Four-strokes to the fore

Chris Beattie | VOLUME 29, ISSUE 4
The new line-up runs from 75 to 115hp and is also suited to dual installations.
Mercury expands its FourStroke range of outboards and releases a new V6 sterndrive.

Mercury has taken the wraps off an expanded range of four-stroke outboards, along with a new 4.5lt MerCruiser V6 sterndrive. In a special media event held on the Gold Coast in late June, company representatives from the US were on hand to unveil the new engines.

During the briefing, Dusty McCoy, CEO of Brunswick Corporation, which owns Mercury, made reference to Mercury's 75-year history, as well as bringing journalists up to date on the company's corporate health and where it's headed for the immediate future.

McCoy said that Mercury continued to invest heavily in R&D (approx US$120 million per year) and despite being hard-hit by the GFC in 2008 the company had continued to release new products on average every six weeks. He predicted that the current global economic situation would result in only slight growth in Mercury's business over the coming 18 months.

The new additions to the company's FourStroke range of outboards span the 75 to 115hp segment and are based on the architecture of Mercury's 150hp FourStroke released in late 2011.

During the presentation we were told outboard users needed to "unthink" everything they knew about Mercury's FourStroke range to fully appreciate the significance and achievements of the new engines.

Mercury says the new powerplants - all based on the same 2.1lt four-cylinder engine block, which is claimed to be the largest displacement in the class - provide compact and low-weight packages that produce outstanding torque and horsepower.

Low friction

The new members of the FourStroke range, which comprise the 75, 80, 90, 100 and 115 power categories, incorporate special low-friction, zero-maintenance valve trains into their eight-valve, single-overhead-cam cylinder heads. This, along with other friction-reducing measures, results in up to 23 per cent more torque over previous FourStroke models, according to Mercury.

Due in part to the engines' lower friction losses, fuel economy at cruise speed is also improved by up to 14 per cent. According to Mercury, the 115hp engine is also the lightest on the market, weighing 9kg lighter than the lightest rival four-stroke engine.

Low maintenance is also another feature, with Mercury claiming the design of the new valvetrain means the top end of the engine is maintenance-free for the life of the powerplant.

And the company says over 17,000 hours of durability testing, including "vicious log strikes", ensures that the new series offers the utmost in reliability and endurance.

Noise reduction was a high priority and Mercury has implemented a number of measures, including a tightly sealed top cowl and special muffler system to reduce high frequency exhaust noise, while a top-mounted throttle body helps reduce intake noise. Mercury says engineers even redesigned the trim pump to deaden sound on the new range.

A new Focused Mount System has also been developed to lengthen engine mount life by moving the rubber mounts away from the heat of the power head, while the mount design also helps greatly reduce vibration.

Engineers also came up with a new hydrodynamically designed gearcase, claimed to reduce drag by 15 per cent, for improved efficiency and performance, with the byproduct of improved fuel economy. A new clutch also reduces shock when shifting gears.

While on the driveline, Mercury also offers a new heavy duty Command Thrust gearcase option for heavier boats or craft that carry their hulls deeper in the water. Command Thrust is available for the 90 and 115hp FourStroke models and uses the same larger gearcase housing as the 150 FourStroke, but with a 2.23:1 drive ratio, which is tailored to heavier boats. The benefit, says Mercury, is that heavier boats will be able to achieve plane easier and faster, resulting in greater acceleration and easier on-plane running.

The 90 and 115hp Command Thrust models are also available with left-hand rotation for dual engine installations.
The new FourStrokes also boast Mercury's effective anti-corrosion protection, including Mercury's own XK360 low-copper alloy, extensive use of stainless steel components and the MercFusion paint process, which is engineered specifically for the harshest marine environments. Mercury backs up its corrosion protection with a three-year, factory-backed limited warranty.

Mercury's Senior Category Manager for the new range, Steve Miller was on hand to field questions and said the foundation of the new FourStrokes was to offer a large displacement engine to produce good power without having to work too hard.

"The result is that we have engines that are very low-stressed, but still deliver a lot of performance," he said.

A full range of Mercury's dedicated SmartCraft digital gauges, including SmartCraft SC1000 gauges, VesselView4 and VesselView7 screens, can be optioned with the new engines.

We had the chance to sample a few different applications of the new FourStrokes over a morning on the Coomera River and in the relatively brief time we had on each craft I came away particularly impressed by their smoothness, quiet running and strong mid-range response.

V6 sterndrive

The company also chose the launch to take the wraps off an all-new V6 petrol sterndive powerplant, although it stressed that it won't be officially launched until late 2014 and is intended primarily as an OE fitment for boat manufacturers.

Designed as a replacement for the company's long-serving 5lt V8 sterndrive, the all-new 250hp MerCruiser 4.5L V6 offers almost as much power and torque as its eight-cylinder predecessor, but with a substantial weight saving of 60kg in a more compact package.

"We are proud to introduce the next generation of sterndrive technology with this ground-breaking new engine," said Mercury Marine President, John Pfeifer. "This is a great power source that provides features, benefits and technology that make boating more enjoyable and worry-free. This engine was purpose-built for marine use and it delivers Mercury's proven performance, durability and ease of service."

The mostly cast iron powerplant, which Mercury says offers improved corrosion-resistant properties over aluminium when used in engine blocks and cylinder heads, also employs traditional pushrod valve actuation for its conventional valvetrain system.
A long runner, scrolled intake manifold and comparatively large displacement for a V6 contribute to the new sterndrive's impressive performance alongside the V8.

Other design innovations include a rear-facing throttle body and anti-whistle throttle plate for reduced noise, and a lightweight flywheel for improved throttle response. The result is an engine that delivers a superior idle and smoothness, along with low noise and vibration for a better boating experience, says Mercury.

"One of the great things about the new V6 is that because it's smaller than the V8, boat builders have more room to use for other things inside the boat," said Steve Miller.

Mercury has also launched a new throttle system with the new V6. Called Adaptive Speed Control (ASC), it automatically maintains a set rpm point regardless of load or condition changes, such as in tight turns, when performing tow sports or when running at lower speeds on plane. Basically, once the speed is set by the driver, the throttle body will adjust throttle position to maintain the speed. In practice, the boat maintains the desired speed with no input from the driver, leaving them free to concentrate on steering or towing.

The MerCruiser 4.5L is also compatible with SmartCraft Digital Throttle & Shift and can be optioned up with Mercury's Joystick Piloting system to enhance docking control and manoeuvrability.

Mercury says its engineers paid particular attention to ease of maintenance when designing the MerCruiser 4.5L V6, eliminating the need for the traditional 20-hour service. This new engine features a 'maintenance centre' near the top-front section of the engine, ensuring that consumer touch-points - including oil filter and fill - are easily identifiable and accessible. Additionally, the valve train is maintenance-free for the life of the engine.

Available in single or twin installations and compatible with Mercury's full series of Alpha and Bravo Drives, the MerCruiser 4.5L should begin appearing in new boats early in 2015.

New trollers

For those who rely on stealth when fishing, Mercury also showed off two new electric trolling motors from its MotorGuide range.

The Xi5 boasts a new composite shaft for added strength when encountering obstructions and is backed with a lifetime warranty. It also employs MotorGuide's Pinpoint GPS technology as standard or as an upgrade. Pinpoint uses an ultra-precise GPS receiver and precision control algorithms for extremely accurate performance through a compact, easy-to-use remote control.

Mercury says the Xi5's high-efficiency electronics are fully encapsulated in a high-tech coating, which makes them impervious to water and dust. There's also a protection circuit that prevents lower unit damage if the prop is stalled.

The Xi5 includes wireless capability, allowing anglers to command precise motor and steering control from anywhere on the boat. Its wireless pedal has an intuitive, pro-style 'heel-toe' operation, offering very quiet and precise steering.

Digital variable speed control enables exceptional low-speed trolling capability and longer run time and the Xi5 has cooler-running electronics that are 50 per cent more efficient. By capturing and storing energy that is typically lost as heat, the Xi5's batteries have longer run times and require fewer recharges, says Mercury.

The X3 is all-new and, according to Mercury, has been designed and engineered to be the best in its class for quiet operation, reliability and precise control.

Mercury says the new troller incorporates durable components, premium features and top performance and is also priced right. With eight cable-steer foot-operated models and two hand-operated models to choose from, there's an option for everyone's fishing style and budget.

The X3's mount is constructed using rigid aircraft-grade aluminium. The outer shaft is corrosion-resistant stainless steel, with a large diameter for added strength, while the shaft is made from a premium composite material, with a lifetime guarantee against breaking.

Tight-fitting components and fewer metal-to-metal interfaces make the X3 a quiet performer on the water, says Mercury.

The X3's Variable Ratio Steering (patent pending) gives anglers higher-response steering and precise boat control in the primary fishing zone. Torque-steer feedback is also reduced, making for smoother operation. Premium dual-cable, pull-pull steering is standard.

For more information on all of the latest Mercury range, go to: