Briggs & Straton Lawn Mower Engine Troubleshooting

Updated February 21, 2017

The polar opposite of troubleshooting activities is maintenance activities. Every engine, large or small, requires maintenance to some extent. Briggs & Stratton engines commonly found on consumer machines (lawnmowers and tractors, tillers, snowblowers, trenching machines) are considered small engines. To prevent the need for troubleshooting, you must keep up a regular maintenance program. Otherwise, you troubleshoot your way through regular maintenance tasks to see what is causing the engine problems. The most common need for troubleshooting a Briggs & Stratton engine stems from an engine-starting issue.

Check the oil level in the crank case. Remove the oil plug/dipstick, wipe the oil off of it with a paper towel and reinsert it into the oil fill hole. Pull it out again and look at the oil level indicated on the dipstick. Hash marks on the dipstick indicate the recommended high and low oil level range.

Add oil to the engine if the level is low. Recheck the oil level to be sure it is within range. If the oil level falls within this range, the oil level is not the problem, unless it has been more than 50 operating hours, or one operating season since the oil has been changed.

The oil must be changed regularly to provide the inner workings of the engine adequate protection. If the oil was changed recently and is within range, the oil level is not the problem.

Remove the air cleaner (air filter) cover and check the condition of the filter. If the filter is dirty and shows signs of damage and wear, replace it immediately. Air filters must be changed every 25 working hours, or between operating seasons. The air filter cleans the air as it enters the engine.

Dirty air can have very negative effects on the internal workings of a Briggs & Stratton engine. If the air filter is only slightly dirty, rinse the foam pre-filter and blow the paper filter off with compressed air, either from a can or with an air compressor. Reinstall both filters. Unless the engine has been run for a while with either very dirty or damaged air filters, the air filters may not be causing the problem.

Check the fuel level in the fuel tank. If the fuel tank is empty, this may be the problem you are looking for, and it is a simple fix. Add fresh, stabilised gasoline that does not contain two-cycle engine oil, unless required by the manufacturer. If the fuel tank contains an adequate amount of fuel, the fuel may be stale causing the engine to have starting difficulties.

If the fuel is quite old, the fuel may have turned to a gummy, sticky substance that has clogged your fuel system. This problem should be cleared up with the help of a licensed service dealer. Fresh fuel should always be stabilised because you never know how long it will actually sit in its storage container. Top the fuel off as needed before attempting to start the engine and while the machine is in use.

Unscrew the existing spark plug so it can be inspected and replaced if needed. If the electrode end of the existing spark plug is dirty or if it is damaged or worn, it should be replaced with a new plug. Removal and reinstallation are easy with a spark plug tool.


If after working your way through these four steps and the engine still will not start, take the Briggs & Stratton tool to your local licensed service dealer for repairs.

Things You'll Need

  • Engine oil
  • New air filter set
  • Fresh fuel
  • Fuel stabiliser
  • Spark plug
  • Spark plug tool
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About the Author

Kelly Nuttall is a student at Utah Valley University in Orem, Utah. She is set to graduate in the spring of 2011 with her bachelor's degree in technical communications. She has been writing for various websites since March of 2009.