The durability and reliability of the chainsaw is determined not only by the conditions of its operation but also by the quality of the fuel used for refueling. In addition to the special conditions of use when grinding parts in the first few refills, the quality of the fuel mixture also needs to be given attention.
Professional chainsaws are equipped with Stihl two-stroke engines that require high-quality fuel. a dosed mixture of high-octane gasoline and oil, designed to run the engine at high revs. The right choice of gasoline and oil for a Stihl chainsaw is a guarantee of the long and successful operation of this unit.
The first question that a user encounters before starting work is which kind of gas to pour into the Stihl chainsaw.
Gasoline for Stihl chainsaw is filled exclusively with unleaded high-octane, i.e., with an octane rating above 90. If you refuel with low-octane, it is fraught with engine overheating, jamming of the piston and failure of the motor. Therefore, it is optimal to pour gasoline AI-92 or AI-95 into a chainsaw, but here the question arises about the quality of the fuel.
Poor-quality AI-92 can “not reach” the stated octane number, and AI-95 often contains many additives that do not bring any benefit to the engine. Also, if the additives are of poor quality, they do not last long, and after a few days, the purchased fuel can turn into low-octane, which is not suitable for the engine chainsaw.
At the same time, a good 95 can harm the piston system. “burn” it. Thus, some users found a way out: fill the chainsaw with AI-92 gasoline mixed with AI-95. If it achieves an optimal balance between the octane number and the number of filler impurities.
Unlike four-stroke engines, Stihl 180 chainsaw oil is poured directly into the gas tank, pre-mixed with gasoline. It is recommended to pour oil into the chainsaw specified in the instructions for this model.
In no case can not use oil intended for low-speed engines (boats, scooters, etc.).
It can significantly reduce the life of the motor, and when detecting traces of such a substance in the cylinder-piston group, the tool will be considered as removed from the guarantee, i.e., it will not be subject to warranty repair or exchange.
Synthetic and mineral oils for Stihl chainsaws are sold in bottles or cans of different capacities: from 100 ml to 5 liters. Minerals have a lower cost, and semi-synthetic and synthetic provide complete combustion during engine operation, i.e., no carbon and a minimum of toxic compounds in the exhaust.
Besides, synthetic oils retain their qualities in a much wider range of temperatures and also contain special additives that are useful for the engine: antioxidant, detergent, preservative, etc.
Depending on the model of the saw and the frequency of its use, you can choose engine oil for your tasks: the oil consumption during operation of the device is low, and given the shelf life of semi-synthetic and mineral lubricants, there is a risk that you may not even have time to use a liter bottle.
So with a small estimated amount of work, you can not buy a bulk canister, but restrict yourself to a bottle. Only Stihl mineral lubricants do not have a shelf life.
How to breed?
Stihl saw fuel mixture is prepared by mixing high-octane gasoline and two-stroke oil. The proportion of oil and gasoline for a chainsaw is as follows: if the power of the unit does not exceed 1.5 kW, the ratio will be 1:40 (i.e., 25 ml of oil per liter of gasoline), and at a power higher than this value. 1:50 (20 ml on 1 l).
It is necessary to dilute gasoline for a Stihl chainsaw in a separate canister, in no case do not pour the components separately into the gas tank. In these engines, there is no oil pump, and the possibility of its installation, so only finished fuel is poured into the container. There are even special cans with two necks for sale to make it easier to dilute the mixture, but you can add oil to gasoline for chainsaws and in ordinary cans.
The proportions of refueling chainsaws are best observed as precisely as possible: excess oil will create carbon on candles and pistons and will provoke detonation during the combustion of fuel if can reduce the life of the engine. Also, the user of the saw, in this case, is forced to inhale exhaust gases with unburned fractions. At the same time, excess gasoline can damage the pistons due to insufficient lubrication.
Some craftsmen in the event of the absence of unique dimensional accessories are advised to use a plastic bottle: a full lid (from the same bottle) of oil is poured into a half-liter container filled with gasoline. The output is an approximate ratio of 1:50.
The amount of the mixture for refueling is best calculated in advance based on the estimated amount of work and the stated consumption of this engine. The volume of the tank in most chainsaws is about 0.5 liters, the engine with a power of 2 kW will consume about 1.2 liters per hour of operation (more accurate characteristics of the saw can be seen in the instructions). Thus, it makes no sense to prepare the mixture in volumes exceeding three refuelings in a row.
Before starting the preparation of the mixture, it is recommended to thoroughly clean and dry the neck of the canister and the area around it to avoid ingress of impurities: dust, water, etc. The same is done with the tank before pouring the fuel: the lid and neck are cleaned of dust and adhering dirt, so that it does not hit the gas tank, and then into the engine.
When calculating the proportions, remember that it is better to pour oil a little than to save on it: the formation of soot is dangerous only a substantial excess of lubricant, and a slight excess will not harm the engine. If it is not enough, the consequences can be more dangerous.
When mixing fuel for a chainsaw Stihl, the manufacturer recommends first pouring oil into the canister, then adding gasoline and then stirring the ingredients vigorously. But the practice of use shows that the oil can “stick” to the walls of the canister and not mix well, so it is better to pour the oil into gasoline and mix carefully.
It is better not to leave the remnants of the fuel mixture in the tank to prolong the life of the sealing rubber and other parts subject to chemical damage. After stopping the saw, the fuel must be drained and disposed of: during long storage (more than a month), the octane number and other physicochemical properties of the mixture decrease and it becomes unsuitable for safe use.
Besides, after emptying the gas tank, you need to start the saw engine and let it run at idle speed until it stops on its own. this will mean that the carburetor is also free from residual fuel mixture.
It is important to remember that the long-term operation of technology depends mostly on the user. Saving on fuel in the case of a chainsaw may in the future be much more expensive. non-warranty repair of a failed saw or the acquisition of a new unit. Compliance with the manufacturer’s instructions in most cases helps to understand the principles of operation of the device and extend its trouble-free and trouble-free operation.