O.S. ENGINES were the first manufacturer in the world to mass-produce 4 stroke model engines in 1976. The first engine to be produced - the FS-60 - was enthusiastically received by model fans worldwide. The main feature of this engine, which was acquired by so many modellers as soon as it was released, was its beautiful sound in the air, which was so different to the popular two-stroke engine. Enthusiasts were also won over by its attractive appearance, high torque and power. The FS-60 made a huge impact on the modeling market and is still historically remembered as the forerunner of the many 4 stroke engines that followed it.

Subsequently, the O.S. 4 stroke engine lineup evolved into various styles, such as multi cylinder models with mechanisms that approached those of ‘real’ engines, and went on to power many competition models.

Now, in the spring of 2004, O.S. ENGINES are introducing a completely new type of engine and we feel it is the most exciting of all the 4 stroke engines we have produced. It inherits its basic concept from its forerunner, but this new model - the FL-70 - offers the enthusiast refined, smooth power and is already being hailed as another major advance.

The FL-70 is an engine with a completely new design. In the ‘FL’ series, the ‘F’ of ‘Four Stroke’ has been combined with ‘L’ ‘Light weight’. The basic design and mounting size is the same as that of the ‘FS-70 Ultimate’ which made its debut last year, and although it is in the same 70 size class, it is both lightweight and compact.The aim of the FL series is to introduce the O.S. 4 stroke engine to even more enthusiasts, which is why we have made it as easy to handle as possible. The ringless cylinder and piston (never before seen in an O.S. 4 stroke engines) greatly improves the ease of maintenance and thanks to the introduction of a new type of breather system, fuel level problems are minimized, giving stable power and response.

To make maintenance even easier, we are using the same type of shielded front crankshaft bearing as we use on the FS-70U. This not only reduces maintenance but also ensures there is no oil leakage from the front. The special carburetor installed at the rear of the engine is of simple construction requiring only the adjustment of the main needle - an important feature taking advantage of the superiority of 4 stroke engines.

The teardrop shape bulge for rocker arm clearance is impressive, as is the special gloss finish of the head cover. The two characteristic 4 stroke engine pushrod tubes and the rounded shape of the cylinder head impart a touch of nostalgia despite their new design. All of these elements come together in this new FL series engine.

It not only delivers high power, but also the atmosphere and enjoyment of owning a quality four stroke model engine. With the release of this new powerplant, O.S. ENGINES aims to bring the four stroke experience to even more modellers.