How to Adjust a Stihl Chainsaw 250 Video
Chainsaw carburetor adjustment: we analyze all the technical nuances of work
Suburban construction and repair can not do without the use of chainsaws, as well as garden care. Due to a malfunction of the tool, all the work can get up, so it is so important to be able to disassemble it yourself, find problems and fix them. With enough experience and dexterity, even adjusting the carburetor of the chainsaw is possible. The procedure is complex, or rather, jewelry. How to carry out adjustment procedures, we suggest that you take apart today.
Chainsaw carburetor device
Not a single repair measure is complete without knowledge of the fundamentals of the mechanism. Understanding the components and the principle of operation, it is easier to determine the cause of the breakdown.
Any malfunction in the carburetor threatens to stop the engine
The carburetor is one of the main functional parts of the engine, which serves to prepare and supply the fuel mixture, consisting of certain proportions of fuel and air. As soon as the proportions are violated. The engine begins to “junk”, and even completely stops working.
You can achieve the correct operation of the carburetor by examining its “filling”:
- Tube with transverse flap for adjusting air flow.
- Diffuser. Constriction to increase air flow rate, located near the fuel inlet.
- The atomizer from which the fuel is supplied (fuel needle in the diagram).
- A float chamber that controls the fuel level at the entrance to the channel.
Here’s what it looks like in the diagram:
The diagram shows the interaction of fuel and air flow.
Principle of operation: a stream of air in a diffuser sprays fuel, creating a mixture entering the cylinder. The greater the amount of incoming fuel, the higher the engine speed. Carburetors of various models work according to the same scheme.
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When is adjustment necessary at all?
Specifically, adjusting the carburetor of the chainsaw is required in rare cases, more often there are problems associated with the flow of fuel or the wear of parts. But sometimes “symptoms” indicate that it is necessary to regulate the mechanism. Here are some signs:
- After the engine starts, it immediately stalls. As an option. It won’t start at all. The reason is an excess of air and a shortage of fuel.
- Increased fuel consumption, and as a result. A large amount of exhaust gas. This is due to the reverse process. Supersaturation of the mixture with fuel.
The reasons for the adjustment failure can be mechanical:
- Due to strong vibration, the protective cap is damaged, as a result, all three bolts lose their installed fixation.
- Due to wear on the piston of the engine. In this case, setting up the carburetor of the chainsaw will help out only for a while, it is better to replace the worn part.
- Due to clogging caused by low-quality fuel, scale or damage to the filter. The carburetor requires complete disassembly, flushing and adjustment.
If the chainsaw suddenly stops working, it is necessary to disassemble it to find out the reasons.
Step-by-step disassembly instructions
The carburetor device of models of different brands is almost the same, so let’s take the Partner chainsaw as an example. Each element is carefully removed and stacked in order, so that later it is easier to assemble.
Carburetors of chainsaws from different manufacturers, if they differ, then not fundamentally
The top cover is removed by unscrewing the three bolts. Following it is foam rubber, an integral part of the air filter.
The arrows indicate the bolts that must be unscrewed to remove the cover
Then we remove the fuel hose, followed by the drive rod.
The upper arrow indicates the fuel hose, the lower arrow indicates the drive rod.
Next, remove the tip of the cable.
The arrow shows the tip of the cable to be removed.
To the left of the fitting we tighten the gas hose.
We also carefully remove the gas hose indicated by the arrow
The carburetor is finally disconnected, it is ready for adjustment. Its mechanism is quite complicated, therefore, if further disassembly of the carburetor is required, the elements should be removed very carefully. They are small, therefore they can be lost.
The carburetor consists of many small parts that should be laid out in order during disassembly
Features of adjustment and adjustment
To learn how to adjust the carburetor on a chainsaw, you should learn to distinguish between three screws (some models have only one).
Screws L and H are similar only in appearance, in fact they are different
Each screw has its own letter designation:
- “L” is used to set low revs;
- “H” is necessary to adjust the upper revs;
- “T” is needed to adjust the idle speed (only one model is present on models with one screw).
Factory adjustment is optimal, and with the help of screws adjust the engine in special situations (work associated with different climatic conditions).
The diagram shows the outputs of the carburetor adjustment screws with the lid closed
A special tool is used to set up the chainsaw
The adjustment is carried out only with screws L and N. To increase the speed, they are rotated clockwise. To lower. Counterclockwise. The sequence of use of the screws: L. H. T.
If you have doubts about the adjustment, it is better to consult a specialist, as improper tuning can damage the engine.