As long as you use small engine oil you're fine. I'm sure there's alot of people that say normal oil is fine and it may be but why chance it? Small engine oil has added Zinc for your internal parts, better wear resistance. Also unlike normal car oil/ diesel oil, small engine oil is designed for air cooled engines operating at 450 degrees or more. Car oil is designed for liquid cooled engines with operating Temps closer to 200-250.