A 10w30 oil is recommended as the standard generator motor oil to use in our home standby generator engines.
Above 40°F, use SAE 30. Below 40°F and down to 10°F, use 10W-30. Below 10°F, use synthetic 5W-30. Oil should be changed after the first 8 hours of operation and every 200 hours of run time thereafter.
Briggs & Stratton 30W Engine Oil - 48 Oz. 100028