bwalker, For 18 years I ran Stihl 4-mix machines as well as Echo and Husqvarna in my personal lawn care business in metro Atlanta. I've found, from my experience, that Stihl quality has been superb and actually better than the other brands. I have run every gas station oil, outboard motor oil, and ratios from 24:1 to 64:1 in my 4-mix machines. They seem to survive, as do many 2 strokes, with carbon all over the place. But does it have to be that way? No, it doesn't. I have learned that Amsoil Saber will run very clean. So far, it's the only oil that I have found that runs clean in my br800. I'd like for other people to know that, and whether or not other oils will run clean in a 4-mix. Is it a big deal? Not really, because they will run for decades with crappy oil. That's ok for people who have blinders on or who may be too busy to notice. This is not about me. It's about my hatred of Stihl's arrogance. I plan to get two more oils that will work and publicize it through YouTube and forums. Stihl has insulted it's customers by pushing the pathetic Stihl Ultra and they are seemingly hellbent to keep pushing their "green" "tree hugging" agenda and for some reason the redneck republican Alabama boy in me just wants to speak out and let other people know that there are oils that work better in 4-mix engines than Ultra. I'm like Bill Murray trying to kill groundhogs. I don't just dislike Stihl Ultra, I despise it so much that I've asked you and others for your thoughts about this subject, and I'm grateful for your help. I'm not some crazy individual who is obsessed with his 4-mix oil, I want to help others who can benefit by getting away from Stihl Ultra, that nasty and stinky skunk oil.