Displacement: 170 cc (10.37 cu in) Bore: 2.05" (52mm) Stroke: 1.57" (40mm) Weight: 9.06lbs (4110g) RPM Range: 1,100-9,000 Output: 17.5 hp @ 9,000 rpm Compression Ratio: 9.5:1 Gasoline/Oil Mixture: 30:1 Weight: Engine 7.83lbs (3,550g) Two Mufflers: 7.05 oz (200g) combined weight Ignition: 5.64oz (160g) Replacement Spark Plug: NGK CM6 (DLEG5626) or equivalent Carburetor Settings: Carburetor was preset from the factory and only requires small incremental adjustments. Low Speed Needle: 1 turn open High Speed Needle: 1 turn open Adjust high speed needle to peak RPM. If the engine slows or dies, the high speed mixture is too lean. Adjust low speed needle for a smooth idle and reliable transition to high throttle. If engine dies when throttle is advanced, the mixture is too lean. If engine stumbles when throttle is advanced, the mixture is too rich.