Today’s outboard motors are more powerful, more efficient, more reliable, smoother, and quieter than ever before.
If you’re interested in powerboats of just about any type, ranging from speed boats to sportfishing yachts, you need to know all about outboard motors. Outboards have been around for over a century – and these days, they’re the fastest-growing segment of the marine power market. That’s in no small part because outboard engine technology has advanced by leaps and bounds in recent years, and today’s modern outboard motors are better than ever. Let’s start with the basics, then we’ll look at some of the newest outboard models this year. (Or skip the overview and head straight to 2019’s best outboard motors below.)
What Are Outboard Motors?
Outboard motors are fully contained marine propulsion systems that can be mounted onto the transom of a boat. The powerhead, driveshaft, and a lower unit with running gear (the part with the propeller that sits underwater) are all contained together in one unit. Like most marine power systems, the engine spins a shaft, which then spins a propeller shaft, which in turn spins a propeller to create thrust.
Outboard motors have several advantages as compared to other marine propulsion systems. A boat manufacturer can take an outboard and bolt it right onto the back of a boat, hook up the control cables and fuel lines, and the boat’s ready to go. That greatly simplifies the boatbuilding process, because with an inboard or stern drive they’d have to mount the motor and then line up and attach the drive system.
It also makes the engine very easy to replace in case of failure; it improves a boat’s handling because outboard motors provide articulated thrust as opposed to the rudders used with inboards; and modern outboards offer an excellent power-to-weight ratio as compared to the other options. See Inboard or Outboard: The Boat You’ll Buy Next, for more a more in-depth inboard-versus-outboard comparison.
History/Evolution Of Outboard Motors
Ole Evinrude, a Norwegian immigrant who arrived in the U.S. at age five in 1882, is usually credited with inventing the first outboard motor in 1906. The tale is quite famous, and with good reason – it’s an excellent example of American ingenuity. According to the lore, Ole and his fiancé Bess were picnicking on an island in Okauchee Lake. When Bess expressed a desire for ice cream, Ole jumped into their rowboat and took off, rowing vigerously for the mainland. But the two-and-a-half-mile trip was just too far, and by the time he returned to Bess the ice cream had all melted.
Ole knew there had to be a better way, and he was right: he invented and built a 1.5-horsepower outboard motor that could be clamped to the back of a rowboat. He and Bess (by then married) produced 25 outboards in 1909, and sold them all in one day. Thus, Evinrude Motors was born.
Obviously, outboards have come a long way in the past 110 years. Through the earlier years of development outboard sizes gradually increased, until 1975 when the first V-6 outboards finally broke the 100-horsepower barrier and put 175- and 200-horsepower outboards on the market. The biggest turning point in modern times, however, came with EPA emissions standards first introduced in the 1990s and then phased in over a number of years.
New emissions standards forced outboard manufacturers to turn in a different direction, completely replacing the carbureted two-stroke engines they depended on and instead developing cleaner-burning four-stroke technology. While four-stroke engines were significantly more efficient than two-strokes of the time, they were also much heavier and more complex, so there was a lot of trial and error involved in the process. But eventually, all of the major outboard motor manufacturers with the lone exception of Evinrude made the switch for four-strokes.
Evinrude instead developed two-stroke direct-injection in order to meet emissions standards, but early versions were a disaster and Outboard Motor Corporation (by then Evinrude’s parent company) filed for bankruptcy in 2000. It was eventually bought by Bombardier Recreational Products (BRP). BRP then made major reinvestments in two-stroke technology and their new E-TEC G2 outboards were introduced. These outboard motors are extremely efficient and clean-burning, in many cases more so than four-strokes, and are the only two-strokes built by a major manufacturer still on the market today.
Current Outboard Motor Market
In recent years, the biggest push in the outboard engine market has most certainly been producing larger, more powerful motors. In 2007 Yamaha introduced a monstrous V-8 outboard, the F350, producing 350 horsepower. Then in 2011 industry newcomer Seven Marine rolled out a shocking 557-horsepower outboard, at the time the most powerful outboard ever built, based on a marinized 6.2-liter GM LSA Gen IV V-8 engine designed for the Cadillac CTS-V. Just a few years later, they’d top this mark with their own 627-horsepower version. Meanwhile, Mercury constantly upped the ante with their Verado models, bringing a 350 and then 400 horse models to the market. Suzuki followed a similar path by introducing the DF350A V-6, a model notable for its twin-propeller lower unit.
But all of the interesting outboard developments haven’t taken place with these huge powerplants. As outboard-powered boats have grown larger and larger and outboard manufacturers have matched this demand with increasing horsepower, there have also been some big developments in the world of small outboard motors. EFI has been incorporated into smaller and smaller models and Suzuki made a breakthrough in 2014 when they introduced battery-less EFI to small, portable outboards like the DF25A and the DF15A. Yamaha quickly followed up with battery-less EFI when soon after, they introduced a series of engines including their new F25, F75, and F90 outboards.
And yes, that F25 features battery-less EFI.
Newest 2019 Outboard Motors
In the past year, the fast-moving world of outboard tech has continued to evolve with some rather amazing new innovations. Yamaha rolled out their largest outboard motor ever, the V-8 F425 XTO, a 5.6-liter beast that weighs in at nearly 1,000 pounds and is designed to be utilized in multiple-engine applications for very large, heavy boats up into the 50-foot range. The F425 is also the first four-stroke outboard to incorporate direct fuel injection (DFI), the same technology utilized by Evinrude’s two-strokes and which has also been widely adapted in the automotive market.
Another recent development is Evinrude’s next-generation G2, which now includes a wider range of applications. Evinrude has been “walking” the G2 DFI two-stroke technology down their model line, and as of 2019 it appears in their new in-line-three 1.9-liter outboards. These come in 115 HO, 140, and 150 horsepower sizes and like other engines in the G2 line (which runs up to 300 horsepower), offer a 10- to 15-percent fuel efficiency advantage when compared to average four-strokes.
The introduction of diesel outboard engines has also made news recently. Other outboard diesels have come and gone, but in 2019 Cox introduced the largest yet produced, the CXO300. The Cox diesel was designed from the ground-up (previous diesel outboards were adapted from existing diesel powerheads designed for other purposes) to be an outboard incorporating common-rail technology. And at about the same time, a Swedish company called Oxe announced it would be building 150- to 300-horse diesel outboards based on a marinized GM diesel block.
Electric outboards are also becoming more widely available in ever-growing horsepower sizes. While few companies have managed to penetrate this market with a wide range of offerings, German company Torqeedo now has a model line ranging from one to 80 horsepower. The newest is the Travel 1103C, a three-horsepower electric outboard that has GPS-calculated range data, fully variable forward and reverse, and a removable 915 Watt-hour battery that weighs only 38 pounds.
You can check out our huge range of Outboard Motors on the site today.
Future of Outboard Motors
Where will the future of outboard motors lead? Almost certainly to a continued mix of technology, as we see in today’s market. Gasoline, diesel, and electric options will all surely play a role and no one system can be expected to dominate the market, as each has its own set of advantages and disadvantages.
It’s important to note that the growing dominance of electric and hybrid-electric power systems we see in vehicles designed for use on land isn’t likely to be mirrored in the marine world, because the application of technology is so different. Regenerative braking, for example, (which uses an automobile’s braking to feed power back to a car’s batteries) isn’t possible in a boat. And unlike automotive applications boat motors generally run at high RPM for extended periods, quickly sapping the juice out of the battery banks. So internal combustion outboards aren’t likely to go away any time soon.
We can expect, however, for four-stroke and two-stroke DFI technology to continue to evolve and advance. Outboard engines have enjoyed a steady march towards better efficiency, more digital integration with the boat as a whole, and constantly improving technology and that should continue unabated.
Outboard Motor Brands
Considering the popularity of outboard engines, one might think the field of competing outboard motor brands would be fairly large. However, there’s a limited number of major players. These include:
The model line of this company’s newest two-stroke tech, the G2 outboards, goes from 115 to 300 horsepower. Evinrude also has 3.5 to 150 horse E-TEC engines, 40 to 105 h.p. jet drive outboards, plus 30 and 55 horse multi-fuel engines (which can run on just about anything from kerosene to diesel) designed for military applications. Evinrude is the only outboard manufacturer producing a completely two-stroke line.
Honda Outboard Motors
Honda Marine offers four-stroke outboards from 2.3 to 250 horsepower, including jet outboards from 40 to 105 horses.
Mercury Outboard Motors
Mercury Marine’s line-up includes four-stroke outboards from to 2.5 to 400 h.p. They also have jets from 25 to 80 horsepower. In addition, Mercury is one of the few outboard manufacturers to utilizes superchargers, which are present on their 350 and 400 Verado models. A separate division, Mercury Racing, offers a 450-horsepower supercharged model.
Minn Kota Outboards
Minn Kota manufactures a line of electric motors which can be bow- or transom-mounted, ranging from 30 pounds of thrust to 112 pounds of thrust (approximately 1.5 to 2 horsepower)
Motorguide Outboard Motors
Another electric motor manufacturer, MotorGuide offers bow- and transom-mount motors between 30 and 109 pounds of thrust.
Seven Marine Outboards
This industry newcomer builds 527, 577 and 627-horsepower supercharged four-stroke outboards, based on a marinized GM LSA Gen IV V-8 Cadillac engine. Their 627sv is the largest outboard engine in production today.
Suzuki Outboard Motors
This manufacturer’s line-up of four-stroke outboards ranges from 2.5 to 350 horsepower, and includes one of the few twin-propeller outboard engines (the DF350A) on the market today.
Tohatsu Outboard Motors
Tohatsu’s line of four-stroke gasoline outboards ranges from 2.5 to 250 horsepower, and the company offers a limited number of two-stroke low-pressure direct-injection (TLDI) models. Tohatsu has a rather unusual five-horse outboard as well, which runs on LPG. They also produce jet-drive options from 25 to 115 horsepower.
Torqeedo Outboard Motors
The biggest player in the electric outboard motor market, Torqeedo makes outboards from one to 80 horsepower.
Industry giant Yamaha Outboards has a four-stroke model line ranging from 2.5 to 425 horsepower, including the only direct-injected four-stroke on the market, the F425 XTO. They also produce jet outboards from 40 to 150 horsepower.
Outboard Motors FAQ
When it comes to outboard motors, two of the questions we hear asked all the time are “what’s the biggest outboard?” and “which is most fuel efficient?” So let’s take a quick look at information regarding these topics.
Most Powerful Outboard Motors
Everyone wants to hear about the biggest, most powerful outboards in existence. The top 10 most powerful outboards are:
- Seven Marine 627
- Seven Marine 577
- Seven Marine 527
- Mercury Racing 450R
- Yamaha F425 XTO
- Mercury Verado 400
- Suzuki DF350A
- Yamaha F350C
- Mercury Verado 350
- Evinrude G2 300
You should think about how big an outboard will actually fit on your boat however. We’ve put together an article on this subject for you here.
Smallest and Most Fuel-Efficient Outboards
Setting aside electric outboards and alternative fuel outboards, size and fuel efficiency often go hand in hand – the smaller an outboard is, the better economy it’s likely to post. Aside from that, testing has showed that Evinrude’s G2 models consistently attain slightly higher fuel efficiency numbers than their four-stroke competitors, usually in the 10- to 15-percent range. What about comparing those four-strokes, which certainly dominate the market, to one another?
Different sizes in the manufacturer’s line-ups may do slightly better or worse than one another, but as a rule of thumb the vast majority of the four-stroke outboards on the market offer very competitive efficiency and rarely differ by more than a tenth of a mile per gallon or so.
On top of the similar nature of four-stroke outboard efficiency, due to the number of variables in the boats they’re mounted on, very accurate apples-to-apples comparison between different outboards is rarely possible. Different model outboards may post slightly better or worse efficiency numbers on one type of hull design as compared to another. And boat manufacturing is not an exact science; often the same model boat will vary from one hull to the next in weight, sometimes by hundreds of pounds. So testing two outboards side by side on the same model boat can provide unreliable results.
Finally, note that there are other variables that can come into play. Sea conditions, for example, have a big impact on efficiency and can change from one moment to the next. Then, there’s outboard propellers choice to consider. And then there are variables that can make an outboard engine perform better,
as well as a few techniques that can be used to make a boat engine run faster.
The bottom line? Today’s outboard motors are far more efficient than they were a decade or two ago across the board, and it’s rare to see major differences among modern outboards of similar horsepower.
Today, the popularity of outboard engines is at an all-time high. Even on boat types that have traditionally been built with stern-drive and inboards, such as runabouts and cruisers, more and more outboard models are being introduced every year. In fact, approximately four out of five new powerboats sold in the United States are now powered by an outboard motor, while stern drive sales have steadily declined and inboard options have remained flat. And this shouldn’t come as a surprise. Boaters regularly cite the easy maintenance, high reliability, and quiet operation as reasons why they prefer outboard motors over the other options – and truth be told, today’s outboards really are better than ever before.
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