This is the O.S. GT55 Gasoline Engine with Electronic Ignition. FEATURES: Produces 20-30% more power than any other engine in its class IG-01 Capacitive Discharge Ignition uses a microcomputer programmed for optimum spark advance through the use of magnetic sensors on the crankcase and prop drive, the IG-01 also detects and compensates for wet plugs to ensure consistent quick starts, also requires minimum current in stand-by mode and features a low voltage warning (intermittent engine operation) Front mounted WLA-2 carburetor stays cooler for less heat percolation and more consistent performance, simple and direct throttle and choke linkages Unique one-piece crankcase eliminates gaskets and enhances strength and precision Front induction rotary valve crankshaft design for positive opening and closing of valve for optimum timing, no oil seal required which eliminates RPM loss due to additional friction Massive front and rear crankshaft bearings for longer life and maximum power output Thin high-performance piston ring and high-strength aluminum alloy piston for reduced break-in and high compression from the very first run Two year limited warranty through Hobby Services beginning at date of purchase INCLUDES: O.S. GT55 Gasoline Engine with Electronic Ignition, Carburetor, CM-6 Spark Plug, Prop Washer with four 5x40mm Socket Head Cap Screws, Exhaust Gasket and Instruction Manual REQUIRES: Propeller: 22x8 for break-in 22x10, 23x8, 23x10, 24x8, 24x10 for sport/acro/scale use Two-Cycle Oil: Break-In, Klotz Modelube recommended, mix at 30:1 gas/oil mixture for 10 flights, 1.3 - 1.6 gallons (5-6 liters) of gas After Break-In: mix at 50:1 ratio, See COMMENTS below Electric starter NOTE, The propeller must be brought up to at least 100RPM in order for the electronic ignition to work Muffler: See COMMENTS below Fuel: Unleaded regular gasoline (no need to use high octane) SPECS: Displacement: 54.9cc (3.35 ci) Bore: 1.62" (41.2mm) Stroke: 1.62" (41.2mm) Output: 5.5 PS, 5.42 HP/7000 RPM Practical RPM: 1,500 - 8,000 Weight: Engine 1,580g (55.7oz) Igniter 140g (4.9oz) Muffler 6.28oz (178g) Carburetor Settings: Two turns out on high and low speed needles from fully closed position, then start engine and follow break-in instructions on pages 18-25 in manual Distance/center of Mounting Standoff Holes Top to Bottom: 2.6" (66mm) Distance/center of Mounting Standoff Holes Side to Side: 3.1" (78mm) Distance/center/Mounting Standoff Holes/Crankshaft Center:1.3" (33mm) Height/bottom of Mount to Top of Cylinder Head: 7.1" (180.4mm) Height/center of Crankshaft to Top of Cylinder Head: 5.5" (139.2mm) Width at Cylinder Head: 2.9" (75mm) Center of Crankshaft to Center of Exhaust Outlet: 2.9" (74.6mm) Length from Mount to End of Drive Spacer: 5.9" (150mm) Length from Mount to Crankcase Center: 1.5" (37.5mm) Thread size of pilot shaft for spinner bolt 5mm COMMENTS: If using a different brand of oil other than Klotz, OS recommends their own mix ratio which may differ from the manufacturers" For 40:1, and 50:1 oils, OS recommends a 30:1 gas/oil mixture 25:1 is 5oz of pre-mixed 2-cycle oil or 151 ml per gallon of fuel 30:1 is 4.3oz of pre-mixed 2-cycle oil or 126 ml per gallon of fuel 40:1 is 3.2oz of pre-mix 2-cycle oil or 95 ml per gallon of fuel 50:1 is 2.6oz of pre-mix 2-cycle oil or 76 mll per gallon of fuel The following mufflers are ideal for different applications; J"TEC Large Wraparound Pitts Muffler, JTCG7950 for inverted mounting applications. Bisson Wraparound BISG9250, and Inverted BISG9251 mufflers will also fit. Slimline offers the following, #2125 Inverted Pitts Muffler, #2156 Side Canister, and #2155S w/Smoke System. jxs 10/15/09 ir/jxs updt jxs 03/17/10 updt jxs 04/20/10 updt jxs 10/12/10 updt jml 10/11/11