How to Troubleshoot a Lawn Mower That Won't Start

Follow troubleshooting steps if you have problems starting your lawnmower.

Starting your lawnmower should be straightforward; simply follow the instructions and away you go. Unfortunately, lawnmowers don't always cooperate by starting and running properly. Troubleshooting your lawnmower helps detect common problems and saves you money on unnecessary repairs. A lack of quality gasoline, a defective electricity supply and other technical failures can be the cause of your lawnmower's starting problems.

Instructions

Gas Powered Lawnmowers

1. Ensure the choke lever is in the correct position for the engine's current condition. Place it in the "Start" position when the motor is cold or "Fast" when the engine is still warm from previous use. Press the primer bulb, if fitted, on the engine before trying to start a cold engine.

2. Ensure you are supplying sufficient pressure to the operator handle, the metal or plastic lever that must be held in place while using the lawnmower. The engine stops when the operator releases the handle, preventing the engine running unattended.

3. Open the fuel tank and ensure there is sufficient gas to start the engine. Empty the fuel tank and add fresh gasoline if the fuel has been stored longer than a few months without use. Over time, moisture and dirt can contaminate the fuel, preventing the engine from running. Ensure the fuel cut-off switch, if fitted, is in the "On" position.

4. Replace the spark plug after making sure the rubber boot that supplied electricity from the battery is firmly in place. Vibration from the motor or too much jarring can create a loose connection.

5. Remove and clean the air filter, brushing away leaves or other debris blocking the engine's air intake. The engine may have difficulty starting or struggle to idle if there is a blockage in the air intake system. Consider replacing the filter if it is old or damaged.

6. Charge the lawnmower's battery, if possible, or purchase a replacement after checking the connections. A flat, disconnected or defective battery stops the spark plug from producing the ignition necessary to start and run the engine.

Electric Lawnmowers

1. Check the lawnmower's power cord; a strong jerk during mowing could have pulled the cord loose. Make sure the outlet is switched on at the main panel, and that there is power at the plug. Check the fuses or breakers in your home if the outlet is not working.

2. Make sure the lawnmower's rechargeable battery, if fitted, has enough remaining charge to power the engine. Some battery powered lawnmowers will not start unless the battery charger cable has been removed.

3. Disconnect any extension cords helping to connect the lawnmower with an outlet; it may not be suitable for use with your lawnmower. Try connecting the mower directly to an outlet; if the engine starts, replace the extension cord with a higher-gauge replacement.

4. Ensure you are supplying sufficient pressure to the operator handle, the metal or plastic lever that must be held in place while using the lawnmower. The engine stops when the operator releases the handle, preventing the engine from running unattended.

Tips & Warnings

• Make sure the lawnmower blades are not standing on top of a hill or mound of earth. At the same time, with the motor off and the power disconnected, check the blades for signs of a blockage.

References

• Husqvarna: Poulan Pro 600 Lawnmower Owner's Manual
• Manage My Life: Craftsman 24-Volt DC Cordless Rechargeable Mower Manual