Does it deliver the proper amount of power at full speed? If it revs higher than you expect even at idle, and lacks power as well, you may have an induction leak. If the power is OK, it may just be that you are not used to the normal speed of a Powertorque: 2 strokes can sound faster than they are, because they fire twice as often as a 4 stroke at the same speed. This can give them a rapid exhaust beat.
It is normal to set a speed with the speed control that delivers the amount of power you need. For light mowing you would probably use a mid-range speed setting. The governor will then adjust the throttle setting to maintain that speed. If you hit heavy grass, there will not be enough power available even at full throttle, so the engine will bog down. To overcome that, you use a higher speed setting when you are mowing heavy grass: the power the mower can deliver increases with higher engine speed. The governor will then adjust the throttle continuously to maintain the higher speed you have set.
