What Proportions of Oil and Gasoline Should Be For Preparing a Fuel Mixture of a Chainsaw (Video)

What Proportions of Oil and Gasoline Should Be For Preparing a Fuel Mixture of a Chainsaw (Video)

The chainsaws of various companies are based on a two-stroke internal combustion engine, which drives the cutting headset of the tool. To activate the internal combustion engine, the proportions of gasoline and chainsaw oil are used. Combining gasoline with oil is an obligatory procedure, so if you just bought a tool, you need to understand the features of its refueling.

Characteristics of household chainsaws

The speed of the chain depends on the speed of the engine, which is cooled by air. A separate oil tank is provided for lubrication and cooling. With an increase in the frequency of its rotation, the automatic oil supply also increases. For normal operation of the chainsaw, it is necessary to control the contents of two tanks. for the operation of the engine and the chain.

Chainsaw Partner 351

The Partner 351 chainsaw belongs to a number of Chrome models that have a chrome plated cylinder. Due to this, the operation of the saw equipment becomes more reliable, and the service life is much longer. The chainsaw belongs to the professional class, it is used for harvesting firewood, sawing dead wood, pruning branches, twigs and even during construction. Advanced air purification, vibration and noise absorption systems make Partner 351 the most comfortable for the operator.

Chainsaw Partner 351


stringent selection criteria for the oil component. In the best case, this is a mineral or semi-synthetic engine oil recommended by the manufacturer, designed for use in high-speed two-stroke ICE with air cooling.

The advantage of mineral oils in their lower cost. Their more expensive semi-synthetic and synthetic counterparts stand out for their superior performance and environmental standards.


  • keep working properties in a wide range of working temperatures;
  • do not form soot;
  • contain detergents, antioxidants, preservatives and other additives useful for the operation of the power unit.

Basic equipment and assembly of a chainsaw

Partner 351 chainsaws are supplied in the factory box in disassembled condition. In the kit for the power unit you will receive:

  • 40 cm guide rail
  • sharpened saw chain;
  • case protecting the saw during storage and transportation;
  • keys and screwdrivers for assembly and maintenance of chainsaws;
  • instruction manual and warranty card.

Partner is a Swedish company that has been part of the huge Husqvarna concern since 2006. Speaking about the history of the brand itself, Partner is the first company to launch motor chainsaws. The entire production of the concern is scattered around the world. It is worth noting that the main forces of the assembly of Partner chainsaws are concentrated in the homeland of the brand. And the main part. the engine. is supplied from America by Briggs & Stratton, whose products are of high quality and durability.

The ratio of gasoline and oil for chainsaws

The proportion of oil and gasoline for refueling two-stroke engines of chainsaws of different brands is 40 to 1. This ratio is standard, which is used not only by beginners, but also by experienced filers. It is this ratio for the preparation of the fuel mixture that is close to ideal, and provides lubrication of the rubbing parts of the crank mechanism and piston.

The proportions of the fuel mixture

It is interesting! Before mixing petroleum products, external factors should be considered. If the chainsaw is new, then it requires a break-in, and for this you need to add 20% more to the fuel oil than the standard values. 20% more lubricant must also be added if the tool is used at low temperatures.

How much oil do you need to pour in gasoline in milliliters? Per ml ratio of oil and gasoline 1 to 50 is 20 ml per 1 liter. In order to prepare the right mixture, pour 1 liter of gasoline into a plastic bottle and dilute it with 20 ml of oil. In order to correctly measure how much oil to pour, you should take a special measuring container, and fill it to the appropriate mark. If it is immediately planned to prepare 2 liters of fuel, then 40 ml of lubricant should be added to this amount of gasoline.

There are other ratios offered by different manufacturers. These values ​​of the ratios differ slightly, but if you subtracted other values ​​in the passport to the tool, then you need to stick to them. Values ​​of 1 k are standardized. Pour 15 ml of oil per 1 liter of fuel in the summer, and in the winter add at least 20-25 ml. Knowing the recipe for the preparation of the mixture, you should also understand the question of which gasoline to pour into the chainsaw?

What kind of gasoline to pour?

The quality of the combustible material affects the engine traction, speed and coordination of the work of all elements of the system. In different models of saws, fuel with a different octane number is poured. Local tool manufacturers advise taking low-grade AI-80 fuel. Sometimes make a mixture of AI-80 with AI-92. For foreign models, the octane number should not be less than 90, therefore, AI-92 and AI-95 gasoline are recommended. In all cases, unleaded fuel must be used so that it does not contain lead, which adversely affects the details of the tool. How to breed gasoline with chainsaw oil? It is necessary to follow the manufacturer’s recommendations. Otherwise, it is easy enough to damage the tool and violate all factory settings.


Should I use the AI-95?

Whoever only gets acquainted with a chainsaw and makes attempts to carry out some chores, instead of AI-92 fuel, refuel it with AI-95, believing that it is of the best quality. Gasoline with an octane rating of 95 is obtained from AI-92 by adding various additives. Special additives have a negative effect on two-stroke engines due to their design features. They accumulate on the inner walls of the tool and eventually peel off, disrupting its operation. Therefore, experts advise buying only AI-92 for preparing a mixture for chainsaws.

Safety during operation of a chainsaw

First of all, the manufacturer in the instructions indicates the importance of the presence of special protective clothing, shoes and accessories. So, for example, for safe work you should get:

  • closed comfortable shoes, preferably with a metal edging;
  • adjacent, but not restraining, clothing;
  • non-slip, tight gloves;
  • safety glasses;
  • helmet or special noise-canceling headphones.

Partner 351 chainsaw is controlled with just two hands. Using the saw with one hand can cause injuries and injuries not only to the operator, but also to those around him. Since the gasoline drive produces harmful and toxic emissions, Partner 351 is not permitted to work in rooms and in poorly ventilated areas.

Why add oil

At the heart of any chainsaw is a two-stroke internal combustion engine. This is one of the simplest mechanisms, consisting of a single cylinder and without a separate lubrication system. The technology is such that the lubricant must enter the cylinder with the fuel mixture, settle there, and lubricate the cylinder walls, piston rings, etc. The simplicity of the design of the tool has many advantages, among which the main one is the ability to carry out repair work of the engine and component parts independently.

Diluting gasoline, which is poured into the chainsaw, is required in order to extend the life of the tool. Diluting fuel with chainsaw oil is mandatory, and if for some reason you forgot to do this, then the use of the tool is strictly contraindicated.

It’s important to know! In chainsaws there is no special tank for pouring oil, which would be spent for lubricating the rubbing parts of the engine, as in cars. This is due to the simplest design of a two-stroke motor. The oil tank present in the chainsaw is designed to lubricate the chain and tire during the operation of the tool.

Proportions of oil and gasoline for chainsaws

How much oil to add to gasoline for a chainsaw is indicated primarily in the instructions for use of the tool. If you forget what the proportion of oil and gasoline should be, then you can always open the instructions and update your knowledge. If the instruction is lost, then this material will help you. To begin with, it is worth noting that there are several options for mixing oil materials with fuel. Choosing any, it is worth noting that the main criterion for each is the correct measurement of the components. Only exact observance of the proportion of oil and gasoline will achieve the fuel mixture of the required technical qualities.

One of the most common proportions is 1:50. This means that 1 liter of gasoline must be diluted with 20 ml of oil. This recipe for the preparation of the mixture is relevant for tools whose power exceeds 1.5 kW. This option is one of the most popular, so if you forget the exact proportions for your instrument, you can always focus on the first option.

Video: What Proportions of Oil and Gasoline Should Be For Preparing a Fuel Mixture of a Chainsaw (Video)

The second option provides for a proportion of 1:25. To mix 1 liter of gasoline with 10 ml of oil is recommended by Chinese manufacturers for their tools. For tools whose power does not exceed 1.5 kW, it is recommended to pour oil in an amount of 25 ml per 1 liter of gasoline. Chainsaws of each manufacturer have their own limitations, and recommendations for the preparation of the fuel mixture, which are recommended to be followed. The two main options that are universal are listed above.

It’s important to know! The excess amount of the oil mixture in the fuel is also negative, as this will lead to a reduction in engine life due to increased shock loads on the cylinder and piston, and will also lead to the formation of soot.

Not everyone knows what kind of gasoline to pour into a chainsaw. This is also indicated in the technical documentation for the chainsaw. In modern saw models, it is recommended to pour fuel of a brand not lower than AI-90, that is, AI-92 or AI-95. And it doesn’t matter who the tool manufacturer is, China or Europe. Professionals recommend the use of AI-92 gasoline, since the 95th is in most cases made from 92 by adding additives. If you know for sure that it is really pure 95, then it is better to use it.

Many craftsmen continue to pour gasoline of grades lower than AI-90 into modern chainsaw models, as this was allowed to be done for obsolete models of tools: Friendship, Taiga, and others. This is not recommended!

Which oil to use to lubricate the chainsaw chains depends on the model of tool. Stihl brand saws and the like produce special lubricants, which are intended only for use in such tools. Recommended oils can also be found in the technical documentation. When choosing a lubricant, attention must be paid to ensure that it is intended for two-stroke engines. Oils for mixing with gasoline and for chain lubrication differ in composition, quality and purpose. You can not mix them, as this will accelerate the failure of the tool. Recommended brands of oils for two-stroke engines:

Saw refueling algorithm

A mixture of gasoline and oil is best prepared in a 2.5-liter plastic bottle if you often need to refuel the tool. If it is necessary to prepare fuel for only a few refueling, it is better to use a smaller tank. It is recommended that you acquire measuring containers, this will allow you to observe the exact proportions of both liquids. Most oil manufacturers offer such measuring devices.

Initially, fuel is poured into the tank, and then oil is added. It is important to consider that there should be enough space in the tank to thoroughly mix the fuel mixture.

It’s important to know! It is strictly contraindicated to prepare the fuel mixture directly in the tank of the instrument.

After preparation, it is recommended to store this mixture no more than 2 weeks. At each filling, it is recommended to shake the mixture thoroughly. If you are not sure that all fuel will be used up, it is better not to cook it in large quantities.

Risks of using fuel and oil substitutes

To avoid premature failure of the chainsaw, it is recommended to refuel the tool with exclusively high-quality and branded consumables. Finding such materials is not difficult, since they are usually sold at branded points of sale. The use of low-quality gasoline can cause engine failure, so it is recommended to buy fuel at gas stations where high fuel quality is guaranteed.

It is strictly contraindicated to mix gasoline with motor oil for cars, since it is not at all intended for such purposes. Compliance with the number of proportions, as well as the use of quality materials will extend the life of your tool for many years.

Chinese oil dosage

Many Chinese chainsaws are simplified copies of popular models of European design. The lack of special materials and proprietary technologies helps to maintain an outdated proportion of gasoline and oil in a ratio of 25: 1.

Twice the consumption of engine oil is offset by its lower cost. According to the assurance of the developers, the original components are introduced into the composition of Chinese oils, which contribute to increasing the wear resistance of power units and real extension of their designated resource.

According to independent experts, the best brands of Chinese motor lubricants in quality correspond to analogues of European manufacturers in the mid-price range. This is the level of standard engine oils of the Standard group and partially Super.

User manual

Before you start working with the Partner 351 chainsaw, you must read the instructions. It indicates the features of the operation of the equipment, the nuances of its assembly and maintenance, the rules for adjusting the carburetor of the chainsaw, the most frequent breakdowns and methods for their elimination are described, as well as the brands of fuel and oil that are suitable for this model.

You can study and download the instruction manual for the Partner 351 chainsaw at the following link: Download the instruction manual

The main brands of motor oils for chainsaws

Leading chainsaw lubricant companies are Stihl and Husgvarna. The following oils are used for saws:

  • Stihl HP is a mineral lubricant for tools of the same brand. It has a red color, is available in different packaging, even for single use, which is very convenient.
  • HP Ultra. is made on a synthetic basis, has improved qualities, is used at low temperatures.
  • Vitals Semisynthetic. designed for budget models, used year-round.
  • Husgvarna HP. semi-synthetic, equipped with additives to compensate for the low quality of gasoline. Suitable for use in technology and other brands.
  • Champion Jaso FD. provides reliable protection for all engine parts.

In the market for two-stroke engines, a large selection of products from different manufacturers. How to dilute the oil for the chainsaw is indicated on the package. Buying better products from well-known companies, this will help to keep the tool in working condition longer.

Oil and fuel mixture

For the correct and smooth operation of the chainsaw, it must be lubricated. This process occurs automatically, so carefully monitor the presence and level of oil in the tank. If there is not enough lubricating fluid, then the guide bar and chain overheat, and, consequently, their rapid wear.

American Briggs Engine & Stratton guarantees long and stable operation provided that it is refueling with high-quality fuel. To do this, use a mixture of unleaded gasoline and special oil for two-stroke engines and air cooling in a ratio of 40: 1. That is 5 liters. gasoline is mixed with 125 ml. oils. It is very important to observe proportions to ensure the health of the tool and good work. Avoid car and marine oil.

The working proportions of the fuel mixture

The standard ratio of gasoline and oil in the fuel mixture for chainsaw carburetor engines of different models is 40: 1 and 50: 1. This proportion provides a complete lubrication of the rubbing parts of the crank mechanism and the piston group, and also does not interfere with the 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 arises at the break-in stage of a new tool, as well as at high air temperature. In this case, the standard dosage of oil is increased by 20%.

In practice, an increase in the percentage of oil in the fuel mixture is applied if its characteristics do not fully meet the stated requirements. How much oil per liter of gasoline is needed in each case, the sawmill himself determines.

Carb setting

The chainsaw comes with a carburetor already set at the factory, but after a while you notice that the saw is not functioning so stably. In order not to carry the tool to the service center, you can try to do the adjustment of the carburetor of the Partner 351 chainsaw yourself. This procedure may be required only in two cases:

  1. the chain is idling;
  2. the saw is not idling.

Read the carburetor adjustment information provided in the instruction manual and the video reviews of the users in which they perform this procedure.

Video review on how to adjust the carburetor:

Measured tanks

To maintain the correct proportion of gasoline and oil, a spreadsheet applied to the saw body may be used. The branded packaging of leading manufacturers of motor oils is equipped with built-in measuring devices that provide an accurate dosage of oil for different volumes of the fuel mixture.

Measuring utensils are included in the factory kit of many budget chainsaw models. In some cases, a medical syringe with a volume of 20 cm3 will help dilute gasoline with oil in a predetermined proportion.

Basic malfunctions and their elimination

One of the most common complaints is that the Partner 351 chainsaw will not start. This may be due to a crowded engine, an empty fuel tank, the absence of sparks in the spark plugs, or because the fuel mixture does not enter the carburetor. For troubleshooting, check the presence and level of gasoline, as well as the cleanliness of the fuel filter. If it is dirty, clean it or replace it.

If the engine does not work at full power or stalls when the load increases, then you are advised to clean or replace the air filter, spark plug or disconnect the chain brake. If none of these steps changes the status of Partner 351, contact a service center for qualified assistance.

Excessive smoke emission during sawing indicates a large part of the oil in the fuel mixture. Drain the old fuel, mix the new one and fill it into the tank. And if the engine idles incorrectly, then the reason lies in the carburetor. Try to adjust the carburetor with your own hands as described above.

Advantages and disadvantages of a chainsaw

This model stands out from the entire range of Partner chainsaws with a powerful professional engine that can withstand even large and long loads. Increased safety is ensured by a more sensitive and sharper chain brake, which blocks the saw chain in emergency situations. An easy-start electric system ensures quick engine starting with a primer that helps the carburetor fill with fuel mixture.

  • poor engine tolerance of low-quality fuel;
  • lack of visual indicators of fuel and oil levels in tanks;
  • insufficient vibration damping.

How to use chain oil?

The lubricant for chain lubrication is recommended by the manufacturer and is indicated on the instrument data sheet. Usually these are branded products with high quality. While the chainsaw is new, it is necessary to apply it. Otherwise, if the tool breaks, it is removed from the warranty and repairs are carried out at the user’s expense. Subsequently, the oil is replaced with a cheaper one, but it must comply with the following requirements:

  • protect the chain from corrosion;
  • increase wear resistance, reducing friction;
  • do not form soot;
  • keep the ability to work with the tool in a wide temperature range.

For long-term operation of the chainsaw in good condition on oil for the chain is better not to save.

Video chainsaw reviews


We were lucky to get the Partner 351 chainsaw for a very long time, about 9 years ago. Of course, during this time there were breakdowns and repairs. That tire will fail, to adjust the carburetor, then the tank will leak. However, with proper care, regular maintenance and quality repairs as necessary, the tool will last you a very long time. In addition, some procedures can be done by ourselves, and not taken to a service center: sharpen the chain, tighten the bearings, adjust the carburetor, etc.

Fedor Savelievich:

I use the saw exclusively in the country and in season. I’ll prepare firewood, cut dry branches, etc. In total, sawed about 2-3 cubic meters per year. With such a load, the first problem appeared a year after the purchase, and then, he managed it himself. It was necessary to adjust the carburetor. Then the automatic start broke. Here I have already contacted a service center.

Advantages: 7 years of serviceable and reliable operation, easily copes with construction waste, low weight, available spare parts in the markets, easy maintenance.

Disadvantages: due to the fact that I did not use the saw very often, the electric start-up system quickly failed.


The article describes in detail how to dilute gasoline with oil for a chainsaw. When preparing the mixture, try to strictly observe all the proportions so as not to harm the technique. When running a new tool, remember to add 20% more oil in hot weather than indicated in the instructions.

Features of running a new tool

This concept includes the gentle operation of a chainsaw at the initial stage of its operation. The technology also provides for engine operation on a mixture with a 20% increase in engine oil content.

Break-in time in hours is indicated in the attached instructions. In practice, for the tool to reach the working level, it is enough to develop 3-5 gas stations for the saw’s gas tank.

New models do not need a run-in, but the first hours of operation of the chainsaw are not recommended for use with heavy loads.