Gasoline to oil ratio for lawnmowers

Working ratio of fuel mixture

The standard ratio of gasoline to oil in the fuel mixture for different models of carbureted chainsaw engines is 40:1 and 50:1. Such proportion ensures proper lubrication of friction parts of the crank mechanism and piston group, and does not prevent complete combustion of the gasoline-air mixture.

Taking into account external factors, the fuel mixture can be adjusted in the direction of increasing the amount of oil. Such a need may arise during the run-in phase of a new tool or in high ambient temperatures. The standard dosage of oil is then increased by 20%.

In practice, it is used to increase the percentage of oil in the fuel mixture, if its characteristics do not fully meet the stated requirements. How much oil per liter of gasoline is needed in each case is up to the sawyer.

Standard ratios

It’s not unusual to have problems with oil and fuel proportions for the reliable operation of a brushcutter. The reason for all this is completely different information in the sources. You might see differences in the ratio by a dozen units or sometimes by half. That is why you can’t help wondering how much oil you need for 1 liter of gasoline: 20 ml or 40 ml. But for this, there is a technical data sheet for the product you buy in the store. It should have a description of the device, the instructions for use and instructions on how to prepare the fuel mix.

The first thing to consider is the information recommended by the manufacturer, because if your brushcutter breaks down, you can make a claim against it and not against a third-party source. If there is no instruction in the passport, and even more so if the passport is missing, we recommend to look for another model of grass trimmer from a more reliable seller.

For all the other cases when you have a lawnmower model in your hands and there is no way to know its technical features, there are standard proportions of the most likely fuel mixture components for a two-stroke engine. Basically, these units use gasoline AI-92 and a special synthetic oil, which contains a solvent for better mixing with fuel. Such oil evaporates slowly and has the ability to burn completely in the cylinder, leaving no carbon residue.

The standard ratio of synthetic oil to gasoline is 1:50. This means that you need 100 ml of oil for 5 liters of gasoline, and accordingly, the oil consumption per 1 liter of gasoline is 20 ml. Knowing the amount of oil needed to dilute 1 liter of fuel, you can easily calculate any rates when preparing fuel for grass trimmer. When using mineral oils, a ratio of 1: 40 is often standard. Consequently, 25 ml of such oil is required per 1 liter of fuel, and 125 ml for a 5-liter canister.

During the operation of the lawnmower, a person with little experience in the operation of such equipment will not be difficult to determine and adjust the actual amount of oil needed for a particular model. You only have to pay attention to the exhaust gases (their color and odor toxicity), the stability of the cycles, the engine heating and the power output. information on what to expect when mixing petrol and oil in wrong proportions is available in another article. There are versions of brushcutters that run on gasoline AI-95. This also has to be taken into account.

gasoline, ratio

If the manufacturer recommends this octane rating, it is important to follow the recommendation so that the operating life of the equipment is not affected.

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Standard proportions

The standard specifies that to prepare the gasoline-oil mixture, it is necessary to take technical liquids in the proportion of 1 to 50. It means that to 10 liters of gasoline you must add 200 milliliters of oil. If you need to dilute the amount per 1 liter of gasoline, then use the formula according to the rule of proportion.

Note that when using mineral oil, the proportion is less and is in the standard version per liter of gasoline 1 to 40.

Deal with the choice of gasoline for lawnmower AI-92 or AI-95

So many people, so many opinions, which applies not only to the choice of oil for the grass trimmer, but also gasoline. Similarly, in order not to make a mistake with the choice, it is recommended to use gasoline of the brand recommended by the manufacturer (indicated in the manual to the tool). However, it is not so simple here, because at each filling station gasoline brands only have the same name, but have completely different composition. Need to understand, and come to a single conclusion about what brand better to fill the gasoline in a two-stroke engine for your trimmer for grass.

Manufacturers recommend using A-92 gasoline for their equipment, and some models require the use of A-95 grade, which does not contain ethanol. Use gasoline AI-90 and below is not recommended, as they will entail rapid deterioration of the engine parts. Buying gasoline of one brand you can not be 100% sure that it corresponds to reality. The result is the following picture:

  • The manufacturer recommends filling the grass trimmer with fuel of AI-92 brand
  • The outdoorsman uses only this brand of gasoline, but buys it at gas stations where the price is lower or wherever he has to
  • This negatively affects the internal parts of the engine, because at one gas station it is really high quality gasoline AI-92, and at the second. at best if it is AI-80, not AI-76

As a result, the motor suffers, and after a couple of years of operation of the new grass trimmer is the need for overhaul. To not have to analyze the quality of fuel or buy only expensive gasoline, it is recommended to fill only one gas station. Gas stations only fill metal cans, not plastic cans.

There are manufacturers that produce special purified fuel for two-stroke engines. If you choose this option, then you do not need to choose the best filling station, brand of gasoline and monitor its shelf life.

Conclusion on the choice of gasoline for grass trimmer!


The grass trimmer must be filled with gasoline of the brand recommended by the manufacturer. If you fill the grass trimmer tank with gasoline A-95, instead of A-92 (which is recommended by the manufacturer), the engine will warm up faster and work unstably. It is also better to choose gasoline A-92 Ecto, which has better characteristics in terms of environmental friendliness.

What oil to pour into the 2-stroke trimmer engine for grass

For a gasoline grass trimmer, the key element that determines its longevity is lubrication. A two-stroke motor that receives oil along with fuel will last significantly longer if the owner is selective enough in this matter and will pour only high quality products from reliable suppliers.

Our review presents some of the best oils for 2-stroke trimmers. Rating was based on the manufacturer’s claims about the performance of the lubricants. The rating also takes into account the experience of two-stroke equipment owners who have had a long history of successful use of one of these lubricants.

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How to Dilute Gasoline with Grass Trimmer Oil

Dilute petrol for the grass trimmer in the right proportion. Not enough oil can lead to poor lubrication of the elements of the lawnmower, which contributes to rapid wear. In case of more oil than it is supposed to, it will form soot on pistons and spark plugs. Soiling on the moving parts prevents proper engine performance and leads to premature engine failure.

To determine the correct mixing ratio for your model of grass trimmer, consult the instruction manual. The mixture most commonly used for 2-stroke gasoline lawnmower engines is 50:1, where 50 is part gasoline and 1 is part oil. That is, 20 ml of oil should be added to 1 liter of gasoline. The table will help you find the right ratio.

Use milliliter measuring jars to measure the proportions correctly. A special canister with double neck is a good choice for this purpose, it is designed for mixing and storing oil and gasoline. For example, oil can be taken with a medical syringe without a needle. Before mixing liquids, be sure the container for the fuel mixture is free of water, dust, and particles of dirt.

It is unacceptable to dilute petrol with lubricant directly in the fuel tank, moreover the proportion of oil and petrol should be strictly observed. If you ignore this rule, the operation of the grass trimmer engine can be unstable, causing it to fail quickly.

It is not recommended to use plastic bottles or canisters for this purpose. This is due to the fact that gasoline tends to dissolve plastic, which means that some of the plastic can get into the fuel tank, which can lead to carburetor failure. Although there are special plastic canisters marked “flame”.

  • gasoline;
  • oil suitable for two-stroke engines with air cooling system;
  • A canister, preferably a metal canister;
  • a mixing pail, also preferably made of metal;
  • gloves;
  • respirator.

In addition to protective equipment, do not forget about the rules of fire safety, because gasoline and motor oil are easily flammable:

  • it is better to work outside in order to avoid accumulation of gasoline fumes in the room;
  • Do not smoke or create situations connected with sparks.

Make a mixture of gasoline and oil as follows:

  • Pour 1 liter of gasoline into a container, add half of the desired portion of oil. Stir thoroughly, do it very carefully away from sources of open flame.
  • Add the rest of the oil to the gasoline of the weed trimmer and mix well again. Now the fuel can be poured into the fuel tank of the grass trimmer.

The mixture can be stored for no more than three months, so it is better to dilute the gasoline in such an amount that is enough for several uses.

Only quality oil may be used for dilution, and it is recommended to buy it only from trusted stores, such as specialized hypermarkets.

Preparing the mixture

Many novice users believe that if you add more oil to the gasoline for the fuel mixture than necessary, it will benefit. This is not how. The unburned oil will not be removed from the engine with the exhaust gases, but will settle inside as a sludge. This buildup threatens the integrity of the piston. If you use a mixture with too much oil regularly, the grass trimmer will smoke a lot and a drop in power is inevitable.

If there is not enough oil, the grass trimmer will overheat, the piston rings will collapse and the piston will jam. If the oil deficiency is minor, the grass trimmer will last 30 to 40% less than its life expectancy. If there is not enough lubricant over 20%, the motor will jam after 20 to 30 minutes of intensive work. Each trimmer manual gives proportions on how to dilute the fuel mixture. Usually it is 1:25. 1:40 or 1:50. In practice it looks like this:

  • 1:25 to 40 milliliters of oil per liter of gasoline;
  • 1:40 to 25 milliliters of oil per liter of gasoline;
  • 1:50. 20 milliliters of oil per liter of gasoline.
See also  Lawn mower, how much oil to a liter of gasoline. How to dilute gasoline and oil for trimmer grass

Gas found in Oil Lawn tractor Edition

From the table you can determine how much oil to pour in a certain volume of clean fuel:

Will a 4-cycle lawnmower run on 2-cycle gas/oil mix?

Gasoline (liters) Oil (milliliters)
25:1 30:1 35:1 40:1 50:1
1 40 33 28 25 20
5 200 165 140 125 100
10 400 330 280 250 200
16 500 495 420 375 300

Which oil to choose

For effective operation of the grass trimmer, select two-stroke engine oil. This is due to the absence of an oil sump in such a device. Depending on the chemical composition of the oil, the following classification is distinguished

  • mineral. based on petroleum distillate, suitable for machinery with low power and air type of cooling, but requires frequent replacement and can only be used in good weather in the warm season;
  • semi-synthetic. suitable for air-cooled and liquid-cooled garden equipment;
  • Synthetic. based on esters, it does not require frequent replacement and can be used at any time of year.

Oil for 2-stroke engines is characterized by good solubility and a feature of complete combustion. For the grass trimmer, it is recommended to use a lubricant that is suitable for devices with an air-cooled system. Most often the packaging indicates that the oil is intended for garden equipment and is labeled TA, TV or TC. The last one is the preferred brand.

If the consumption of engine oil during the dacha season is planned to be large due to the presence in the garden arsenal also a chainsaw, brush cutter, lawn mower, it is advisable to buy 5 liters of oil at a better price. If you need it only to mix it with gasoline and fill up a single tool, then 1 liter will be enough.

Often manufacturers of chain saws produce a suitable oil, so you can make the choice easier if you pick up a liquid of the appropriate brand.

Requirements for the combustible mixture for a two-stroke engine

The difference of a two-stroke engine is its increased power compared to a four-stroke. The combustible mixture for it is prepared in a certain ratio of gasoline and special oil. What is the optimal ratio of oil to gasoline for the lawnmower, written in the manual. The recommended proportions should be followed precisely. When adding additives the manufacturer has taken into account the type of engine. It is therefore forbidden to mix different oils.

If you use mineral oils, mix in the proportions 1:25, 1:30, 1:35. For synthetic oils use a ratio of 1:50 or 1:80. This means that in each of the suggested blends, the right amount of oil is dissolved in the volume of gasoline. Gasoline and lawnmower oil can be mixed like water and syrup. It is necessary to pour petrol, add a precise amount of oil and shake the mixture. For work it is desirable to use a fresh solution. Storing for more than two weeks changes the composition and the oil film will cause malfunction of the carburettor.

gasoline, ratio

You cannot use PET bottles for diluting and storing the combustible mixture. Gasoline destroys plastic, the polymer dissolves in the combustible mixture and further deteriorates the quality of the fuel, creating a risk of stray currents.

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