Like the others say, if not legally required in your area, I'd remove the spark screen. Also, while the Echo oil is good, it is not the most advanced. Try the Shindaiwa RedArmor Oil, (Also an Echo product) my Echo dealer stocks it. It actually cleans out the old carbon and varnish from inside the engine and muffler too. Just remember that spark screen if you keep it in, you will have to check it and clean it if you don't use a better oil.