Just so you know, here there aren't many "stupid" questions, and I probably hold the title for the most if there are. But about your lawn mower maintance, I would say change the oil replace it with a good straight 30 weight (for briggs thats what you need, Kohler is 10w30). Also, I would take a look at the spark plug and air filter (replace these based on how you feel they look), another thing is the fuel filter, if you have the urge to make sure your machine runs well, replace it, if not it's probably not in that bad of shape, unless your engine is running very uneven. Now, I don't recall if you said it was a V-Twin or if it wasn't, for V-twins the only thing is there are obviously 2 spark plugs. If you have an oil filter replace it when you change the oil. I would take all the deck guards off and clean throughly under them, and while you have them off grease up any grease point you can, another thing while you are looking at your deck check your blades and your secondary and primary deck belts (some only have one deck belt, some have 2). I would say its always good to get a sharper blade, but thats also your opinion. If you do all this, you should be ok, if it doesn't make your machine run well, I don't know what will. Good Luck