What engine oil do people run. My Franklin calls for straight weight mineral oil but like someone mentioned, that’s what they had. Oil has changed. They suggested Phillips x/c 20w50 with a cam saver additive. What’s your thoughts. I agree so far with his choice & plan to run it. Honestly, I’m considering shell Rotella. My brother is an engine builder & that is what he runs in everything (non aircraft) . He puts engines to the test & swears by it. Spec wise the stuff does have the goods. Lots of zinc.