There's nothing more frustrating than having tall grass and a mower that won't start. Or perhaps you've mowed half of the lawn and the machine dies. There are several things you can do to troubleshoot your lawn mower problems before throwing in the towel and calling a professional. Being able to diagnose the problem yourself could save you time, money and a huge headache.

Your Mower Won't Start

Mowers refuse to start for many reasons. Usually, though, the main reasons are spark related, fuel related, or battery related. A mower needs fuel and spark to burn the fuel to get combustion. Checking different areas of the engine related to spark, fuel, or battery can help get your mower up and running.

Spark Related

• If it's early in the season and your mower worked when you put it away, check to see if you reconnected the spark plug wire.
• A bad spark plug will keep your engine from turning over. Check your spark plug to make sure it's properly gapped and fresh. You'll want to check that it's the right type for your mower. Also, make sure you've installed the spark plug properly.
• If you're getting spark but the machine is still not starting, you may need new points (in an old machine) or an ignition module (in a newer machine).

Fuel Related

• You may have bad fuel. Try siphoning out the old fuel and adding fresh.
• If you have new fuel and spark, next check to make sure the carburetor is getting the fuel it needs to run. Check the fuel line to make sure there are no kinks.
• Try changing the fuel filter, because a clogged fuel filter can inhibit the flow of fuel enough to make the engine not start.
• Try tapping the side of the carburetor to see if the float becomes unstuck and allows fuel to flow freely.

Battery Related

• Try charging the battery.
• Check to make sure the battery cables are correctly and tightly connected. You'll also want to check to see if the connections are free of corrosion.
• If the battery won't hold a charge, it could be bad. Replace the battery and try again.

Mower Runs for a Moment Then Dies

There's nothing more frustrating than having your mower's engine crank over and run for a moment only to sputter and die off. Below are some things to look for if you're having this problem with your mower.

• If you haven't changed the fuel or checked the spark plug, try those solutions first.
• Chances are you need to have the carburetor cleaned and rebuilt.
• Your engine could also have an air leak. Check to see that all bolts are tightened down and that the gaskets aren't missing pieces.

Mower Runs and Dies While Mowing

Okay, maybe this is more frustrating than having it die right after starting. If your mower runs and dies while mowing you've probably hit something. You'll want to check out the underside to see if something is stopping the mower from running.

• Before doing anything, disconnect your spark plug wire so the mower won't accidentally start.
• Tip the mower over. Keep the spark plug side up.
• Check the blade to make sure it's not bent or broken. You'll also want to make sure it's balanced properly.
• Remove the blade and check the crank shaft. If it's wobbly or bent you'll need to replace it. Trying to straighten the crank shaft will only prolong the inevitable break.
• Sometimes the flywheel key breaks when you hit something while mowing. This will keep your mower from starting.

Mower is Hot and Won't Restart

If your mower won't start when the engine is hot it could be resulting from a range of problems.

• First, check to see if your engine has overheated. You'll want to see if the cooling fins and engine shrouding are blocked with some form of debris.
• Another simple problem is checking the fuel level to make sure you haven't run out.
• Next, check the spark plug to make sure it hasn't fouled while mowing.
• Finally, check to see if the throttle is in the midway or stop position.

Your Mower Vibrates While Using

• Check to see if the underside of the mower is clogged with debris or grass clippings. Make sure you disconnect the spark plug before inspecting the underside. Never use your bare hands to clear away debris. Instead, use a long item, such as a stick or a screwdriver.
• Check the blade to make sure it's not bent or damaged. If your mower has two blades and only one is damaged, make sure you replace both so the machine remains balanced.
• Check to make sure the blade doesn't need to be tightened.