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Chainsaw dies under load or full throttle.

Discussion in 'Chainsaw' started by AaronB, Feb 24, 2013.

  1. AaronB

    AaronB ArboristSite Operative

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    I was milling this last week and all of the sudden the saw would die when at full throttle or die if it would have any type of load put on it at half throttle. Basically it would start and idle just fine, and even sounded good at half throttle but when I would push to mill it would die, and if I tried to go to full throttle it would die. After it died I never had a problem re-starting it.

    At first I thought it might be the fuel, but my other saw (same brand) ran just fine with the same fuel, then I thought it might be the fuel filter, cleaned it and even changed it.

    Also, this happened Wednesday morning, then ran fine after lunch for a while, I didn't mill Thursday, when I went to mill Friday morning the saw ran just fine for a while, until late afternoon, but then it started dieing again so I stopped, started the saw Saturday morning just to see if it would work (not milling) and it worked fine at full throttle. Its almost like something quits working when it gets hot.

    What might cause this that I am over looking?
    I am pretty new to saws so it might be something simple, but thought I would ask and see if there are other things to change/try/clean.
    Thanks

    *********Answers to other questions I got from anther thread.*********
    Saw: Stihl 660, 3 yrs old
    Wood: White Oak, 22" diameter
    Running before: I used it the weekend before and did not have any issues, ran it through three 8' logs and everything ran fine.
    Work done: none

    My FIL and I finally took out and cleaned the spark plug (don't have a new one) and it ran fine after that, but it had been sitting overnight so it was cold, so it probably would of ran fine had we not cleaned it, but I didn't get to mill with the cleaned spark plug.
     
  2. fearofpavement

    fearofpavement Trying them all

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    Could be a coil related issue but sounds like fuel starvation to me. Check the fuel hoses.
     
  3. R/C Pilot

    R/C Pilot ArboristSite Operative

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    Ckeck the fuel line inside the tank for being to soft and collapsing.
     
  4. chadihman

    chadihman Addicted to ArboristSite

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    Tank vent? Loosen the fuel cap when it runs crapy. That will tell you if the tank vent is your problem.
     
  5. autis

    autis ArboristSite Member

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    sounds like fuel lines to me
     
  6. Fish

    Fish Account Hold

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    Keep doing what you are doing, and you will be starting rebuilding threads, it may be too late now.

    Take off the muffler cover and show us a pic of the piston for starts.
     
  7. CTYank

    CTYank Peripatetic Sawyer

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    You can insert an ignition tester inline with the plug lead. With that, the internal light show (in neon tube) will give you an indication of the health of the ignition. Just watch the tube when the engine acts up.

    Mine happens to be a Lisle 20610.

    This presumes you can locate things out of harm's way, of course.

    If the spark's okay, cease and desist cutting until you see that it's getting fuel. Or, melt a piston.
     
    Last edited: Feb 24, 2013
  8. Fish

    Fish Account Hold

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    Screw that!!! Fix the saw before running it again!!! Start with the fuel system, and do it correctly!!!
     
  9. jughead500

    jughead500 Sasquatch

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    fuel filter sounds to be stopped up.my husky 55 done the same thing.
     
  10. HuskStihl

    HuskStihl Chairin'em for the sound

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    Check the arrestor screen. Also check cold and hot compression. Good luck
     

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