OMC Wankel Rotary Race Outboards

Johnson and Evinrude Rotary Outboards: OMC's Daring Leap into Wankel Rotary Power

OMC’s Vision for Rotary Innovation

In the early 1970s, Outboard Marine Corporation (OMC)—the parent of the Johnson and Evinrude brands—embarked on a bold mission to redefine marine propulsion. Their inspiration came from the groundbreaking work of German engineer Felix Wankel, who invented the rotary combustion engine (known as the Wankel engine) in the 1950s.

Unlike traditional piston engines, the Wankel design offered smoother operation, higher RPM potential, compact size, and fewer moving parts—all advantages that aligned perfectly with the needs of high-performance outboard motors.

OMC first applied rotary technology in 1972 by introducing a Wankel rotary engine into snowmobiles. The engine's lightweight construction, simplicity, and remarkable power-to-weight ratio impressed engineers and corporate leadership alike.

Seeing its success on land, OMC’s next ambitious step was to bring this innovation to the water, believing that a rotary-powered outboard could outperform anything Mercury Marine had in their arsenal.

The result was a series of Johnson rotary outboards and Evinrude rotary outboards featuring single-rotor, twin-rotor, and even an experimental four-rotor design engineered for racing at the highest competitive levels.

OMC believed these engines could offer smoother throttle response, lighter weight, and superior top-end speeds, setting new standards for marine propulsion.

Racing Debut and Triumphs

By 1973, the Johnson and Evinrude rotary outboards were ready to face their fiercest competition—Mercury Racing and Mercury High Performance. OMC fielded these revolutionary engines in tunnel boat races on both sides of the Atlantic, powered by some of the biggest names in the sport, including Jimbo McConnell and Johnnie Sanders.

The rotary outboards demonstrated blistering acceleration, smoother throttle response, and competitive top-end speed that challenged Mercury’s long-standing dominance.

The racing community’s reaction was electric. Many marveled at OMC’s technological leap forward, while Mercury Racing crews quickly recognized the serious challenge Johnson and Evinrude posed.

For a brief but thrilling period, Johnson and Evinrude vs Mercury Hmatchups became headline events, symbolizing one of the most intense rivalries in outboard racing history.

🥇 1973 Windermere Grand Prix (United Kingdom)

OMC’s first major international success came at the 1973 Windermere Grand Prix in England. Johnson and Evinrude rotary-powered boats outpaced the competition on the narrow and technical course, showcasing the rotary engine's smoothness and agility. This victory proved that rotary power could dominate in real-world race conditions, even against Mercury High Performance equipment.

🏆 1973 Galveston Speed Classic (United States)

Later that year, OMC’s rotary boats swept the Galveston Speed Classic in Texas. Johnson and Evinrude entries finished 1st, 2nd, and 3rd, while a fourth rotary-powered boat had been leading before crashing out. The Galveston sweep sent shockwaves through the racing world, showing that OMC's new technology was not just competitive—it was dominant.

🚤 1974–1975 U.S. Tunnel Boat Championships

Throughout the 1974 and 1975 tunnel boat racing seasons, rotary-powered Johnson and Evinrude boats continued to make headlines. Drivers like McConnell and Sanders often secured pole positions and led laps against Mercury Racing’s best.

Although endurance issues occasionally forced retirements, the sheer speed of the rotary engines repeatedly pushed Mercury Hi-Perf engineers to rethink and improve their racing programs.

OMC’s rotary engines had changed the game—but keeping up the momentum proved difficult.

Strengths and Setbacks

Although the OMC rotary outboards proved incredibly competitive, several critical hurdles emerged. Manufacturing costs were extremely high due to the complex nature of the Wankel rotary engine.

Maintenance was more complicated than the rugged, simple designs Mercury High Performance engines relied on. Furthermore, tightening environmental regulations made the fuel economy and emissions of the rotary engine less favorable compared to Mercury's traditional two-stroke powerplants.

Despite their superior speed and innovation, the Johnson and Evinrude rotary outboards struggled to find a path to commercial viability. Enthusiasm from racers and engineers could not overcome the practical challenges facing production and widespread adoption.

The End of the Rotary Dream

By the late 1970s, OMC officially ended the rotary outboard project. Without the ability to mass-produce economically or satisfy environmental standards, the rotary Johnson and Evinrude engines were shelved.

Mercury solidified their dominance in the performance and racing markets, while OMC retreated to focus on more traditional two-stroke designs.

Nonetheless, the impact of the Johnson and Evinrude rotary outboards remains significant. Their brief but brilliant presence pushed technological boundaries, forced Mercury Racing to innovate, and left an enduring legacy of daring engineering that marine historians and collectors still celebrate today.