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 good 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.
“One of the things that stopped people from getting out on the water is the daily checks, and that meant getting the cowl off,” said David Foulks, chief technology officer for Mercury parent company Brunswick Corp. “We gradually try to work through what are the small irritations and pain points for owners of our products.”
The motors were introduced at Mercury’s longtime secret test facility, Lake X, which is in St. Cloud, Fla. The company returned to the facility in August. (More on that in an upcoming issue.)
Those who read the story “Horsepower Race” in the February issue of Trade Only may remember the quote from Pfeifer saying that Mercury currently has a 400-hp motor but that won’t be the most powerful offering from the company in 2018. That probably led many to expect the announcement of a 450- or 500-hp motor early this year. While a motor of 450 to 500 hp might peg the wow meter, it appeals to a much smaller audience than a V-6 that can be used on a bass boat, a flats model, a pontoon, a center console, a deck boat, an aluminum multispecies craft and more.
“This is more in the sweet spot of the mainstream,” Pfeifer said of the new V-6. “But we invest an enormous amount of money in a lot of programs, and this is not the only introduction we’re going to have in 2018.”
Out on Lake X, regardless of the boat the engine was installed on, the experience from the helm was the same. Even on a Regency 22-foot pontoon boat and a twin-engine 27-foot center console with twin steps — boats not known for acceleration — the hole shot was quick. None of the boats we tested took more than a few seconds to plane.
“This motor, the acceleration with the hole shot and at the midrange, it is just immediate,” said Rick Emmitt, marketing manager of pro staff and angler programs for White River Marine Group, which owns Tracker, Nitro, Mako, Regency and other brands.
One of the most underrated but important measures of an engine’s performance is midrange acceleration. Few people run at wide open for long periods, but they do spend most of their time at cruising speeds. Getting a boat running at its cruising speed and then slamming the throttles forward is a good way to determine if you can use power to get out of a potentially threatening situation. Based on our tests, the Mercury 3.4-liter 4-stroke has the punch to make a boat leap forward.
One of the boats we tested was a Boston Whaler 270 Dauntless. Some might think twin 200-hp outboards on a 4,800-pound boat that measures 27 feet long with a 9-foot beam would be an underpowered situation, and the motors did look kind of small, but they worked. 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. The acceleration is that sudden.
Another of the test boats was a Yellowfin 21 Bay with a 200-hp 3.4L V6 FourStroke on a jack plate. This boat was the preferred ride of Willie Young, a professional football player for the Chicago Bears who was at the event. It topped 60 mph and blasted on plane.
“It feels like a 2-stroke punch,” said Yellowfin president Wylie Nagler. “This motor will snap you a little bit.”
He also praised the fuel economy with the new motor. “We’re seeing over 5 mpg at 40 mph, which is spectacular,” said Nagler.
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.
Mercury’s competition has sold against the superchargers in the Verado series for years, saying the component was just another item that can break (Mercury has had a 1 percent warranty claim rate on the Verados).
“In the beginning, everybody was nervous about the superchargers,” Nagler said. “But as 10-plus years have gone by, we really haven’t seen any supercharger issues.”
Pfeifer said the decision to go without a supercharger had nothing to do with the Verados. “If you look at our quality with Verado, with the supercharger, our quality is top-notch,” he said. “We’re not going to go away from the supercharger.”
Instead, the new engine’s light weight, natural aspiration and higher displacement were based on consumer demand. He explained that when the decision was made to develop a new outboard, Mercury’s development team looked at a variety of platforms.
“Mostly we’re looking at what consumers care most about,” he explained. “We put that in a Functional Requirements Document. We say, ‘Here’s the criteria we have to meet’ and the engineering teams design an engine that’s going to meet that criteria.”
The result is a light weight, naturally aspirated motor with a higher displacement. “That’s the type of platform you’re going to see going forward,” Pfeifer said.
Lightweight with a heavyweight punch
Despite the fact that the engine has a displacement of 3.4 liters, it weighs just 475 pounds. By comparison, Yamaha’s six-cylinder 200-hp engine has a displacement of 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. A wide-range oxygen sensor allows for more precise fuel delivery, and the driveshaft housing is reconfigured, with the oil sump in the housing. The latter minimizes weight, improves strength and keeps the oil cooler because it’s not next to the exhaust, where it would have been in older designs.
A new tri-ram trim system is designed to make the overall trim operation smoother. The engines have electronic throttle and shift controls but can work with mechanical systems, so they can be used in repower applications.
Specific control strategies include Advanced Range Optimization, which lets the engine stay in lean-burn mode for a longer time. A lean-burn air/fuel mixture is more efficient because it uses less gas. The engine’s electronic control unit automatically adjusts fueling ratio and can run on 87 octane fuel.
Transient Torque Enhancement is a mode in which the engine senses increased demand, such as during hard acceleration, and increases the spark advance. The result, according to Mercury, is a 25-percent torque advantage through the rpm range versus a competitive 4-stroke.
In Adaptive Speed Control, the motor maintains rpm regardless of changes in load or conditions. We saw this in sharp turns when the motors advance the rpm to maintain boat speed. The electronic control unit monitors demand and engine load, and automatically adjusts the throttle position.
To meet the increased voltage demands that virtually every consumer is expected to place on the new motor, Mercury gave it an alternator with a charging output of 20 amps at idle and 85 amps at wide-open throttle. Idle Charge Battery Management is designed to keep an eye on the voltage, and when it is depleted, the engine will automatically increase idle rpm to boost alternator output to recharge low batteries.
Sound and sight
Even though 4-strokes are known for quiet operation, Pfeifer and Foulks said Mercury focused on output sound.
“We will not produce an engine that is not the smoothest and quietest,” Foulks said.
NVH is an acronym that Mercury uses for Noise, Vibration and Harshness, all three of which it aimed to reduce. Tuned multichamber air intakes minimize airborne noise, and enhanced cowling seals and a stiffer cowling structure keep noise from escaping. The 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.
Mercury says that compared to the competition, the new motors are 15 percent quieter at idle, 25 percent at cruise and 30 percent at wide-open throttle.
Regardless of which boat I ran, I could talk with other people on board without yelling even on models such as pontoon boats and bay models, which are known for being windy. “When we were running wide open, we could have a conversation at normal tones,” said White River Marine Group’s Emmitt after we ran the new 225 3.4L V6 FourStroke on a Mako 21 LTS flats boat.
The new engine is smaller than a 1.7-liter four-cylinder Verado, and it has a modern, angular look compared to the more rounded Verados. It fits on 26-inch centers, which is important for multiengine installations on center- and dual-console models. In addition to the dipstick and the oil fill, there’s a single latch that releases the other fastening mechanisms for the cowl. This is smart for the salt environment because all the latches are inside the cowling, protected from the elements. And there’s no more having to reach around the back of the motor to remove the cowl.
The engine will 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.
Accessories include an oil-level sensing option on the SmartCraft gauge so an owner doesn’t have to open the inspection hatch. Commercial operators can get a diagnostic SmartCraft gauge, a gear case oil drain and a boat-mounted, water-separating fuel filter.
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.
Moving forward, when Mercury comes online with other motors in different horsepower ranges, it plans to phase out the equivalent Verado models.
“We typically won’t want to operate two types of engines,” Foulks. If the first versions of this new generation of motor are anything to go by, customers shouldn’t have any problem with that.
This article originally appeared in the March 2018 issue.