I have a question for you guys using 4 stroke trimmers . I was talking to the Stihl Rep yesterday about the FS100RX , he was saying the valves need adjusting from time to time . Are any of you finding this to be true ? Does the same go the Shindaiwa T254 Hybrid 4 . If this is the case it sounds like a huge PIA . TIA My local dealer has both models on sale , the Stilh is 320 and Shindaiwa is 313 .