O.S. Engines FSa-72II with F-5030 Silencer OSM34721

O.S. Engines FSa-72II with F-5030 Silencer OSM34721
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Price: $619.99

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This is the O.S. Engines FSA-56II Four Stroke Engine with the F-5030 Silencer. O.S. leads the way in advanced 4-stroke engine technology, and you’ll see for yourself when you mount the FSa-72II in your model! Sport flyers will enjoy greater performance, while scale pilots will experience more realistic flight. Plus, everyone will benefit from the FSa-72II’s deep, rich sound.

O.S. Engines FSA-72II Engine, F-5030 Silencer, Type F Glow Plug and

Fuel: 10%-20% nitromethane with 18% lubricant. Synthetic, castor, or
a synthetic/castor lubricant blend may be used.

NOTE: Certain four-cycle fuels cannot be used due to low oil content
However, SOME four-cycle fuels such as the Wildcat 4-Cycle 15%
(CATP9109) may be used due to its 18% oil content.

When choosing fuels for this engine, be sure to select a fuel with
at least an 18% lubricant content.

Propeller: Sport & Aerobatic 12x7-8, 13x6-8
Scale 14x6-7


  • Blow-by oil exits through the breather nipple on back plate for more stable operation
  • Black rocker covers
  • 61N aluminum body carburetor with rotary throttle lever, high speed needle valve, and low speed mixture control, extended intake tube eliminates reverse flow tendency of air/fuel mixture, carb is reversible 180°
  • Adjustable F-5030 muffler for quiet operation can be rotated 360° for tight fitting applications
  • Two-year limited warranty through Hobby Services beginning at date of purchase


Displacement: 0.719 cu in (11.79cc)
Bore: 1.063" (20.7mm)
Stroke: 0.811" (20.6mm)
Max Power: 1.2PS/12,000 RPM, 1.18HP/12,000 RPM
Engine Weight: 16.79oz (476g)
Silencer Weight: 1.9oz (54g)
Practical RPM: 2,400 - 12,500
Crankshaft Thread Size: 1/4 x 28
Height from Bottom of Mounting Tab/Top of Rocker Cover: 3.5" (90mm)
Height bottom of Crankcase/top of Rocker Cover: 4.2" (108mm)
Width of Crankcase below Mounting Tabs: 1.4" (36mm)
Center of Mounting Holes Same Side: 0.79" (20mm)
Center of Mounting Holes Opposite Side: 1.8" (45mm)
Center of Front Mounting Hole to Drive Washer: 1.9" (49.5mm)
Center of Rear Mounting Hole to Drive Washer: 2.7" (69.5mm)
Center of Crankcase to Center of Needle Assembly: 1.3" (33.7mm)
Muffler Angle in Relation to Engine: 11°

Carburetor Needle Settings:

  • High Speed: 2.5 - 3 turns out from fully closed
  • Mixture Control (low speed): 2 turns out from fully closed

This product was added to our catalog on September 6, 2018