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OS FX .25

The new state-of-the-art in sport/competition engines!

  • All FX engines come with remote needle valve - the feature most asked for!
  • A longer crankshaft provides more secure attachment for spinner, prop and nut
  • Dual ball bearing construction adds durability and longevity
  • Semi-square head shape creates more fin area to increase cooling capacity
  • Each engine comes with a high-performance carburetor and muffler with adjustable exhaust direction and built-in pressure tap
Displacement 0.249 (4.08cc)
Bore 0.710 in (18.034mm)
Stroke 0.630 in (16mm)
RPM 2500 - 19000


0.84 BHP @ 18000 RPM
Weight 8.8 oz (250g)
Recommended Props 9x5, 9x6, 10x6
Not Available