I have a brand new Stihl FS90 Trimmer/Brushcutter. I got it on Wednesday and It was bogging of the low end right when I gave it throttle. So I brought it into the dealer to have them check it out. Well they fixed it for about 5 min. After that back to bogging. Now it also smells as though the clutch is burning up. Has anyone else had this problem? They adjusted the valves and lubed the trimmer head.