I use 10% omega in mine, an 11 7 apc, and it pulls a great planes supersportster 40 arf very well. this engine is at least 10 years old, was in another SS for a few years, and has sat on the bench a few years before I put it in this SS a couple of years ago, and it just runs like new. I do use marvel mystery oil as an after run in all of my engines, even though it may not be neccessary. just a habit.(probably a good one for a change!! )