I'm helping my sick uncle care for his house and yard. He has a newer Toro "Guaranteed to start" "Personal Pace" 6.5 hp lawn mower. He does not have the owners book and can not tell me what kind of oil to use. What oil would be good for this engine? I'm using Castrol GTX 5w30 in my Honda mower and for the last 3 years it has ran smooth with no problems. Can I put the Castrol GTX in the Toro? Also how many ounces does it take? Many thanks for the help!!!