Almost all motorised scooters use some kind of a metal cable to actuate the throttle on the engine. As the cable is pulled, more fuel flows through the system, accelerating the engine. Over time, however, these steel cables extend, stretch or loosen. Adjustments can reduce these problems.
Control cable systems on scooters frequently come with adjusters. These basic tools are screwed into the brackets that the cables run through. By twisting the adjuster, it creates more distance for the cable to travel, which can be just enough for the cable to tighten again. Alternatively, twisting the adjuster in the opposite direction will loosen the cable.
Sometimes the throttle cable has stretched too much and is too loose for minor adjustments. This requires dismantling the scooter's carburettor and headset to access the throttle cable. The cable securing nut needs to be loosened and then re-tightened after the slack in the cable is pulled out.
Once a cable is past its useful life, it gets so stretched from running through the scooter body to the engine that it frays. This will eventually lead to breakage. The only solution at this point is to replace it with a brand new throttle cable. The old one must be pulled out of the housing and a new one routed in its place.