Yamaha SHO: This changes everything

Yamaha is optimistic they've solved the problems that many bass anglers and boaters have long had with four-stroke engines.

"This changes everything."

That's the tag line Yamaha Motor Corporation is using to promote their new line of four-stroke engines, the VMAX SHO series. SHO stands for "Super High Output," and the company is optimistic that they've solved the problems that many bass anglers and boaters have long had with four-stroke engines.

For years, four strokes in the bass market were considered too heavy, too slow and too bulky to compete with two-stroke engines. With new engines in 200-, 225- and 250-h.p. models, Yamaha has answers for each problem.

The new VMAX SHO motors are lighter than their two-stroke counterparts of matching horsepower (34 pounds lighter in the 250-h.p. model). They accelerate faster than the two strokes (13 percent faster from 0 to 200 feet than Yamaha's equivalent two stroke), and the engines are just 1-inch wider than the comparable two strokes. The new four strokes are also 12 percent more fuel-efficient than Yamaha's two-stroke counterparts.

Different strokes for different engines

The technical difference between a two-stroke and four-stroke engine can seem quite complicated. The term "stroke" refers to the movement of the piston in the engine, and two stroke means one stroke in each direction. A two-stroke engine has a "compression stroke" followed by an explosion of compressed fuel. On the return stroke, new fuel goes into the cylinder.

A four-stroke engine has a compression stroke and an exhaust stroke. Each is followed by a return stroke. The compression stroke compresses the fuel and air mixture prior to the explosion. The exhaust stroke pushes out burnt gases.

Two-stroke engines have long dominated the outboard market because they're easier to construct, generally offer more power, are lighter and cost less to manufacture.

The traditional disadvantages of a two-stroke engine are that they tend not to be as durable as four strokes, burn more oil, are not as fuel efficient and produce more pollution (which has led to them being banned or restricted in certain states and on certain waterways).

How they did it

Borrowing technology from the world of aircraft engines and high performance racing autos, Yamaha managed to drop weight from its outboards while adding displacement (4.2 liter) and power.

A new series of propellers designed specifically for the Yamaha VMAX SHO by its own Precision Propeller, Inc., give their engines improved acceleration, handling and top-end speed.

In conjunction with Yamaha's new product line, Skeeter has launched a new line of bass boats — the FX Series. The FX 20 and FX 21 were designed to be combined with Yamaha's new VMAX SHO 200-hp, 225-hp and 250-hp engines. Fully loaded and paired with the new SHO outboards, these rigs have MSRPs between $67,000 and $71,000.

Will these new products "change everything" as Yamaha promotes? It's too early to tell, but the company is certainly banking on its new technologies and product lines. The engines went into production in late October and should be on display at winter boat shows. The Yamaha BASS pros who qualified for the Bassmaster Classic will be running the new motors. In addition, Yamaha will be conducting an aggressive demo campaign at the Classic and all Bassmaster Elite Series events in 2010. At each of these tournaments, Yamaha will have the new engines on display, and visitors can ride along or test-drive the new products.

For more on the Yamaha Marine product introductions, visit www.yamahaoutboards.com.