Hi, i have a Stihl FS36 that i brought from a work mate, anyway when i brought it it wouldnt rev out properly, and it idled too high, as soon as i dropped the idle it dies. Ive replaced spark plug, cleaned out muffler, took out mesh spark arrester, and cleaned air filter. Also striped and blew out carbie, everything is spotless and looks fine. But now it will start and only run for about 5 seconds, then stops. I have mixture screws at Low@1.25turns and Hi@1.5 turns out. Not sure what else to try? Any help appreciated, cheers.