Big chainsaw troubles..... help needed

hemlock Posted By hemlock, Apr 10, 2013 at 8:22 PM

  1. basod

    basod
    Minister of Fire 2.
    NULL
    

    Sep 11, 2009
    937
    351
    Loc:
    Mount Cheaha Alabama
    When it loosened up it wiped the key off the flywheel? I'd think the casting/machining would make it difficult to cast a key into a flywheel(could be wrong)

    New flywheel is $76 here
    http://www.partstree.com/parts/?lc=husqvarna&mn=365 Special EPA (1999-11)&dn=082960011

    It's an M8X1 nut which I believe is 28-32N-m torque spec
    If the flywheel moves it'll be the equivalent of an engine "jumping time"
    Except this one's spinning at what? 12k+ rpm - Hopefully there's enough safety margin built into the jug/casing to hold it together
     
  2. MasterMech

    MasterMech
    Guest 2.
    NULL
    

    That's the way many small flywheels are made now.

    Hemlock,

    I wouldn't attempt to run the saw again until you get a replacement flywheel. The current flywheel will most likely shift position a bit every time the saw accellerates/decellerates and while starting. I would order a new flywheel and make sure the nut is torqued to spec. Definitely do not use loc-tite on that taper, as that will make future removal unnecessarily difficult.
     
    Ashful likes this.
  3. nate379

    nate379
    Guest 2.
    NULL
    

    I'd just cut a keyway into the flywheel before spending $75 on a new one! If you aren't setup to do it, bring it to machine shop with a case of beer. ;)
     
    Ashful likes this.
  4. Ashful

    Ashful
    Minister of Fire 2.
    NULL
    

    Mar 7, 2012
    9,062
    3,784
    Loc:
    Philadelphia
    ... also has a lower likelihood of shearing again, if you use a standard key in the new slot, versus a casting.
     
  5. MasterMech

    MasterMech
    Guest 2.
    NULL
    

    Keep in mind that the shear strength of the key just may have been engineered into the saw to prevent excessive energy from being transferred to the crankshaft in the event it comes to a very sudden stop. (although such an event would be rare on a saw.) If I were to cut a keyway into the flywheel and locate or make a suitable key, it would definitely be an aluminum key.
     
  6. mikefrommaine

    mikefrommaine
    Guest 2.
    NULL
    

    There are plenty of flywheels available on ebay for < $35. I'd just replace it and be done worrying about it.
     
  7. hemlock

    hemlock
    Feeling the Heat 2.
    NULL
    

    May 6, 2009
    455
    7
    Loc:
    east coast canada
    Ordered a new flywheel. Should be here in a couple of days. I ran it for an hour or so with the old flywheel, but it made me noervous. I think it was going slightly out of time. It dieseled after shutting it off when I went to refuel.

    Edit - of course, now I can't get the old flywheel off. Is feathering it with a torch a bad idea?
     
  8. MasterMech

    MasterMech
    Guest 2.
    NULL
    

    Wedge it with wooden wedge driven in snug and back the nut off 1 turn. Give it a good sharp rap with a hammer (The nut should be in position to protect the threads and the end of the shaft.) and it will pop loose.
     

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