I have a Scag Cheetah 2011. It has a 31HP Kawasaki motor, 61" cut. So far I love it. I mow about 2 1/2 acres in 1 1/2 hours. I use Valvoline 10W30 Dino oil but next year I think I will go synthetic. I did my first oil change & it seemed to run quieter afterwards. One thing the original...