In loving memory of Kenis D. Keathley 6/4/81 - 3/27/22 Loving father, husband, brother, friend and firewood hoarder Rest in peace, Dexterday

Critique my tune

Discussion in 'Chainsaws and Power Equipment' started by rotorburn, Sep 24, 2022.

  1. rotorburn

    rotorburn

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    On my roughly 30 hour 372 xp, I noticed the engine screaming more and less willing to four stroke. Also, the idle would surge and a pull on the trigger would cause bogging if I didn’t nurse it up with a few taps.

    I gave the L screw an eighth turn CCW which smoothed out the idle and improved throttle response. Hooked up the tach and got the idle to 2700. Gave the H screw the same eighth turn CCW and it maxes out at 12800 and blubbers a little when I lift it out of a cut. Does this sound like a good safe tune or should I screw in the H to get closer to the rated max rpm of 13600?
     
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  2. Chud

    Chud

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    It doesn’t hurt to be a tad rich on H. How does it feel pinned in the cut.
     
  3. The Wood Wolverine

    The Wood Wolverine

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    What I'd recommend, make a bunch of longer cuts and get that saw nice and hot, then make sure you have a good 4-stroke burble when you rev it unloaded. I personally don't rely on a tach. I do have one just to see what the saw is turning but I don't tune w/ it.
     
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  4. Sandhillbilly

    Sandhillbilly

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    So if you can’t get the burble at WOT without a load, is it too rich or too lean?
     
  5. Screwloose

    Screwloose

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    Typically lean.
     
  6. rotorburn

    rotorburn

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    It feels more like it did right out of the box. Revs up quick and settles in to a nice happy zone where it’s cutting with torque rather than horsepower. Before the adjustment, it had more of a peaky, sport bike character. When the chain was less than perfectly sharp, I was catching myself cutting at part throttle to avoid overrevving.
     
  7. BuckthornBonnie

    BuckthornBonnie

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    Numbers seem good. Replace the fuel filter and clean the air filter… then check again after it’s been hot like said above.
     
  8. The Wood Wolverine

    The Wood Wolverine

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    If you can't get 4stroke, it's lean.


    Here's a vid (not mine) w/ decent sound quality.
     
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  9. rotorburn

    rotorburn

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    That was an excellent use of 4 minutes. I’ve read a bunch of tuning guides but nothing explains it this consicely. Love me some YouTube!
     
  10. Sandhillbilly

    Sandhillbilly

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    That’s a good video and sound. Me thinks I gots a little tuning to do
     
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