OS Engines FS120S III Four Stroke Aircraft Engine, 1.20 Size, with E5040 Silencer

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The FS-120SⅢ is the latest mid-range model in the well-established FS-120S series of 20cc four-stroke engines. This series extends from the standard suction-feed FS-120S-E to the unique ultra-high performance FS-120S-SP, the world's only production model engine to be equipped with a genuine crankshaft-driven supercharger.

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  • E5040 Silencer included
  • 4-stroke engine with pump
  • Front and rear bearings sealed and greased internally to prevent corrosion.
  • Cubic capacity of 19.70 cc.
  • Recommended use of type F spark plugs.
  • With extension cord for needle adjustment included.
  • With the new lubrication system, it is not necessary the oil discharge tube of the carter
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OS Engines FS120S III Four Stroke Aircraft Engine, 1.20 Size, with E5040 Silencer

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Product Information

The FS-120S Ⅲ is fitted with the new O.S. PD-07 diaphragm type fuel pump and matching Type 70N carburettor incorporating a built-in pressure regulator. These features ensure that fuel/air mixture strength is maintained at a constant level through maneuvers, for consistent performance and reliable throttle response. In the interests of improved durability, certain ferrous parts that are particularly susceptible to corrosion in four-stroke engines, have a corrosion-resistant plating and, for the same reason, a special grease-packed twin-sealed rear ball-bearing is used. To maintain the four-stroke engine's reduced noise levels, the FS-120 Ⅲ is supplied with an O.S. E5040 silencer (muffler) of substantially enlarged volume, as standard equipment. 


19.70 cc
Piston diameter
30.40 mm
27.50 mm
RPM range
2,000 - 12,000
2.1 hp at 12,000 RPM
Complete weight with exhaust
920 g
Recommended propellers
14x9, 14x10 , 14x11, 15x8, 15x9, 15x10, 16x6

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