Maximize Your Mower: The Ultimate Guide To Petrol Lawn Mower Maintenance

Petrol Lawn mower maintenance

Maintaining a petrol lawn mower is crucial to keeping it running smoothly and ensuring it lasts for a long time. Regular maintenance can also save you money in the long run by preventing costly repairs. Here are some tips to help you maintain your petrol lawn mower.

If you are looking for a new petrol lawn mower, check out our recommendations for the best petrol lawn mower If you can’t decide between a petrol lawn mower, or an electric one, check out our guide

Read the owner’s manual and familiarise yourself with your lawn mower

Maintaining and caring for a petrol lawn mower requires a thorough understanding of its operation and inner workings. A crucial yet often overlooked step is reading the owner’s manual and warranty information. Despite its importance, many people skip this simple task, even though it provides essential guidance on proper maintenance, operation, and troubleshooting.

The owner’s manual provides step-by-step instructions on how to operate your petrol lawn mower, including starting and stopping the engine, adjusting the cutting height, and engaging the blades. Furthermore, it contains valuable information on maintaining your mower, such as the frequency of oil and air filter changes and how to sharpen the blades. Familiarizing yourself with this information, though it may seem tedious, is necessary to ensure the longevity and efficiency of your mower.

Another crucial aspect covered in the manual is the type of fuel to use in your petrol lawn mower. With the introduction of E10 petrol, it is vital to determine whether your mower can handle this new fuel type. If your mower is older or the manual is unavailable, it is best to assume that you should use E5 or “super” grade petrol to avoid damaging the engine.

The warranty information included with your mower outlines the terms and conditions for keeping the warranty valid. Some manufacturers require annual servicing by a professional company, while others allow competent owners to maintain their mowers themselves. Neglecting the maintenance guidelines in your manual may affect your warranty coverage, so it is essential to read through it thoroughly before undertaking any servicing or tinkering.

Before resorting to online resources or attempting a one-size-fits-all approach to maintenance, consult the manufacturer’s manual. Each lawn mower has unique care requirements and making assumptions can result in more harm than good. By taking the time to read and study the owner’s manual and warranty information, you can operate your petrol lawn mower safely, correctly, and in accordance with the manufacturer’s recommendations. This diligence will not only prolong the life of your mower but also prevent unnecessary repairs and the potential voiding of warranty coverage.

Store your fuel in proper containers and discard old fuel

Proper storage of fuel for your lawn mower is crucial for maintaining its effectiveness and lifespan. To ensure optimal fuel quality, always keep it in a sealed container, stored in a cool and dry place. Plastic containers are the preferred choice, as metal cans or tins tend to rust over time, decreasing fuel effectiveness and reducing its lifespan.

If you want to extend the life of new fuel, consider adding a fuel conditioner. This additive can prolong the fuel’s usability by up to two or three years. However, keep in mind that it is not possible to extend the life of old fuel, and attempting to do so would be a futile endeavour, wasting both time and money. By storing your fuel correctly and using additives when necessary, you will ensure the longevity and performance of your lawn mower.

Use the right fuel

Utilizing the appropriate fuel in your petrol lawn mower is crucial to guarantee its smooth and efficient operation. Following the manufacturer’s recommendations for the correct fuel type ensures optimal performance and helps prevent serious damage to the engine, which could lead to expensive repairs or the need for a replacement mower.

Most petrol lawn mowers require unleaded petrol with an octane rating of 87 or higher, as using petrol with a lower octane rating can cause the engine to knock or ping, potentially resulting in long-term damage. It is essential to note that some petrol lawn mowers may also require specific fuel types, such as E5 or “super” grade petrol. Always consult your owner’s manual or contact the manufacturer to determine the right fuel for your mower. Find out what the new E10 petrol means for your lawn mower.

In addition to selecting the proper fuel type, using clean, fresh fuel is equally important. Stale or contaminated fuel can lead to poor engine performance and reduced fuel efficiency. If you have doubts about your petrol’s quality, consider adding a fuel stabilizer to preserve its freshness and prevent degradation.

By consistently using the right fuel in your petrol lawn mower, as recommended by the manufacturer, you can ensure peak performance and avoid costly repairs in the future. Remember to check your owner’s manual and adhere to the guidelines for fuel type, and always use fresh petrol to maintain your mower’s optimal functionality and longevity.

Check the fuel and top up with fresh petrol

Proper fuel management is essential for maintaining your petrol lawn mower’s optimal performance and longevity. Each time you plan to use your mower, it’s crucial to check the fuel levels and ensure it has sufficient fuel for the task. If the mower needs a top-up, always use fresh fuel to avoid any issues with stale fuel that may have been stored for an extended period.

Fuel stored for longer than three months can become stale, losing some of its effectiveness. While it may still work, it won’t deliver optimal performance for your mower or your lawn. Stale fuel can lead to suboptimal cutting results and put unnecessary strain on your mower’s engine.

By handling fuel management correctly, such as using fresh fuel and keeping an eye on fuel levels, you can significantly extend the life of your petrol lawn mower. This proactive approach will help ensure that your mower continues to operate efficiently and effectively, providing you with a well-maintained lawn for years to come.

Regularly check the oil and change it as necessary

Regularly checking and maintaining the oil level in your petrol lawn mower is a crucial step in ensuring smooth and efficient operation. Before each use, check the oil level using the mower’s dipstick, and add more oil if necessary. This helps prevent the engine from overheating and ensures proper lubrication. It is essential to check the oil level regularly and change the oil every 50 hours of use or at least once a year. Over time, oil can become contaminated with dirt and debris, reducing its effectiveness in protecting the engine. Running your mower with low or dirty oil can cause serious damage, leading to costly repairs or the need for a new mower.

To check the oil level, pull out the dipstick, wipe it with a clean cloth, and reinsert it. Then, pull it out again and ensure that the oil residue is within the minimum and maximum marks. If the oil level is insufficient, refill it to the required amount. The oil level should be checked at the start of the season and at regular intervals throughout the year. This helps to keep all moving parts in the engine well lubricated and prevents overheating.

Different oil change intervals are recommended depending on the mower’s usage and age. Refer to your mower’s instruction manual for specific information about what oil the engine needs and the intervals at which it must be changed.

Changing the oil in your petrol lawn mower is a relatively simple process. Locate the oil drain plug and remove it to drain the old oil into a container. If your mower doesn’t have a drain plug, carefully tilt the machine to one side and drain the used oil via the fill hole or use a siphoning syringe. Be sure to responsibly dispose of the old oil according to local regulations.

Once the old oil has been removed, replace it with quality oil according to the manufacturer’s recommendations. Use a funnel to accurately pour the new oil in, and check the oil level with the dipstick. Regular oil changes will help prolong the life of your petrol lawn mower and ensure optimal performance. By checking the oil level frequently and changing it as needed, you can keep your mower running smoothly for years to come.

Check, clean and/or replace the air filter

Maintaining a clean and functional air filter is crucial for the optimal performance of your petrol lawn mower. The air filter is responsible for preventing dust, debris, and other particles from entering the engine and carburettor, ensuring the smooth operation of your mower. Neglecting this vital component can lead to reduced fuel efficiency, increased maintenance costs, and even engine damage.

To keep your petrol lawn mower running efficiently, it is essential to clean or replace the air filter at least once a season or after every 25 hours of use. This regular maintenance ensures that the engine receives the proper airflow it needs to function effectively. In fact, a dirty air filter can decrease your lawn mower’s efficiency by up to 25 percent, which translates to increased time, money, and effort spent on maintenance and fuel costs.

Cleaning or replacing your lawn mower’s air filter is a simple process that you can perform yourself. If your mower has a foam air filter, it can be removed and washed in warm, soapy water. Once dry, reinsert it into the mower. If your mower has a paper air filter, simply replace it with a new one. Some manufacturers require specific air filter models, so be sure to consult your mower’s user manual for the appropriate replacement type.

In addition to replacing the air filter, cleaning the housing that holds the filter is important. This ensures that no residual debris or dust will come into contact with the engine, further protecting its performance. When removing the air filter, clean the housing thoroughly before installing the new or cleaned filter.

Air filters are relatively inexpensive and easy to obtain from your local hardware store or garden centre. By investing in this simple maintenance task, you can prolong the life of your mower and ensure optimal performance throughout its lifespan.

Check and sharpen the blades as necessary

Maintaining sharp blades on your petrol lawn mower is a critical aspect of proper maintenance that should never be overlooked. Dull blades can not only reduce fuel efficiency and cause potential damage to the engine but also negatively impact the health and appearance of your lawn. A sharp blade will cleanly slice through the grass, while a dull one will tear and hack at it, leaving an uneven, ragged cut that makes your lawn more susceptible to diseases and pests.

Sharpening your mower blades at least once a year is recommended to ensure optimal performance. However, if you mow your lawn frequently or encounter rough terrain, you may need to sharpen the blades more often. A useful guideline is to check the blades before each mowing session to guarantee they are sharp and free from damage.

There are several methods to sharpen your petrol lawn mower blades, including using a sharpening stone, a file, or a bench grinder. Regardless of your chosen technique, always follow the manufacturer’s instructions to avoid any damage to the blades or the mower itself. If you are unsure about sharpening the blades, consider taking your mower to a professional for sharpening.

Removing the mower blades is typically a straightforward process. Most petrol mowers have a central bolt that can be undone to remove the blade safely. Remember to wear heavy-duty gloves when handling the blade to protect yourself from potential injuries.

In some cases, your blades may be beyond sharpening and require replacement. If they are severely damaged or have been in use for an extended period, it is best to install new ones. Always refer to the manufacturer’s guide when purchasing replacement blades to ensure you select the appropriate model for your mower.

Check and clean or replace the spark plug

The spark plug in your petrol lawn mower plays a crucial role in igniting the fuel in the engine, allowing it to start and run smoothly. Over time, the spark plug can become dirty or worn, causing the engine to misfire or fail to start altogether. A clean spark plug ensures quick starting, smooth running and prevents stalling and overheating. Ideally, it should be replaced annually to maintain optimal performance.

To ensure your petrol lawn mower is running at its best, check the spark plug at least once a year, ideally when performing other maintenance tasks such as changing the oil or air filter. To do this, first, disconnect the spark plug wire and then unscrew the spark plug from the engine. Inspect the tip of the spark plug for any signs of wear or damage, such as cracks or blackened deposits. Slight discolourations of the electrodes can be removed with a simple wire brush. However, if the spark plug is black or even completely oily, there is a defect in the system that must be repaired urgently.

If the spark plug is dirty or worn, it’s time to replace it with a new one. When purchasing a new spark plug, always ensure that the type designation is correct, which can be found on the ceramic body. Replacing the spark plug is a simple process that you can do yourself. Simply screw the new spark plug into the engine and reattach the spark plug wire. Tighten the spark plug securely but not too tightly, as this can damage the engine. Adding some oil around the thread of the plug will make for easy removal next time.

By regularly checking and replacing the spark plug as needed, you can ensure that your petrol lawn mower starts and runs smoothly every time. This simple maintenance task can save you time and hassle in the long run, and help prolong the life of your mower. Remember, before undergoing any maintenance yourself, always disconnect the spark plugs to remove the risk of the mower accidentally starting, ensuring you can work on it safely.

Check the starter rope/cord

One aspect of lawn mower maintenance that requires attention is the starter rope, as it is subjected to significant wear and tear over time. The repeated tugging of the starter cord can cause it to become brittle, fray, or even break off completely. If you notice that the rope is no longer in good condition, it is essential to replace it immediately, as repairing it is usually not possible.

Thankfully, replacing the starter rope is neither a difficult nor time-consuming task. To do so, you’ll need to remove the housing and then replace the old cord inside the pulley system with a new one. While installing the new cord, be careful not to turn the pulley. Once the new cord is in place, wrap it around the pulley a couple of times without spinning the pulley. After completing these steps, test the new starter rope to evaluate its performance.

Regularly inspect your lawn mower

Regularly inspecting your petrol lawn mower is a crucial aspect of maintenance that ensures safe and efficient operation. By taking the time to inspect your mower, you can identify potential problems before they become serious, saving you time, money, and hassle in the long run.

Before each use, take a few seconds to give your lawn mower a quick once-over. Check for loose or damaged parts, such as bolts, screws, worn or damaged belts, or broken and cracked components. Make sure all of the bolts and screws are tight and in place, as they can become loose over time due to the mower’s vibrations. If you find any loose parts, tighten them before your next mowing session. If any parts are missing, replace them before cutting your lawn again to prevent further damage or potential safety hazards.

Servicing your mower at the start of a new gardening season is an excellent opportunity to ensure all nuts, bolts, and other parts are secure. This is not only a safe practice but also helps prevent any significant performance issues. Pay particular attention to the mower’s wheels, as they bear the brunt of the work and may become loose over time. Make sure all wheels are fixed and tightened accordingly.

In addition to checking for loose or damaged parts, it’s essential to inspect the blades and undercarriage for any debris or buildup. Grass clippings and other debris can get stuck in the blades or undercarriage, reducing the mower’s performance and potentially causing it to overheat. Remove any debris or buildup before using the mower to ensure optimal efficiency.

By inspecting your petrol lawn mower and addressing any issues before they escalate, you can maintain your mower’s performance and safeguard your health and safety while mowing.

Clean under the mower deck

Grass build-up and debris accumulation in the undercarriage of your lawn mower is inevitable and can affect its normal operation. If left unattended, grass clippings can clog the discharge chute, while shrubbery and other garden debris can impede the blades and decking. To maintain optimal performance, it is essential to clean the undercarriage regularly and remove debris lodged within the mower.

Scrape grass clippings and soil from the undercarriage using a wire brush, and employ a garden hose to spray away any stubborn residue. Some mowers even feature an attachment where you can connect a hose to rinse the underside of the mower deck. This cleaning process should be part of your regular mower maintenance, as it helps prevent rust on steel parts and keeps the mower functioning smoothly.

The best time to remove debris is immediately after mowing, as the grass will still be moist and easier to remove. Allowing grass and debris to harden only makes it more difficult to dislodge. Be aware that unremoved debris can clog your mower, potentially preventing it from starting, and may also cause it to overheat by blocking airflow.

When cleaning the undercarriage, ensure the air filter is facing upwards to prevent dirt and oil from entering it. Additionally, always disconnect the spark plug before cleaning, as there is a risk of accidentally starting the engine and activating the spinning blade, which poses a significant danger. Simply unclick the coil from the spark plug, and it will pull off easily.

It is crucial to consult the manufacturer’s manual before tipping your mower on its side, as doing so could damage the mower due to fuel or oil leakage into the engine. By diligently cleaning your lawn mower’s undercarriage and removing debris, you will prolong its life and maintain optimal performance.

Drain the fuel

Preparing your petrol lawn mower for winter or extended storage involves several crucial steps, one of which is draining the fuel tank to avert any engine damage. Stale fuel can impede engine performance and harm the carburettor, potentially leading to expensive repairs or even necessitating a new mower.

To drain the fuel tank, run the engine until it consumes all the fuel, ensuring that no residual fuel remains in the tank or carburettor to cause damage. Alternatively, employing a siphon or pump can effectively remove the fuel from the tank. Proper disposal of the drained fuel is essential. Running the engine for a few minutes after draining the fuel ensures that any leftover fuel in the carburettor is burned off, preventing the residual fuel from causing engine damage.

Lawnmower experts emphasize the role of old petrol in causing startup issues and recommend draining any remaining petrol at the end of each mowing season. Some experts even advocate draining the petrol tank after every use or every second cut, highlighting the importance of regularly draining the tank and using fresh fuel to maintain optimal mower performance. Old fuel is the leading cause of misfires and startup problems.

As old fuel loses its ignitability and can clump together in winter, it is crucial to empty the lawn mower’s fuel tank before the season and refill it with fresh fuel in spring. If you neglected to empty the tank over winter, it is safer to do so now and replenish it with fresh fuel. Remember that petrol has a lifespan of around 30 days, after which it risks going stale and causing long-term engine damage. Draining your petrol is a vital practice to protect your engine and extend your mower’s life.

In addition to draining the fuel tank, cleaning the carburettor and fuel lines is also recommended for extended storage, as it helps remove any debris or residue that could cause problems when restarting the mower.

Check and clean the carburettor and primer

As part of your lawn mower maintenance, it is essential to examine the carburettor, particularly if you have not already cleaned it during the winter. Inspect whether cleaning is necessary, and pay attention to the primer, which is often located nearby on many models. The primer serves as a manually operated fuel pump, filling the carburettor with fresh fuel in just a few strokes. This feature proves especially useful if the carburettor has been run empty or has emptied over the winter. Be sure to also verify the functionality of the primer by performing a few pump strokes.

Properly store your lawn mower when not in use

Proper storage of your petrol lawn mower plays a significant role in its maintenance, ensuring it remains in good condition and prolonging its lifespan for years to come. After you have finished using your mower, it is crucial to store it in a dry, sheltered location, protecting it from the elements and potential damage.

The ideal storage solution for your lawn mower is a garage or shed, where it is safeguarded from rain, wind, and other weather conditions that can negatively impact its performance and longevity. If you do not have access to a garage or shed, an alternative option is to use a lawn mower cover. This protective cover will shield your mower from dust, debris, and other environmental factors, ensuring that it remains in optimal condition for your future lawn care needs.


How often should I change the oil in my petrol lawn mower?

You should change the oil every 50 hours of use or at least once a year.

Can I use regular unleaded petrol in my lawn mower?

Yes, most petrol lawn mowers require unleaded petrol with an octane rating of 87 or higher.

How often should I sharpen the blades on my lawn mower?

You should sharpen the blades at least once a year or more often if you mow frequently or over rough terrain.

How do I know if the spark plug needs to be replaced?

A dirty or worn spark plug can cause the engine to misfire or fail to start. Check the spark plug at least once a year and replace it if necessary.

How do I store my lawn mower properly?

To store your lawn mower properly, you should make sure it is stored in a dry, sheltered place. This can be a garage or shed, but if you don’t have access to one, consider using a lawn mower cover. It’s also a good idea to remove any excess grass or debris from the mower before storing it. This will prevent moisture from building up and causing rust or corrosion.


Jonathan Gaze

Content Editor

Hello there! I’m Jonathan Gaze, Content Editor for Harry Rufus.

With my technical problem-solving skills and meticulous attention to detail, I present sustainable living advice clearly and understandably. I’ve developed a knack for filtering out the fluff, presenting you with only the most practical and reliable sustainable living guidelines.

Here’s what you can anticipate from my content:

  • Clear, reliable advice on sustainable living.
  • Informative articles that simplify complex concepts.
  • Trustworthy recommendations for eco-friendly practices.

I’m committed to making your transition to an eco-conscious lifestyle a breeze, turning challenges into opportunities.

Similar Posts