O.S. Engine OSMG0935 FS-120 Surpass III with Pump - High-Torque 4-Stroke Engine  [OSMG0935]

O.S. Engine FS-120 Surpass III Engine with Pump
Price:
NZD$875.82
Brand:
O.S. Engine
Model:
OSMG0935
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Precision 4-Stroke Performance for Scale and Sport Models

Enthusiasts who build and fly scale or sport aircraft will appreciate the O.S. Engine OSMG0935 FS-120 Surpass III with Pump for its steady power delivery and refined running characteristics. The engine's layout supports pilots looking for linear throttle feel and dependable midrange power.

Fuel Management and Acoustic Improvements

The new regulating pump design improves metering consistency, helping the engine respond cleanly across different RPM bands. Noise is mitigated by a larger muffler that quiets operation while keeping exhaust flow efficient.

Construction That Handles Field Use

Engine reliability is enhanced by internal greasing of the rear ball bearing with dual rubber seals to keep out grit. Corrosion resistance is addressed via plated crankshaft, cam shaft and piston ring surfaces. The reversible carb and black rocker cover add practical convenience and a neat look.

Specifications

  • Displacement: 1.2 cu in (19.7 cc)
  • Bore: 1.197 in (30.4 mm)
  • Stroke: 1.083 in (27.5 mm)
  • Practical RPM: 2,000-12,000
  • Output: 2.1 hp @ 12,000 rpm
  • Weight: 32.5 oz (920 g)
  • Recommended Props: 14x9, 14x10, 14x11, 15x8, 15x9, 15x10, 16x6

The FS-120 Surpass III is a dependable choice when you need a rugged, smooth-running 4-stroke engine for hobbyist builds and serious scale projects.

Is this engine suitable for aerobatics?

Yes, its steady powerband and reliable fuel delivery make it suitable for many aerobatic routines when paired with the right prop and airframe.

Can I swap the muffler for a different silencer?

Aftermarket mufflers can be fitted but check backpressure and mounting compatibility to preserve performance and avoid lean conditions.

What break-in routine do you recommend?

Follow a progressive run-in with a mix of low and medium throttle runs, allowing the engine to cool between sessions and checking for secure fittings.

How weather tolerant is the sealing system?

The dual rubber seals around the rear bearing give good protection against dust and moisture, suitable for regular club-field conditions.

What props should I try first?

Begin with mid-range sizes like 14x9 or 15x8 to assess climb and cruise, then fine tune for your model's weight and flying style.

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