5 FAQ's on Petrol Mowers
06 August 2024
How to start a petrol lawn mower?
Starting your petrol mower can be difficult, especially for beginners or for the first cut after winter when the mower is cold and has been stored for a long time. To maximise your chances of starting your petrol lawn mower with a starting rope first time, follow these simple instructions:
1) Place the lawn mower on a flat surface
A flat surface will help the distribution of oil and fuel within your mower. Ensure there are no things in the immediate vicinity or cutting area that could damage the mower, for example stones or large twigs.
2) Complete the pre-mowing checklist
As detailed below, there are a range of checks such as checking the oil, fuel and blades to do before starting the mower. These are designed to ensure your safety as well as maximising the efficiency of the mower.
3) Press the fuel button a few times
Especially important for new mowers or mowers that have been unused for a lengthy period of time. Pressing the fuel button will pump petrol into the engine ready for the mower to be started. It is important not to press the button too many times, as this could flood the engine with too much petrol. To locate the fuel button on your petrol mower, consult the manual.
4) Put the mower’s throttle into the start position, if applicable
Some petrol lawn mowers come with a throttle that will need to be put into place before starting. Check the manual to see if your mower has a starting throttle. If it does, it will be a handle that is normally halfway between the handle and the handle.
5) Engage the engine brake lever
To ensure the mower doesn’t shoot off when you start it, pull the engine brake lever towards you. It is often located at the top of the handle.
6) Pull the starter rope
Once you have a firm grip on the engine brake, pull firmly on the starter rope. Then, guide the rope back to the starting position. Do not let go of the starter rope or let it slip back to its position, as this is not good for the engine. You might be required to pull the starter rope a few times before the engine kicks in and starts.
For certain new petrol lawn mowers, the starting rope has been replaced with a start button.
Check out our range of petrol lawn mowers
What to check on your petrol mower before starting?
Once you have assembled your mower and read the manual, starting the mower will likely be your next concern. However, there are a few important steps to take before you attempt to start your petrol lawn mower. These are:
1) Check the oil
To maximise the working life of your mower, it is recommended to check the oil in your mower every time you use it. The oil will lubricate the moving parts of the engine, helping to reduce wear from the friction, which helps to improve the longevity of the parts and reduce maintenance costs.
To check the oil, put the mower on a flat surface and take out the oil dipstick. The manual will point out where to find this oil dipstick. Now, clean off the dipstick on a dry cloth, and re-insert the dipstick back into the oil. This time, take it out again and check the oil level indicated on the dipstick. There will be a mark on the dipstick indicating the recommended oil level. It is recommended to do this process 3 times to ensure the results are consistent.
When topping up the oil, make sure to check the manual so that you use the correct oil. Mowers will use specific types of oil with different lubricating qualities, so you shouldn’t just use any old oil you find lying about the shed.
2) Inspect the air filter
The air filter on your mower serves the purpose of ensuring no damaging small particles can enter the engine. However, a clogged up air filter will reduce the air intake to the carburettor, starving it off oxygen. This will have the effect of causing a poor start, risking damage to the engine and worsening the fuel consumption.
The air filter will be located either next to the carburettor, or on top of the mower. Again, check the manual to find the exact location on your particular petrol mower.
Depending on which type of air filter your mower has will determine how you proceed should the air filter be blocked with dust, grass or particles.
For foam air filters, these can be cleaned and put back in the mower. However, paper air filters will need to be replaced once they have been filled with dirt, grass, dust and other particles.
3) Check and replace the fuel
Stale fuel is a leading cause of a petrol lawn mower that won’t start. If the petrol in your mower is more than 10 weeks old, you should drain this old petrol and replace it with fresh fuel to improve the starting process and overall mower performance. Petrol is an organic substance and breaks down naturally of its own accord over time.
To save money and to ensure you minimise wasted fuel, only buy as much petrol as you will use within the coming weeks. Even petrol that has been sat in jerry cans will not be suitable for replacing old fuel if this petrol itself has been sat in the jerry can for a prolonged period of time.
4) Ensure the cutting blade is functioning and sharp
Before attempting any work with the cutting blade on a petrol mower, ensure the mower is fully turned off and has the spark plug cap removed to ensure the mower does not unexpectedly start. It is also important to turn the mower over according to the specific guidelines in the manual, to minimise the risk of flooding the air filter or exhaust system with oil.
Blunt blades cause a poor quality cut, increase consumption of petrol and can cause unnecessary wear and tear on the engine, so it is important to check the blades are functioning correctly and are as sharp as intended. The blade can be quickly damaged by loose shingle garden debris such as small rocks and stones, so it is important to clear these from the cutting area.
If your blades are too dull, we recommend getting these sharpenned and balanced to help to improve the overall cut performance. This is a service our repair team can provide - simply contact us if you are interested.
How to drain oil from your petrol lawn mower?
Draining the oil from your petrol mower is one of the most important maintenance tasks you can undertake to maximise the performance, longevity and safety of your lawn mower. When done correctly, draining the oil will ensure the lubricating qualities of the oil are maximised. However, incorrectly draining the oil can accidentally flood the carburetor or exhaust system with oil; a costly and damaging mistake.
Follow these four steps to drain oil from your petrol lawn mower:
- Firstly, remove the spark plug from the mower to ensure the lawn mower does not accidentally start and the blades begin turning whilst you are carrying out the oil change. This is a vital safety tip.
- Clean the area around the oil tank, ensuring to remove any debris and dried up oil. The purpose of this is to ensure nothing falls into the oil tank whilst you are draining the oil. Debris in the oil tank can cause costly and damaging faults.
- Making sure to keep the air filter facing upwards, tilt the lawnmower on its side. The mower manual will likely include directions on how to tilt the mower whilst avoiding damage to any other component of the mower. Keeping the air filter pointing upwards will prevent this filter and the engine being damaged by oil or leaking petrol.
- Place a suitably sized container under the dipstick and oil filling hole. Then, remove the dipstick so that the oil drains out into the container below. Once all of the oil has been drained, put the lawnmower back into the upright position, clean away any excess oil and replace the dipstick.
The petrol lawn mower is now ready to be stored until it is next needed. If the oil draining has taken place at the end of the mowing season, do not add new oil until the next time the mower is used. If you have drained the oil during the cutting season, then refill the mower with fresh new oil.
Ensure you use the correct stated oil as set out in the manual, as your mower will require a specific type of oil. Using the wrong oil can cause the engine to seize up which we all want to avoid at all costs of course!
Other methods of draining the oil from your petrol mower...
On some four-stroke petrol mowers, it is possible to drain the oil by removing the sump plug under the engine. On all petrol mowers, it is possible to syphon the oil out of the oil filling tube, however this is a considerably lengthy process.
How often should the oil be drained on a petrol lawn mower?
Your mower’s manual will set out the exact timings and usage periods of when the oil needs to be drained from your petrol mower. If in doubt, contact your mower repair centre or lawn mower shop.
A general rule of thumb for petrol lawn mower oil drainage is:
- After the first five hours of using a new petrol lawn mower. This is due to the risk of small bits of metal making their way into the oil tank from other parts after the initial build.
- After every 25 hours of usage if the lawn mower has been used in high temperatures or under a heavy load.
- If used in usual circumstances, draining the oil every 50 hours will be sufficient.
- At the end of the cutting season, so that oil is not left in the mower whilst stored. Stale oil can leading to difficulties starting the mower.
What fuel should I use in my lawn mower?
For petrol lawn mowers, the best fuel is unleaded petrol with an octane rating of at least 87, or 91 RON. It is important that the petrol does not have an ethanol content of more than 10%, as excess ethanol can attract water, especially in fuel tanks for mowers that remain unused for long periods of time. This water will sink to the bottom of the fuel, attracting bacteria that leads to corrosion in the fuel tank of your mower. With this in mind, petrol with 15% ethanol, commonly known as E15 petrol, should not be used in your petrol lawn mower.
In the UK, the most commonly used fuel for your petrol lawn mower is Super Unleaded 97 or 98 RON, which has an ethanol content of just 5%. Premium fuels, such as Shell V-Power or BP Ultimate add little benefit compared to the standard Super Unleaded 97 or 98 RON when used in small fuel tanks like those found in petrol lawn mowers.
Can you use e10 petrol in lawn mowers?
Yes, e10 petrol can be used in most modern lawn mowers. However, it is not the most suitable petrol for use in lawn mowers due to the high ethanol content. E10 petrol contains 10% ethanol content, which is the highest ethanol content that is recommended for use in mowers, with a lower ethanol content such as E5, with a 5% ethanol content recommended instead. As mentioned above, ethanol can cause corrosion in fuel tanks, especially when left stagnant for long periods of time.
Whilst modern mowers can run using e10 petrol, the older the mower; the poorer the performance. This is because prolonged use of e10 petrol can cause corrosion of some alloys and rubbers used in the engine and fuel systems of these older mowers. This is especially true for mowers built before 2010. For mowers of this age, it is highly recommended to use petrol with a lower ethanol content compared to e10.
Whilst it is recommended to not leave fuel in mowers over an extended storage period of time, this is especially pertinent for E10 fuel, as the fuel can begin to go thick over time, and the high ethanol content will increase the corrosion of the fuel tank due to the bacteria attracted to the water collecting at the bottom of the tank.
If you have purchased a petrol mower from us and would like it to be serviced or repaired then make sure to advantage of our specialist repair & servicing team:
We hope you have enjoyed reading our article convering some of the most popular FAQ's regarding petrol mowers. If there is anything else you would like answered or want to delve deeper into any of the mentioned topics then do not hesitate to contact us and our team of experts will gladly assist you.