In early September, Mercury Marine announced the launch of a new six-horsepower outboard powered by an indirect fuel injection system. It is currently the only six-horsepower outboard to feature this technology combined with a twin-cylinder architecture
In the automotive sector, fuel injection systems have dominated for decades, offering functional advantages that carburetors cannot match. However, carburetors are still widely used in small auxiliary engines due to their low cost, mechanical simplicity, compact size, and ability to operate without batteries, ECUs, or sensors. Examples include garden equipment engines and portable outboards with power below eight horsepower. These engines are mechanically simple and mainly operate at fixed speeds—a mission profile that carburetors handle exceptionally well.
Until early September, this represented the standard design approach for all manufacturers in the sector. Mercury Marine’s new 6 EFI outboard could change that. As the name suggests, it is a six-horsepower engine utilizing the same electronic indirect fuel injection system already used in Mercury’s compact, portable outboards over eight horsepower. Mechanically, it is aligned with these larger units, featuring a twin-cylinder layout and 209 cc displacement achieved with 55 mm bore and 44 mm stroke cylinders. This is currently unique in this power class, along with the four valves per cylinder driven by a single overhead camshaft.
This exclusive outboard was designed with the French market in mind, where six horsepower is the maximum power allowed without a license. For local recreational boaters, the option to upgrade a six-horsepower engine to ten is particularly attractive. Mercury also retains the compact 6 HP single-cylinder 123 cc model in the lineup to serve those who do not need high performance but require more torque than single-cylinder six-horsepower units can provide—for example, when trolling larger boats.
The new engine is free from external service components, except for the fuel tank, because the Mercury injection system operates without a battery, making it suitable for compact engines while preserving this characteristic. An ECU is included to facilitate cold starts and optimize fuel delivery according to engine condition and the operator’s power demand, balancing performance and fuel consumption. Standard features include the Mercury multifunction tiller for one-hand throttle and gear control, which can be replaced with remote control, and a quick-connect freshwater flushing system, making the engine not only powerful but also easy to maintain and operate
Table
This table summarizes the current market offering of six-horsepower outboards from major brands with strong distribution and technical support across Italy. Mercury Marine’s 6 EFI introduces a twin-cylinder architecture with 63% more displacement than the previous six-horsepower average of roughly 131 cc. This results in higher weight, near 40 kg versus an average of 26 kg, and likely a higher price—expected to be slightly below €3,000, close to the 8 EFI outboard it shares mechanics with.
From this perspective, the lightest engine in terms of weight is the Suzuki “Df 6” while the cheapest, according to the price lists reported by the magazine “Il Gommone”, is the Selva Marine “Oyster”, closely related to, if not identical to, the Yamaha “F6”. Mechanically, the Mercury “6 Hp” and the Tohatsu “Mfs 6” are also completely similar, the latter being built by the Japanese manufacturer on behalf of the American company.
