I buy the Kubota brand oil from the dealer Reason - so if there ever was a engine problem they cannot void warranty saying my fault I used crappy oil. Learned this from shindaiwa they want to claim every warranty item is my fault ethanol gas and not cover under warranty. Currently exploring new brand of trimmersFirst oil change coming up for my Z123 -48 Kubota. I'm thinking of using Mobile1 10-30 oil. Any thoughts on why not, or other oil brand/w?