I had a YS63 on my 2nd Burrito and it was more than adequate. Maybe even a bit scary. I swiched to an OS 50 and it is more than enough too. I originally had an OS 46 fx on it and it was just enough with no margin. The Burrito weighs a tad under 4 lbs. I also have a Mojo 40 that is waiting for the Burrito to die or get boring, neither of which are happening very fast. I will start the Mojo 40 with the OS 50 'cause the engine is so reliable and user friendly. Not to say the YS isn't nice to deal with - I love them all.