This is the O.S. Engines FS110-a P 4-Stroke Aircraft Engine with Pump and 5040 Silencer. FEATURES: Muffler adjusts in or out with threaded header pipe and rotates a full 360° for more mounting options with fewer modifications Broad power band suitable for scale as well as sport models 61P carburetor with integrated pump regulator to ensure powerful flights and stable fuel delivery regardless of model attitude and fuel level change Two year limited warranty through manufacturer beginning at date of purchase INCLUDES: O.S. Engines FS110-a P 4-Stroke Engine, muffler, 61P carb w/pump, header pipe, F glow plug, instruction manual and needle valve extension cable REQUIRES: Fuel: 5-20% nitro content with at least 18% lubricant content Propeller: Sport & Aerobatic 13 x 9-11, 14 x 8-10 Scale 15 x 8, 16 x 8 Electric starter and other field equipment SPECS: Displacement: 1.10cu in (18.0cc) Bore: 1.20" (30.4mm) Stroke: 0.98" (24.8mm) Practical RPM: 2,000 - 11,000 Power Output: 1.8 PS, 1.77 HP /10,000 RPM Weight: 21.5oz (610g) Muffler Weight: 2.5oz (72g) Crankshaft Size: 5/16-24 Height from Mounting Tab/top of Cylinder Head: 4.1" (103.8mm) Height from Crankcase Bottom/top of Cylinder Head: 4.9" (125.4mm) Width at Mounting Tabs: 2.4" (61mm) Width of Crankcase Below Mounting Tabs: 1.7" (42.6mm) Length from Carb to Prop Washer: 4.5" (114.5mm) Length from center of Crankcase to Prop Washer: 2.6" (66.5mm) Length from center of Crankcase to center of Carb: 1.8" (46.3mm) Needle Valve Setting: High Speed: 1/1/2 - 2 turns from fully closed Mixture Control (low speed): Factory set, do not adjust jxs 09/01/09 ir/jxs