I have several 15's all run with Amsoil 100:1 at 64:1, since Saber Amsoil came out about 4 years ago...(air cooled equipment oil), I've run everything with needle and roller bearings at 100:1 with non oxy fuel and Saber. I am very satisfied with the results. All of my 15's are from the 70's and 80's and we began running Amsoil as soon as it came available. I am sure you will be okay at any ratio up to 100:1, but I suggest Saber....as it's a better product. I do not recommend 100:1 premix in either form, for oil injection, however. Amsoil provides a specific oil for 2 stroke injection systems.....why? Ratios are automatic and the 100:1 premix oils will be over oiling.....wasting your money. Yes, the Amsoil Injector oils are actually cheaper. The bets are all off for me, however, if ethanol is used in the mix here.....why? I have no experience using ethanol because it is crap for what I'm doing..What I'm doing is closing the camps for 6 to 7 months at a time, then go back and fire things up. Now we are locked out of Canada. Just got another tax statement....really makes me angry. When we finally get back to camps, it will have been nearly 18 months.....and guess what, my fuel will still be perfect because it's non-oxy clear.