Adjusting The Carburetor On A “Huskvarna” Chainsaw.

Chainsaw Husqvarna (Husqvarna) 137. carburetor adjustment.

The best advice that I can give you is to consult specialists! Believe for very little money specialists will adjust the carburetor, check the overall condition of the saw. But if you still need to hold carburetor adjustment on a saw Husqvarna 137 I will try to describe this process in detail. Also at the end of the post added a video about how adjust the carburetor chainsaw at idle.

Adjustment and adjustment of the carburetor Husqvarna 137.

husqvarna137. carburetor adjustment
The screw T is needed to adjust the idle speed.
The screw L is used to adjust the low revs.
Screw H adjusts the high revs.

Adjustment order:

First, the screw L (rotating it), we are looking for the highest idle. After we have found them, it is necessary to turn this screw a quarter of a turn against the clock hand. If in this position the chain continues to rotate, then with the rotation of the screw T we achieve its stopping.
Then we warm up the engine at full speed in the region of 10-15 seconds and turn screw H a quarter counter-clockwise. We wait 10 seconds and listen. the engine should work as a 4-stroke sound. If a screech is heard, then the mixture is poor (we unscrew the screw), if the enriched mixture smokes (we tighten the screw).
After adjusting the low and high revs, set the idling speed with the screw T.

This is done as follows:

1. The engine should work
2. Rotate the screw T clockwise until the chain begins to rotate.
3. Rotate the screw in the other direction to stop the chain.
With a properly adjusted carburetor, your chainsaw is quickly gaining momentum and sound like a 4-stroke engine.
Remember that a tachometer and experience are necessary for correct adjustment of the carburetor of the chainsaw. Therefore, it is better to contact a specialized service!

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Adjusting the carburetor with your own hands on a chainsaw.

Adjusting the carburetor chainsaw ensures efficient operation of the tool at full power with economical fuel consumption. The adjustment must be made with clean fuel and air filter. For a more significant number of carburetors, calibration is carried out with three screws: for maximum and minimum turns and adjustment of idling.
The screws H and L regulate the ratio of the mixture of gasoline and air determined by the opening of the throttle valve of the carburetor. When the screws are unscrewed, the mixture is enriched, and the turnovers fall accordingly while tightening the combination is depleted. the turnovers grow.
The designation H refers to the maximum rotation screw driving the main jet, L refers to the minimum rotation screw driving the idling jet. Using screw S, precise adjustment of the idling speed is carried out. Sometimes, to simplify adjustment, the number of available carburetor adjustment screws is reduced.
Setting the carburetor chainsaw is divided into two stages. the basic (factory settings), carried out with the engine off. And final, produced on a running engine. The exact value of the angles of rotation should be taken from the operating instructions for a specific chainsaw. Failure to follow the manufacturer’s instructions may result in engine damage.

Basic carburetor adjustment.

The adjusting screws of the maximum H and minimum L turns are slowly turned clockwise until it stops, then turned back two turns, other settings are also possible

Check and adjustment of idling.

We are looking for the greatest idle speed; for this, we slowly turn the screw L in different directions. After finding the position of the highest revolutions of the engine, you must turn the screw L 1/4 of a turn counter-clockwise. If the chain rotates at idle, screw T or (S) should be turned by simply turning it clockwise until it stops.

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Check and adjust the maximum speed.

The change in the maximum number of revolutions is carried out with the screw H. When it is turned (clockwise), the turns increase, and when turned, they turn down. Chainsaw engines have the highest rotational speed of 11500 r / min. up to 15,000 rpm Higher speed does not provide ignition; in addition, it becomes dangerous for the engine. Interruptions can determine limit revolutions in the ignition. If they do, turn screw H slightly counter-clockwise.
If the engine is not tested for acceleration and maximum speed, the adjustment of the chainsaw cannot be considered complete.
When the gas trigger is gently pressed, the engine should confidently and quickly pick up speed from idle to maximum (from 2800 rev to 11500-15000 rev. Depending on the unit). If the revolutions are slower, with a delay, screw L must be slowly turned counter-clockwise, but not more than 1/8 of a turn.
After adjusting the acceleration and maximum speed, the saw should be rechecked at idle. the engine should work stably, the chain should not move. The setting of the chainsaw should be repeated if this condition is not fulfilled but except the stage of basic adjustment.

Adjusting the carburetor chainsaw

The carburetors of most chainsaws have three screws to adjust:

  • L. nozzle screw for adjusting the low speed
  • H. nozzle screw to adjust high revs
  • Screw. T at Partner and Husqvarna (at Calm LA ). adjustment of idling of the chainsaw

The screws H and L regulate the ratio of the mixture of gasoline and air determined by the opening of the throttle valve of the carburetor. When the screws are unscrewed, the mixture is enriched, and the turnovers increase accordingly, when the screw is turned, the mixture is depleted. the turnovers fall.
Screw T (LA) is designed to adjust the idle speed. The primary setting of the chainsaw is made at the factory during the final test. The carburetor is typically adjusted to supply a richer (than optimal) fuel mixture. The factory adjustment is necessary to maintain the first hours of the saw. Then (optionally) a more precise carburetor adjustment is made.
We start the adjustment by setting the idle speed; to do this, rotate the screw T (LA) counter-clockwise, ensuring that the circuit stops entirely at steady engine speed.
For further fine adjustment, you need a tachometer, and it is better to entrust it to specialists. over, in most cases, it may not be necessary.
We start the tool setting with screw L, then use screw H and at the end screw T (LA).

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We are looking for the highest idle speed, for this, we slowly turn the screw L in different directions. After finding the position of the highest revolutions of the engine, you must set the screw L 1/4 of a turn counter-clockwise. If the chain rotates at idle, the screw T should be turned by simply turning clockwise until it stops.

Screw H regulates the power and frequency of turns. Adjusting the carburetor to a lean mixture leads to excessive speed, overheating of the engine, and failure of the piston chainsaw.
We warm up the chainsaw engine at idle for at least 10 seconds and turn screw H 1/4 turn counter-clockwise. We give the engine to work for about 10 seconds. Then check the maximum engine speed with a tachometer. In case of discrepancy between the maximum revolutions of the passport, the operation should be repeated. When feeding too rich a mixture, the silencer starts to smoke, when too poor, the saw squeals and overheats.
We finish the adjustment by setting the idle speed, as already described above. Idling speed is set correctly if the engine runs without failures at minimum speed and the circuit does not rotate.
The carburetor can be considered adjusted if the engine accelerates quickly and sounds like a four-stroke at full throttle.