Suzuki unveils outboard engines with integrated steering

Suzuki announced overnight it had created the 300hp DF300BMD and the 350hp DF350AMD, the first of its powerplants to feature integrated power steering as well as full digital controls.

Both 4.4-litre six-cylinder engines keep their contra-rotating propellers that help them get more bite on the water to improve holeshot performance and acceleration, while the lower gearcase is redesigned to make it more streamlined.

The engine mount is also designed to give better clearance from the transom, meaning the new engines are ideal for boats where the power steering’s hydraulic ram touches the transom while tilting up. On that, the engine can tilt much higher than before, but you can also still just limit how high it goes.

Unlike an external steering system that uses a third-party hydraulic ram to push or pull the leading edge of the engine, the integrated steering uses a hydraulic rack and pinion system that sits right on the axis point. Because it is more compact, the bracket mounting the engine onto the transom does not need to be as long as for a conventional engine, meaning the engine's weight is shifted further inboard.

A new lower leg now uses less oil – 2.8 litres compared with 3.2 litres for the engine on which it is based – with changes made to move a higher volume of oil around the gearcase, which in turn lowers the running temperature and improves oil life and effectiveness.

When it comes to changing the gear oil, Suzuki has added a special channel so that the engine no longer needs to be tilted.

Narrowing the width at the top of the lower leg by 4.0 per cent sounds like a small change to make, but the result is a 2.0 per cent improvement to the top speed via less drag.

The new DF300BMD and DF350AMD also carry over the technologies rolled out to the traditionally steered engines such as a self-adjusting timing chain tensioner, keyless start, a water detection system, and trolling modes.

The engines will come in 20-inch (L), 25-inch (X) and 30-inch (XX) transom heights.

The gearcase changes have also rolled out to Suzuki’s DF350A, DF325A and DF300B engines featuring external steering. The new lower leg is also compatible with existing engines, so owners can retrofit one.

Suzuki Australia was asked for comment.

A new 75hp DF75A was also launched, but at this stage the new outboard engine, a detuned version of the 1.5-litre four-cylinder four-stroke DF100, is only earmarked for the North American market.

It has also made a microplastics filter standard on the DF115A and DF140A outboard engines.