So I am dumping the 10w-30 MC syn-blend from my kohler courage 26hp and switching to SAE 15W-40 diesel oil (1 Quart) and a quart of SAE 10W-30 diesel oil. Anyone think this will help clean the engine out before I switch to AMSOIL? And I am assuming this is probably a conventional lube, right? And it says on the bottle "Do not use in gasoline engine equipped with catalysts." Do kohler courage 26hp's have catalysts?