It’s no secret there is a growing demand for more powerful outboard motors. These new outboard motors have fueled a demand for larger boat designs that previously may have been powered by stern drive or other inboard power. As more powerful outboards are introduced, the boats get bigger and as the boats get bigger, outboards are getting more muscular.
To say the least, 2020 was the year of unpredictability yet the decision for Evinrude to discontinue production of its two-stroke outboards along with Seven Marine’s similar announcement with its four-strokes seemed to catch many by surprise. However, as the popularity of outboards continues to skyrocket on the Great Lakes, there is plenty to get excited about heading into 2021. Here is a look at some of the industry’s largest four-strokes.
Honda 250
Honda’s flagship model is its 250hp 3.6-liter EFI four-stroke V6 that has proven to be a durable and dependable engine. Available in 20-, 25- and XXL 30-inch shaft lengths for taller transoms, the 250 makes a lot of sense for a twin setup. The 250 weighs in at 613 pounds, which is above average for an engine of this size. Rated to turn a maximum of 6,300 rpm, the Honda has a 90 amp alternator to charge the boat’s batteries. A new feature is AMP+, which senses electrical loads and automatically increases idle speed 53 minutely (about 100 rpm) to increase charging output by another 9 amps.
The Honda “BLAST” system, which stands for “Boosted Low Speed Torque,” rapidly advances ignition timing while enriching the fuel mixture electronically for quicker holeshots and more low-end torque. IST—electronic shift and throttle controls— are standard. Color choices include silver and white. Honda backs up the 250 with a 5-year non-declining transferable warranty as standard—one of the best warranties available.
Mercury 450R
Mercury recently released its 400hp Verado, but turns out it was only the beginning. Its new Mercury Racing 450R outboard is purpose-designed for the high-performance disciple craving unrelenting power. Steeped in Mercury Racing DNA, the 450R features a 4.6-liter V8 FourStroke powerhead boosted by an exclusive Mercury Racing supercharger to produce 450 peak propshaft horsepower and 40 percent higher torque than the powerful 400R.
At over 300 pounds lighter than the nearest competitor, the new 450R delivers industry-leading power-toweight in a compact, efficient package. The 450R writes a power prescription that combines unprecedented acceleration and top speed potential with rugged reliability and the latest technology from Mercury Racing. Multiple gearcase, control system, tie bar, and styling options are available to create the ultimate customized outboard performance package, ready to run Wide Open all day long. Best of all, the Mercury Racing 450R delivers all of its performance on readily available 89-octane (95 RON) pump fuel.
Suzuki DF350A
Suzuki has embarked on a major engineering expedition to build the ultimate fourstoke outboard motor. In developing the DF350A, Suzuki engineers started with a clean sheet of paper and considered many factors for this design. Making more horsepower can be accomplished in many ways. The engine design can include larger displacement and adding turbo chargers or super- chargers. However, larger displace- ment engines typically burn more fuel and increase the overall weight. While adding complex mechanical components can create reliability concerns. Once you have all of that 54 horsepower, now the challenge is getting it to hook up or grab traction in the water. Suzuki Engineers labored through years of trial and success with computer simulations and on water testing to significantly improve the way an outboard motor converts engine power to underwater thrust.
The introduction of the DF300B is the latest outboard model to join Suzuki’s revolutionary series of dual-propeller outboards and features the full range of Suzuki’s award-winning technology, including the unique contra-rotating props, which provides superior thrust and directional stability.
Yamaha 425
When Yamaha released its XTO Offshore 425hp four-stroke in 2018 to say it’s their largest outboard would be an understatement. While shaving weight is a top priority for some outboard builders, Yamaha instead focused its efforts on durability.
The naturally-aspirated 5.6L V8 started with a target propeller size for large offshore fishing boats and the engineers built an outboard that could spin the bigger prop. To spin a bigger prop you need a bigger prop shaft, diameter and gears, and much more displacement in the engine to give you the torque. The average weight depending on the shaft versions is 976 pounds but when you’re pushing 30,000 pounds of boat it’s not as big a factor as you might think.
