Time to get familiar with Dolkitas... picked up a 6401 today.

Pretty much. It usually won't idle well/long if it's set that rich too. Stalling when the trigger is released, especially under load, can be a H issue as well. Of course this asses the LA is set appropriately as well. Dizzy yet?

 

Yes. Get the saw to idle and slowly take the L screw in (lean) until it starts to stumble, then take the screw out (rich) and you will hear it start to stumble or fall out.

That is the usable "range" for the L screw. But you have to find the area in that range, that both let's the saw Rev and snap up into the Power, but yet will sit and idle all day.

As I said earlier. Once I find that good snappy L spot, I go in about 1/8 turn more. The furthest in I can with good throttle response. You can have good snap with it set fat. You'll know it's fat because of the conditions that MasterMech mentioned, and also if the saw loads up quick under a short idle time. If every time you let it idle for a minute and pick it up, and you have to hold it at full throttle to clean up (smokes heavily because of all the extra fuel from the L screw at idle) .

It's fine line on carb settings. But once you get it, your good to go. It seems your close on the H side of things. The L is just the finishing touch. Little more practice and you will be good to go.

 

The Stihl could just take that much. My 036 Pro was about the same. 3-5 pulls on Choke till it Pops. Then 1 pull on High idle.