This is the .65LA Engine from O.S. Max Designed for Sport Airplane Use. This is a Non-Ringed Engine and has a Two-Year Warranty. This Engine has a Natural Finish w/"O.S." & "65LA" on the Sides. FEATURES: One-Piece Crankcase Long Crankshaft Rides In One Long Bronze Oilite Bushing (No Bearings) Schnuerle Porting (AKA Schnuerle Scavenging) Side Exhaust, Bolt-Through Muffler Mounting Metal Remote Needle Valve Allows Change From A Vertical to Horizontal Orientation Composite Backplate Mount Hex Head Air-Bleed Carb Screw For Safer and Easier Adjusting #60J Carb Aluminum Piston with Nickel-Plated Brass Cylinder Liner INCLUDES: One Assembled Engine with Carb One Expansion-Style Muffler (E4010S) with Rotatable Exhaust Outlet One #A3 Glow Plug One Set Instructions, Decal Sheet, and Warranty Sheet Two 3x40mm Screws to Bolt Muffler to Engine SPECS: Construction: Aluminum 1-Piece Crankcase, Piston, Cylinder Head. Displacement: 10.85cc (.66 cu. in.) Bore: 24mm (.945") Stroke: 23.5mm (.925") Practical RPM: 2,000 - 16,000 RPM Horsepower: 1.7 PS, 1.68 HP/16,000 RPM Weight: 535g (18.9 oz) Distance Between Mounting Holes Same Side: 0.98" (25mm) Distance Between Mounting Holes Opposite Side: 2" (52mm) Length: 91.2mm (3.59") From Backplate to Front of Drive Washer 25mm (1") Center-to-Center, Front-to-Rear Mounting Holes Width: 42mm(1.65") Neglecting Engine Mounting Flanges 52mm (2.05") Center-to-Center, Side-to-Side Mounting Holes Height: 85.4mm (3.36") Mounting Flange To Top Of Head Overall Height: 107mm (4.21") Crankshaft Thread Size: 5/16-24 Recommended Props: Break In: 12x6 Trainer & Sport models: 12x7,12x8,13x6,13x7, or 13x8 Practical RPM Range: 2,000 - 16,000 RPM (This engine will not turn this RPM on the ground) RPM curve is when the engine unloads. Remote Needle Valve Setting: 2-1/2 Turns Counter-ClockWise From The Closed Position Air Bleed Screw: Tip Of Screw Will Cover 1/2 Of The Hole In The Front Of The Carb REQUIRES: Fuel: 5%-15% Nitromethane and 18% (Minimum) Oil Content Propeller Medium (Standard) Silicone Fuel Tubing Misc Items: Plug wrench, starter and field equipment tlw 6/22/07 ir/jxs