A tool's maximum power starts with the right fuel

It is logical that every piece of equipment has its own energy source. So there is no point in expecting a diesel engine to run on petrol, or a torch powered by AAA batteries to run off a mains cable. Common sense tells us that operating a device with a fuel it was not designed for is, at best, ineffective and, at worst, ends in a costly repair.

Using the correct fuel in your STIHL device is critically important to ensure its safe and efficient operation. All STIHL petrol-engine machines run on a fuel mix at a ratio of 1:50 (1 part two-stroke oil, 50 parts petrol), including four-stroke 4-MIX engines. Knowledge of how to prepare the correct fuel mix, of two-stroke oils and also of chain oils is the first and most important step in ensuring the long-lived and robust health of your machine.

Below are some recommendations:

Read the instruction manual!

Before preparing the fuel mix, we recommend reading your machine's instruction manual for more information about the fuel mix and refuelling. If you have lost your machine's instruction manual, you can download it again here.

Use the correct fuel can

You must use a fuel can intended for motor fuels. Our recommendation is to use a STIHL fuel can, or a combi can, which is available in 3 L/1.5 L or 5 L/3 L sizes. Quick-fill valves also make refuelling easier, helping to avoid fuel spilling or running over the edge of the fuel tank.

Choose the best option available

When choosing which fuel to use, we recommend using the best available - 98 fuel from a filling station or the special alkylate fuel available from garden and forestry equipment dealers - and mixing in STIHL HP Ultra fully synthetic two-stroke oil.

The correct ratio

All STIHL power tools use a fuel mix at a ratio of 1:50. The table below helps you more easily choose the right amount of oil

Mix the fuel mix

When preparing new fuel, first pour the two-stroke oil into the can and only then the fuel, then close the can properly and shake vigorously so that the oil and fuel are mixed as thoroughly as possible. The can should also be shaken vigorously after it has stood for a longer period, because STIHL two-stroke oils repel foreign substances from the fuel (for example moisture and water), which separate into layers in the can.

Clean the fuel-tank cap before refuelling

When refuelling, clean the fuel-tank cap and also the can's pouring opening/spout. When removing the fuel-tank cap, always position the machine so that the cap faces upwards. Remove the fuel-tank cap slowly so that any overpressure that has built up in the tank is released gently.

Storing the fuel mix

The best of all options is to prepare exactly the amount of fuel mix needed for a specific job. In practice, however, this is not always possible. So any fuel mix that has been prepared should be kept in a dry, cool and shaded place. As a rule, using a fuel mix that has stood for more than three months is not recommended, but if you use STIHL HP Super or Ultra two-stroke oil, whose additives also extend the shelf life of the fuel, such fuel mixes can be stored for up to a year under favourable conditions.

STIHL two-stroke oils

+ Good ++Very good +++Best

STIHL chain oils

Source: https://www.farron.ee/blog/kutused/