I am the new owner of a very well maintained 1997 Grasshopper 721 with the Kubota gas engine. It has just over 1100 hours, and is in great shape for its age. I am a freak about my maintenance, and usually try to buy the best quality fluids for all of my vehicles. I was trying to find oil reccomendations online, but could not find much information. Most of what I have found pertains to the 721D. Does anyone know the proper oil weight for this mower, and does anyone have any recommendations on what oil brand to use?