There’s nothing more frustrating than a beautiful Saturday morning, a lawn that needs cutting, and a Craftsman mower that simply won’t start. You pull the cord once, twice, a dozen times, and you’re met with nothing but the sound of your own effort or a sputtering engine that refuses to come to life. Before you resign yourself to an expensive trip to the repair shop or consider buying a brand-new machine, take a deep breath. More often than not, the solution is simpler than you think.
This comprehensive Craftsman Lawn Mower Not Starting: A Step-by-Step Guide is designed to walk you through the most common issues in a logical, easy-to-follow sequence. We will move from the simplest, most frequent fixes to the more complex possibilities, saving you time, money, and a whole lot of frustration. By following these steps methodically, you can often diagnose and solve the problem yourself, getting your mower back to peak performance and your lawn looking great again.
The Simple Checks You Should Always Do First
It’s easy to overlook the obvious when you’re focused on a stubborn engine. Let’s start with the basics that take only seconds to check but are the cause of a huge percentage of non-starting mowers.
First, is the spark plug wire securely attached? Sometimes, during transport or cleaning, this crucial wire can become loose or disconnected. Give it a firm push onto the spark plug to ensure a good connection. Next, check your mower’s drive system. If your Craftsman is a model with a drive lever that must be disengaged to start, make sure you have it in the correct position. Similarly, if your mower has a blade control lever (often called a “dead man’s” control), it must be held down while pulling the start cord.
Finally, and this is a very common one, check the fuel shut-off valve if your model has one. This valve is located on the fuel line between the gas tank and the carburetor. It needs to be in the “On” position for fuel to flow. It’s a simple thing, but it’s missed more often than you’d imagine.
Investigating the Fuel System
If the simple checks don’t solve the issue, it’s time to look at the fuel system. Problems here are the single biggest cause of small engine troubles.
Begin with the fuel itself. Is there gas in the tank? It sounds silly, but it happens. More importantly, how old is that gas? Gasoline begins to degrade in as little as 30 days, losing volatility and forming gummy deposits that can clog the carburetor. If your fuel is from last season or has been sitting in the tank for months, it’s likely the culprit. Drain the old fuel completely and fill the tank with fresh, clean gasoline.
If bad gas has been sitting in the system, the carburetor’s tiny jets and passages are probably clogged. You can try adding a fuel system cleaner to a fresh tank of gas, but for a mower that won’t start at all, a cleaning is often necessary. This involves removing the carburetor, disassembling it, and cleaning it with carburetor cleaner and compressed air. While this sounds intimidating, there are many helpful tutorials online specific to Craftsman mower models.
The Air Supply and Filtration
Your mower’s engine needs a precise mix of fuel and air to run. A clogged air filter restricts the airflow, creating a mixture that is too “rich” with fuel, which can prevent starting.
Locate the air filter cover on your mower—it’s usually a black plastic box on the side of the engine. Remove the cover and take out the air filter. Is it caked with dirt, grass clippings, and debris? Hold it up to the light. If you can’t see light passing through it, it needs to be cleaned or replaced. A foam filter can be washed in warm, soapy water, rinsed, dried, and then lightly re-oiled. A paper filter should be tapped gently to dislodge loose dirt, but if it’s very dirty, it’s best to simply replace it. A clean air filter is a cheap and easy way to ensure your engine can breathe properly.
Craftsman Lawn Mower Not Starting: A Step-by-Step Guide to Spark and Compression
For combustion to occur, you need fuel, air, and a spark at the right time. If you’ve addressed the fuel and air systems, the next logical step is to check for spark.
Important Safety Note: Before performing this test, disconnect the spark plug wire from the plug to ensure the engine cannot accidentally start.
Remove the spark plug using a spark plug socket wrench. Inspect the plug’s condition. Is the electrode worn down? Is it covered in black, sooty deposits or a white, chalky substance? Any of these conditions can prevent a strong spark. If it’s heavily fouled or the electrode is eroded, replacing it with a new plug of the correct type is an inexpensive and effective fix. To confirm you’re getting a spark, reconnect the spark plug wire to the removed plug and carefully ground the metal base of the plug against the engine block. Pull the starter cord and look for a bright blue spark jumping across the electrode gap. If you see no spark, you have a problem with the ignition system, which could be a faulty spark plug, a broken ignition coil, or a disconnected kill switch wire.
Finally, while less common, an engine with low compression can also refuse to start. This is caused by worn piston rings, a blown head gasket, or a damaged valve. If you’ve checked everything else and the engine still has no life, a compression test with a gauge is the next professional step.
Wrapping Up Your Troubleshooting Journey
Diagnosing a Craftsman mower that won’t start is a process of elimination. By starting with the simplest and most common issues—like the spark plug wire, old gas, and a dirty air filter—you can often solve the problem without any special tools. Moving methodically through the fuel system, then to the spark, allows you to isolate the cause systematically.
Remember, regular maintenance is the best way to prevent these issues. At the end of each mowing season, or before storing your mower for winter, consider adding a fuel stabilizer to a fresh tank of gas or simply running the carburetor dry. Replace the air filter and spark plug annually. These small habits will ensure your Craftsman mower is ready to start on the first pull, season after season, giving you more time to enjoy your perfectly manicured lawn.