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FR7-420 Sirius-7 7-Cylinder

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FR7-420 Sirius-7 7-Cylinder

O.S. Engines OSMG1307 Airplane Engine Nitro
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  • FR7-420 Sirius-7 7-Cylinder

    This is the O.S. Sirius7 FR7-420 7-Cylinder 4-Stroke Engine.


    Main internal parts such as the crankshaft, cam holder and reduction
    gear are all plated to resist corrosion
    V-shaped individual valve covers for vintage scale appearance
    Impeller system distributes air-fuel mixture equally to each cylinder
    ensuring high performance and smooth idle
    Padded and lockable aluminum silver colored storage case
    Two year limited warranty through Hobby Services beginning at date of


    O.S. Sirius7 FR7-420 7-Cylinder Sirius 4-Stroke Engine, seven type F
    glow plugs, valve adjusting kit, radial mount & hardware kit,
    needle valve extension cable, drain plug, carburetor insert, decal,
    glow plug cable set, instruction manual and aluminum case


    Fuel: Aircraft blend 5-10% nitro content with 8-10% lubricant
    content (it is suggested to dilute commercially available 15%
    nitromethane and 18% lubricant fuel with methanol half and half to
    make a 7.5% nitro and 9% lubricant fuel)
    Propeller: 22x10-12, 23x8-12, 24x8-12, 26x8


    Displacement: 0.6071cu in x 7 (9.95cc x 7)
    Bore: 0.944" (24.0mm)
    Stroke: 0.866" (22.0mm)
    Practical RPM: 1,500 - 7,000
    Weight: 111.7 oz (3,167g)
    Crankshaft Size: UNF3/8-24
    Distance from Backplate to Drive Washer: 6.2" (158.5mm)
    Outer Edge of Backplate to Pushrod Covers: 4.8" (122mm)
    Outer Diameter: 9" (230mm)
    Carburetor Settings:
    Needle valve, 2-1/2 turns open from closed position
    Throttle Valve, approximately 1/4 turn open from closed position,
    then start engine and follow break-in instructions on pages 19-25
    in manual

  • O.S. Engines FR7-420 Sirius-7 7-Cylinder Parts List (1 items)

  • O.S. Engines FR7-420 Sirius-7 7-Cylinder Hop-Ups & Optional Accessories (0 items)

  • Manuals and Support

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