The History of Outboard Motors: Two Claims to First, a Horsepower War and the Four-Stroke Turn

The history of outboard motors begins with an argument the record books still have not settled — because there are two honest answers. Hang a motor on a transom and a rowboat becomes a powerboat — the most democratic idea in boating — and its descendants still power the boats in our center consoles and fishing boats listings. But ask who did it first and you must choose your definition — the man who sold one first, or the man whose outboard actually worked. This history gives both their due.

Before the Outboard: Launches, Inboards and Muscle Power

Before the outboard, small-boat power was a compromise. Launches carried little steam or inboard engines that ate the boat's interior and could not be removed; everything else moved by oar, paddle or sail. The portable motor existed only as an experiment: the standard history of the outboard records that the first known example was Gustave Trouvé's small electric unit of about five kilograms, designed around 1870 and patented in May 1880, and that the American Motors Co produced some 25 petrol outboards in 1896 — adding, drily, that "neither of these two pioneering efforts appear to have had much impact."

What was missing was the execution: a motor light enough for one man to carry, cheap enough for a fisherman, and reliable enough to start on a cold morning. Two Americans attacked the problem almost simultaneously in the 1900s — and their overlapping claims created the industry's founding dispute.

Whose Was First? Waterman's Porto (1906) vs Evinrude (1909)

Cameron Waterman began developing his motor in 1903 and filed his patent application in 1905. As the feature history of Waterman's invention tells it, he went into production in 1906 with the "Porto": an air-cooled motorcycle engine driving a propeller by chain and sprockets — 2 hp, 35 lb, fifty dollars — advertised at the 1906 Sportsman's Show at Madison Square Garden. A water-cooled redesign followed in 1907; within two years he was building some 3,000 motors a year. The standard record credits the company with claiming 25,000 sales by 1914, with Detroit's Caille Motor Co building the engines.

Ole Evinrude, a Norwegian-born Milwaukee machinist, launched his 1.5 hp motor in 1909. It was lighter, simpler and — the standard record's verdict — "the most successful early outboard motor": thousands sold between 1909 and 1912, with 3 hp versions sold worldwide. Waterman himself supplies the reason no court ever crowned a winner: as he noted, no basic patent on the outboard was possible, because an 1883 patent had anticipated the idea. So the honest presentation is the one this history adopts: Waterman sold first; Evinrude's motor worked better and sold far more. Any source that gives you a single inventor is selling you a slogan, not a record. (Our history of speedboats makes the same point briefly; this is the full version.)

Evinrude, ELTO and Johnson: The Outboard Goes Mainstream, 1910s–20s

The 1920s were the outboard's first golden age. Evinrude sold his original company and, after sitting out a non-compete, returned in 1921 with ELTO — the Evinrude Light Twin Outboard — built around a two-cylinder motor of his own design. Lou Johnson, in partnership with his brothers, founded the Johnson Motor Company in Terre Haute, Indiana, in 1921, and Johnson's light, well-made twins became the third leg of the market. Dozens of smaller makers filled the catalogues, motors shrank to true portables, and the outboard settled into its defining role: the engine of the small fishing boat, the farm pond and the summer-camp dock — the same role that underpins the small-boat end of the best boat brands story.

The Depression culled the herd; the survivors were gathered into the Outboard Marine Corporation, and the pattern — a mass market of a few big names, defined by reliability rather than novelty — held until one man decided the outboard business needed showmanship.

Carl Kiekhaefer and Mercury: Power, Marketing and Racing, 1939 Onward

In 1939 Carl Kiekhaefer bought the bankrupt Cedarburg Manufacturing Co — maker of Thor outboards — and inherited, per the feature history, a truckload of defective returned motors to rebuild. He rebuilt the company as the Kiekhaefer Corporation of Fond du Lac, Wisconsin, and Mercury attacked the market on every front: engineering, unprecedented advertising, private-label volume for Montgomery Ward and Western Auto, and racing.

The racing was the advertisement. Kiekhaefer's Mercury teams dominated outboard competition, and the technology spilled straight into production: in 1957 the 60 hp Mark 75 arrived as the most powerful production outboard of its time and the head of the inline-six "Tower of Power" lineage. Brunswick bought the company in September 1961; the same year brought the MerCruiser sterndrive, and for 1962 the Merc 1000 became the first production outboard rated at 100 hp, wearing the new Phantom Black paint that still defines the brand.

The Horsepower Wars and the Family Runabout Era (1950s–70s)

Mercury's escalation forced everyone's hand. Through the 1950s and 1960s the flagships climbed from 25 to 40 to 70 hp and beyond, and the outboard graduated from the fishing skiff to the family runabout, whose fiberglass hulls needed power to pull skiers and plane with a family aboard. OMC's Evinrude and Johnson answered with their own V4s and, in the 1970s, the V6 era pushed production outboards past 200 hp, a figure that would have read as fantasy in the Porto's day.

This is the era that made the modern used market: the two-stroke outboard became cheap, ubiquitous and effectively universal on small and mid-size boats, from the bass boats whose parallel story we tell in our history of bass boats to the center consoles that would later stack three and four of them across a transom. It also set up the reckoning: two-strokes were light and simple, but dirty.

The Japanese Makers and the Four-Stroke Turn

The challengers arrived from Japan with motorcycle engineering behind them. Yamaha's own history records its first outboard, the P-7 — a 7 hp air-cooled two-stroke — reaching the market in July 1960 for Japanese coastal fishing boats; Suzuki followed with its first outboard, the 5.5 hp D55, in 1965. Both built export empires on refinement and reliability. Honda arrived with a doctrine: Honda's company history records its first outboard, the four-stroke GB30 of 1964, and preserves Soichiro Honda's instruction — "I don't care if everyone is making two-stroke outboards, Honda must make four-stroke outboards." Honda held that line for four decades, through to the world's first 225 hp four-stroke in 2001.

The industry followed Honda when the law required it. United States and European exhaust-emissions rules adopted in the 1990s tightened in stages, and carbureted two-strokes could not comply; direct-injection two-strokes bought time, but through the 2000s the four-stroke — cleaner, quieter and thriftier — became the default on new boats. Yamaha's first four-stroke had come as early as 1984; by the 2010s the conversion was essentially complete.

Electric Outboards and 600hp Flagships: What the History of Outboard Motors Means for Buyers

Today's market is bookended by extremes Evinrude could not have imagined. At one end, compact electric outboards own the portable niche Trouvé sketched in 1880. At the other, the flagship war reached Mercury's 7.6-litre V12 Verado, introduced on 11 February 2021 at 600 hp and billed by Mercury as the world's first V12 outboard — with the first two-speed automatic transmission in an outboard and a steerable gearcase — arriving just as Seven Marine's 627 hp production run ended. Triples, quads and quintuples now hang on big center consoles, doing inboard work.

For buyers: the outboard won by being portable and serviceable anywhere, and the used market reflects every era — carbureted two-strokes (cheap, smoky, simple), direct-injection two-strokes, and four-strokes (the safe default). Repowering an older hull with a modern four-stroke is often the best upgrade in boating — our finance providers can help structure it, and complete rigs await in the boats for sale.

History of Outboard Motors FAQs

Who invented the outboard motor?

The record refuses a single name. Gustave Trouvé patented an electric outboard around 1880 and an 1883 patent anticipated the whole concept — as Cameron Waterman himself admitted. Waterman's gasoline Porto was in production in 1906; Ole Evinrude's 1909 motor was lighter and far more successful. First sold and first successful are different titles, and two different men hold them.

What is the difference between Waterman's and Evinrude's claims?

Waterman's claim is chronological: his Porto was advertised and sold from 1906. Evinrude's is practical: his 1909 motor was the design that worked reliably and sold in the thousands, founding the industry's first durable company. The standard record uses exactly this split — "first real gasoline-powered outboard offered for sale" for the Porto, "most successful early outboard" for Evinrude.

Why did four-stroke outboards replace two-strokes?

Emissions law, mostly. Two-strokes are light and simple but exhaust unburned fuel; US and European rules adopted in the 1990s tightened in stages until carbureted two-strokes could not comply. Honda had built four-strokes from 1964 on principle; the rest converted through the 1990s–2000s, and four-stroke quietness and economy finished the argument.

What is the most powerful production outboard?

The current flagship class sits around 600 hp: Mercury's V12 Verado, introduced in February 2021 at 600 hp as the world's first V12 outboard (the maker's billing), arrived just after Seven Marine ended production of its 627 hp V8 in January 2021.

Bottom line: The history of outboard motors is Waterman's 1906 Porto, Evinrude's better 1909 motor, Kiekhaefer's horsepower theatre and Honda's four-stroke patience. To see what a century of that progress hangs on today, browse the boats for sale at Boat Deals Direct.