Uhhh, Theres not many 2 stroke lawnmowers in existance anymore... Though I did once have a 4 stroke motor that said to use 2 stroke oil in its crank! (Or maybe im misremembering something). Generaly people run 1:16 to 1:24 (more often 1:20~1:24) for initial break in (first 1 gallon of fuel), and 1:30 or so after that. Do not use 1:60 unless its a high end synthetic and you have allready broken in the motor.