The Outboard Expert: More Miami Heat
Intriguing developments demand a second look.
February 28, 2007
The new Suzuki DF9.9 High Thrust features a four-blade propeller designed for efficient trolling on heavy boats.
These items also made it into my reporter's notebook at the 2007 Miami International Boat Show:
Suzuki will offer a new version of its DF200 V6 with a 20-inch shaft length. The DF200TL is being pitched by Suzuki (www.suzukimarine.com) as a perfect fit for pontoon boats, but it can also be used on other craft with a 20-inch transom. Other than the shorter mid-section, the DF200TL is mechanically identical to the standard 25-inch DF200. The 3.6-liter powerhead features a narrow 55-degree cylinder spacing and sophisticated electronic fuel injection. A low 2.29:1 gear ratio means the DF200TL can swing a big, 16-inch diameter prop. All that blade area is perfect for moving a heavy pontoon boat.
Anglers may be interested in the new Suzuki DF9.9 High Thrust, a four-stroke kicker designed expressly for use as an auxiliary for trolling. Available with a 20- or 25-inch shaft, this is the first 9.9-hp model from Suzuki available with power trim. A special high-thrust, four-blade prop is designed to move a heavy fishing boat efficiently at low speeds.
The Tohatsu MFS 30 puts EFI efficiency on a rope-start, portable four-stroke outboard.
Tohatsu/Nissan has introduced MFS 30/25, a new three-cylinder, 526cc four-stroke model rated at 30 and 25 hp that features an electronic fuel injection system that does not require a battery to function. This puts the advantages of EFI on rope-start outboards, and also means that the electric start versions of these engines can be started by hand (they come with a rope starter) even when the battery is dead. If this sounds familiar, it's because Mercury Marine also offers a new 526cc four-stroke rated at 25 and 30 hp with the same EFI system. That's because Tohatsu (www.tohatsu.com) and Mercury manufacture this motor and other four-stroke portables as a joint venture at a factory in Japan. The Tohatsu/Nissan version has a different cowl and plastic cover for the mid-section. There are also some feature differences. The Tohatsu models have a front-mounted shifter instead of the twist-grip shifting found on the Mercury models, and the Mercury powerhead features a decompression device that is not on the Tohatsu. At 179 pounds, the lightest version of the Tohatsu MFS 25 weighs 16 pounds more than the Mercury 25 EFI Four Stroke.
In the Yamaha booth, I spotted a flyer announcing that Yamahalube 4-M (www.yamahaoutboards.com) four-stroke marine oil is now available in a 20W-40 formula designed specifically for warm climates, joining the original 10W-30 Yamahalube 4-M on dealer shelves soon. My source at Yamaha suggests that unless you operate in temperatures below freezing, the new 20W-40 formula is the better choice simply because it will not loose as much viscosity at high operating temperatures. Unless the weather is really frosty, the 20W-40 will flow well on cold starts. Both Yamahalube 4-M formulas meet the new FC-W standard developed specifically for four-stroke marine engines. You always want to use FC-W oil rather than automotive-spec oil in a four-stroke outboard.
Finally, I noticed that the latest Mercury Verado outboards now carry a Two Star emissions rating, rather than the Three Star rating sticker they've carried since introduction in 2004. What gives?
According the Mercury (www.mercurymarine.com), the emissions rating was changed over the past six to eight months after Merc recalibrated the fuel and ignition systems in an effort to improve fuel economy on all six-cylinder and four-cylinder Verado models, which have delivered disappointing fuel economy since the motors debuted. The new calibration is leaner, and Merc says mid-range fuel economy is 5 to 15 percent better. However, leaner operation also slightly increased the level of NOX (oxides of nitrogen) in the exhaust. These motors were previously just under the Three Star limit, and this change put them into Two Star territory.
Mercury engineers told me the original Verado calibrations were on the rich side "just to be safe," but now that they better know the mechanical limits of the engine they are confident the motors can run a leaner calibration and remain reliable. Because Mercury is selling enough other models with a Three Star rating, it can sell the Two Star Verados in California.
Editor's Note: Charles Plueddeman is the editor at large for Boating, the nation's largest boating magazine.
