FOND DU LAC, Wis. — The new MerCruiser 4.5-liter 250-hp sterndrive unit will be the first in a series of gasoline engines built in-house by Mercury Marine, company president John Pfeifer said Tuesday.
He said Mercury will spend the next few months driving the point home to dealers and boat manufacturers that the engine is manufactured at Mercury’s world headquarters in Fond du Lac.
"We need to make it clear that this is not just another sterndrive," Pfeifer said. "It represents a big change in course for the industry. We're holding events in a lot of different locations. We started in the Keys down in Florida, where we brought some customers together to show them exactly how we design the product and how we build the product."
The engine will go on sale in September. Pricing is not available yet. Mercury said last year that it will no longer rely on automotive engines for its gasoline sterndrives.
At a press event held in Fond du Lac and nearby Oshkosh, Wis., Mercury introduced the 4.5-liter engine and three outboards — 75-, 90- and 115-hp second-generation 4-strokes.
The sterndrive's design innovations include a long runner scrolled intake manifold and high displacement, which produces an outstanding power-to-weight ratio, Mercury said. The V6 engine weighs 130 pounds less than a 5.0-liter V8 small block, but delivers similar performance, the company said.
Its newly designed aft-facing throttle body, anti-whistle throttle plate, engine cover and mounts, lightweight flywheel, fuel supply module and structural oil pan contribute to smoothness and low noise and vibration, the company said.
The MerCruiser is compatible with SmartCraft Digital Throttle & Shift. An option for the 4.5-liter V6 with DTS is Joystick Piloting.
Eighteen boats were on hand for journalists to test. A 31-foot Sundancer from Sea Ray was powered with a pair of the new 4.5-liter engines, which I operated for 20 minutes on Lake Winnebago Tuesday afternoon. The Axius sterndrive joystick system was installed in the boat, which worked well, and I tried out the engine's "Adaptive Speed Control," which automatically maintains the set rpm point, regardless of load or condition changes, such as tight turns, tow sports and lower speeds on plane. I did a few donuts in both directions, and sure enough the two rpm gauges held steady at my chosen 3,000-rpm setting.
The engines pushed the boat onto plane effortlessly. The 250-hp motors were relatively quiet and accelerated nicely in the mid-range. In the engine compartment I saw that all of the maintenance points are right in front of you, within easy reach.
Mercury uses durable cast-iron components wherever the engine encounters seawater, and corrosion-resistant aluminum and composites elsewhere.
The 4.5-liter engine will excel in single or twin installations and can be teamed with Alpha and Bravo drives, the company said.