Symptoms
- Starter spins the engine over normally
- No firing, popping, or catching sound
- Engine has cranked fine before but not started in a while
- Fuel gauge low or unknown fuel age
Likely causes
- CommonEmpty or stale fuelRiding mowers are often left with old gas over winter, which won't ignite reliably.
- CommonFouled spark plugA plug with no spark or a wet/black tip prevents ignition even with fuel present.
- PossibleClogged fuel filter or lineDebris or gum from old gas can block fuel from reaching the carburetor.
- PossibleBad ignition coilA weak or dead coil produces cranking but no spark.
- PossibleClogged carburetorDeposits can fully block fuel delivery even though the engine turns over.
What to do
- Confirm there's fresh fuel in the tank; add new gas if it's been sitting more than a month.
- Pull the spark plug and check for spark by grounding it against the engine block while someone briefly cranks the engine (keep clear of fuel and the blade area).
- Replace the plug if it's fouled, cracked, or shows no spark.
- Check the inline fuel filter, if equipped, and replace it if it looks dark or clogged.
- Squeeze the primer bulb (if equipped) several times before cranking to verify fuel is reaching the carburetor.
- If there's spark and fuel but still no start, the carburetor may be gummed up and need professional cleaning.
Tools and parts
- Spark plug socket
- Fresh gasoline
- Insulated pliers
Riding mower spark plugSearch: “riding lawn mower spark plug”
Inline fuel filterSearch: “small engine inline fuel filter”
When to call a pro
If spark and fuel both check out fine, a small engine mechanic can test the ignition coil and carburetor.
Safety
Use caution
Keep hands and tools away from the blade deck and never crank the engine with the plug removed and fuel present near an open spark.