Husqvarna 128 R Trimmer Carburetor Setting

Husqvarna carburetor adjustment is done if:

And, to be sure that the Husqvarna engine works as expected and that the maximum trimmer performance (lawn mowers, lawn mowers) is ensured.

Husqvarna carburetor adjustment

Before adjusting the Husqvarna, perform trimmer maintenance (wash the lawn mower and engine, replace the spark plug, and remove minor defects).

Be sure to wash the foam element of the air filter. Wash the element in warm water with soap, then squeeze and dry (or replace if it is old or damaged).

Note: If you adjust the Husqvarna carburetor with a dirty air filter, after cleaning the air filter, the fuel mixture will become much poorer (which can lead to poor performance or even engine failure). Install a trimmer head with a cord of maximum permissible diameter and standard length (up to the cutting knife in additional protection) to create a load on the engine while adjusting the Husqvarna carburetor high-speed screw. Start the lawn mowing machine according to the Husqvarna Manual and warm it up for 10 minutes (if the trimmer head rotates at idle, the idle screw, i.E. The lower screw, must be turned counterclockwise until the trimmer rotation stops). Carefully turn both needles (right and left) to the middle position between fully twisted and fully twisted (do not turn the stopper!, This may cause the Husqvarna engine to malfunction).

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The adjusting screws for adjusting the Husqvarna carburetor are three: right, left and bottom.

Husqvarna 128 R Trimmer Carburetor Setting

1) Right screw L. Regulates the enrichment of a mixture of low speed (regulated first):Find maximum idle by slowly turning the right screw to the right and left.Then turn this screw ¼ turn counterclockwise.Note: From the Husqvarna factory, the right screw was completely unscrewed (0.5 turns). Now he is looking at 11 o’clock. 2) Bottom screw T. Adjusting the idle speed of the Husqvarna engine (if necessary): turning the screw clockwise increases the idle speed, counterclockwise decreases it.

Correct is considered to be idle speed adjustment when:

  1. A cold engine idles steadily.
  2. A hot engine does not have too high idle speed.
  3. Before the start of rotation of the trimmer head, a sufficient margin of speed remains.
  4. The engine runs stably in any position (for example, when the knife is sharply lowered).

Note: From the factory (Husqvarna), the idle screw from fully tightened was unscrewed by 8 full turns and “2 hours” (now it remains). The recommended idling speed of the Husqvarna lawn mowing engine is 2.900 rpm. 3) Left screw H. Regulates the enrichment of a mixture of high speed (last but not least).It regulates the maximum speed, engine power, temperature and fuel consumption.

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Note: The Husqvarna engine must not run at full speed for more than 10 seconds!

  • Open the throttle fully (full throttle) and slowly turn the left screw clockwise until the Husqvarna engine speed is reduced (by ear).
  • Then turn the left screw very slowly counterclockwise until the engine starts to run unevenly.
  • After that, turn the screw slowly back a short distance clockwise until the Husqvarna engine runs smoothly.

This completes the Husqvarna adjustment.

Note: Recommended maximum high engine speeds of Husqvarna. 11.500 rpm.The maximum power output of the Husqvarna 333R lawn mowing engine is 1.6 kW (2.1 hp) at 8,400 rpm.

Note: On the new Husqvarna trimmer from the factory (Husqvarna), the left screw was completely unscrewed (0.5 turns) and locked (filled) with hard plastic, which I drilled after the warranty period. Now the left screw (as well as the right one) looks at approximately 11 o’clock.

Checking the correct setting of the Husqvarna carburetor

The engine quickly, smoothly and confidently picks up speed, and quadruples a little at maximum speed, the T-35 trimmer head should not rotate at idle.

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Reference. Read to understand what you are doing!

The required composition (quality) of the air-fuel mixture is adjusted (changed) by turning the screws to adjust the fuel supply to the intake air flow (left and right). The amount of mixture supplied to the cylinder is dosed by the throttle.If you turn them clockwise, the mixture that is sucked into the cylinder is leaner (less fuel in the air / fuel ratio) and the engine rpm increases, while the Husqvarna engine runs softer (weakly gaining speed) and the power drops drastically. In addition, having increased revolutions, less oil (less lubrication) enters the cylinder on the lean mixture with gasoline (worse lubrication), and so you can screw up the engine. Well, the trimmer will not start well.If you turn the screws counterclockwise, the mixture that is sucked into the cylinder enriches (more fuel in the air / fuel ratio) and the engine rpm decreases, while at low rpm more gasoline and oil gets into the cylinder (better traction, better lubrication), but the Husqvarna engine “Unwinds” poorly (poorly gaining momentum) and more carbon deposits form in the cylinder!