Briggs & Stratton produces several horsepower ratings for small four-cycle gasoline engines. The lineup of engines includes 12.5 horsepower motors for use on lawnmowers, garden tractors, motors, and other external power supply. These 12.5 HP units are built for four-cycles in a sump isolated from a fuel system by the lubricating oil.
Briggs & Stratton calls for 48 SAE 30 fluid ounces (1,5 quarters) of heavy-duty SF-SJ motor oil (40 cycle engine oil) or higher if the 12,5 HP motor is running at temperatures above 40 degrees Fahrenheit. The company says that you can use 48 ounces of 10W-30 mineral oil or 5W-30 synthetic oil if it runs at temperatures below 40 degrees Fahrenheit.