Recommended Oils for a Briggs-Straton Lawn Mower

Single-weight Oil

• Petroleum-based engine oil with a viscosity rating of 30W is recommended for mowers operated at 40 degrees Fahrenheit and above. Single-weight oils remain at the same viscosity, or thickness, in most temperatures encountered. Adhesion is another characteristic of viscosity, and oil of this weight affords good lubrication by firmly sticking to moving parts. At temperatures below 40 degrees, the thick and sticky oil can make starting more rigorous by increasing engine drag.

Multiweight Oil

• Oils that are rated at multiple weights gain viscosity as they warm up. A multiviscosity oil of 10W-30 is recommended for operating temperatures between 0 and 100 degrees. The light weight at startup allows quicker distribution to relatively cold moving parts. As the engine heats up, the oil becomes thicker and lubricating qualities are maintained. Use of 10W-30 petroleum-based oil at temperatures regularly above 80 degrees may result in slight losses due to oil consumption.

Synthetic Oils

• Multiviscosity synthetic oil is recommended for a wider range of operating temperatures you may encounter. High and low temperatures are more easily tolerated by synthetic oils due to their designed compositions. Synthetic multiviscosity oil rated at 5W-30 is recommended for operating temperatures from 20 below zero to 120 degrees. The weight and composition of the synthetic oil provides optimum lubrication under any circumstance, and also resists degradation common to petroleum-based oils.

Oil Changes

• Briggs and Stratton guidelines recommend an oil change after the first eight hours of service, also known as the "break-in" period. After the break-in oil change, the interval is extended to 25 hours of service. An oil change is also recommended before any long-term storage, such as in the offseason. Synthetic oil is more expensive than petroleum-based oils. However, it more readily resists contamination and degradation in storage and provides better heat dissipation in operation.