reset your idle to about 600 rpms before you ajust the carb, then start at about 1 1\2 turns out on both screws (maybe 2 out) the turn in slowly until the engine just starts to lose rpm do both sides,back out to obtain smooth idle recheck idle( approx 600 rpm's)
repete above a couple of times or more to get even and smooth idle. reset idle to spec's and done. vac or tach will help.
dave