Adjusting The Trimmer Carburetor.

Increased fuel consumption and the rapid formation of soot on the candle Trimmer when using properly prepared fuel mixture suggests the need to adjust the carburetor. It describes trimming with carburetors with one screw to adjust the fuel supply.

Carburetor adjustment.

Wash the air filter before adjusting the carburetor. It is recommended to wash it after every 10 hours of operation. After that, you can begin to adjust. The photograph, for example, shows the carburetor trimmer PRORAB-8406. The numbers indicate the adjustment screws that we will use.

The purpose of the adjusting screws:

  1. Screw adjust the supply of the fuel mixture.
  2. Screw adjust the idle.
  3. The screw limits the maximum speed.

Start the gas mower and wait for it to warm up.

Fuel control.

Start slowly turning the fuel mixture adjustment screw until the engine starts to stall or until it stops if you do not have time to catch the moment. After that, unscrew the screw a quarter turn if the engine is not stalled, or a half turn if it is stalled. Get a stalled engine. Check by opening the throttle valve as the engine picks up speed. Continue to loosen screw number 1 by a quarter turn until the engine starts to accelerate at a higher speed during gassing. It will be the moment of the most economical stable engine operation. In the PRORAB-8406 petrol trimmer, the adjusting screws are turned in a clockwise direction, unscrewed. against, in some other brands of trimmers can be the opposite.

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Idling adjustment.

We start to adjust the low speed. Screw number 2 limits the return movement of the throttle lever. wrapping it, we increase the idling speed, unscrewing. reduce. Adjust so that the engine works confidently at low revs and even slightly accelerated (for a better start), but so that the reel or knife does not rotate, and before the start of their rotation there was sufficient stock of revolutions. If the engine does not start well, increase the idle speed further.

Max rev limit.

After adjusting the fuel supply and low speed, check how the engine of the gas mowers will operate at maximum speed. If necessary, limit the maximum speed to the required level with the # 3 hollow screw. Loosen the locking nut and tighten the screw to reduce the maximum speed, or turn it to increase. After adjustment, tighten the nut. Setting the maximum speed is necessary to protect the trimmer motor from overheating and the possibility of using the release button lock to reduce fatigue of the right hand.
In the future, it may be necessary to adjust the trimmer carburetor. For example, if the engine starts to gain momentum when operating at full load, loosen screw No. 1 by another quarter of a turn. With a difficult start, increase idling speed. Weather conditions and the quality of the fuel mixture can affect the operation of the gas mowers. From the vibration can themselves adjust the screws to turn.

May prevent spring.

My first attempt to adjust the carburetor of the gas mowers did not give anything, since the spring of the screw for adjusting the fuel mixture prevented it. The factory spring turned out to be too thick in the compressed state and did not allow the fuel supply to be reduced to the required level. I had to pick up another spring and continue to adjust after its replacement.
Adjusting screw supplying the fuel mixture with a spring
In the photo above is a factory spring, below is an adjusting screw with a selected spring. I am writing about this because I am not sure that this is an isolated case, and someone else may be faced with the same situation.

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From personal experience.

Gas cutter or trimmer.

Trimmer is a broader concept than a trimmer, as it can also be electric. The gas trimmer and the gas mower are the same.
Some authors claim that the trimmer is a weaker tool, unlike the more powerful trimmer that can be used to cut shrubs. I have a tool with a maximum power of 1.7 kW and capable, as stated in the instructions, to mow shrubs up to 10 mm thick. The user manual is called “Trimmer petrol. “.

Proportion of fuel mixture.

I read somewhere that if in the instruction manual for the gas mowers and on the canister with oil different proportions of the preparation of the fuel mixture are indicated, the proportion indicated in the instruction manual should be used.
For a long time, this was the case. excess oil flowed from the engine to the gas tank, and the candle was constantly forming carbon since the guide indicated the proportion for a running engine of 1:25, and on the canister. 1:50. After the transition to a proportion of 1:50, the appearance of oil drips stopped. The candle continued to burn, but with less intensity (the carburetor was not yet adjusted).
Until now, some users of gas-powered tools the proportion of the fuel mixture is determined “by eye”. If during the preparation of the mixture the amount of oil will be underestimated, after a while there may be a strange sound immediately after the engine starts, which gradually disappears during warming up, and the engine stops with a sharp jerk. Continuation of the trimmer operation in this mode will lead to its failure.

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Candle cleaning.

In the worst times, with a trimmer with an unregulated carburetor, the engine stopped running after using each fuel tank. And only after cleaning the candle from soot could work continue.
Fine sandpaper was used to clean the electrodes, and a thin paper clip with a curved end was used to clean the space between the insulator and the body. First, the electrodes were wiped off with large dirt with a cloth, then washed with sandpaper. After that, the candle was lowered into the diesel fuel, and the soaked soot was scraped off with a paper clip from the surfaces of the insulator, the inside of the body and between them. Further, the candle several times dipped into diesel fuel, which was then shaken off from it along with contaminants. Sometimes the cleaning procedure with a clip and washing was repeated. After that, the candle was wiped dry and was ready for further use.
Incredibly, one tank of the fuel mixture with an unregulated carburetor can be consumed in less than 10 minutes. tested in practice when the trimmer was started and operated at high speeds with maximum fuel supply (the adjusting screw was unscrewed much more than the norm).