This is the OS Max 15CV-A R/C Airplane Engine With Muffler. Add "CV" power to your racing or combat models with this airplane version of OS Max"s popular buggy engine. FEATURES: Based on the .15 CV Buggy Engine, this engine was adapted for air- craft use with an aircraft style cylinder head, rotary carb, and a remote needle valve to reduce chance of injury from spinning props. Front and rear crankshaft bearings for increased power and long life. Two year warranty against manufacturing defects in parts and workman- ship. INCLUDES: One 15CV-A R/C Airplane Engine with #871 Muffler. Two 2.2 x 22mm phillips head muffler mounting screws. #A3 Glow Plug (OSMG2690) Decal Sheet Instruction Manual REQUIRES: Fuel: 10% to 20% Nitro and 18% Oil content is recommended. Prop: Break in: 7x5. Sport: 7x5, 7x6, 8x4, 8x6, 9x4. Aerobatic: 8x4, 8x6. SPECS: Displacement: 2.49cc (0.152 cu in) Bore: 15.2mm (0.598") Stroke: 13.7mm (0.539") Output: 0.5 PS, 0.49 HP @ 18,000 RPM Practical RPM: 2,500 - 19,000 RPM Weight: 170g (5.99oz) Crankshaft size: 5mm Distance between mounting tabs: 1.53" (39mm) Distance between mounting holes on opposite side: 1.34" (34mm) Distance between mounting holes on same side: 0.57" (14.5mm) Width of crankcase below mounting tabs: 0.97" (25mm) Height from bottom of crankcase to top of cylinder head: 2.48" (63mm) Length from end of crankshaft to backplate: 3.07" (78mm) Needle Settings: High Speed: 2.5 turns out from fully closed Low Speed: 2mm gap between the needle and spray bar Looking down the neck of the carb JXS 3/9/01 ir/jl updt lmm 3/30/09 updt jml 10.10.11