This is the Thunder Tiger F-91S Four Stroke Model Airplane Engine.

FEATURES: CNC machined construction for precise tolerances
          Front and rear ball bearing supported crankshaft with Ni plating to
            reduce corrosion
          Easy to adjust updraft airbleed carburetor
          Black anodized aluminum muffler with pressure tap
          Redline RF glow plug
          Forged aluminum connecting rod with dual bushings
          Lightened hypereutectic machined Al-Si ringed piston with XC2
            (extreme composite coating) cylinder liner with etched criss cross
            pattern
          Three year limited warranty through Hobby Services beginning at date
            of purchase

INCLUDES: Thunder Tiger F-91S Four Stroke Engine with header pipe, muffler,
            glow plug, valve gauge, valve adjusting wrench, 1.5mm, 2mm, 2.5mm
            and 3mm hex wrenches, instruction sheet, Redline RF glowplug,
            decals and box wrench with 14mm & 12mm hex sizes

REQUIRES: Fuel: 18% lubricant and 10-15% nitro content, synthetic/castor blend
            lubricant recommended
          Propeller: Break-in: 11x10
                     Stunt/Aerobatic: 11x10, 11x11, 12x10, 12x11, 13x9
                     Scale: 14x7, 15x6, 16x6, 12x8 (3-blade)
          Glow starter, plug wrench and field equipment

SPECS:    Displacement: .91 cu in (14.97cc)
          Bore: 1.114" (28.3mm)
          Stroke: 0.937" (23.8mm)
          Practical RPM: 1,800 - 12,000
          Output: 1.6 HP @ 11,000 rpm
          Weight: 26.20oz (742.8g) without muffler
          Crankshaft Size: 5/16-24
          Height from Mounting Tab Bottom to Top of Rocker Arm: 3.77" (95.7mm)
          Height from Crankcase Bottom to Top of Rocker Arm: 4.63" (117.7mm)
          Width at Mounting Tabs: 2.36" (60mm)
          Width of Crankcase below Mounting Tabs: 1.69" (43mm)
          Center of Mounting Holes Same Side: 0.98" (25mm)
          Center of Mounting Holes Opposite Side: 2.05" (52mm)
          Center of Crankcase to Drive Washer: 2.62" (66.5mm)
          Distance from Backplate Screw to Drive Washer: 3.64" (92.5mm)

                                                                   jxs 10/20/10
                                                                         ir/jxs