I hope I'm not the first one to such such an idiotic thing, but this morning, yes, I did it. I couldn't start my always-reliable Stihl MS 250. Kept trying and it just wouldn't fire. Never happened before. Long story short, I realized that I had accidentally put the gas mix in the bar oil receptacle, and the bar oil into the has tank. Ugh! I dumped both tanks and filled them up correctly, hoping that maybe if I could get the engine to run enough, it might clear itself by "burning out" the oil and all would be well. It ran ok for abut 10 minutes, but now it dies after a minute or two. Maybe ten times I restarted, ran it as hard as I could until it died, and then repeated. Now I'm not so sure whether this is going to work. Has anyone else done this? Is there any hope of clearing out the engine this way, or are more drastic measures needed (meaning probably going to the shop to clean the carbs or some such thing)?