How to Tune a Chainsaw by Adjusting the Carburetor? A Step-by-Step Guide!

Tuning your chainsaw is basically making carburetor adjustments to enhance the working of the chainsaw.

If you’ve been a chainsaw user for some time now, you’ll definitely know it’s extremely important to keep your chainsaw tuned. However, if you’re a beginner, we’ll help you through the guide to tuning your chainsaw and you’ll know how it keeps your chainsaw working efficiently and smoothly.

As I’ve mentioned earlier, to tune a chainsaw, the carburetor is going to be the object we’d be working on. You’ll often see that your chainsaw lacks the power to work fastly and you sense a certain type of weight on the chainsaw’s engine. That’s because there’s clogging in there (in the carburetor which lies in the engine) and to fix that for enhanced performance, you’ll need to tune the chainsaw.

How to adjust the chainsaw carburetor? Our article contains an easy step-by-step guide to the tuning of a chainsaw and all that you need to know about the carburetor and its working. Continue reading to know the details.

What is Basically a Carburetor and How Does It Work?

A carburetor lies within a chainsaw’s engine. The function of a carburetor is to mix an appropriate amount of oil with gasoline which then gives power to the engine by igniting it. If the mixed amount of oil and gasoline doesn’t have an appropriate proportion of each, which must be 40:1 or 50:1, it would cause the carburetor to NOT function properly. 

Sometimes, what happens is, that more than the required amount of air enters the carburetor and when it mixes with the fuel, carbon gets filled and resists giving full power to the engine. 

What is Basically a Carburetor and How Does It Work

When this happens, smoke accumulates, which leads to carbon build-up. And now, in order for the chainsaw to function better, you need to tune the carburetor. However, you need to know about the carburetor’s three adjustment speeds in order to adjust it properly.

Idle Speed When the throttle is released, the saw runs at this speed. Approximately, 2700 rpm should be the saw’s idle speed. You should set the speed at idle so that when you release the throttle, the chain stops rotating if you don’t have a tachometer.

Low Speed Now this adjustment adjusts the air-gas mixture which means it keeps control of how much fuel is being delivered to the engine. By adjusting the throttle, you can make the engine load up and then bog down which will run the engine at low speed.

Now here’s how. You can do this by holding down the trigger and turning the knob clockwise in order to starve the engine of fuel and make it stumble. Then make a slight counterclockwise movement of the screw and let the trigger free. Continue doing so until the engine responds and starts running smoothly and slowly. 

High Speed This is the max speed setting and when the throttle is released, it should rev up the engine. However, prior to this step, make sure the RPM setting has been adjusted as described above in the low-speed adjustment. 

Remember, to sync the engine speed to the throttle setting, use a tachometer or strobe light instead of adjusting it by hearing through your ears. Synchronizing them will allow you to set high-speed fuel settings correctly and properly.

Tuning Your Chainsaw

Before we move on to the steps to be followed for tuning the saw, here are a few things you should be checking.

  1. A chainsaw’s chain tension is the first thing to check when tuning it. To ensure that the chainsaw chain does not sag under load, it should be sufficiently tuned. Also, make sure the saw is not tangled up by being too tight. 
  2. Then, the bar and chain must be aligned in such a way that the bar is level with the ground, and the chain is perpendicular to it (at a 90-degree angle). 
  3. Lastly, the chain needs to be sharpened. Files or sharpeners can be used for this, but a sharpener will yield the best results.

Tuning Your Chainsaw

Step-by-Step Guide to Tuning a Chainsaw/Adjusting the Carburetor

Now that you’ve come here and you know what things to check before starting up with the process, you can now continue following the steps to get the tuning done.

  • You should check and clean the air filters first. In order to keep the chainsaw running smoothly, make sure there are no clogs left.
  • Checking the fuel should be next. The best time to turn the wheel is when the tank is half-full. A full tank will result in a rich adjustment which isn’t something we’d suggest.
  • Now, the exhaust port and muffler should be checked for carbon build-up. In the event that the muffler is plugged, changing the carburetor settings may result in the saw running lean. You will only be able to do this if you have cleaned all the carbon from the ports that were clogging them. Then adjust the screws on the carburetor. After screwing them into their positions, you should return them to their original positions.
  • Warming up your chainsaw is the next thing to do. Warm it up by running it for a few minutes. You will end up with an over-optimized engine if you DO NOT do this step. Hence, it’s necessary to do it. You can warm it up by repeatedly squeezing the throttle if the idle is not being maintained. The chainsaw should run steadily.
  • Idle speed should now be adjusted just the way I’ve described above. Then, do the low-speed adjustment and then finally, the high-speed adjustment. 
  • The screw inside should be turned until the fuel leans out when you make a high-speed adjustment. Then, in reverse, as you turn it toward the inside again, a sound will be heard. By using a tachometer at this point now, you should be able to adjust the RPM to the right level.

Your gas chainsaw will work at its best after all this tuning. Remember that the surface you are working on should be flat and your saw must be surrounded by nothing extra.

How to Tune a Chainsaw – FAQs

How do you adjust the H and L on a chainsaw?
The H and L adjustments are simply the High-speed and Low-speed adjustments. To know about their adjustment, you can read above.
What is the T adjustment on a chainsaw?
The T adjustment is the Idle-speed adjustment of the carburetor in a chainsaw. The process of doing it has been explained above.
Should chainsaw be run at full throttle?
Yes. If it’s a two-stroke engine, it must run at full throttle. Two-stroke engines are designed for this, and they run very easily without any engine problems. Running below full throttle is therefore not recommended.
Why does my chainsaw go blunt so quickly?
Contact of a chainsaw with the ground is the fastest thing that makes it go blunt. This is due to the presence of sand and dust on the ground, which are abrasive and contain many tiny rocks. You should avoid cutting ground-surfaced wood in order to prevent such occurrences.
How do you adjust carburetor screws?
To adjust the carburetor screws, slow the engine by turning the high-speed or main jet screw clockwise. As the engine slows, turn the screw in the opposite direction. Then return the screw to its midpoint. When the engine has been adjusted, move the throttle from idle to fast and check engine acceleration.
Why is my chainsaw weak?
Out of the many reasons for a weak chainsaw, the two most common ones are 1. If the chainsaw chain or bar is dull and or improperly lubricated. The solution is to sharpen the chain and clean the oil holes in the bar. 2. If there’s any sort of clogging, contamination, or resistance in the air filter and fuel filter. The solution is to clean or replace as needed.



And this is it for the tuning of your chainsaws. We hope that we’ve been helpful to you through this guide.

We’d like to conclude with two tuning tips. 

  1. The paper air filter can be cleaned with hot water and dish soap. Make sure to let it dry before using.
  2. Clean wire-type air filters with chainsaw gas. You don’t have to let them dry.

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