What kind of oil should you use in a craftsman 7.0 horsepower walking lawnmower with a Briggs and stratton engine?

Briggs & Stratton recommends high quality detergent straight 30 weight but this can result in hard starting and may damage the engine at colder (below 40 F) temps. Multi-viscosity standard automotive oils (5w-30, 10w-30, etc.) are acceptable but will result in very high oil consumption at ambient temperatures over 40 F, and may void your warranty. High quality synthetic multi-viscosity oils are best for all temperatures.