Stihl hedge trimmer problems

Discussion in 'Mechanic and Repair' started by nbuzz, May 14, 2009.

  1. nbuzz

    nbuzz LawnSite Member
    Messages: 157

    Hey guys, wondering if you can give me some advice.

    I bought a new hedger last fall, Stihl HS 81 T. I've had nothing but problems with this unit. took it back to the dealership 3 times!!! every time it came back it worked better than before. but now its doing it again

    Here's the issues:

    1. hard starting when cold
    2. won't rev up until its run for 5-10 mins
    3. won't re-start after fuel fill up (motor still warm)
    4. dies out on certain angles regularly
    5. won't stay revved, bogs down (not on a load either)

    The dealer claims he has cleaned and adjusted the carb. also said the fuel pick-up came unhooked, said that was fixed. I've never had a problem with these guys, they're my fav dealer. BUT I can't wait a week right now to have the fixed!! so %^&* frustrating.:help:

    any ideas on how to fix it?? or should I suck it up and take it in again:hammerhead:

    sry for the long post... thanx guys
  2. Yuanding

    Yuanding LawnSite Member
    from England
    Messages: 82

    I've had a different Stihl hedge trimmer for six years and it performed just like yours for the first six months i .e. like a pig. It seems they need a long break in period unfortunately, and in my experience they run better if revved to the max and used for an extended time, i.e. half an hour at a go. My hedgetrimmer has been used for hundreds of hours and runs loads better than when new.

    Also, one of the biggest stumbling blocks with all two strokes is breathing. Make sure that air filter is scrupulously clean.
  3. mowerknower

    mowerknower LawnSite Senior Member
    Messages: 766

    check the fuel line again, if all they did was reinstall it there is a good chance it came off again, it needs to be clamped on the nipple
  4. 4.3mudder

    4.3mudder LawnSite Silver Member
    Messages: 2,227

    Hmm, won't restart after it is warm, sounds like a bad coil.

    Bogs down at angles, sounds like the fuel line is not in the right spot.

    It might be cold natured, I have a coulpe of things that do that.
  5. nbuzz

    nbuzz LawnSite Member
    Messages: 157

    thanks for the info guys. that night I took them home and checked the fuel line.. it was connected. I had it running really well, I ended up adjusting the low end screw and it seemed like that was the problem. Ended up calling the dealer and letting them know about the problem, they said if I had any more issues with it to bring them in, so naturally they worked well friday and saturday.

    took them out today to touch up some areas that a client wanted, and guess what same frickin problems!!

    the air filter is spotless, clean fuel pickup, I've beening running 93 octane with the stihl premo oil to see if that would help... nothing seems to work.
    the unit just decides when it wants to... wtf?

    any ideas? before I just take them back... or do i try to have the dealer fix them again?
  6. mowerknower

    mowerknower LawnSite Senior Member
    Messages: 766

    Check the spark arrestor, for some reason the hs81 acts lean when the exhaust is plugged.
  7. DT Lawn Care

    DT Lawn Care LawnSite Senior Member
    Messages: 850

    I just got a Stihl Hedge Trimmer going for a neighbor, and all I had to do was adjust the high and low screws and now it's great! I did have to do it a couple of times though, so I wouldn't give up on it yet. GL
  8. nbuzz

    nbuzz LawnSite Member
    Messages: 157

    thanks for the help guys!! really appreciate it. I had some time to tinker with it some more:hammerhead: can't really believe I'm stuck working on a brand new unit when my mowers with 900+ hrs. on them are running great. But anyways I checked the spark arrestor and it was spotless (as I expected, it has less than 40 hrs on it). I took it out anyways, no change in performance. played with the carb again, checked the fuel lines again. I dont see what the problem is... It ran Ok today, I mean I got the job done but I wanted to throw them in the water:cry:

    so tomorrow I'm going to the dealer to see what can be done, but who knows.
  9. mowerknower

    mowerknower LawnSite Senior Member
    Messages: 766

    Yep, take it to the dealer, you have done what you can. Have them do a presure and vacuum test and determine what the problem is. If it has no leaks I would install a new carb.
  10. 4.3mudder

    4.3mudder LawnSite Silver Member
    Messages: 2,227

    ya, I would seriously take it back and demand another one. That one seems to be a lemon.

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