Update on Seafoam treatment for the old 041 Stihl...
It seems to have worked... it was running rich for a little while, then got really rich. Bet something cleared out, and I ran it a couple days ago, and again today. Needed a retune and holy crap, this thing seems to have woke up a bit.
I'd say it's worth a shot in any saw that runs like it's okay but not quite at top performance. Might even work as a solvent in a jar in an ultrasonic cleaner to clean a carb.
So, new fuel line, and carb kit, then Seafoam treatment equals a good farm saw that seems to be a little better now.