This is the O.S. 65AX ABL Aircraft Engine with the E4010A Muffler. FEATURES: Ideal for trainers, sport planes and scale aircraft Drops in easily in the same mounting space as the O.S. 61FX ABL ABL-Advanced Bi-Metallic Liner process uses a double layer of plating material rather than one thick layer. This helps the metal bond to the cylinder and makes the plating more durable. Also, the plating process is more consistent, resulting in a more precise fit between piston and sleeve for better compression and longer life. Newly designed 61D carburetor with a rearward angled needle valve for safer adjustments Two year limited warranty through Hobby Services beginning at date of purchase INCLUDES: O.S. 65AX ABL, 61D carburetor, E4010A Muffler, #8 Glow Plug, Needle Extension Cable and Instruction Manual with Decals REQUIRES: Aircraft blend fuel containing 5%-20% Nitromethane with at least 18% lubricant content. Propeller: 12x6, 13x6-7 or 14x6 Field Equipment SPECS: Displacement: 0.65cu in (10.6cc) Bore: 0.95" (24mm) Stroke: 0.93" (23.5mm) Weight Without Muffler: 17.5oz (497g) RPM Range: 2,500-16,000 Output: 1.75 PS, 1.73 HP @ 16,000 RPM Crankshaft thread size: 5/16-24 Distance from center of engine to drive hub: 2-5/8" (65mm) Distance between exhaust bolt mounting holes: 1.6" (42mm) Distance from center of engine to end of crankshaft: 4" (102mm) Distance/crankshaft center to muffler exhaust outlet: 1-1/2" (38mm) Height from crankcase bottom to top of cylinder head: 3-7/8" (98mm) Height/crankshaft center to top of cylinder head: 3-1/16" (77mm) Width including mounting tabs: 2-3/8" (60mm) Width not including mounting tabs: 1-9/16" (39mm) Width between mounting holes same side: 15/16" (25mm) Width between mounting holes opposite side: 2.04" (52mm) jxs 10/29/10 ir/jxs