There's more to tuning a chainsaw than just adjusting the high end, but this is a start. It also gives an excellent example of what 4-stroking sounds like.
In the first cut, the saw continues to 4-stroke, even towards the bottom of the cut. That's a little too rich. It should run clean all the way through the cut once under load.
After that first cut, I tune the H screw. I turn the H screw in clockwise until the engine peaks out and is totally 2-stroking. No 4-stroke at all. I then quickly richen the mixture back up by turning the H needle counter-clockwise. Immediately you hear the engine begine 4-stroking again.
The next cut you can hear the engine immediately clean out once underload, and stay that way for the entire cut. After that cut I rev the saw and you can hear that it is still 4-stroking at WOT. It's important to check for that after a cut, since that's when your saw will be its hottest and leanest.
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I'll try to make a more detailed tuning how-to video that includes L and LA adjustments.
