2lumbarleft
ArboristSite Operative
I am looking for some tuning advice on an Echo CS-590 Timberwolf chainsaw. I called Echo, and they told me that a range of between 12,000 and 13,000 rpms with no load and bar an chain attached was acceptable. In the past I have read very few threads actually identifying a target rpm for this saw using a tach. Here is the thing. I am old school, and tune in wood. I use my ear. I listen for the 4 cycling that suddenly cleans up in the cut. With this saw, I hear four cycling around 11,300 to 11,500 rpm. Even then, it sounds a little lean to me, but I understand that there is an rpm limiter incorporated with the ignition system. Not wanting to be fooled, I go overly rich and work my way lean. Here is the thing. I have the saw running reasonably well the way it is currently set. The plug looks to be running hotter than I would like, even though I am running 40:1 mix with 100% synthetic high quality oil. Currently, I am only 7/8ths of a turn open on my high speed jet. I understand that this Echo has a different type of metering system that has a by-pass channel to augment carburetor fuel supply. I know I have a reliable tach. The machine is running the way I trust it to run, yet I am 1000 rpms under recommendations from Echo. I am not willing to burn up a saw to meet recommendations from a manufacturer that is notorious for running a lean saw. If I am way off base here, please - someone straighten me out, as I clearly have something to learn. One last thing. As I run higher rpms, the four cycling sound is GONE! That tells me the rpm limiter is really set higher. That tells me that there is no 4 cycling in the recommended rpm range until you actually hit the limiter. My guts tell me to stay away from factory recommendations.
