This is the O.S. GT60 Gasoline Large Scale Airplane Engine with Pitts Style E-6020 Muffler. FEATURES: Linerless cylinder with the cylinder head integrated with the cylinder, this arrangement allows for extremely precise intake/ exhaust timing and very high scavenging efficiency resulting in higher output IG-02 electronic ignition system can be powered by 4-6 cell NiCd/ NiMH batteries or 2-cell LiPo batteries Custom designed Walbro carburetor mounted to rear of engine with integrated choke rod guide Two year limited warranty through Hobby Services beginning at date of purchase INCLUDES: O.S. GT60 Gasoline Engine, IG-02 Electronic Ignition. E6020 Muffler, CM6 Spark Plug REQUIRES: Propeller: Break-In 23x8 Acro/Scale 22x10-12, 23x8-10, 24x8-10 Unleaded regular gasoline (no need to use high octane) 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 SPECS: Displacement: 3.656 (59.91cc) Bore: 1.732" (44.0mm) Stroke: 1.551" (39.4mm) RPM Range: 1,600-8,000 RPM Output: 6.00 hp @ 7,000 RPM Weight: Engine, 49.38oz (1400g) Ignition module, 3.7oz (105g) Muffler: 6.28oz (178g) Suggested Propeller Size and RPM Data: 22x10 6,900 RPM 23x8 7,000 RPM 24x8 6,550 RPM 24x10 6,150 RPM Distance/Vertical Mounting Hole Centers: 2.6" (66mm) Distance/Horizontal Mounting Hole Centers: 3.1" (78mm) Height of Mounting Tabs: 3.4" (85.6mm) Height Lower Mounting Tab/Top of Cylinder Head: 6.9" (175mm) Height Lower Mounting Tab/Crankshaft Center: 1.7" (42.8mm) Height Crankshaft Center/Top of Cylinder Head: 5.2" (132.2mm) Cylinder Head Width: 6.6" (168mm) Width at Mounting Tabs: 3.8" (97.6mm) Center of Muffler Mounting Holes: 1.6" (40mm) Distance/Crankshaft Center to Muffler Hole Center: 2.7" (69.5mm) Length from Carburetor to Backplate: 1.5" (38.8mm) 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 jxs 10/29/12 ir/jxs