Ok, some more info:
Saw is an older (2yrs or so) red-cover saw, has seen maybe 5 tanks in the past month/50 in its lifetime, and runs 93 octane/Echo semi-synthetic at 40:1 (never more than 2 weeks old). Saw runs great, but it occasionally when I let of the throttle after a cut it just dies. Other times it does not. Otherwise it idles well (maybe a bit slow, definitely not fast/lean), revs up perfectly, and runs at WOT in and out of the cut perfectly. I think that the tuning is right on, but if anything, the saw may be a bit rich.
No local dealer that actually has saws/parts/knowledge; even if there were, I'd prefer to figure this stuff out myself if possible...