Mercury Marine has introduced a naturally aspirated 3.4-liter V-6 outboard in 175-, 200- and 225-hp versions. In tests ranging from single-engine flats and bay boats and pontoons to twin-engine stepped-bottom center consoles, the engines showed strong acceleration and smooth, quiet operation.
Perhaps more impressive to maintenance-weary consumers: There’s a small inspection door on top of the motor. Open it to access the oil dipstick, oil fill cap and the latch to remove the cowling.
“Every time we put a product into the market, the way our product development people measure it is how are we responding to what boaters really care about,” said Mercury Marine president John Pfeifer. The marine industry is always looking for ways to make it easier to go boating and this is yet another example.”
Members of the media got a sneak peek at the motors at Mercury’s longtime secret test facility, Lake X, which is in St. Cloud, Fla. The company returned to the facility in August.
I ran the motor on a variety of boats in single and twin-engine applications and the experience at the helm was similar on all of them. Hole shot was quick and so was midrange acceleration. After getting a boat to its cruising speed, I slammed the throttles forward and felt plant-you-in-your-seat punch
One test boat was a Boston Whaler 270 Dauntless with twin 200-hp 3.4L V6 FourStrokes. Some might consider the boat underpowered, but in midrange tests, if a passenger is standing next to the helm when the captain nails the throttles, he will be on the deck if he’s not hanging on. I found the same on a single-engine Yellowfin 21 Bay with a 200-hp 3.4L V6.
Perhaps the most noteworthy thing about the new motor is what it doesn’t have: a supercharger. Rather than go with the lower-displacement supercharged platform that was the basis for the company’s successful Verado series, Mercury went with a high-displacement, low-weight approach. The new 3.4-liter engine weighs just 475 pounds. Yamaha’s six-cylinder 200-hp engine has displaces 3.3 liters and weighs 608 pounds. Its 200-hp four-cylinder outboard displaces 2785cc and tips the scales at 487 pounds. Evinrude’s 2-stroke E-TEC G2 200 has a displacement of 2.7 liters, and the lightest version is listed at 528 pounds.
Part of what makes the new Mercury motor so compact is the location of the exhaust inside the valley between the cylinder heads. The design gives it a lower profile and longer runners between the intake plenum and fuel intake ports, and helps increase torque while keeping fuel cooler, which reduces the chance of vapor lock. The driveshaft housing is reconfigured, with the oil sump in the housing to reduce weight and improve strength.
Specific control strategies include Advanced Range Optimization, which lets the engine stay in lean-burn mode for a longer time. The engine’s electronic control unit automatically adjusts fueling ratio and can run on 87 octane fuel. Transient Torque Enhancement responds to increased demand and Adaptive Speed Control maintains rpm regardless of changes in load or conditions. The alternator has a charging rate of 20 amps at idle and 85 amps at WOT.
For quieter operation, tuned multichamber air intakes minimize airborne noise, and enhanced cowling seals and a stiffer cowling structure keep noise from escaping. Fuel-injector covers attenuate high-frequency noise, and engine mounts are designed with larger dimensions to reduce vibration. The exhaust is tuned to take out tinny, high-frequency noise and keep a more appealing, throaty rumble.
The new engine fits on 26-inch centers, which is important for multiengine installations. It will also be offered in four colors: traditional Phantom Black and three shades of white called Warm Fusion, Cold Fusion and Pearl Fusion. Polycarbonate trim panels can be finished in silver, blue, red and graphite gray. Mercury will also offer the trim panels in a primed finish that can be painted.
A video of the new motor can be seen here:
In addition to the new V-6 outboards, Mercury introduced a 4-stroke 150 Pro XS to replace the 2-stroke model, and Mercury’s racing division unveiled a sterndrive that can run at 1,350 hp on high-octane fuel or at 1,150 hp on 89 octane. The latter is similar to the company’s 1350/1550 model from a few years ago.