A frustrating experience for any homeowner is pulling the cord on their lawn mower, only to be met with silence. While various factors can contribute to a non-starting lawn mower, one of the most common culprits is bad gas. But what exactly constitutes “bad gas,” and can it truly prevent your mower from roaring to life? Let’s delve into the intricacies of fuel, its degradation, and how it impacts your lawn mower’s performance.
What Exactly is “Bad Gas?”
“Bad gas” isn’t simply old gasoline; it’s gasoline that has undergone chemical changes, losing its optimal properties for combustion. Fresh gasoline is a complex mixture of hydrocarbons, carefully blended to provide the right balance of volatility and energy. Over time, and especially when exposed to air and moisture, this mixture can break down, leading to several problems.
Gasoline degradation is a natural process. Oxygen and moisture in the air react with the gasoline, causing it to oxidize. This oxidation leads to the formation of gum, varnish, and other deposits. These substances can clog fuel lines, carburetors, and other critical engine components.
Another critical aspect of “bad gas” is the presence of water. Gasoline is hygroscopic, meaning it attracts and absorbs moisture from the air. Water in gasoline can lead to corrosion of fuel system components and can also interfere with the combustion process. Ethanol, a common additive in gasoline, exacerbates this problem as it attracts even more water.
Fuel separation, or phase separation, is also a significant issue, particularly in gasoline containing ethanol. When gasoline absorbs too much water, the ethanol separates from the gasoline and settles to the bottom of the fuel tank. This leaves a layer of water and ethanol at the bottom, while the gasoline above has a lower octane rating. Your lawn mower won’t run well, if at all, on this diluted fuel.
How Does Bad Gas Affect Your Lawn Mower?
The effects of bad gas on a lawn mower can range from minor performance issues to complete engine failure. Understanding these effects can help you diagnose the problem and take appropriate action.
One of the most common symptoms of bad gas is a difficulty starting the lawn mower. The degraded fuel may not vaporize properly, making it difficult for the engine to ignite. You might find yourself pulling the starter cord repeatedly without any success.
If the lawn mower does start, it may run poorly. Common symptoms include rough idling, stalling, and a lack of power. The engine might sputter and cough, and it may not be able to maintain a consistent speed.
Gum and varnish deposits from bad gas can clog fuel lines and carburetors. This restricts the flow of fuel to the engine, causing it to run lean. A lean-running engine can overheat and suffer damage.
Water in the fuel can lead to corrosion of fuel system components, such as the fuel tank, fuel lines, and carburetor. Corrosion can cause leaks and further restrict fuel flow.
In severe cases, bad gas can cause complete engine failure. If the engine is run for an extended period with bad gas, the resulting damage can be irreparable.
Why Does Gasoline Go Bad? Factors Contributing to Fuel Degradation
Several factors contribute to the degradation of gasoline. Understanding these factors can help you prevent fuel problems in your lawn mower.
Time is a primary factor. Gasoline naturally degrades over time, even when stored properly. The rate of degradation depends on several factors, including temperature, humidity, and the presence of oxygen and moisture.
Temperature fluctuations can accelerate the degradation process. When gasoline is exposed to fluctuating temperatures, it expands and contracts, drawing in air and moisture. This accelerates oxidation and water absorption.
Exposure to air and moisture is detrimental to gasoline. Air contains oxygen, which promotes oxidation, while moisture leads to water absorption and phase separation.
Ethanol content in gasoline is also a factor. Ethanol attracts water, which can lead to phase separation and corrosion. Gasoline with higher ethanol content is more susceptible to degradation.
Storage conditions play a crucial role. Gasoline stored in a sealed container in a cool, dry place will last much longer than gasoline stored in an open container in a hot, humid environment.
Preventing Bad Gas: Tips for Proper Fuel Storage and Maintenance
Preventing bad gas is essential for maintaining the performance and longevity of your lawn mower. By following these tips, you can minimize fuel degradation and avoid costly repairs.
Use a fuel stabilizer. Fuel stabilizers are additives that help prevent gasoline from degrading. They work by inhibiting oxidation, preventing gum and varnish formation, and protecting against corrosion. Add fuel stabilizer to your gasoline whenever you store it for more than a month.
Store gasoline in a sealed container. A sealed container will prevent air and moisture from entering the gasoline, slowing down the degradation process. Use an approved gasoline storage container that is designed to prevent leaks and spills.
Store gasoline in a cool, dry place. High temperatures and humidity can accelerate gasoline degradation. Store your gasoline in a cool, dry place, away from direct sunlight.
Avoid storing gasoline for extended periods. Gasoline degrades over time, even when stored properly. Avoid storing gasoline for more than six months. If you have gasoline that is older than six months, it is best to dispose of it properly.
Use fresh gasoline. When fueling your lawn mower, always use fresh gasoline. Avoid using gasoline that has been sitting in a container for an extended period.
Drain the fuel tank before storing your lawn mower. If you are storing your lawn mower for the winter, drain the fuel tank completely. This will prevent gasoline from degrading and causing problems when you start the mower in the spring.
Run your lawn mower periodically. If you are not using your lawn mower regularly, run it for a few minutes every month or two. This will help keep the fuel system clean and prevent gasoline from degrading.
Consider using ethanol-free gasoline. If available, consider using ethanol-free gasoline in your lawn mower. Ethanol-free gasoline is less susceptible to degradation and will not attract water.
Diagnosing Fuel Problems in Your Lawn Mower
If your lawn mower is not starting or running properly, fuel problems may be the cause. Here are some steps you can take to diagnose fuel problems:
Check the fuel. The first step is to check the fuel in the tank. Smell the fuel. Bad gas often has a sour or varnish-like odor. Look at the fuel. If it is cloudy or discolored, it may be contaminated with water or other impurities.
Check the fuel filter. The fuel filter is designed to remove contaminants from the fuel. If the fuel filter is clogged, it can restrict fuel flow to the engine. Remove the fuel filter and inspect it for debris. If it is clogged, replace it.
Check the fuel lines. Fuel lines can become clogged with gum and varnish deposits from bad gas. Disconnect the fuel lines and inspect them for blockages. If they are clogged, clean or replace them.
Check the carburetor. The carburetor is responsible for mixing fuel and air in the correct proportions. If the carburetor is clogged with gum and varnish deposits, it can cause the engine to run poorly. Clean the carburetor using a carburetor cleaner. If the carburetor is severely clogged, it may need to be rebuilt or replaced.
Troubleshooting a Lawn Mower with Bad Gas
If you suspect that your lawn mower has bad gas, here are some steps you can take to troubleshoot the problem:
Drain the fuel tank. The first step is to drain the fuel tank completely. Dispose of the old gasoline properly. Do not pour it down the drain or into the environment.
Clean the fuel system. After draining the fuel tank, clean the fuel system. This includes the fuel tank, fuel lines, fuel filter, and carburetor. Use a carburetor cleaner to remove gum and varnish deposits.
Replace the fuel filter. Replace the fuel filter with a new one. This will ensure that clean fuel flows to the engine.
Refill the fuel tank with fresh gasoline. Refill the fuel tank with fresh gasoline and add a fuel stabilizer.
Try to start the lawn mower. After completing these steps, try to start the lawn mower. If it starts and runs properly, you have successfully resolved the fuel problem.
If the lawn mower still does not start or run properly, there may be other underlying problems. Consult a qualified mechanic for further assistance.
Other Potential Causes of Starting Problems in Lawn Mowers
While bad gas is a common culprit, other issues can prevent your lawn mower from starting. It’s important to consider these possibilities when troubleshooting.
A faulty spark plug can prevent the engine from igniting the fuel-air mixture. Check the spark plug for damage or fouling. If necessary, clean or replace it.
A clogged air filter can restrict airflow to the engine, making it difficult to start. Clean or replace the air filter regularly.
A dead battery (in electric start mowers) will prevent the starter motor from turning the engine over. Check the battery voltage and charge it if necessary.
A loose or disconnected wire can interrupt the flow of electricity to the engine. Check all wiring connections for looseness or damage.
Low oil levels can trigger a safety shutoff mechanism, preventing the engine from starting. Check the oil level and add oil if necessary.
A faulty safety switch (such as the blade engagement switch or the operator presence switch) can prevent the engine from starting. Check the safety switches to ensure they are functioning properly.
Conclusion
Bad gas is a common problem that can prevent your lawn mower from starting or running properly. By understanding the causes of fuel degradation and following proper storage and maintenance practices, you can minimize fuel problems and keep your lawn mower running smoothly. If you suspect that your lawn mower has bad gas, follow the troubleshooting steps outlined in this article. Remember, regular maintenance and preventative measures are key to avoiding fuel-related issues and ensuring your lawn mower is ready to tackle your lawn care needs.
Question: What exactly is “bad gas” and how does it form in lawn mower fuel?
“Bad gas” in lawn mower contexts usually refers to gasoline that has deteriorated or become contaminated. The primary culprit is ethanol, an alcohol added to gasoline. Ethanol attracts water from the atmosphere, and this water can then separate from the gasoline, forming a layer at the bottom of the fuel tank. This process, known as phase separation, leaves the gasoline with a lower octane rating and diminished ability to burn efficiently.
Additionally, gasoline left sitting for extended periods (especially over the winter) can oxidize and degrade. This degradation leads to the formation of gums and varnishes that can clog fuel lines, carburetors, and other engine components. The resulting fuel is no longer the high-octane, combustible liquid your lawn mower engine requires. Improper storage and the type of fuel used are significant factors in the formation of “bad gas”.
Question: How can bad gas negatively affect my lawn mower’s performance?
Bad gas can cause a variety of problems in a lawn mower, ranging from minor inconveniences to serious engine damage. Initially, you might experience difficulty starting the mower, rough idling, or a lack of power during operation. The engine might sputter or stall, especially when under load, such as when cutting thick grass. These symptoms indicate that the fuel is not combusting properly due to its degraded state.
More severe consequences include clogged fuel lines and carburetors due to the gums and varnishes formed by old gasoline. These blockages restrict fuel flow, preventing the engine from receiving the necessary fuel for combustion. In extreme cases, bad gas can even lead to engine damage, requiring costly repairs or even engine replacement. The water absorbed by ethanol can also cause corrosion within the fuel system.
Question: What are the common signs that my lawn mower is suffering from bad gas?
Several telltale signs can indicate that your lawn mower’s fuel has gone bad. Difficulty starting is a frequent symptom. You might find yourself pulling the starter cord repeatedly without the engine turning over, or it might start only briefly before stalling. Rough idling, where the engine runs unevenly or sputters when at rest, is another common indicator.
Furthermore, a noticeable decrease in power, particularly when cutting through thick grass, suggests a fuel issue. The engine might struggle and bog down, or it might stall completely under load. Visible deposits in the fuel tank or a strong, unusual odor emanating from the fuel can also point to degraded or contaminated gasoline. These signs should prompt you to inspect and potentially replace the fuel.
Question: What kind of fuel should I use in my lawn mower to prevent fuel-related problems?
Using fresh, high-quality gasoline is crucial for preventing fuel-related issues in your lawn mower. Opt for gasoline with an octane rating recommended in your mower’s owner’s manual. Generally, a minimum octane rating of 87 is sufficient for most lawn mowers. Always purchase gasoline from a reputable gas station to ensure its quality and freshness.
Consider using ethanol-free gasoline, particularly if your lawn mower is stored for extended periods. Ethanol-free fuel is less prone to water absorption and phase separation, reducing the risk of fuel degradation. If ethanol-free gas is unavailable, use a fuel stabilizer specifically designed for small engines. These stabilizers help prevent fuel oxidation and maintain its quality during storage. Regular use of fuel stabilizer is highly recommended, especially during the off-season.
Question: How can I properly store my lawn mower’s fuel to prevent it from going bad?
Proper fuel storage is essential for preventing gasoline from degrading. Always store gasoline in an approved, airtight container specifically designed for fuel storage. These containers are typically red and clearly labeled. Avoid using containers that have previously held other liquids, as contamination can occur.
Store the fuel container in a cool, dry, and well-ventilated area, away from direct sunlight and heat sources. A garage or shed is often a suitable location. Avoid storing gasoline in damp or humid environments, as this can accelerate fuel degradation. If possible, store the fuel in a location with a stable temperature to minimize condensation. Always add fuel stabilizer when storing fuel for more than a few weeks to further extend its lifespan.
Question: What steps should I take if I suspect my lawn mower has bad gas in the tank?
If you suspect your lawn mower has bad gas, the first step is to drain the fuel tank completely. Safely dispose of the old fuel at a hazardous waste collection facility or recycling center. Do not pour it down the drain or onto the ground. Once the tank is empty, inspect it for any signs of sediment or contamination.
Next, clean the fuel tank and fuel lines to remove any remaining residue. Consider removing and cleaning the carburetor as well, as it is often a primary target for gum and varnish buildup. After cleaning, refill the tank with fresh, high-quality gasoline, preferably with a fuel stabilizer added. Try starting the mower again. If the problem persists, further maintenance or repairs may be necessary.
Question: Can adding fuel stabilizer to old gas make it usable again?
While fuel stabilizer is excellent for preventing gasoline from deteriorating, it generally cannot restore gasoline that has already significantly degraded. Fuel stabilizer primarily works by slowing down the oxidation process and preventing the formation of gums and varnishes. It’s best to add the stabilizer to fresh fuel, before the degradation process begins.
In some cases, adding a double dose of fuel stabilizer to slightly stale fuel *might* improve its combustibility, but this is not guaranteed, and it’s often more effective to simply replace the old fuel with fresh gasoline. Severely degraded fuel, especially if it contains water due to phase separation, should always be discarded. Attempting to use excessively old or contaminated fuel, even with stabilizer, can lead to engine damage and is not worth the risk.