Mercury Racing's 300XS OptiMax remains the horsepower-to-weight ratio king, with performance that matches the 300X.

As our readers know, we cover the Miami International Boat Show every year. In recent years, we’ve seen a push from the major outboard engine manufacturers toward (and beyond) the 300-horsepower barrier.

The horsepower race is on, and this is driving outboard technology toward more powerful engines that work within the constraints of current and future emissions laws.   The marine industry is undergoing the same transformation that the automotive industry dealt with back in the early 1970s - using technology to produce powerful engines that are more environmentally friendly.  While this path was somewhat rocky for the musclecar, technologies available today will make this metamorphosis easier to digest for the consumer than it was for motorsport enthusiasts back in the 1970s.

Mercury Marine: 300 horsepower on Two Platforms

Mercury Marine is no stranger to 300-horsepower outboards, and they remain the benchmark by which all other performance outboards are judged. Mercury was the first to introduce a consumer 300-horsepower outboard back in 1982, which was much later followed with the more refined ProMax 300 and 300X.
 

Mercury's new Verado 300 showcases the latest in marine technology.

The real challenge for Mercury came in the 2006 model year – the year that marked the end of traditional two-stroke engines like the 300X. Defying predictions that it was not possible, Mercury Racing introduced the OptiMax 300XS – a direct-injected, emissions- friendly outboard that matched the performance of the 300X and provided better fuel economy. This year Mercury Marine escalated the horsepower race by introducing a 300-horsepower version of their supercharged Verado at the Miami show.

The Verado 300, based on the 2.6 liter, 24-valve inline-6, brings with it over 25,000 hours of testing during its development. We always knew the 275 Verado had greater horsepower potential, and I think there’s more to come from this high-tech platform. Standard Verado features apply, such as Digital Throttle and Shift (DTS), a valvetrain that requires no adjustments for the life of the engine, Shadow Mode capability with multi-engine installations, electro-hydraulic steering, and Mercury’s three-year, non-declining warranty.

The OptiMax 300XS remains a very strong seller for Mercury Racing, and for very good reason - it's the highest performing, emissions friendly outboard in the world.  Eventually, the 300XS will inherit Mercury's Digital Throttle and Shift system, creating an even more refined package for high performance boaters.

Yamaha F350: 5.3 Liters, Eight Cylinders, and 800 Pounds

To the astonishment of the press, Yamaha introduces a 5.3 liter V8 outboard rated at 350 horsepower.

Yamaha shocked members of the press by unveiling an all-new 350-horsepower V8 outboard. That’s right – the V8 is back, only this time it’s larger than the engine in a 2007 Ford Mustang GT and produces more horsepower as well. The question many are asking is if the buying public is ready for an outboard that weighs over 800 pounds.

Let’s think about that for a minute – those extra 50 horses the Yamaha offers over competing outboards brings with it a 200-pound weight penalty. That may sound like an unreasonable tradeoff, but horsepower is just part of the equation here. A 5.3 liter V8 is sure to deliver tremendous torque – something very large boats can never get too much of. Yamaha claims that the new F350 will usher in a new type of boat – the “F350 class” vessel – hull sizes previously powered by stern drive systems. The F350 will reportedly produce 45 percent more torque than 250-horsepower V6 engines. Whether that potential extra torque benefit justifies the extra weight of the engine remains to be seen – the Yamaha F350 is scheduled to be released this April.

Cutaway view of the Yamaha F350.

The 5.3-liter V8 utilizes a 32-valve, overhead cam design with Variable Camshaft Timing. Variable valve timing became mainstream in the automotive industry back in 1990 with Nissan’s 300Z, and proved to be very effective at increasing torque at lower RPM ranges. The F350 adopts this technology, as well as a unique in-bank dual exhaust system. To be honest with you, I’m very interested in how this engine sounds – an outboard with the exhaust note of a V8 stern drive?

Key features of the F350 include an offshore-specific design utilizing forged engine mounts, an oversized mounting transom bracket, and a streamlined gearcase with hardened gears, enhanced bearing surfaces, and dual water inlets. The F350 also features Yamaha’s all-digital Command Link Digital Electronic Control system.

 

Evinrude: Only A Question of When

Currently, Evinrude's top gun is the E-Tec 250, but that's expected to change.

Despite many active rumors, Evinrude did not introduce any new large outboards at Miami this year. Last year, BRP told us that they had no intention of entering the 300+ horsepower outboard power bracket at that time. Times are changing though, and we feel that a 300-325 horsepower Evinrude E-Tec is on the horizon, and has likely been in development for quite some time.

Right now, Evinrude’s top engine is the 3.3 liter 250 horsepower E-Tec. What will Evinrude’s next large outboard be? I believe it will remain a V6 with slightly higher displacement, and although rumors of a V8 E-Tec have been circulating in our forums for a long time, I think this unlikely.  Considering the claims on the E-Tec DVD, Evinrude will need to gain some ground in the horsepower race to live up the E-Tec engine marketing hype.

One thing is for sure, Evinrude's E-Tec engines have created a rebirth of the company, and have reestablished a lot of consumer confidence in the brand - much of which was lost near the end of the OMC days.

Suzuki DF300: Upping The Ante

The Suzuki DF300 is the largest displacement V6 outboard at 4 liters.

Suzuki entered the big leagues with their new DF300, a four-liter, four stroke engine that is currently the largest displacement V6 production outboard in the world.  A narrow 55-degree engine design allows easier installation of multiple engines, and Suzuki claims its offset driveshaft design better balances the engine on the transom. 

The DF300 is the first Suzuki outboard to feature Precision Control - Suzuki's fly-by-wire throttle and shift system.  While it's clear that Mercury ushered in the digital throttle and shift system with its Verado back in 2004, no other engine manufacturer has anything to compete with Mercury's exclusive Shadow Technology, which allows three or four-engine operation with the ease of dual controls.

A newly-designed lower unit reduces drag by 18 percent, according to Suzuki, and carries a very low final drive ratio of 2.08:1.  The DF300 will be available at dealerships in fall, 2007.

What's next to come?  As outboard marine technology plays a larger role in overcoming EPA mandates, these engines will become lighter, more sophisticated, and more powerful.  The DFI two-stroke vs. four-stroke debate will continue, but it's likely that both of these platforms will continue to mature.  The buying public has been exposed to marketing from both camps for a number of years now, but for all-out performance, it still seems that the DFI two-stroke engines are still the way to go.

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