420CC R420 EPA3. Air Cooled, 4-stroke, Our Head Valve (OHV). 1" Keyed Shaft. ENGINE SPECIFICATIONS Model: Powerease R420-18A Type: Air-Cooled, 4-Stroke OHV Displacement: 420 cc Net Power: 15 HP @ 3,600 RPM Net Torque: 17.8 ft-lb @ 2,500 RPM Fuel Type: Unleaded Gasoline Minimum Octane: 86 Maximum Ethanol: 15% Fuel Tank Capacity: 6.1 L (1.6 US gal) Oil Type: SAE 10W-30 Oil Capacity: 1.1 L (1.16 US qt) Lubrication: Forced Splash Compression Ratio: 8.2:1 Starting System: Recoil Shaft Type: Keyed 1" Horizontal Shaft Rotation: Counterclockwise (viewed from PTO side) Valve Clearances: 0.06" Intake / 0.08" Exhaust Charging Output: 18 Amps