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Stihl FS 91

Discussion in 'Chainsaws and Power Equipment' started by NBourque, Jul 10, 2019.

  1. NBourque

    NBourque

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    I bought a brand new FS 91 trimmer last summer. It has maybe 2 tanks of fuel run thru it. It is very slow to rev up. Is this normal? I took it back to the dealer and they said it was fine.
     
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  2. papadave

    papadave

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    Right where I want to be.
    Mine does the same thing (also bought last year). I just give it a bit of time to "warm up" and a few blips of the trigger.
     
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  3. NBourque

    NBourque

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    It’s almost like it has no low end power. Gotta keep it revved up to get anything out of it. Such a weird powerband. I think I’d prefer it to be a straight 2 stroke rather than the 4 mix...
     
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  4. bocefus78

    bocefus78

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    The 4mix takes some getting used to if you are coming from a 2 stroke. When tuned right, they have way more torque than a 2 stoker.

    Sounds as if the dealer didnt tune the carb outta the box. This year they seem ultra lethargic outta the box.

    This is coming from a guy who sells them and tunes them upon delivery daily.
     
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  5. NBourque

    NBourque

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    Feels as if there is no throttle response. I have the special tool to adjust the carb...
     
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  6. bocefus78

    bocefus78

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    If you've got a spline carb tool, tune it yourself. It should accelerate quickly and barely hit the rev limiter on the high end without a load. Ie....not in grass.

    Get it warm before tuning.
     
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  7. Sandhillbilly

    Sandhillbilly

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    I have a Husqvarna that I’ve had for about 10 years. It’s always acted like that also. I have a gearbox head rather than a flex shaft & I’ve always just blamed it on that. I’ve never tried to tune on it though, just kinda lived with it. But since I’ve been here awhile I’ve been thinking I better give it a try. ..... also been wondering if anyone has ever done a muffler mod or ported a string trimmer/ weed wacker:emb:
     
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  8. NBourque

    NBourque

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    Any tips on tuning these 4 mixes?