The YS has a different fuel delivery system than your run of the mill 4 stroke so setting it up takes a bit of learning. Once you understand the YS engine they are a dream.

As for the fuel you want 20% lubricant and preferably synthetic. They will run on less than 20% nitro but the needle valve settings are more sensitive and you will down a little on power. I personally would get the engine and some 20/20 fuel made for YS engines.