I have a Stihl FS 36 line trimmer that leaks gas when it is sitting not running. It does not leak enough for me to tell where it is coming from or even make the floor below it wet, but it is enough to make my garage smell strongly of gas. I tried tearing it apart but I cannot get the back half of the cover off (the white part) even though I removed the 4 star bolts. Any tips on this? I see where there is a groove on the bottom and tried prying all around with a screw driver but could not find what it was catching on....it acts like its barely loose. Also, the thing runs great, but it vibrates an awful lot, any ideas on how to find the source of this vibration? The head spins fine by hand so I don't think that is the problem and you can tell the vibration is coming from the motor end of the trimmer.