Electronic Handheld Tach.....

[Chilly807]

IMO the easiest way to set a carb without spending any money for a tach is.

Adjust carb till it 4 strokes out of the wood and cleans up in the wood as your cutting. Perfect IMO.

Here is a Dolmar 166 sounding like crap out of the wood 4 stroking and then listen to it clean up in the cut.

YouTube - Sachs Dolmar 166 30" 404 making 21" cookies

My thoughts are the same.. I've found that the actual speed varies a bit from day to day depending on the atmospheric conditions. I usually give the saw a quick check by ear at the beginning of the day and tweak to suit if needed. I tried the Stihl tach a few years ago on a Husky 242, it changed a few thousand rpm from day to day.

The right setting for a cold winter day is often too rich in the heat and humidity of summer with less oxygen available in the air, and vice versa.

The Dolmar is still a bit rich for my liking, but better safe than sorry. I find if I can smell raw gas out the exhaust, or it's sickly-sweet and smoky the saw is too rich, but the ear is the best tuning aid I have.

Sean