O.S. Engine OSMG0981 81FS-a 4-Stroke Power Unit for 60-Size Models  [OSMG0981]

O.S. Engine 81FS-a 4-Stroke Engine
Price:
£281.42
Brand:
O.S. Engine
Model:
OSMG0981
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Refresh Your 60-Size Model with the O.S. Engine 81FS-a

The O.S. Engine 81FS-a, model number OSMG0981, is aimed at pilots who want a durable 4-stroke upgrade for 60-size kits. It fits the FS-70SII mounting area and delivers a notable improvement in steady power output for general sport and precision flying.

Cleaner running thanks to smart engineering

The 81FS-a uses a sealed lubrication configuration that removes the need for crankcase ventilation, reducing oil loss and simplifying upkeep. The 60RA carburetor with venturi optimises the air and fuel mix while reducing the risk of fuel reaching the cowl. A rubber O-ring on the muffler manifold also helps to prevent oil from leaking at the exhaust joint.

Technical highlights at a glance

Specifications

  • Displacement: 0.809 cu in (13.26 cc)
  • Bore: 1.091 in (27.7 mm)
  • Stroke: 0.866 in (22.0 mm)
  • Weight w/muffler: 20.11 oz (570 g)
  • Practical rpm range: 2,200-10,000
  • Output: 1.3 hp @ 11,000 rpm
  • Includes: 60RA carburetor, F-5030 muffler

The O.S. Engine 81FS-a delivers a combination of straightforward installation and robust 4-stroke performance suitable for a wide range of 60-size aircraft applications.

Will this engine improve throttle response?

Yes, compared with many smaller units the 81FS-a offers stronger midrange and top-end response, which can improve throttle control in 60-size airframes.

Are there special break-in steps?

Follow standard 4-stroke break-in procedures and monitor running conditions; ensure secure prop and muffler fittings while checking for any unusual oil or fuel signs.

What should I check after installing the engine?

Verify carburettor mounting, muffler O-ring seating, propeller security and that the engine clears the cowl at all control throws before the first flight.

Is the included muffler the correct unit for this engine?

The F-5030 muffler is supplied with the engine and is the intended match, with the manifold O-ring helping to maintain an oil-tight exhaust joint.

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