why is my stihl weed eater losing power

why is my stihl weed eater losing power why is my stihl weed eater losing power why is my stihl weed eater losing power why is my stihl weed eater losing power why is my stihl weed eater losing power why is my stihl weed eater losing power why is my stihl weed eater losing power why is my stihl weed eater losing power why is my stihl weed eater losing power why is my stihl weed eater losing power