How to Properly Configure a Chainsaw Carburetor

Chainsaw carburetor is a part of the engine whose purpose is to mixing in certain proportions of fuel and oxygen with the subsequent supply of the mixture to the engine.


As a result of the malfunction of this part of the chainsaw significantly will lose productivity and may even completely fail. If even the slightest error in the operation of the motor is detected, then most likely you need to adjust the carburetor of the chainsaw.

Running in a new tool is also of great importance. Non-compliance with the running-in conditions may reduce the working life of the device, and in some cases, lead to engine jamming.

How to Properly Configure a Chainsaw Carburetor

For any malfunctions, it is best to contact a competent service center to avoid additional breakdowns. For each chainsaws Foresta adjustment is made under warranty.

When is carburetor adjustment for a chainsaw needed?

The most common situations:

  • The engine stalls after it starts up, or does not start at all. The reason is an excess of air and a low amount of fuel;
  • Increase in fuel consumption. Occurs due to oversaturation of the fuel mixture;
  • Damage to the protective cap against vibration and loss of fixation of bolts as a result;
  • Engine pistons are worn out. In this case it is recommended to completely replace the worn part;
  • Blockage (low-quality fuel, filter damage). In this case, complete disassembly of the carburetor with its subsequent adjustment and flushing will be required.

How to adjust the carburetor

Optimal parameters mixing the components of the fuel mixture mean factory settings. In the process, they naturally go astray. Even a slight shift of ¼ revolution of any screw can cause a serious change in the operation of the entire device.

The carburetor on the chainsaw is adjusted by three screws, each of which has its own designation:

  • H. Is responsible for tuning to maximum revs and manages the main jet;
  • L. Is responsible for controlling the idle jet and allows you to control the formation of the mixture on low revs;
  • T. Allows you to change idling.

The setting must be carried out exclusively on a hot motor.

The adjustment sequence itself has the form L-H-T. This means that you first need to configure the saw at low revs, then at maximum and, finally, switch to idle. In the end, you should check how the device works in any mode.

Generally, carburetor adjustment steps chainsaws have the following form:

  1. Place the saw on a solid, level surface with the tire pointing in the opposite direction from you;
  2. Remove the cover and the cover to gain access to the carburetor;
  3. Next, carefully remove the air filter. Some saws may have a foam rubber shock-absorbing insert. Remove it;
  4. Tighten the screws L and N. Until they stop. Then unscrew them 2 turns. Work with them carefully, as they are easy to damage;
  5. Start the engine and warm it up for 10 minutes.
  6. By slowly turning the screw L clockwise and vice versa, find the highest revolutions. Take a tachometer for accurate measurement;
  7. Turn screw L 90 degrees counterclockwise;
  8. Tighten screw H to find the upper speed limit. The tachometer readings must correspond to the indicated values ​​in the device passport.

Note that with inaccurate determination of the speed point by the regulator H, the engine will fail.

  1. Slowly turn the screw, which is responsible for idle, in a counterclockwise direction. This must be done until the motor starts to run smoothly.
  2. If the engine suddenly stalls, continue the adjustment, gradually returning the screw clockwise.

We check the done settings

Having eliminated all the malfunctions of the carburetor of the chainsaw, you should check its performance on a cold engine.

  1. Start a saw;
  2. Gently press the accelerator. The speed range from idle to maximum should be in the range of 3000-11500 rpm. They must be typed quickly;

The maximum number of motor revolutions per minute should not exceed 11000-11500. If this value is violated, the ignition process is disrupted.

  1. If the desired value is reached with a delay, turn screw L by ⅛ turn counterclockwise.
  2. If the frequency exceeds the nameplate, turn screw H counterclockwise. This will reduce the RPM.
  3. Check the device is idling. If the chain is notmoves, and the motor gains maximum speed, then the adjustment is correct.

If increase and decrease of gas occurs smoothly and quickly, This is a sure sign of proper setup. After that, it is advisable to check the device during sawing. If the power at high speeds is insufficient, this is a sign piston system wear.


Correctly adjust the carburetor in the chainsaw is not difficult on their own and without proper experience. Enough for this follow the algorithm above.

It is important that after setting up your saw for a while worked under working conditions. If there are deviations, correct them according to the same instructions. After eliminating any malfunctions, the setup procedure can be considered fully completed.

If you use the TM Foresta tool, the employees of the branded service center will hold free and professional carburetor adjustment of your chainsaw, without risk of damage to the tool.