SAE 30 is the recommended oil for a 26 hp Briggs and Stratton motor. Depending on the temperature, you may need to change it to SAE 5W-30. SAE 30 is a single-grade oil, while SAE 5W-30 is a multi-grade oil. Multi-grade oils are a better choice for engines that are used in a wide range of temperatures, as they provide good lubrication at both high and low temperatures.
Briggs and Stratton also recommends using a SAE 30 oil if the engine will be used in temperatures above 32°F (0°C). If the engine will be used in temperatures below 32°F (0°C), Briggs and Stratton recommends using a SAE 5W oil.
It is important to use the correct oil in your Briggs and Stratton engine, as the wrong oil can cause damage to the engine.