A man is mowing high grass with an Einhell petrol lawnmower.
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Here's how it works: Find the right engine oil for your petrol device!

Is the engine in your petrol lawn mower not starting, or is it running hot? Among other things, this may be due to a lock or the incorrect engine oil! We have summarised what differences to look out for when it comes to engine oil, how you can find the right oil for your 4-stroke petrol devices such as lawnmowers, ground tillers, scythes or power generators, and how you can properly maintain them and therefore increase the service life of your devices. In addition, we will briefly explain what you should pay attention to when it comes to 2-stroke oil for petrol hedge trimmers or chainsaws, for example. Ultimately, it comes down to this: you can only achieve maximum performance with little wear and tear if you properly maintain your devices.

A man works the soil in the garden with a petrol power hoe from Einhell.
Whether a petrol ground tiller, lawn mower or scythe – you can find out how to properly maintain devices with a 4-stroke engine in the blog.

Engine oil name and meaning

In principle, the choice of engine oil comes down to viscosity at different temperatures. The viscosity denotes the flow property of the oil, i.e. how thick or thin the liquid is. In particular, the engine oil is classified in internationally standardised SAE grades. The abbreviation SAE stands for the Society of Automotive Engineers. This classification defines the limits of viscosity under cold and heat.

We will use a concrete example to explain what the engine oil designation means. The 4-stroke oil called 15W-40 has the following properties:

  • The number before the "W", in this case 15, stands for the viscosity at low temperatures. The lower the number, the better the flow property at low temperatures, so that all moving parts in the motor are quickly reached. Specifically, we would recommend this oil for use at outside temperatures from -20°C.
  • The number after the "W", in this case 40, stands for the flow property at heat, more precisely at 100°C. The higher this value, the better the lubrication of the engine oil at high outside temperatures and correspondingly high temperatures in the engine. We would recommend this engine oil for outdoor temperatures up to 30°C.

In particular, multi-grade oils such as 10W-40 (recommended for -20°C to 30°C) or 15W-40 (-10°C to 40°C) are suitable for our temperatures, i.e. for the central European climate. With multi-grade oils, whether summer or winter, you will always be well equipped in Germany and surrounding areas to properly care for your devices.

A graph shows which engine oil, divided into SAE classes, is suitable for which temperature.
In the table, you can see which engine oil is suitable for which outside temperatures and engines.

In our table, you can easily see which 4-stroke engine oil is suitable for use in your device. If you are still unsure, it's always a good idea to check the user manual, which also includes service numbers to contact if you have any questions or problems.

When should the engine oil be checked and changed?

All 4-stroke petrol devices from Einhell are supplied with a special service booklet that lists exactly how and when you should maintain your device. For example, an oil check should be carried out before each use, in the same way you should also check how much petrol you have left in the tank. You check the oil the same as you would in a car: Pull the dipstick out of the filler neck, wipe it and insert it again as far as it will go. When you pull the dipstick out of the filler neck again, the oil level should be visible between the minimum and maximum line.

When changing the oil, remember the following: Ideally, the first engine oil change should be after the first 20 hours of use of your petrol device. You can then change the engine oil after every 50 operating hours. How exactly to do this can be found as a step-by-step guide in your user manual.

In order to keep track of the oil changes and other maintenance work such as replacing spark plugs or cleaning the air filters, you can make a clear note of the times and later add them to your logbook so that you have a clear record.

How do I find the right engine oil?

Choosing the right engine oil always depends on the outside temperature at which you want to work with your device. While you usually work with petrol lawn mowers in summer, when it can get very warm in Germany, for example, you will need another special engine oil for an electricity generator that you might want to use in winter in particular. The choice of engine oil is therefore always regional and seasonal, so depends on the location and time of year, or on the outside temperatures. Whether an engine oil is suitable also depends on the type of fuel used in your device, i.e. whether it is diesel or petrol. You will find additional information on the recommended type of engine oil in the operating instructions for your device.

Incidentally, you should be careful if the oil is stored for too long! In the sealed original packaging, the engine oil can easily be kept for three to five years, but then chemical additives could become detached in it. In particular, partially synthetic and fully synthetic oils then lose their functionality in the long term. In case of doubt, you should buy new engine oil to get maximum performance and longevity out of your device.

Extra tip: Engine oil for 2-stroke engines

If you work with a 2-stroke device such as a petrol chainsaw or hedge trimmer, you should make absolutely sure that you buy a high-quality engine oil. In addition, the right mixing ratio is important here, because the fuel and oil must be mixed in these devices. You can read what type of oil and fuel you are allowed to use in the operating instructions. You will also find the mixing ratio in the booklet, which you should make sure to keep in a safe place. Often a mixing bottle is already included in delivery, and you can use this to easily establish the specified mixing ratio. For example, a ratio of 1:40 means one part of oil per 40 parts of petrol.

A man trims a hedge with a powerful petrol hedge trimmer from Einhell.
In 2-stroke petrol devices such as chainsaws or hedge trimmers the petrol-oil mixing ratio is crucial.

What happens if there is too little or no oil in the device?

Too low an oil level or no engine oil at all can do significant damage to your petrol device. A petrol-powered engine is capable of maximum performance and also works without engine oil, but you have to remember that the moving parts in the engine rub against each other countless times per hour of operation. A lubricant ensures that the parts wear less and thus reduces the generation of heat. Engine damage is likely to occur if there is no oil, often because the increased friction has led to overheating. This means that an engine that is not sufficiently oiled will wear out faster. In addition, in the case of incorrect use, warranty claims are usually omitted, which is also mentioned in the operating instructions.

For example, you may notice that you are using an unsuitable engine oil because it causes oil loss. This happens in particular if the oil is too fluid for the current outside temperature. If you use too thick an oil, which naturally becomes even more viscous in cold temperatures, the parts will not be lubricated properly. This can cause problems when starting the engine and the fuel consumption can also be higher. If you use the wrong engine oil, the problem can be solved quite easily. Refer to your user manual to find out how to correctly perform an oil change, which is usually explained step by step. Then simply replace the oil with a more suitable engine oil and your device will be ready for use again.

A man cuts the grass in his garden with a powerful Einhell petrol lawnmower.
To ensure you can enjoy your petrol lawn mower for a long time, you should always use it with sufficient and suitable engine oil.

Additional regular maintenance work

So that your petrol device always works optimally and you can enjoy it for as long as possible, additional maintenance work at different intervals is also recommended. As always, you will find out how to carry out this work in the associated operating instructions. We have listed the work that is required for devices with 4-stroke engines:

  • After 20 hours of operation: Check the screws on the exhaust for a tight fit
  • After 50 hours of operation: Clean the air filter, petrol filter and spark plugs
  • After 300 hours of operation: Change the filter insert
  • At the specialist company after 300 operating hours: Check and adjust the throttle valve on the carburettor, clean the cylinder head, adjust the valve clearance
A woman mows very tall grass with a powerful petrol lawnmower from Einhell.
Do you take care of and maintain your petrol lawn mower properly? Some maintenance work should be carried out regularly at specific intervals.

Summary: The right maintenance makes all the difference!

You can fundamentally influence how long you ultimately enjoy your petrol lawn mower, your power generator or your hedge trimmer for by properly and regularly maintaining your devices. The choice of the right engine oil significantly influences the functionality and longevity of the engine. So, what are you waiting for? An inventory of your devices and their condition is never a bad idea. Then you can immediately apply the new knowledge about oil changes and maintenance!