How Much Oil in a 4.0 Horsepower Briggs & Stratton Lawn Mower Motor?

Oil Capacity

• Any mowers using the Briggs and Stratton Quattro 4-horsepower engine have a maximum of 20 ounces for oil capacity. It is important to note this because when you service or change the oil you can damage the engine by filling beyond capacity. Oil will overflow from the crankcase and into the combustion chamber, inhibiting combustion or causing overheating. Any oil that drains into the exhaust or muffler will cause heavy smoke on start.

Oil Type

• The Quattro engine also requires specific quality attributes for its oil. Engine oil must be rated at SF, SG, SH, or SJ. Oil must also meet ILSAC GF-2 with the API certification mark on the container. Also look for “SJ/CF Energy Conserving” or higher on the container and ensure there are no additives in the oil.

  10W30 weight synthetic oil is authorized for all operating conditions. Use 5W30 weight or 10W30 for operating your mower at zero to 40 degrees Fahrenheit ambient temperature. Use SAE 30 for operating above 40 degrees. Be warned that using SAE 30 when temperatures are below 40 degrees can damage engine bores or cause hard starting.

Maintenance

• If oil is below recommended levels, engine parts will lack lubrication and can cause damage to each other. Dirty oil can reduce heat transfer capability as well as introduce contaminants into the combustion chamber. To maintain best operation for your 4-horsepower mower, the owner’s manual states to check oil levels before daily use and every 5 hours of operation. If operating under heavy loads and/or high ambient temperatures, change oil every 25 hours or every season. Otherwise you should change every 50 hours.

Changing Oil

• To change the oil, first open the oil fill port located on top of the engine. Open the drain at bottom of mower by using a 3/8 drive ratchet with an extension. If the drain port is too rusted or is difficult to open, you can drain oil through the fill port as long as you tilt the engine with oil filter pointing up. If you are using the fill port to drain, ensure you drain fuel first by running the engine until fuel is burned out or manually drain it. Refill the oil slowly a few ounces at a time to capacity. Close the oil drain port and fill port.