Try choking it briefly as you gently open the throttle. That might be enough to flush out the gremlin.

Most come adjusted to lean thanks to the EPA, it's best to get them adjusted a little richer. If your carb isn't clogged from old gas the low adjuster would need to be turned out around 1/4 turn and the high also if it really screams at full throttle with no load, you'll also find more power with a little more gas. On 3 out of 4 saws I've had to pull the caps and adjust a little richer and that's running good gas. If you started using gas with ethonal that just make them leaner and it doesn't keep very well, use Stabil or Sea Foam for storage. Steve