The return of spring, the warmer weather, and the urge to get your lawn looking pristine – it’s all part of the joy of homeownership. But nothing can put a damper on that springtime enthusiasm quite like a lawn mower that refuses to start after months of storage. You pulled it out, expecting a smooth start to the season, but instead, you’re met with a frustrating silence. This is a common problem, but thankfully, often a solvable one. Let’s dive into the most likely culprits and how to get your mower roaring back to life.
The Fuel Factor: Old Gas, Clogged Carburetors, and More
One of the primary reasons why a lawn mower won’t start after sitting idle for an extended period revolves around the fuel system. Gasoline, unfortunately, doesn’t stay fresh indefinitely. It degrades over time, forming varnish and gummy deposits that can wreak havoc on your mower’s engine.
The Perils of Stale Gasoline
Gasoline begins to deteriorate relatively quickly. After just a month or two, the volatile compounds in gasoline start to evaporate, leaving behind a thicker, less combustible fuel. This stale gas can be difficult to ignite and can clog the small passageways in the carburetor. Using fresh gasoline is crucial for proper engine operation.
If you left gasoline in the tank over the winter, it’s almost certainly the first thing you should address. You’ll need to drain the old fuel and replace it with fresh gasoline. Locate the fuel shut-off valve (if your mower has one) and close it. Then, disconnect the fuel line from the carburetor and drain the old fuel into a suitable container. Dispose of the old gasoline properly according to local regulations.
Carburetor Clogs: A Major Culprit
The carburetor is responsible for mixing air and fuel in the correct proportions to create a combustible mixture. The tiny jets and passageways within the carburetor are easily clogged by varnish and deposits from old gasoline. This is a very common reason for starting problems.
Symptoms of a clogged carburetor include difficulty starting, rough idling, stalling, and a general lack of power. If you suspect a clogged carburetor, you’ll need to clean it. This can involve removing the carburetor and disassembling it for cleaning.
Cleaning the carburetor usually involves using carburetor cleaner spray and small brushes to remove any deposits. Pay close attention to the jets and ensure they are clear. If the carburetor is severely clogged, you may need to soak it in carburetor cleaner for an extended period. In some cases, carburetor replacement might be necessary.
Fuel Lines and Fuel Filter Issues
Beyond the carburetor and the gas itself, the fuel lines and fuel filter can also contribute to starting problems. Fuel lines can become brittle and cracked over time, leading to leaks or air entering the fuel system. A clogged fuel filter restricts the flow of fuel to the carburetor, starving the engine.
Inspect the fuel lines for any signs of cracks, leaks, or damage. Replace any damaged fuel lines immediately. Locate the fuel filter (usually located in the fuel line) and inspect it for debris. If the filter is clogged, replace it with a new one. A clean fuel filter ensures a steady supply of fuel to the engine.
Ignition System Problems: Spark Plugs, Coils, and More
Even with fresh fuel and a clean carburetor, your lawn mower won’t start without a properly functioning ignition system. The ignition system is responsible for generating the spark that ignites the fuel-air mixture in the engine cylinder. Key components of the ignition system include the spark plug and the ignition coil.
Spark Plug Inspection and Replacement
The spark plug is a crucial component of the ignition system. Over time, spark plugs can become fouled with carbon deposits, corroded, or simply worn out. A faulty spark plug will not produce a strong enough spark to ignite the fuel-air mixture.
Remove the spark plug and inspect it for any signs of damage or wear. Look for cracks in the ceramic insulator, excessive carbon buildup on the electrode, or a worn-out electrode. A healthy spark plug should have a clean, dry electrode with a sharp edge.
If the spark plug is fouled or worn, replace it with a new one of the correct type for your mower. Before installing the new spark plug, check the gap using a spark plug gap tool. Ensure the gap is set to the manufacturer’s specifications.
Ignition Coil Issues
The ignition coil is responsible for generating the high-voltage electricity needed to create a spark at the spark plug. If the ignition coil is faulty, it will not produce enough voltage, and the spark plug will not fire.
Testing the ignition coil typically requires a multimeter. You can check the primary and secondary resistance of the coil to see if it falls within the manufacturer’s specifications. If the coil is not functioning correctly, it will need to be replaced.
Replacing the ignition coil usually involves disconnecting the wiring and removing the old coil from the engine. Install the new coil and reconnect the wiring, ensuring all connections are secure.
The Importance of a Clean Air Filter
While often overlooked, the air filter plays a vital role in the overall performance of your lawn mower. A dirty or clogged air filter restricts the flow of air to the engine, causing it to run poorly or not start at all.
Why a Clean Air Filter Matters
The air filter prevents dirt, dust, and other debris from entering the engine. When the air filter becomes clogged, the engine is starved of air, resulting in a rich fuel mixture (too much fuel, not enough air). This can lead to starting problems, reduced power, and increased fuel consumption.
Inspect the air filter for dirt and debris. If the filter is paper, you may be able to clean it by tapping it gently to remove loose dirt. However, if the filter is heavily soiled, it should be replaced. Foam air filters can usually be washed with soap and water, then oiled lightly before reinstalling.
Replacing a dirty air filter is a simple and inexpensive way to improve your mower’s performance and ensure it starts reliably. Refer to your owner’s manual for the correct type of air filter for your mower.
Oil Level and Condition: Low Oil Shutdowns and More
Most lawn mowers have a low oil shutdown feature that prevents the engine from starting if the oil level is too low. This is to protect the engine from damage due to insufficient lubrication. The oil also needs to be clean to properly lubricate.
Checking the Oil Level
Before attempting to start your lawn mower, always check the oil level. Remove the dipstick, wipe it clean, reinsert it, and then remove it again to check the oil level. The oil level should be between the “add” and “full” marks on the dipstick.
If the oil level is low, add the appropriate type of oil until it reaches the full mark. Refer to your owner’s manual for the correct type of oil for your mower.
Oil Condition
Besides the level, the condition of the oil is also important. Over time, oil can become contaminated with dirt, debris, and fuel. This contaminated oil loses its lubricating properties and can damage the engine.
Check the oil for any signs of contamination. If the oil is dark, gritty, or smells strongly of gasoline, it should be changed.
Changing the oil is a relatively simple maintenance task that can significantly extend the life of your lawn mower engine. Refer to your owner’s manual for the recommended oil change interval and the proper procedure for changing the oil.
Battery Issues (For Electric Start Mowers)
If you have an electric start lawn mower, a dead or weak battery can prevent it from starting. Batteries lose their charge over time, especially when left unattended for extended periods.
Checking and Charging the Battery
Check the battery voltage using a multimeter. A fully charged 12-volt battery should read around 12.6 volts. If the voltage is significantly lower, the battery may need to be charged.
Use a battery charger to charge the battery according to the manufacturer’s instructions. If the battery is old or damaged, it may not hold a charge and may need to be replaced. Proper battery maintenance is crucial for electric start mowers.
Battery Connections
Also check the battery connections for corrosion or looseness. Clean any corrosion from the terminals using a wire brush and ensure the connections are tight. Loose or corroded connections can prevent the battery from providing enough power to start the mower.
Safety Mechanisms: Bail Lever and Safety Switches
Lawn mowers are equipped with various safety mechanisms to prevent accidental starts. These mechanisms often involve safety switches that must be engaged for the mower to start.
Bail Lever
The bail lever is the lever on the handle that you must hold down to keep the engine running. If the bail lever is not fully engaged, the engine will not start or will stall immediately.
Ensure the bail lever is fully engaged and that the cable connecting it to the engine is properly adjusted. If the cable is loose or damaged, it may not be activating the safety switch correctly.
Safety Switches
Many lawn mowers have additional safety switches located under the seat, on the side of the mower, or in the handle. These switches prevent the mower from starting if certain conditions are not met, such as the blade being engaged or the operator not being present.
Check all safety switches to ensure they are functioning correctly. Make sure they are clean and not obstructed by debris. If a safety switch is faulty, it may need to be replaced.
The Importance of Professional Help
While many lawn mower starting problems can be resolved with a little DIY troubleshooting, there are times when it’s best to seek professional help. If you’ve tried all the basic troubleshooting steps and your mower still won’t start, it may be time to take it to a qualified lawn mower repair technician.
A professional technician has the expertise and tools to diagnose and repair more complex engine problems, such as valve issues, compression problems, or electrical system faults. Don’t hesitate to seek professional help if you’re unsure how to proceed or if you suspect a major engine problem.
In conclusion, diagnosing why your lawn mower won’t start after storage involves a systematic approach. Start with the basics – fresh fuel, a clean air filter, and a healthy spark plug. Then, move on to more complex issues such as carburetor problems, ignition coil faults, and safety switch malfunctions. With a little patience and perseverance, you can often get your lawn mower running smoothly again and enjoy a beautifully manicured lawn.
Why won’t my lawn mower start after being stored for the winter?
A common reason for a lawn mower not starting after storage is stale fuel. Gasoline can degrade over time, especially when left in a lawn mower’s fuel tank. This stale fuel can clog the carburetor and fuel lines, preventing the engine from receiving the necessary fuel to start. The process of degradation leads to the formation of gum and varnish deposits which hinder the proper function of the fuel system.
Another frequent issue is a dead or weak battery if your mower has an electric start. Batteries naturally lose charge over time, and the cold temperatures common during storage can accelerate this process. The lack of sufficient power to turn the engine over will obviously prevent the mower from starting. Furthermore, corrosion on the battery terminals can also inhibit a good electrical connection, exacerbating the problem.
How do I deal with stale fuel in my lawn mower?
The best approach is to drain the old fuel from the fuel tank completely. Then, inspect the fuel lines for any signs of clogging or deterioration and replace them if necessary. It is often beneficial to clean the carburetor, as this is the most likely place for fuel deposits to accumulate. This can be done with carburetor cleaner spray and, if you’re comfortable, disassembling it for a more thorough cleaning.
After cleaning or replacing the fuel system components, add fresh gasoline. Consider using a fuel stabilizer when you fill the tank, which helps prevent fuel degradation in the future. Fuel stabilizers work by preventing the formation of gum and varnish, extending the life of the fuel and ensuring easier starts after periods of storage.
What if the spark plug is the problem?
A faulty spark plug can certainly prevent your lawn mower from starting. Over time, spark plugs can become fouled with carbon deposits or oil, hindering their ability to produce a strong spark. This spark is essential for igniting the fuel-air mixture in the engine. Visual inspection can often reveal if the spark plug is the problem.
Remove the spark plug and check for signs of wear, damage, or excessive buildup. Clean the spark plug with a wire brush or replace it with a new one. Ensure the spark plug gap is set to the manufacturer’s specifications for optimal performance. A weak spark, or no spark at all, means it’s definitely time for a replacement.
How do I check the air filter?
A clogged air filter restricts airflow to the engine, leading to starting problems and poor performance. Debris such as grass clippings, dust, and leaves can accumulate in the air filter over time. This restriction starves the engine of the necessary air needed for proper combustion.
Inspect the air filter for dirt and debris. If it’s dirty, clean it by tapping it lightly against a hard surface to dislodge loose particles. If the filter is excessively dirty or damaged, replace it with a new one. A clean air filter ensures proper airflow, contributing to easier starting and improved engine efficiency.
What about the pull cord being hard to pull?
A pull cord that’s difficult to pull can indicate a problem with the engine’s compression or a seized engine component. This resistance can be caused by internal friction or an obstruction preventing the engine from turning freely. It could indicate a need for lubrication or even more serious mechanical issues.
Before attempting to force the pull cord, check for any obstructions around the blade. Remove any debris that may be preventing the blade from moving freely. If the issue persists, try spraying a small amount of lubricant into the cylinder through the spark plug hole. Let it sit for a while, and then try pulling the cord again. If the problem persists, it may need professional repair.
Is there a safety switch that could be the culprit?
Yes, many lawn mowers are equipped with safety switches designed to prevent accidental starts. These switches are typically located on the handle, under the seat (for riding mowers), or on the side discharge chute. They are designed to disable the ignition system if certain conditions aren’t met, such as the operator not being present or the bail lever not being engaged.
Make sure all safety switches are properly engaged. Check that the bail lever is fully depressed and that the mower is on a level surface. Also, inspect the switches for any signs of damage or corrosion. If a switch is faulty, it may need to be replaced to allow the mower to start.
Could the carburetor be completely blocked?
A completely blocked carburetor is a common cause of lawn mower starting problems, especially after storage. The carburetor’s jets and passages are very small and easily clogged by varnish and residue from old fuel. This blockage restricts the flow of fuel and air to the engine, preventing it from starting.
Disassembling and thoroughly cleaning the carburetor is often the best solution for a complete blockage. Use carburetor cleaner spray and small brushes or wires to clear any obstructions. If the carburetor is severely damaged or corroded, replacing it might be the most effective option. It is imperative to follow the manufacturer’s instructions or seek professional help to ensure correct reassembly and adjustment.