Mercury 225 four-stroke

The debut of Mercury's first big four-stroke outboard should be occasion for a major press event. So I was surprised to stumble upon a prototype Mercury four-stroke V6 at a recent dealer meeting for US Marine (parent company of Bayliner, Maxum and Trophy) at the Coeur d'Alene Resort in Idaho.

There was no advance notice. No fanfare. Not even a news release or flyer on the new Merc. An inauspicious occasion, to be sure. Yet there it was for us to see and run. In fact, an on-the-spot phone call to Mercury Marine's Fond du Lac, Wisconsin, headquarters revealed that some officials were not aware that the demo outboard was at the dealer meeting. "I guess you could call this a 'soft introduction'," said one Mercury manager.

Like a feature film that the studio refuses to promote, this V6 four-stroke is an outboard that Mercury seems hesitant to push. There could be a number of reasons behind this train of thought.

For one, Mercury does not build this engine. Yamaha Marine does. Aside from a new cowl, Merc prop and black paint, it is the same 225hp Yamaha four-stroke outboard we featured in the September issue of Trailer Boat ("Grudge Match"). In fact, the powerhead on the test unit was painted Yamaha blue-grey. These two companies have joint-ventured outboard design and production for nearly 30 years, so this engine is not a shocking development.

A second reason for the lack of Merc promotion: this engine may not be in the line for as long as most. Many industry people - including some Mercury insiders - view this engine as a stopgap measure, a quick way to add a big four-stroke to the Merc line and satisfy dealers, boatbuilding partners (such as US Marine) and loyal Mercury customers.

Though Merc says its supply agreement is for several years, the company will soon begin introducing a series of in-line six and in-line four-cylinder four-strokes ranging from 135-250hp and beyond in 2003 - all built by Mercury.

Finally, Yamaha Marine may not want to supply the V6 four-strokes to Merc for long, as the situation has irked many Yamaha outboard dealers in the US who feel they have had a unique selling proposition pulled out from under them. To help placate these dealers, Yamaha has held back its 200hp four-stroke. It is not available as a Mercury.

In any case, the engine we found tucked away in the marina at the Coeur d'Alene Resort was the first 225hp four-stroke with Mercury badging. That alone made it worthy of a full test. Besides, it was bolted on the transom bracket of one of my all-time favourite boats - a 2000kg (hull only) Trophy Pro 2509 walkaround hardtop.

Our previous tests with this powerplant (in Yamaha badging) had been on smaller, lighter hulls, including a 1100kg Skeeter ZX 2200 bay boat and a 1250kg KenCraft Challenger 215 centre-console. The big Trophy gave us the opportunity to test the 225's "oomph" on a boat with a cabin and hull designed for bigger waters. This was also a chance to see how the 225 performed at moderate elevations. Coeur d'Alene is about 2000ft above sea level.

LITTLE TO SPARE
We were not overly impressed with either acceleration or top speed. For example, our 0-50kmh acceleration times averaged 15 seconds, and that was with three adult males, a half tank of fuel (276lt), safety gear and test equipment. Spinning a 15in-pitch Mercury Mirage three-blade stainless prop, the 2509 achieved a top speed of about 66kmh at 6000rpm. The engine would not plane the Trophy until it revved to 4000, and that was with the trim tabs deflected substantially.

For a point of comparison, US Marine touts a top speed of around 75kmh when the same boat is equipped with a Mercury 225 EFI outboard.

Though slower, the 225 four-stroke is more fuel-miserly. Its best economy occurred at 4500rpm and 48kmh, where it achieved 1.16km/lt. This gives the 2509 a cruising range of 583km, based on 90% of its 556lt fuel tank's capacity.

US Marine's figures peg top fuel economy at 0.89km/lt at 62kmh with the 225 EFI. Cruising range is dramatically reduced to 449km, based on 90% fuel capacity.

QUIET GIANT
Merc's four-stroke V6 is a quiet giant, particularly when powering the 2509. The boat's full transom shields the cockpit from engine noise, and the optional tempered glass enclosure virtually eliminates windblast.

Our sound meter registered only 53 decibels (dBa) at the helm at idle, 84 at cruising speed (4500rpm) and 94 at wide-open throttle (6000rpm). The idle and cruising speed readings are slightly lower than those we recorded when testing the Yamaha 225 four-stroke, but we suspect this is due more to the shielding effect of the full transom than Mercury's cowl design for the four-stroke.

In rigging, we see some inconsistencies between this and other new-technology Mercs. For example, our unit would not accept SmartCraft gauges, though Merc says an add-on kit will be available in January. Also, if you upgrade from current Merc twin outboards, duals of this model must be mounted on 30in centres versus the standard 26in centres. So you'll have to patch the old mounting holes.

Overall, I liked this engine. After all, in its Yamaha iteration, we called it a technical knockout. Yet, in this test, it was overwhelmed by the heft of the Trophy 2509 - and this would be true whether the four-stroke wore black or blue-grey paint.

Also, if you are a die-hard Mercury man and you crave a large four-stroke, you may want to wait a few months.