Along with that, the return spring can be a little on the weak side, not having enough umpf to pull back the throttle. And in some cases the spring on the cable is too long, and won't let the throttle open all the way. Also you need to check both sides of the equation, after you have the actual throttle on the engine working correctly, you need to check the operation of the throttle handle/cable to see that it moves smoothly in both directions.