How to Change Lawn Mower Oil

Proper care and maintenance of your four cycle Briggs & Stratton lawn mower engine has repeatedly proven to be the key to long engine life. It is important that you drain the oil from your engine after the first five hours of use. Doing so will ensure that any debris created by the engines break-in process is removed from the engine oil. Regular engine maintenance specifies that you drain the oil after fifty hours of use or every season. Heavy usage requires changing the oil after 25 hours of use, follow the directions in your owner’s operators manual to provide your lawn mower with the attention it requires or view the video for directions.

The following are acceptable oil drain methods:

  • Through the dipstick tube
  • Through the drain plug
  • By using an oil extractor tool

Draining the Oil

Drain the engine oil when the engine is warm, this allows the oil to suspend any internal debris in the oil and doing so will allow for impurities to drain, along with the oil.

  • Run the lawn mower for a minimum of 15 minutes then turn off the engine
  • Disconnect the spark plug wire from the spark plug and drain the gasoline from your engine


  • Remove the gas cap and place a plastic sandwich bag over the tank neck and threads, then simply screw the cap back on to prevent the gas from leaking

Tipping to Drain the Oil

When tipping the mower to remove oil, the oil drain is located via the dipstick tube. Tipping the engine and draining the oil through the dipstick tube is done by removing the dipstick cap, and tipping the mower to the correct side. The correct side is established by noting which direction will cause the air filter and/or spark plug to be up and the dipstick tube to be closest to the ground.

  • Locate your air filter, spark plug and dipstick tube
  • Place a drain pan on the floor
  • Tilt the engine so that the dipstick tube is towards the pan and drain the oil through the dipstick tube

If while tipping, some oil drains from the muffler, wipe the access oil with a rag, when restarting the engine, allow the oil to burn off as smoke. If the engine smokes excessively, see your local Briggs & Stratton Dealer.

Using the Oil Drain Plug

Not all engines have a drain plug, your operator’s manual will help identify the location and type of drain plug, if equipped. Depending on the age and type of your motor, you may have one of several types of drain plugs. Each drain plug uses a different tool. If your engine is equipped with a drain plug, it would be located under the lawn mower deck. Look carefully as the drain plug may be obstructed by clumps of turf or debris, the belt guard or the mower blade (use caution when moving the blade).
Note: if you must move the blade to get at the drain plug, do so slowly and with the spark plug removed. Moving the blade may cause excess oil to appear in the muffler, if this occurs, the oil will smoke in the muffler the next time the engine is started. This is only temporary, the smoking will subside and soon stop. Place the drain pan under the deck, remove the drain plug and drain the oil. You may also purchase any of the widely available oil extractors to remove oil from the engine.

Filling the Oil Tank
After draining the oil, you are almost ready to start your small engine again. If you removed the drain plug, reinstall and tighten. Place the mower on a level surface, add the required amount of oil, check the oil level , replace the dipstick, reconnect your engine spark plug, remove the plastic baggie from the gas tank and start your engine.

To help protect the environment and conserve valuable resources, recycle your used engine oil. Briggs & Stratton has made recycling used engine oil even easier. You can recycle your used oil free of charge at any participating local Briggs & Stratton Dealer. Oil recommendations are located in your engines operator’s manual. You should see your local Briggs & Stratton Dealer if your oil level is too high and you did not overfill the engine with oil, your oil level is consistently too low and there are leaks on the engine or stains underneath, your engine smokes excessively.