Chainsaw Repair

I would tune it myself ..... its easy
Just do the muffler mod and then back out the high speed screw about 1/2 of a turn and start cutting some wood slightly larger than your bar. Make sure your chain is sharp. You should hear a crisp sounding 2 cycle while "in the cut" and keeping WOT while you lift out of the cut, it should warble and 4 stroke. Look for max chain speed while in the cut as you slowly turn the high speed screw. You may need to go slightly leaner than the 1/2 turn out - but it should be close. Double check yourself by lifting the saw out from the cut, with WOT so you hear that 4 cycle warbling.

You should notice more power right away. I tune my saws while in the cut for max power, or max chainspeed while cutting (same thing) and when out of the cut mine 4 strokes heavily. I turn the screw as she is cutting and try for a slight 4 stroke warble while she self feeds in the cut (no pressing down on the handle, just holding WOT and allowing the chain to pull itself down into uncut wood)