I rebuilt the carb on my S25DA (did not take the welch plug out per advice on this site).
I am having a heck of a time tuning this. I started the needles at 1 1/4 turn out (per modifiedmark) but still can't make it idle. It does spit fuel out the carb a bit when I rev it up. As soon as I let off the trigger it winds down and dies. When I had the muffler off I did not see any damage to the piston, very thing looks very clean and unscored.
Also, my tuning progress has been interrupted because the rewind spring keeps coming off the center where the 4 tines are. The spring looks to be in great condition but how do I keep it from coming off the center tine?
I have had success in bending, ever so slightly, that inner-most end of the spring coil that comes in contact with the rewind pulley. Use a pair of needle-nose pliers to reform it slightly toward the center.