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MS 441 WITH BIG BORE NEW POT.

Discussion in 'Arborist 101' started by Phill Cresswell, Dec 20, 2016.

  1. Phill Cresswell

    Phill Cresswell ArboristSite Lurker

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    Can any one help,I have rebuilt a 441 with big bore po and piston, the saw starts fine ticks over fine but under no load at hi revs the revs are not regular, it is as if it wants to scream but then hesitates, is this normal when a big bore is fitted.
     
    SeMoTony likes this.
  2. SeMoTony

    SeMoTony Addicted to ArboristSite

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    I expect that you have done a pressure/vacuum test, using new plug, have double checked all torque values on removed replced engine fasteners.
    I haven't read about BB on 441; on 660's there is an ocassion of free line of site thru exhaust under piston tdc which isn't sposed to do much bad. The real experts will show up with more experience to draw on.Good luck straightening this saw out.
     
    Wrenchbender16 likes this.
  3. Phill Cresswell

    Phill Cresswell ArboristSite Lurker

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    Thank you very much indeed for your reply, does this iregular reving at hi revs under no load sound normal and un damaging, i have also checked all you mention and all seems good.
     
  4. ironman_gq

    ironman_gq Addicted to ArboristSite

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    Does this saw have a rev limited coil? Have you put a tach on it to see how fast it's actually turning? Have you tuned the carb so you know it's rich and tried slowly leaning it out till it cleans up?

    Lots of things we need to know before we can really help. It could be that the carb is way out of adjustment or it could have a rev limited coil
     
  5. Phill Cresswell

    Phill Cresswell ArboristSite Lurker

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    Nailed it, coil resistance was high on primary winding, new coil job done, thanks for all input, rely appreciate it guys, THE CHAINSAW DOCTOR UK. PHILL.
     

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