The amount of engine oil a lawn mower takes depends on the lawn mower engine. Generally, the oil capacity of a walk-behind lawn mower is around 15 to 20 ounces. A riding mower will typically have an oil capacity of 48 or 64 ounces.
Filling to the Correct Level
You should check your owner’s manual to determine the oil capacity of your lawn mower. Most manuals provide all the pertinent details necessary to determine the amount and type of oil needed for your lawn mower.
Unless you are 100 percent sure about the amount of oil to use in your lawn mower, you should gradually add it. Pour only about half of the estimated oil into the engine and then check the dipstick to gauge how full the oil tank is.
If the dipstick indicates that additional oil is required, add an additional ounce of oil and recheck the dipstick. Keep adding an ounce of oil until the dipstick indicates that the oil is full.
The dipstick should look similar to the below image. Be aware that new oil may be difficult to see on the dipstick. We suggest viewing the dipstick at various angles in an area with bright lighting.
Overfilling and Underfilling Lawn Mower Oil
Both underfilling and overfilling engine oil can lead to problems for a lawn mower.
A sign of too much oil is white or blue smoke coming from the engine. The engine may also be challenging to start. Additionally, oil may be seen exiting out of the muffler when the mower is in operation. You should drain excess oil into a container approved to hold oil. Be sure to check the dipstick to be sure the oil is at the correct level.
When you underfill your lawn mower with oil, you run the risk of major problems. Engine oil provides both lubrication and cooling abilities for the engine. In other words, a lawn mower with insufficient oil may cause friction and improper cooling inside the engine. This can lead to engine damage. Again, verify with the dipstick that the oil is at the appropriate level.
What Type of Lawn Mower Oil?
The type of oil you should use for your lawn mower will typically be referenced in the owner’s manual. Generally, oil can be selected based on the average outside temperature you plan on running your mower. Briggs and Stratton has a helpful guide that explains what oil works best for various temperature ranges. Most walk-behind lawn mower users opt for SAE-30, which is designed to use between temperatures of 40°F and 100°F.
How Often to Change Lawn Mower Oil?
Lawn mower oil should be changed once a year or every 50 hours of operating time. Oil is a minimal cost at about $3 to $5 to refill the lawn mower. We recommend purchasing an oil extractor pump that allows the oil to be pumped out of the mower instead of having to tip it on its side to drain the oil as is required for many mowers. Reference your lawn mower’s manual for directions on how to change the oil or review this tutorial from Tractor Supply.