* Low fuel. Check the fuel level in the mower's fuel tank. If it is low, add fresh fuel to the tank.
* Stale fuel. If the fuel in the mower is old, it can lose its potency and cause problems, or damage components, with starting. Drain the old fuel from the tank, and add new fresh fuel.
* Dirty fuel filter. A dirty fuel filter can restrict the flow of fuel to the carburetor, causing the mower to shut off. Remove the fuel filter and inspect it. If it is dirty, replace it.
* Clogged fuel line. A clogged fuel line can also restrict the flow of fuel to the carburetor, causing the mower to shut off. Disconnect the fuel line from the carburetor and blow compressed air through it to clear any clogs.
Carburetor Issues
* Dirty carburetor. A dirty carburetor can cause the mower to shut off. Remove the carburetor and clean it with carburetor cleaner.
* Damaged carburetor. A damaged carburetor can also cause the mower to shut off. Inspect the carburetor for any cracks or damage, and replace it if necessary.
* Faulty choke. A faulty choke can cause the mower to shut off. Check the choke to make sure it opens and closes properly. If it is faulty, replace it.
* Wrong choke setting. Check the choke lever. If it is not fully disengaged, move the choke lever to the fully open position (up).
Other Issues
* Loose or damaged spark plug. Check the spark plug wire to make sure it is properly connected to the spark plug. If it is loose, tighten it. If the spark plug is damaged, replace it.
* Faulty ignition switch. A faulty ignition switch can prevent the mower from starting. Check the ignition switch to make sure it is working properly. If it is faulty, replace it.
* Dirty air filter. A dirty air filter can restrict the flow of air to the carburetor, causing the mower to shut off. Remove the air filter and inspect it. If it is dirty, replace it.
* Low oil. Check the oil level in the mower's engine. If it is low, add oil to the engine.
* Faulty governor. A faulty governor can cause the mower to shut off. Check the governor to make sure it is working properly. If it is faulty, replace it.
* Worn out starter: If the mower is difficult to start, or dies shortly after starting, the starter could be worn out and need replacing.
