How to Clean a Chainsaw Carburetor Video
Any chainsaw is equipped with a two-stroke single-cylinder carburetor engine. Early chainsaw models were equipped with contact ignition, but now almost all manufacturers use electronic ignition, so you do not need to constantly clean the contacts and adjust the gap between them.
The air-fuel mixture for engine operation is mixed in a carburetor. Using a special damper, you can manually impoverish or enrich the fuel mixture for a specific purpose. For example, for cutting solid wood.
From the good technical condition of the carburetor, both the serviceability of the engine and the performance of the chainsaw directly depend. Let us consider in more detail how the chainsaw carburetor is arranged.
Chainsaw carburetor device
Almost all chainsaw models use the identical carburetor design. As an exception, you can call the carburetor of some very cheap Chinese chainsaw. There may not be some parts there, and most of the components are made from very cheap materials.
The main components of the carburetor are:
- Body. It is made of aluminum to facilitate construction, has a one-piece mold. A diffuser, an inlet fitting, an impulse channel, a main screw and an idle screw, a damper regulating the air supply, as well as other elements are installed in the housing.
- Diffuser. Located at the carburetor inlet.
- Jets. Special valves by which the amount of fuel is regulated.
- Float chamber.
An approximate diagram of a carburetor chainsaw
The principle of operation of the carburetor chainsaw
Before you adjust the carburetor on a chainsaw, you need to understand the principle by which it works.
- When the motor starts, the air damper located at the bottom of the housing opens.
- In the air channel and the float chamber, a vacuum is created due to the stroke of the piston, as a result of which an air stream is sucked through the diffuser.
- The suction rate of the air flow is controlled by the position of the air damper.
- Gasoline through the inlet fitting from the gas tank enters the float chamber.
- The speed of gasoline passage from the chamber to the diffuser is regulated by means of jets.
- In a diffuser, gas is mixed with air.
- The prepared air-fuel mixture enters the inlet channels, from where it is sent to the working combustion chamber of the cylinder.
The main malfunctions of the carburetor on a chainsaw
It should be understood that the dimensions of all holes are very small. Even the smallest pollution can block the flow of air or fuel, so filter elements are installed on the inlets. Unfortunately, they do not always cope with the task. The following symptoms indicate malfunctions of the carburetor of the chainsaw:
- High gas mileage and heavy smoke from the exhaust;
- The engine does not pull;
- Floating revolutions;
- The motor starts, but stalls immediately or after a few seconds;
- The motor does not start at all.
- Chainsaw shoots at carburetor
All these malfunctions are a sign of a violation of the carburetor adjustment on the chainsaw or it is dirty. Hence the need for adjustment, cleaning or repair. How to do this. Consider below.
How to adjust the carburetor on a chainsaw yourself
The factory settings of the carburetor of the chainsaw provide for the optimal parameters of suction of fuel and air. But in the process, they can go astray due to vibration. Even a shift of ¼ revolution in any of the screws can lead to a serious change in the preparation of the air-fuel mixture and it is necessary to adjust the chainsaw carburetor.
How to Clean a Chainsaw Carburetor
The chainsaw carburetor is adjusted using three screws marked H (High), L (Low) and S. The last screw, depending on the brand and manufacturer, may have other names, for example T or LA.
- H: responsible for the operation of the main jet and adjusts the maximum speed.
- L: adjusts the position of the idle nozzle and allows you to adjust low revs.
- S / T / LA: is intended to regulate single turns of the engine.
To know how to properly set up a carburetor on a chainsaw, a technical passport is required. It contains information about the angle of rotation of the adjusting screws. After that, go directly to the adjustment. By the way, here you will need a screwdriver to adjust the carburetor of the chainsaw or a regular flat screwdriver:
- Install the chainsaw on a flat surface, preferably a table or something similar.Important: The chainsaw must be positioned so that the tire is pointing in the opposite direction. The engine must be turned off.
- Using a wrench or a screwdriver, unscrew the fasteners of the housing cover and remove it to get to the carburetor.
- Remove the air filter that covers the carburetor for the chainsaw. The manufacturer can install a shock-absorbing foam insert on top of the carburetor. It must also be removed.
- Now starts setting up the carburetor chainsaw. Screws L and H must be fully tightened. Twist them slowly and carefully so as not to break.
- Loosen both screws approximately 1.5 turns.
- Start the engine and let it run for about 7-10 minutes so that it warms up well. It will not work to adjust the chainsaw carburetor on a cold engine.
- After the engine warms up, set its operation at medium speed.
- Slowly start anti-clockwise tightening the idle screw. Spin until the motor runs smoothly. In case the engine starts to stall, it is necessary to continue adjusting the carburetor of the chainsaw and gradually return the screw clockwise.
After adjusting the carburetor of a Chinese-made chainsaw or any other, it is necessary to “drive” the engine at different speeds.
How to remove a carburetor from a chainsaw?
Either the engine does not start or stalls immediately, most likely the carburetor is clogged and needs to be cleaned. How to check carburetor chainsaw? You have to disassemble. Otherwise it will not work.
Before you clean the carburetor on a chainsaw, it is still recommended to check other components: air and fuel filters, spark plug and muffler. It is possible that they are clogged. It’s easier to clean the filter or replace the spark plug than to clean the carburetor on a chainsaw. By the way, it is the problem with the candles that is the reason why the chainsaw shoots at the carburetor. Ignition too late leads to the formation of an excess of air-fuel mixture, since it does not have time to burn out completely.
In the event that the problem persists, you will have to remove the carburetor. It is very easy to do:
- Remove the plastic back cover. It rests on the latch or on the thread.
- Dismantle the air filter.
- Use a flat screwdriver to pry off the air traction and remove it. Traction can be two or three, depending on the model.
- The carburetor is attached with two mounts. They are located diagonally. You need to unscrew them.
- Disconnect the gas hose through which fuel is supplied to the carburetor from the gas tank.
How to clean the carburetor on a chainsaw?
Rinse the carburetor of the chainsaw or clean it only when it is removed and disassembled. Before cleaning, you need to prepare everything you need in advance: two screwdrivers (plus and minus), open-end wrenches, but better a head with nozzles, a clean rag, a special cleaning agent, a pump and an ultrasonic cleaner (recommended). Before you start cleaning, you need to drain all the gasoline. This is a must. After the remaining fuel is drained and the entire tool is prepared, proceed to cleaning:
- Disconnect the top cover and remove it.
- Carefully remove the fuel pump diaphragm.
- On the left side of the case are spring brackets. After they are disconnected, under the brackets you can see the screws. They also need to be unscrewed.
- Unscrew the bottom cover.
- Having unscrewed the screw, you get access to the needle valve. It and the spring located beneath it must be carefully removed so as not to blunt the needle.
- The air damper is dismantled with a small longitudinal force, after which the damper axis is removed.
- Lastly, the throttle, lever and axle are removed.
After the carburetor is disassembled, all parts must be laid out on a flat surface on a clean rag. Carefully inspect every part for clogging or wear. Pay particular attention to the nozzles and the inlet fitting. Their clogging is the main reason why gasoline does not enter the chainsaw carburetor.
If for some detail it is clear that it is worn out, it is better to immediately replace it with a new one, so that in the future you don’t have to think again how to repair the chainsaw carburetor.Do-it-yourself chainsaw carburetor cleaning is done using a special detergent. It is necessary to rinse every detail well, and then dry them with a rag from a lint-free cloth, and preferably with compressed air. All channels are also blown by air.
If you have an ultrasonic cleaner on hand, this is even better. Pour diesel fuel into the bathtub, put the contaminated parts carefully there for 5-10 minutes and dry them with compressed air after cleaning.
Assemble in the reverse order. A very important point is the installation of a needle valve. It should rotate freely in the seat. If the petal wedges, gently squeeze it or press down so that it sits deeper.
After cleaning, it is strongly recommended to wait 20-24 hours. This is necessary so that the cleaning agent completely evaporates. Otherwise, it mixes with the air-fuel mixture and enters the cylinder, leaving carbon deposits on the walls after combustion.