Honda BF40DK4 – 40 HP 4-Stroke Outboard Motor with EFI, Lightest in Class

The Honda BF40DK4 is a 40 HP outboard that stands at the head of its class in terms of weight, compactness, and technology. As part of Honda’s midrange lineup, the BF40 shares the same platform as the BF50 model but is tuned to 40 HP, making it exceptionally light yet capable. With its 808 cc displacement and 3-cylinder design, this engine delivers the power needed to push boats around 15–18 ft in length, without adding unnecessary weight.

The BF40DK4 combines Honda’s legendary build quality with modern systems that set it apart from competitors. Thanks to Programmed Fuel Injection (PGM-FI), the engine starts instantly – even after long storage – and responds lightning-fast to throttle input. This EFI system also optimizes fuel efficiency and helps maintain a steady, consistent output at various speeds.

Honda’s impressive BLAST™ technology boosts torque at low RPMs, which means when you slam the throttle from idle, the boat leaps forward and gets on plane much quicker compared to typical 40 HP engines. Once you reach cruising speed, the Lean Burn Control system engages, automatically adjusting the mixture to run leaner and save fuel – potentially cutting fuel consumption significantly on long runs.

The Honda BF40 comes standard with power trim and tilt, allowing the operator to easily adjust the engine angle and lift the motor out of the water at the push of a button, right from the helm. The BF40DK4 LRTU model specifically is set up for remote control – intended for wheel-steered boats, integrating seamlessly with steering and throttle systems. The engine is also NMEA 2000 compatible, enabling its performance data (RPM, temperature, pressure, etc.) to be displayed on compatible marine instrument displays.

The BF40’s dry weight (long shaft) is about 97 kg, truly making it one of the lightest 40 HP outboards on the market. This low weight contributes to better boat balance and easier installation or removal when needed. At the same time, Honda hasn’t skimped on durability – the corrosion protection, multiple anodes, and a freshwater flush port ensure the engine remains reliable for years, even with intensive saltwater use.

The BF40DK4 gives owners the peace of mind of Honda’s True 5, five-year warranty. Combining low weight, high tech, and Honda’s famed reliability, this 40 HP engine is a great choice for a wide range of boats: from fishing skiffs and mid-size RIBs to smaller family runabouts, where the power-to-weight ratio is key to performance.

Recommended Applications:

• Recommended boat length: ~15 – 18 ft (4.5 – 5.5 m)
• Ideal for: mid-size RIB inflatables, fishing boats, small leisure runabouts
• Perfect when seeking the best power-to-weight ratio and agility on the water, with minimal fuel burn