Gasoline to oil ratio for STIHL grass trimmers

Why you should not buy gas for your lawnmower at an obscure gas station?

A quality fuel must be completely free of foreign and hazardous impurities. Its composition meets the specifications and requirements of specialized GOST 32513-2013, which regulates the quality of unleaded motor fuel. Due to the state standard, the negative impact of such gasoline on the fuel system and other components of the lawnmower should be minimal. However, unscrupulous petroleum product manufacturers and small petrol stations can still sell harmful mixture with artificially increased octane number due to prohibited chemical additives.

Low-quality fuel that does not meet the requirements of GOST, has increased sulfur and various resins. The latter slowly settles on the surfaces of fuel system parts, reducing the flow of combustible fluid and changing the correct proportion of gasoline and oxygen in the fuel-air mixture. And sulfur changes the combustion temperature of the fuel. That is why all elements of the combustion chamber, i.e. the head, valves, cylinder, and piston, operate at higher temperatures than they should. Accordingly, their life is depleted much faster.

That’s why, answering the question what gasoline to fill in the mower, you should choose not only the brand AI-92, but also pay attention to the brand of gas station. Gas stations from among the largest and best-known companies in Russia can always provide a quality certificate for the fuel sold and value their reputation. It is this kind of gasoline can be considered branded and, accordingly, reliable.

Fuel mixture for two-stroke engines

Grass trimmers, which are equipped with a two-stroke motor, do not have a separate system designed for oil supply in order to lubricate the working parts. For this reason you should not fill such devices with pure gasoline, but with a mixture of fuel and engine oil. The latter should be specifically designed for two-stroke engines. The use of the automobile engine fluid will lead to the premature engine failure.

Fuel mixture preparation for two-roller engines

Gasoline for a lawnmower with a two-stroke engine should be of AI-92 brand. When using the Ai-95 may cause overheating of the engine and uneven running of the unit. Gasoline and oil should be mixed in a 50:1 ratio, where 50 is fuel and 1 is oil. It turns out that for 1 liter of fuel, 20 ml of oil is needed.

If the engine is worn out or the tool works with a high load, the proportion is 25:1. If there is little lubricant, there will be burrs on the cylinder walls and piston surface. The piston ring is then destroyed, and the engine seizes up. Too much is not that critical, but it can lead to the formation of carbon deposits. The piston ring will get caked, which will reduce the power of the unit.

gasoline, ratio, stihl, grass, trimmers

Oil and gasoline proportions for the fuel mixture

How to prepare the mixture?

In order for the equipment to serve for a long time and properly cope with its functions, it is necessary to know exactly how much oil should be added to gasoline for STIHL chainsaws. We have found out before that it is better to use STIHL lubricant and unleaded AI92 or AI95 gasoline. Ethyl fuel negatively affects the performance of the unit and puts it out of operation. With such components for a blend, 20 ml of oil is added to a liter of gasoline. Any misproportioning leads to soot deposits on spark plugs and pistons, as well as scuffing. The oils used can be green, blue or red.

gasoline, ratio, stihl, grass, trimmers


The main component of fuel mixture for chainsaw engines is gasoline with octane number not lower than 92. Do not use an expired gas condensate mixture that contains water and mechanical impurities in its volume.

  • Experts’ opinions on the use of different brands of gasoline are controversial. On the one hand, the incomplete compliance of domestic A-92 gasoline with European standards is recognized.
  • On the other hand. the quality of gasoline A-95 is questioned because of the large content of anti-detonation additives. Use this fuel to prepare fuel for a chainsaw can only be used if you are fully confident in its quality.
  • The difficulty lies in the presence of various enhancing additives, with which unscrupulous manufacturers and sellers increase the operational properties of automotive gasoline with a lower octane rating.

There are also irreversible changes in the performance of fuel when it is stored for a long enough time in plastic containers, regardless of its level of gasoline and oil resistance.

What do you have to know?

Choosing the right ratio for the fuel mass is not a simple task. It is necessary to calculate the proportions of mixing in accordance with the established norm. Sometimes drivers add ingredients at their own discretion. At the same time, disciplined owners of vehicles, who are concerned about the engine, know that the recommended proportion is 1 to 50. This is how much oil? See below for an answer.

There are some simple rules for mixing the ingredients. To dilute gasoline with oil 1 to 50, it is recommended to use A-92 fuel. Often people use A-80, explaining such action by the presence of a large number of additives in its composition. This is fundamentally wrong.

Oil of almost any production is suitable for mixing with fuel. The main thing is that it belongs to the auto group, and not intended for tractors or motor boats. You should not use this oil. Otherwise it will obviously shorten the service life of the engine.

Which STIHL chain saw oil to choose?

Any two-stroke chainsaw engine runs on a mixture of gasoline and oil, respectively, the quality and proper mixture of these components depends on how long it will last. Chainsaws also require lubrication of the bar and chain, and the quality of the lubrication is not the last factor affecting the longevity of these chainsaw parts. STIHL chain saws are not the only products STIHL recommends for use in its own chain saws.

Low-quality fuel can cause your tool to malfunction. STIHL chain saws normally use unleaded gasoline with an additive content of more than 90. AI fuel is totally suitable for this application. 92. AI is also used. 95, which is used less frequently. It is made on the basis of AI. 92 contains various additives that can deposit on internal engine components and interfere with machine operation. It is acceptable to mix both fuels for optimal results.

Remember that gasoline is recommended to use fresh t.к. prolonged storage in closed containers loses useful octane properties.

Calculating the ratio of the fuel mixture

Correct filling also implies a strict observance of the proportions. For two-stroke engines use 1 part oil to 50 parts gasoline. To maintain such a ratio, you will need 5 liters of gasoline and 0.10 liters of oil. Remember also that such chain saws can not have an oil pump and therefore the use of pure gasoline is absolutely inadmissible.

In the event that the substances for the mixture have different brands, it is recommended to use a ratio of 1:40.

When petroling a new chain saw, 20 % more oil is added in the first 3 refuellings. In that case 1:42 will be used instead of 1:50 and 1:40 is changed to 1:33.

Violation of the ratios of fuel substances can lead to the formation of scuffing, as well as the appearance of soot on the plugs and pistons.

Is it possible to mix different colors and brands of oil?

It is not advisable to mix different brands of oil. First, they may be made on different, incompatible bases. synthetic, semi-synthetic, mineral. Secondly, in different brand oils may be different additives. It is impossible to predict how they may chemically react with each other and what the result will be.

The main thing is that there is simply no reason to do so. It is more rational to pour the rest of the oil of one brand into the gasoline and work out the mixture. And then start using a different oil.

Pay attention to the labels, these are 3 different STIHL oils, all different, both in characteristics and color. They should not be mixed together, as the manufacturer himself writes in his instructions

Learning the rule of thumb for choosing different brands of lawnmower oil

An engine oil is a special blend of solvents and thinners to reduce friction, keep it flowing and prevent it from thickening at low temperatures.

  • mineral, obtained by distillation of oil;
  • synthetic. by synthesis or processing of natural gas;
  • semi-synthetic. improved mineral oil due to the introduction of synthetic components.

Correct Way To Mix Gas and Oil For a ChainSaw, WeedEater etc.

For safety reasons, the oil is colored red, blue or green so as not to confuse the products. The range varies in composition, the user needs to buy an oil marked “for gardening equipment” 2T if the mixture should be prepared for a two-stroke engine, 4T for pouring into the crankcase.

Synthetic and mineral oils have different bases. When changing to another type of oil, the system must be flushed thoroughly.

The lawnmower oil must be classified as a TC oil for air-cooled engines with a combustion chamber volume of 50 to 200 cm3. When choosing a product, the important parameter is not the price, but the protective properties for the engine of a specific brand. That is why you buy the recommended oil first, if not select an identical one.

The quality of the lawnmower oil is determined by the alkali number. Alkali neutralizes the oxidation process of rubbing materials, slows down the destruction of the surface. When oil becomes oxidized, it loses its protective properties. Normal oil pH is 8-9.

Viscosity is important. There are winter oil, summer oil and multigrade oil. Which lawnmower oil to use depends on whether the user will operate the lawnmower at sub-zero temperatures. Summer oils become thick even when they cool slightly. The flash point indicates how quickly the oil will burn out of the compound. Optimal if this value is greater than 225 0 C.