Hello, Very Excited!! 1st post! Just got an excellent deal on my first ZTR mower. Bobcat Leo, 150hrs, in excellent condition=$1500. No manual.......I'm going to order it online, or even here if available. I'm very excited to start my tune-up. What oil do I use in this motor? B&S 17.5hp ELS 500 motor. Want to do my oil change, and learn about the parts that drive the rear wheels. (are they called hydro's?) What fluid do I put in them? How often do I change it? That's it for now. Blades will be sharpened next!! Thanks for any help you can provide me with!!