Hi all, I purchased this about two years ago and it has about fours hours use on it (dont like getting it dirty!), when i first got it new the engine sounded like it was missing, the Stihl dealer said all the four mix engines sounded like that and got another one out and sure enough it was the same but it does seam to have a good bit of power but when running it sounds like a old engine missing a lot, just wondered if this is really normal?, to the problem, using the hedge trimmer attachment and been using it for about twenty minuites and half a tank of fuel and it just cut out, started up again but cut out straight away, then it would not start. I left it for about ten minuites then opened the fuel tank cap and it sounded like there was a vacume of some sort, put the cap back on and away it went no problem, any ideas?. Also i have a old Hs74 hedge trimmer that i have a problem on but i posted it in the small engine and mower repair under Stihl hs 74 wont start, if anyone has any ideas on any of them i would love to hear them.