FS-120 III Surpass Ringed 4-Stroke Glow Single with Muffler, by OS Engines
This is one of the O.S. Surpass series of 4-stroke model engines. The Surpass series is the 2nd series of 4-stroke engines (The 1st series was the FS series, discontinued and replaced by the Surpass series around 1986-7). "Surpass" refers to this series gaining 30% more power than the previous FS series. The new Surpass engines (Version II and III) have more power than their predecessors and they also have more corrosion prevention on the inside of the crankcases.
Some differences between 2-Stroke and 4-Stroke engines:
- 4-Strokes are quieter.
- 4-Strokes get better Fuel Economy
- 2-Strokes generate More RPM (11,000-13,000 RPM with prop and 4-Strokes rev to around 9,500 RPM)
- 4-Strokes generate much more torque and will swing a larger prop.
- 4-Strokes have a more realistic sound, like a real aircraft engine.
- Specially developed PD-07 pump
- New 70N carb
- Ball bearing-supported camshaft and crankshaft
- New F-5020 Silencer
- Two year warranty
- One Assembled Engine w/Carburetor and #F Glow Plug
- One Muffler w/Manifold
- One Set of Instructions, O.S. Poster, and Decal
- (Mounting Template Is No Longer Included per O.S.)
- One additional coarse needle for less sensitive carb adjustment.
5%-15% nitromethane with 18% lubricant