Power your prized Giant scale plane with an O.S. Multi-Cylinder 4-Stroke Engine. The O.S. FF-320 (Nicknamed "Pegasus") is a Flat-Four Cylinder Engine. It is the ultimate in scale realism: abundant power, realistic noise levels, and scale appearance. This engine is covered by a 2-Year Warranty. FEATURES: Pushrod-Driven Overhead Valves Ringed Pistons Gear-Driven Camshaft 5 -Crankshaft Ball Bearings 2 -Camshaft Ball Bearings Four Cylinders (flat, 2 opposing 2) Firing Order: 1-3-2-4 INCLUDES: One Assembled FF-320 4-stroke Engine One Set of Instructions, Decals, and Poster One Choke Valve Four Glow Plugs (OSMG2692) One Motor Mount (OSMG2804) One Safety Prop Nut Assembly One Glow Plug Extension Harness One Spare Woodruff Key SPECS: Construction: All aluminum and Aluminum alloys Displacement: 13.26 cc (x4) (.809 cu in x4) Bore: 27.7mm (1.091") Stroke: 22.0mm (.866") Power Output: 4.1 BHP at 8,000 RPM Weight: 2,190g (77.3oz) w/mount Practical RPM Range: 1,800 - 8,500 RPM Length: 181.5mm (7.15") from back of mount to front of drive washer Width: 196mm (7.72") Height: 80mm (3.15") from top of mount to bottom of mount. the carb extends 30-40mm farther down. Distance from front-most edge of front header to drive washer: 36mm Crankshaft Thread size: 5/16-24 Suggested Props: 18x10, 18x11, 18x12, 18x13, 18x14, 20x8, 20x9, 20x10, 22x8 Needle Settings: High Speed: 3-3.5 turns out from fully closed Mixture Control (low speed): Turn counter-clockwise until it stops, then 2 turns out REQUIRES: 2-STROKE Fuel with 5%-15% nitromethane and 16% MINIMUM oil content. (All 5%-15% fuels we carry meet these requirements) DO NOT USE 4-STROKE FUELS!!) JBN 7.27.93 These items are no longer included: ir/jl NEEDLE VALVE EXT CABLE, CHOKE VALVE ROD updt lmm 4/6/09 (3) ALLEN KEYS 2.0,2.5,3.0-SCREW DRIVER FOR MIX CNTRL, PROP WASHER,5 WRENCHES ** Please check the ACG for these part numbers***