My Mower Engine Is Turning Over Very Slowly

Gas

• Although you may have gas in your mower’s tank, it may not be enough to keep the mower going. Evaporation from heat can lower you gas tank levels if you checked your tank a few days ago but left the mower out in the sun. The tank should be at least halfway full. Some mowers also use primers to assist with starting your mower. The primer button pushes gas from the tank directly into the carburetor so that combustion can take place faster. Ensure you pressed the primer button sufficiently per your mower’s instructions.

Spark Plugs

• Your mower’s spark plugs create the engine’s combustion by igniting the fuel vapors. Corroded or damaged spark plugs won’t provide the necessary spark for ignition. Dirty spark plug contacts will interfere with any spark, requiring multiple starts to ignite past the debris. Replace the spark plugs every season and regularly clean spark plugs. Also check the spark plug wires for damage.

Vapor Lock

• Vapor lock occurs when too much air enters the combustion chamber. The spark plug ignites when you pull the mower cord to rotate the blade. Too much air pressure prevents the mower blade from rotating far enough to cause the spark. To release the air pressure, unscrew the spark plug, manually rotate the blade three times and then replace the spark plug.

Oil

• Oil is the lifeblood for your mower’s engine, keeping all the parts lubricated and cooled. If your oil levels are low, the engine’s pistons may have trouble firing because the moving parts are grinding against each other. Use your oil level indicator to check it. You could lose oil if your mower has been turned over and the oil leaked out or if your mower was consistently operating at high temperatures. Dirty oil also slows down your mower’s starting process by allowing debris to enter the engine. Check the oil filter to see if it’s clogged and is permitting debris to pass through.