Are these saws bogging every time, or just after some idling? I have an 026 (not from Doc) that has the bog, but only after it idles for a while (re-position a log, walk to a different cutting area, or something like that). It will even shut down coming off idle on occasion. I tried a new 194. No change. If I keep cutting, with no idle time, there is no problem. I have been blaming a fuel puddle in the pleat of the intake boot.
I really hadn't considered that it might be ignition. Ought to know better, I chased a problem on a Homelite Super EZ for months. It turned out to be a cracked spark plug...