Well I just started using MMO+TCW3 2 stroke oil. Have been using just MMO and got 15 mpg. Just started mixing the stroke in, I'll keep you posted on MPG and how well it runs. Now it's non synthetic TCW3 oil, but I just got a jug of Pennzoil marine full synthetis ester based oil. When I finish the other, I'll start on it. I poured some out just to see what it looks like, and what a horrid smell!! I actually gagged from it while pouring. So it is different, the regular oil didn't smell bad at all. No I don't sniff oil! Isn't ester supposed to be more slippery than regular oil? I got this idea from Sarge at the LS1 board, there's a post about it further down.