By Norberto Pereira

Nowadays, as the increase of the cost of fuel has become one of the major factors for the choice about the proper outboard, Suzuki has developed a system called «Lean Burn» that enabled their outboards to get even more with less of fuel.

Suzuki’s Lean Burn Control System

This technology was introduced on DF 70/80/90 in 2008, and added gradually to other models until today. Suzuki's Lean Burn Control System is available, and in use on the DF300AP/250AP/200A//140A/115A/90A/80A//70A/60A/50A/40A/30A/25A/20A/15A and the smallest 9.9B.

To get that intelligent fuel management, Suzuki has improved the electronics into the engine, re-designing every component part, to make it as lightweight mechanically and more fuel-efficient as possible for new generation models outboard, allowing this way the users to spend more time on the water.

How does it work?

Suzuki’s Lean Burn Control System predicts the fuel needs according to operating conditions.

This allows the engine to run on a more efficient fuel mixture through the use of a lean air-fuel ratio. A normal petrol engine will run with an air fuel ratio of 14.7:1, whereas a Lean Burn System can increase this ratio to the high point of 18:1, which is a significant increase in efficiency. The Lean Burn process requires fuel to be injected into the cylinder at a precisely controlled rate and volume with a poorer air-fuel mixture at the start of the injection cycle, leading finally to lower fuel consumption.

This creates a longer burn time and a more controlled explosion of the fuel, over the full downward stroke of the piston. This in turn means that there is power over the whole combustion stroke and subsequently a more efficient and complete burning of all the fuel available; leading to more power for less fuel and less emissions.

Suzuki Lean Burn Control System has been developed so that it delivers these benefits over a wide operating range, providing significant improvements in fuel economy from low speed operation into the cruising range.

Suzuki’s Lean Burn Control System

For example, tests have shown that the new generation DF60A outboards use 16% less fuel than the older 60hp model, mainly in the cruising range, which is where the engine is used for the majority of the time.

Fuel percentages across entire range of «A» series:

DF25/30A = 16%, DF40/50A/60Α = 16%, DF70/90/100/115/140A = 14%, DF 150G = 15%, DF 175G = 16%, DF200A = 19%, DF250/300A = 14%

Suzuki’s Lean Burn Control System


Suzuki’s Lean Burn Control System

To obtain these improvements, Suzuki was focused on optimising volumetric efficiency by using fluid analysis to optimise flow through the passageway. Combustion efficiency was improved by using most advanced fuel injection system combined with technologies that Suzuki already employs, such as multi-point sequential electronic fuel injection, variable valve timing, long track intake manifold and multi-stage induction, electronic throttle and shift system. All these exist on the new generation Suzuki outboards becoming a very attractive power option for leisure and commercial use with reduced running costs.

Besides, this is reflected in sales helping thus Suzuki to be the fastest-growing outboard brand in Europe.

By controlling the air to fuel ratio, the Lean Burn System provides an optimum amount of fuel to the engine to an rpm range including the crusising speed.

Suzuki’s Lean Burn Control System

Suzuki’s Lean Burn Control System

...keep Ribbing!