2025 Suzuki Marine DF40A LMore power, more performance.

The DF40A is the only engine in the 40 HP class to offer DOHC performance, and also the only to incorporate a maintenance-free, oil-bathed timing chain, which provides the outboard with improved durability and maintenance-free operation. With larger displacements for increased power and performance, Suzuki’s Lean Control System improves fuel economy with designs that are more compact and lighter in weight than their predecessors. The new DF40A engines also include the Suzuki Troll Mode System. The Boating Writers of America presented Suzuki Marine with the NMMA Innovation Award for the DF40A/DF50A, during the 2011 Miami Boat Show.

Features may include:

Go your own speed.

Glide into your favorite honeyhole with Suzuki’s Troll Mode System. The engine’s revs can be adjusted in 50 rpm intervals, giving you precise control pressing the Troll Mode control switch from idle up to 1200 rpm, allowing you control over your wake and speeds.

Running like clockwork

The DF40A comes equipped with digital sequential electronic fuel injection, meaning it reads the electronic control unit monitors throttle setting, engine RPM, cylinder wall and air-intake temperature and atmospheric pressure all at once. All of these considerations cause the fuel injection to enter the combustion chamber at the most optimal opportunity, offering smoother and faster acceleration, crisp throttle response and reliable starting no matter what the conditions or temperature are.