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How to Troubleshoot a Gravely Zero Turn Lawn Mower

By Damon Hildebrand ; Updated September 21, 2017
Wrenches are common tools for troubleshooting Gravely mowers.
adustable wrenches closeup image by Warren Millar from Fotolia.com

Zero turn mowers bring a whole new meaning to fast and efficient lawn care. They can perform a 180-degree turn on a dime--and give back nine cents in change. But they are not without hiccups of their own now and then. As with all mechanical equipment, the day approaches when even a Gravely lawn machine requires troubleshooting and maintenance. The most common symptoms also have the most common cures.

Check the gas tank if the mower fails to start. Not only might the tank be empty, but moisture or condensation in the tank can cause the mower to exhibit similar symptoms as an engine starving for gas. Excessive bubbles or clouds in the fuel indicates water contamination. If such a cause is apparent, drain and refill the tank with fresh gasoline.

Inspect the safety cut-outs on the mower. To protect the machine as well as the operator, Gravely incorporates several safety switches to detect if certain conditions are met before allowing the engine to start. Conditions include: the mower blade disengaged, parking brake set and operator in the seat.

Check the condition of the spark plug if the engine fails to start or runs erratically. Replace spark plugs if burn marks or corrosion is apparent. Also, the spark plug wire may have vibrated loose during previous operation and will need to be reattached.

Remove the air filter and clean it with compressed air. Accumulation of dirt on the air filter element restricts air flow to the carburetor--resulting in loss of power and poor performance. If embedded dirt in the filter element prevents cleaning it with air--replace the filter element with a new one.

Inspect the cooling fins and air passages beneath the blower housing of the engine if overheating is an issue. Accumulation of grass and dirt restricts the flow of cooling air across the coils, resulting in inadequate cooling. The oil level might also be low. It is best to check the oil level before each use to prevent engine failure. A low oil level causes the engine to run warmer than normal.

Examine the mower blades and cutting deck if the mower exhibits abnormal vibration while in service. Bent or loose blades, loose pulleys, and a loose or bent blade spindle are all cause for erratic vibration when the mower is operating.


Things You Will Need

  • Regular screwdriver
  • Channel-lock pliers
  • Needle-nose pliers
  • Spark plug wrench


  • Clean the mower after each use to help ensure reliable service.
  • Drain the gas before prolonged storage.
  • Replace the plugs, filters and oil at least once per cutting season.

About the Author


Damon Hildebrand is a retired U.S. Navy veteran. He has more than 15 years within the oil and gas industry in both technical and managerial positions. Hildebrand has been a technical writer and communicator for the last four years. He is a certified specialists in lubrication and tribology, as well as a certified maintenance and reliability professional.