of power on tap. Indeed, all of these "green" engines will save you money at the pump and provide you with some serious giddy-up.
Evinrude launches four new E-Tec engines for 2007: a 115-hp, dual-overhead cam V-4 and 150-, 175-, and 200-hp V-6s. The 1.7-liter four weighs 369 pounds, while the sixes displace 2.6 liters and weigh 419 pounds. Those weights reportedly give E-Tecs best-in-class power-to-weight ratios. All models are equipped with new fuel-injector nozzles for optimized fuel atomization and an improved, quieter exhaust tuner.
For the second year in a row, the Johnson line has been reduced; it now offers only 9.9-, 15-, and 30-hp four-stroke engines in North America. All Johnson carbureted two-strokes, from 3.5- to 175-hp models, have been retired.
The largest engine manufacturer in the world and the longest-running producer of four-stroke outboards in the marine industry, Honda has marinized an in-line four-cylinder automobile engine for its 75- and 90-hp outboards for 2007.
The 1.5-liter, 16-valve powerplants will have a multitude of features borrowed from Honda's on-road products, including Variable Valve Timing and Electronic Lift Control (VTEC), for better low-end torque and improved fuel economy; multiport electronic fuel injection, which controls ignition timing; and a single overhead cam with dual intake valves. These engines also share another technology that is exclusive to Honda outboards: Boosted Low Speed Torque (BLAST), which alters ignition timing to reportedly produce quicker acceleration.
Mercury has expanded its line of four-stroke outboards for 2007 with the addition of 75-, 90-, and 115-hp models. Like their larger siblings, the four-cylinder outboards will feature dual overhead cams, four valves per cylinder, and multiport fuel injection. However, unlike the Verado four-strokes, the new in-line-four models are not supercharged. All three engines are based on the same 1.7-liter block and weigh 399 pounds. The 90- and 115-hp models are available with 20- or 25-inch shafts; the 75's shaft length is 20 inches.
Mercury has also updated its two-stroke OptiMax engines, with a new 250-hp model slated to debut in early 2007. Although Mercury claims its target is freshwater fisherman, it has decided to also offer the new model with right- and left-hand rotation for use in twin-engine configurations as well as with 25- and 30-inch shaft lengths to make it appeal to offshore fishermen.
Suzuki Marine created a big buzz at the 2006 Miami International Boat Show with its industry-first, 300-hp, four-stroke outboard. The 4.0-liter, dual-overhead-cam, 24-valve V-6 features variable-valve timing and a gear ratio of 2.08:1 and weighs 604 pounds. Shaft lengths of 25 or 30 inches are available, as is counter rotation for twin-engine configurations. The engine also features a redesigned lower unit that reportedly reduces drag by 18 percent.
The 300-hp engine is the first Suzuki to feature an electronic throttle called Precision Control, also new for 2007. The fly-by-wire electronic shifters are specifically designed for twin- or triple-engine configurations as well as for twin-helm installations. The dual-binnacle controls have a synchronization switch and a center-engine control switch that, when used in conjunction with triple-engine setups, allows the middle engine to be controlled by the port shifter and to be locked in neutral during close-quarters maneuvering.
No new engines reported.
This article originally appeared in the January 2007 issue of Power & Motoryacht magazine.