Dmacsimum-My first YS 1.20 is four years old and still cranking with Omega 15% fuel; 9000 rpm with a 16x8 apc; I use the castor content as a mixture indicator-when the oil residue on the airplane gets a little darker than light tan, you are too lean. Mine was never touched by an electric starter either; flood it when cold and flip the prop backwards up against compression, presto! No need to choke or prime the rest of the day, one flip backwards and get your fingers out of the way! Used up several chicken sticks! I believe YS sells a compatible afterrun oil that is safe with the silicone diaphragm, etc. JIM