Maybe, I'm wrong but tuning isn't much of a science, just gotta pay attention. I'm still somewhat new to saws, but tuned model gasoline engines $600 per engine and up using a tach and ear, along with lawn equipment. If you get a good throttle response and it runs properly most often you're near a good tune. Ex, no stumbling under load on high end and a proper "note" of the 2 stroke whine when on high end and loaded. Just load the saw and pull out of wood, it should 4 cycle sing to you. I tune until it just starts to 2 cycle sing under a standard load. Mind you under a slight load, soft woods smaller log it may not fully 2 cycle and I think that's fine on occasional use or you may be running slight bit rich and have some carbon.
Like mentioned 500 rpm back off equals just a slight richening. When I tuned my model aircraft engines, I'd tune it for peak on ground and than richen just a tad on rich side. Under load and in flight, the engine tends to lean out to a rich of peak in air for optimal tune. Sort of like putting into wood and pulling out the saw.
I run 32:1 myself, others like Bill run 50:1 with good results. I don't have issues with the exhaust at 32:1, some oils smoke more than others and I try to keep my head away from it and use wind to blow it away from me.
Getting on the second yr with my saw and no problems. I think guys have problems when they try to squeeze every last drop of power out of an engine. You're not gaining much, just start off with big enough to begin with. Tuning is important, but so is keeping inlet air clean and temps in check. Get to know the saw, how hot does it usually run and pay attention to it and the noises it makes. Check your plug, one indication of proper tune.
Figured to chime in, hoping to help others, and or to keep thread alive if needed. When I bought my saw, owners son said 50:1 be fine for milling these stihls were designed to run 70:1 or something like that. I asked the owner if he sold tachs and got a look like, oh no we've got one of those nerdy techy guys here, haha. So never did buy a tach and don't plan too. I just find I don't need one. I've played a bit leaning bit more, richening a bit more and can't really find much differance in cutting speed. Slight rich may mean cleaning out carbon, but doubt it'll kill saw and regardless of tune you're sucking in exhaust to you're lungs. Why I like a breeze going. Every time I mill though I get into a cut and pull back to hear the note change, no change either to rich or too lean. Works for me and a no brainer. Also, if you can let it idle 30 sec or so and than gun it and have a good response with no dying than it's not too rich at idle.
I have to laugh, my gf's dad a firewood cutter and logger along with another guy into saws and guy stuff (LOL) had no idea what I meant by 2 cycling or 4 cycling in a cut. I had to show them and describe the sound, took them a bit to pick up on it as my saw doesn't go crazy with the 2 cycling nor the 4 cycling, happy medium of both. when engines are too lean, you'd think they'd have lack of power and people would know. IDK, LOL!
Hope this helps guys! Everyone has good info, incase anyone needed more or for any stumblers upon this thread.
