This is the O.S. Engines 91 HZ-R 3C Speed Helicopter Engine in Red.

        ****** Because of the competition nature of this engine,******
          ******it is NOT covered by the O.S. 2 Year Warranty.******

FEATURES: Designed for all-out F3C competition
          Demand Regulator System ensures consistent fuel delivery from full
            to empty
          170° exhaust timing for optimal horsepower and stable hovering
          Newly designed combustion chamber shaped to match the big bore
            carburetor and advanced exhaust cylinder timing
          0.44" (11.2mm) Big Bore 61G carburetor for greatest power needed
            for F3C maneuvers
          Crankshaft counter-weight reduces vibration at high RPM

INCLUDES: 91 HZ-R 3C Speed Helicopter Engine with #8 Glow Plug, Aluminum Check
            Valve, 0.008" (0.2mm) Head Gasket,, Aluminum Control Arm, two
            Needle Adjusting screws and Instruction Manual

REQUIRES: Fuel: 10%-30% nitromethane with at least 18% lubricant. Lubricants
            may be either castor or synthetic oil or castor/synthetic blend.
          Field Equipment: glow starter, fuel bulb, fuel can filter, fuel pump
            hexagonal starting shaft (depending on brand of helicopter)
            electric starter, battery and fuel tubing
          Muffler-Depending on heli

SPECS:    Displacement: 0.91cu in (14.9cc)
          Bore: 1.09" (27.7mm)
          Stroke: 0.98" (24.8mm)
          Output: 3.6 PS, 3.55 HP @ 15500 RPM
          Practical RPM Range: 2,000-16,500
          Weight (w/o Muffler): 21.2oz (603g)
          Crankshaft Size: 5/16-24
          Height from crankcase bottom to top of cylinder head: 4" (103mm)
          Height/bottom of mounting tab to top of cylinder head: 3.1" (79mm)
          Distance between mounting hole centers same side: 0.98" (25mm)
          Distance/mounting hole centers opposite side: 2" (52mm)
          Distance/center of muffler screw holes: 1.6" (42mm)
          Distance/bottom of mounting tab to muffler screw holes: 1.7" (42.8mm)
          Distance/crankshaft center to throttle control arm: 1.6" (42mm)
          Length from front bearing to backplate: 3.3" (84mm)
          Length from backplate to end of crankshaft: 4.5" (116mm)
          Width of crankcase below mounting tabs: 1.7" (43mm)
          Width between mounting tabs: 2.4" (61mm)
            Carburetor Settings-
          High Speed Needle: Two turns open from fully closed
          Medium Speed Needle: One turn open from fully closed
          Idle Mixture Control: At basic position when engine leaves factory

                                                                   jxs 04/08/11
                                                                         ir/jxs