How to properly run-in a chain saw. Running-in features for tools from different manufacturers

How to correctly run-in a chainsaw. detailed instructions and recommendations.

every power tool needs a proper running-in period that makes sure the engine and other parts of the tool are working at their optimum capacity. A chainsaw, as a cutting tool that works in harsh and hazardous conditions, needs to be maintained to the greatest extent. One of the most important prerequisites for proper operation is the creation of optimum working conditions during the first days of the tool.

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Running-in of a chainsaw is an important and responsible stage of operation, which requires understanding the meaning and purpose of all the procedures performed. This is an important question and needs to be explained in detail.

Why a chain saw needs a running-in period

Many chain saw owners are wondering if their new chain saw needs a running-in period and if they can do without it? According to the technical standards any tool equipped with a two- or four-stroke internal combustion engine needs a running-in or adaptive period when the engine parts are running-in and all of its parts are lubricated with oil included in the fuel or supplied separately from the crankcase.

The main reasons for running in the chainsaw:

  • Adaptation of the saw headset to the loads and work with wood;
  • Preserving the life of the tool and its long-term performance;
  • lapping of engine parts;
  • Lubricating the engine, the chain, the tire;
  • the owner has time to get used to the new tool and understand exactly how to work with it;
  • After the break-in period the chainsaw will run at its peak performance and productivity.

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How to properly run-in a chainsaw. the main threats

What are the problems with many of these tips. Let’s break it down one by one.

# n/a Advice encountered Arguments “For” The pros
1 The chainsaw should be run in idle speed. Idle RPM is lowest. The most damaging piece of advice you will ever hear. A great way to kill the cylinder-piston group. Idling, even in cars, is allowed only for a short time: in this mode, the fuel does not burn in optimal proportions, the ability to lubricate surfaces deteriorates sharply, heat dissipation deteriorates sharply, fouling appears, with prolonged mode, scuffing occurs.
2 A special mixture of oil and gasoline must be prepared for the chainsaw. In a special proportion (some sites write. more oil, some. more gasoline). Arguments “for” offer both. The one who listens to the advice of “experts” has to decide on what to do. Deviating from the manufacturer’s instructions entails imminent problems from either oil starvation or over-lubrication. No good can be done in either case.
3 You must carefully study the instructions, prepare the mixture, pour the oil into the container to lubricate the chain, and work carefully. “For”. because it is recommended by the manufacturer. There are no arguments against it. But why do so many sites unpack this platitude in a dozen paragraphs? To make a long article?
4 With the help of the adjusting screw “H” you need to lower the minimum speed of the chainsaw and make the mixture richer. Low speeds improve surface lubrication. This is what the “leading saw manufacturers” recommend. That is a lie. No manufacturer would recommend that you fill your saw with oil and thus try to transfer the imperfection of your own production onto the consumer’s shoulders.

Other tips are also available. You can’t list them all.

How to run in the engine after a repair

It is necessary to run in internal combustion engines after a complete overhaul. The difference in the process of lapping between a new engine and after overhaul only in the fact that less running-in hours are required (1 tank is enough). Otherwise all steps are performed similarly to the process of running-in of a new engine.

It is also desirable to install a new guide bar, chain and sprocket after the overhaul of the engine. It allows you to run in all your machines at the same time. Fill the fuel tank with a mixture of gasoline and oil. Gasoline should be chosen brand AI-92, but not lower, and the oil to mix with the fuel picked up a special for two-stroke engines.

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This is interesting! When the tool is not used for a long time (for more than 2-3 weeks), it is necessary to drain the fuel mixture from the tank. This will prevent only one oil from getting into the carburetor, which can lead to negative consequences.

After the running-in

After you have run-in your new chainsaw, you need to do a final carburetor tune-up. It is usually included in the price and is made at the place of sale of a chainsaw.


A fairly common and unpleasant phenomenon for chainsaw owners is kickback, which is when the saw bounces back sharply to its owner. This can lead to uncontrollable operation and as a consequence, tragic consequences. In which cases it is worth being extremely careful to avoid such a thing:

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  • The tip of the tip of the saw blade hits an obstacle. It is important to remember that the tip of the nose of the saw is a vulnerable point, so you should make the cut with the base of the saw and at an angle;
  • Grasping the chain with the top of the bar. To reiterate, when you are using a chain saw you should always check the chain‘s position and avoid pulling it back.

Bouncing a tire nose can cause serious injury. So please be careful!

Of course, such brands of gasoline saws as STIHL, Husqvarna, Champion, Goodluck have taken care of their owners and equipped their tools with special mechanisms, such as straight safety handle, chain brake and others. They certainly reduce the risk of injury, but the degree of risk is up to you!

Before you run in a new chain saw, take a good look at all the photos and videos you can see, read the manual, and be careful.

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Preparing a new chain saw for first use

The first adjustment after purchasing the tool is to install the bar, chain and sprocket, if any. Always handle chain with care. It is necessary for the teeth to face the opposite side of the drive. The tension of the chain should be checked, it should not be too much. When all the parts are installed and checked you can proceed to the next step.

Fuel mixture preparation

To increase the quality of lapping, add a mix with higher concentrations of oil in the mix. This is necessary because during the running-in period the friction of the components increases. Increased amount of oil will reduce the heating temperature.

Gasoline AI-92 is suitable for running-in. Only quality fuel with a declared flammability should be used. Use two-stroke oil. The amount of each component to be mixed is usually specified in the manual. Generally a ratio of 1 to 50 or 1 to 40.

It has been noted that 20% more oil must be added for this procedure. Add 5 to 10 ml to the standard value.

If it is used in winter, the minimum oil addition is 10 ml. 5 ml is sufficient in warm weather.

During the cold season, the proportions increase to eliminate the strong viscosity of the lubricant at low temperatures. Otherwise the lubricant may be of poor quality.

Synthetic oil is recommended, although more expensive than mineral oil. This compound is better for the service life of the engine.

Filling oil pump

When the fuel is ready, you can start filling up. The compound can be stored for two weeks. The oil tank is on the same side as the fuel tank. The oil pump cover is located closer to the chain. Simply turn the machine on to make sure the lubricant gets to the chain. While doing this the lower part of the tire should be placed against the paper sheet. If there is an oily spot, it means that the pump works properly.

Setting and starting the engine

This is the final stage before the running-in. Check that the chain brake is released. Even brief tool operation with an active interlock will lead to rapid wear of the clutch.

If the equipment is equipped with an external fuel pump, it is recommended that it is pressed in several times. Before switching on, the tool is placed on a flat surface. Switch on the ignition, press the handle at the back with your foot. Hold the upper crank with the left hand.

When it is locked in place, pull the starter lever, not too sharply, a couple of times. The motor will first start and then immediately shut off. This will be caused by a closed valve.

The preparatory phase is completed. It remains to open the valve and restart the engine.


When running-in a chain saw and during its subsequent operation it is very important to use high-quality fuels and lubricants. When preparing the fuel mixture, use high-octane gasoline AI-92, 95.

Oleo-Mac Prosint 2T STIHL HP oil Vitals Semisynthetic oil Champion JASO FD oil

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It is not recommended to fill up a chainsaw with gasoline which has been stored for more than 2 months. Pay special attention to the engine oil. It must be of good quality and made for air-cooled two-stroke engines.

Important: Do not use gasoline with an octane rating higher than 95, it can cause serious engine damage.

When running-in the chainsaw, use a fuel mixture prepared in the 1/25 proportion, if not otherwise specified in the chainsaw instruction manual.

Ratio of fuel mix for chain saw

The same oil is used in the second stage of running-in, but the ratio of the fuel mixture is changed by 1/40. 1/50, depending on the manufacturer’s recommendations and the characteristics of the oil.

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Important: you should not store the fuel mixture for more than 30 days.

We recommend using only special chain oils for the automatic lubrication system. Diesel oils, waste fluids, hemp, and other surrogates may not be used as lubricants.

How to run the chainsaw?

Instructions for running-in the chainsaw:

  • First, you need to disassemble the saw. remove the cover, disassemble the body, and get to the carburetor.
  • There will be three screws on the carburetor. two black and one gray (may vary). The black screws adjust the number of revolutions per minute. high and low revolutions. Gray adjusts the idle speed.
  • Turn the right black screw to increase the RPM. Use a flathead screwdriver to turn them. To measure the rpm, use a tachometer. If you don’t have a tachometer, you’ll need one anyway. Turn the screw one-quarter turn towards the fuel. Do not set the number of revolutions too high. the equipment can break because of the increased load. You should be able to set it to 600/700 rpm.
  • Reinstall all components and put the chain saw back together.
  • Pour fuel into the gas tank, mixing oil and gasoline in the proportions for your model (40:1 or 50:1). You can add more oil, as the engine consumes a lot of oil in the first hours of operation. it needs to be lubricated liberally.
  • Start the tool.
  • Listen for a sound. Notice the smoke. It gets bigger than normal. It may be thick and black.
  • Use the chainsaw for its intended purpose for 4 hours. Take regular breaks to allow the engine to cool from running at high rpm.
  • Turn off the unit. Wait for it to cool down. Turn the high speed adjustment screw back to its original position.

“Saw a video showing how STIHL saws are made. I was surprised that after reassembly the carburetor was tuned to run at maximum rpm, no running-in, and the throttle was in the what’s called full throttle position. In my opinion and experience, I would first buy high-quality oil, make a mixture for 2-3 tanks and pour more oil by 15 percent. And then run-in to do on small branches, saw carefully without overheating. It is the best way to break in!”