Like a lot of you I have a "Small Fleet" of "Small Engine, 3.5 to 23 HP". What Oil to use? I want something that will keep these engines running until the rest of the machine falls apart. I have read a lot on here and other places. There are lots of opinions about Oil. Here is what I am planning to do: I am going to pick a Automotive 10W-40 or 10W30 Full Synthetic, Add a liberal dose of ZINC like Roslone Hyperlube. And run it in all my fleet. My Reasoning Full synthetics are not supposed to break down under high heat of a Turbocharger so they should do perfectly well with the temps of a 19 Hp Kohler mower on a 100 degree Ky day. Todays Synthetics appear to eliminate most to almost all internal engine wear these days. The "liberal addition" of of the Zinc should protect against any "flat surface" wear in these engines. So Simple, Common Sense, and relatively cheap. Would really like to hear what ya got to say about this. I have had some really Dumb ideas in my time. If this is one of them please tell me it is dumb.