Attributes & Specifications Brand Name Honda Engine Displacement (cc) 389 cc Theoretical Horsepower (HP) 13 HP Torque Rating (ft-lb) 18.1 ft-lb Engine Speed (RPM) 3,600 RPM Click to see full answer. Then, how many horsepower is a 389cc engine?389cc/11.7HP Honda Horizontal Engine.Subsequently, question is, how many cc is a 13 HP Honda engine? Displacement: 389 cm3. Net power output: 11.7 HP (8.7 kW) @ 3,600 rpm. Net torque: 19.5 lb-ft (26.4 Nm) @ 2,500 rpm. Regarding this, how many horsepower is a 270cc engine? 270cc/8.5HP Honda Horizontal Engine.How many cc is a 10 horsepower motor?The general rule is for every 15 CC there is 1 HP. For example, for a 150 CC engine you would take 150 divided by 15, which equals 10 HP.