Suzuki Debuts the DF350A: Its Largest 4-Stroke Outboard

Suzuki Marine has launched its largest production outboard to date, the 350-hp DF350A four-stroke. Built around a V-6 powerhead, the DF350A combines a high 12:1 compression ratio, a direct intake system, dual fuel injectors per cylinder head and a contra-rotating dual-propeller arrangement to deliver strong performance for modern boats and larger center-console designs.

The engine’s 12:1 compression ratio is notable in the outboard market and, according to Suzuki, represents the highest compression ratio used in an outboard to date. That high compression, combined with the engine’s displacement and tuning, yields an output that works out to about 80 horsepower per liter, a figure Suzuki highlights when describing the motor’s efficiency and power density.

Suzuki designed the DF350A’s induction system to protect performance in challenging marine environments. A direct intake with a dual-louver arrangement reduces the risk of ingestion from microscopic water droplets by diverting those particles away from the intake airflow. This complements the engine’s fueling strategy, which uses two fuel injectors at each cylinder head to help optimize combustion and increase overall output while maintaining smooth delivery across the rev range.

One of the more distinctive features of the DF350A is its contra-rotating, or counter-rotating, dual-propeller setup. By using two props that rotate in opposite directions, the system effectively doubles the available blade area compared with a single prop of similar diameter. That additional blade area increases the propellers’ “grip” on the water, improving hole-shot performance and reducing the time it takes a boat to plane. Suzuki also notes that the dual-prop arrangement pairs well with the DF350A’s increased torque, helping boats accelerate more briskly from a standstill and maintain stability through acceleration.

Practical installation and fit options are provided with two shaft lengths: 25-inch and 30-inch models are available to suit a range of transom heights and boat designs. The 25-inch shaft version of the DF350A has a listed weight of 727 pounds, while the 30-inch version weighs 747 pounds. Those weights reflect the robust construction and the integrated systems that support the engine’s high-performance characteristics.

Market demand is a driving factor behind Suzuki’s move into larger-displacement outboards. As Yasuharu Osawa, executive general manager for Suzuki Motor Corp., explained at the launch, boats—especially center-console models—have been growing in size and capability. At the same time, boatowners and builders have increasingly favored outboards for applications that historically relied on sterndrives or inboard power. The DF350A is Suzuki’s response to that trend, offering a high-output four-stroke option for larger and performance-oriented designs.

For boatbuilders and owners looking for a high-horsepower outboard with modern fuel-injection technology, enhanced intake protection and a counter-rotating propeller layout, the DF350A represents Suzuki’s top-level offering in its current outboard lineup. Its combination of a high compression ratio, dual injectors per cylinder head and the benefits of contra-rotating props aim to balance strong acceleration, efficient power delivery and refined marine operation for a wide range of boats.

Suzuki Motor of America, based in Brea, California, provides regional support and sales for the DF350A. Contact information listed at the time of release included the company’s phone number: (714) 572-1490 and the manufacturer’s site name: suzukimarine.com.

This article originally appeared in the October 2017 issue.