In detail: chainsaw partner 350 do-it-yourself carburetor repair from a real master for the site my.housecope.com.
A chainsaw is needed in construction, gardening, and landscaping - its presence greatly simplifies the implementation of a number of woodworking tasks. The main node of this tool is the engine, the operation of which largely depends on the condition and settings of the carburetor. This is where the fuel mixture is prepared. So, if the saw does not start, stalls or does not provide the required power, it is likely that the reason for this is the incorrect operation of the carburetor. Fortunately, in many cases this can be dealt with on your own. Only for this you need to know and understand the device and principle of operation of this unit and, of course, the chainsaw itself.
The main purpose of the carburetor is to mix fuel with air in the required proportions. If the latter are violated, this almost instantly affects the operation of the engine.
Stihl MS 181 C BE chainsaw carburetor
Chainsaw carburetors may differ in design. However, their basic elements and principle of operation remain approximately the same.
Carburetor device:
This is a wind tunnel, across which there is an air damper - with its help, the intensity of the air supply is regulated.
This part is located where the base tube narrows - here the air flow speed increases, i.e. air is always supplied to the carburetor under some pressure.
In this area, the fuel is in contact with the air flow. Fuel enters the atomizer from the float chamber through a jet (dispenser).
float chamber
This is a container that allows you to keep the fuel mixture in a stable state.
Video (click to play).
Structural diagram of a chainsaw carburetor
The chainsaw carburetor works according to the following principle:
when the engine is started, the main damper opens and a jet of air is supplied to the air channel at a certain speed;
the speed of the air flow, as well as the level of the float in the chamber, are regulated by the position of the damper, namely due to the pressure difference in the float chamber and the air channel;
fuel from the float chamber is sucked into the jet, and from there into the diffuser;
passing through the diffuser, the air captures the fuel entering there;
the resulting mixture is fed into the cavities of the cylinders through the inlet channels.
The pressure in the float chamber is approximately equal to atmospheric pressure, but a vacuum occurs in the air channels of the carburetor when the chainsaw engine is started. Opening the damper increases the intensity of the air supply. As a result, more fuel enters the carburetor, and the number of revolutions of the engine shaft increases.
In the first hours of operation, a 2-stroke chainsaw engine requires a break-in, on which the quality of its further work depends. During the break-in process, the carburetor is initially adjusted - the optimal parameters for preparing and supplying the fuel mixture are set.
Chainsaw initial break-in: working with thin material
Most modern chainsaws go on sale adjusted. Nevertheless, the quality of the factory settings does not interfere with checking - in the end, it is you who will have to work with the tool.
When you first start the chainsaw should work in a gentle mode. Therefore, for several hours after the start, it is recommended not to overload the engine and only cut small branches and trunks up to 10 cm thick.
To insure against failures in the operation of the chainsaw carburetor, simple rules will help:
Always mix gasoline and oil according to the manufacturer's specifications. The proportions of the fuel mixture for the chainsaw engine
Do not prepare the fuel mixture in advance - the properties of gasoline and oil in a mixed state are lost over time. The exception is fuel for an intensively used tool, however, even here one should not exceed about a weekly rate.
Use oil designed for your chainsaw engine. A fuel mixture with an abnormal composition will disable it seriously and for a long time.
When preparing the fuel mixture, take into account the influence of climatic conditions on its components.
The chainsaw must start correctly, provide a stable speed of rotation of the sprocket and a smooth increase / decrease in power. When the engine is running, there should be no extraneous knocks, pops and noises.
Professional manual chainsaw at work
The main thing during the initial break-in of the tool is to ensure that the fuel consumption corresponds to the power used, i.e. in practice, the saw should not go out, “sneeze”, smoke and work in jerks.
Typical carburetor malfunctions are easy to recognize. They are expressed in the fact that the chainsaw engine starts and immediately stalls or does not show any signs of life at all. Well, or with might and main consumes fuel, instead of the required power, producing clouds of black smoke and aggressive vibrations.
Scheme of operation of a chainsaw carburetor
Carburetor settings can be violated when:
lack of fixation of the adjusting screws; Chainsaw adjusting screws
piston group wear; New CPG chainsaw Husqvarna 365
blockage of fuel-air channels;
damage to air filters; Chainsaw air filter with nylon insert
poor quality gasoline or oil.
Faults found should be corrected immediately. But how to determine that the matter is in the carburetor? To do this, follow how your tool works.
A list of typical signs that the carburetor settings have gone astray include:
Unstable motor operation
As a rule, the reason for this is the use of the wrong (lean) fuel mixture.
Fuel overrun
It is expressed in an increased emission of exhaust gases, which become black. This means that the fuel is not completely consumed, i.e. the mixture is oversaturated.
The carburetor is set correctly - the saw starts the first time
Arbitrary changes in engine power
May be associated with damage to the fastening of the adjusting screws or the protective cap.
Increased fuel consumption accompanied by vibrations and pops
It speaks of the critical wear of the piston group, so adjusting the carburetor will postpone the overhaul only for a while.
"Sneezing" and jerking the engine
This pattern is observed when the carburetor channels are clogged or its filters malfunction. In this case, the adjustment should be carried out only after a thorough flushing of the assembly.
Chainsaw fuel filter
Despite the fact that the carburetor is the most difficult part of the engine, you should not be upset if you detect failures in its operation. Instead, you need to arm yourself with some tool, a constructive diagram of the node and healthy logic.
Chainsaw carburetor under repair
First of all, you need to prepare a place for disassembly. It can be a workbench or a regular table. In addition, you need a rectangular piece of fabric or cardboard - on it you will carefully fold the carburetor parts. And finally, the tool: for disassembly, you will need a set of open-end wrenches and screwdrivers, a special cleaning compound and an ultrasonic cavitation bath.
Chainsaw Carburetor Repair Tool
First you will have to dismantle the chainsaw carburetor. This is done in this order:
To get to the carburetor, you need to remove the top cover of the chainsaw, fixed with three bolts. Removing the carburetor cover
After removing the cover, do not forget to remove the gasket, which is an integral part of the air filter, and the latter housing, for which you need to unscrew the corresponding nuts and / or remove it from the latches.
On the right side of the carburetor there is a fuel hose; it must be removed together with the air damper actuator rod, not forgetting to pull it off the fitting located on the left. Removing the fuel hose and drive rod
After removing the hose and rod, remove the tip of the damper cable from the locking socket and finally dismantle the gasoline hose. Removing the throttle cable
After that, the carburetor can be removed from the mounts for subsequent disassembly. After removing the gasoline hose, the carburetor is ready for disassembly
The disassembly of the carburetor must be carried out in the manner prescribed by the design and functional solutions of its elements. The parts of the chainsaw carburetor do not differ in size, so you need to fold them carefully and in order, trying not to lose anything.
After disassembly, it is necessary to carry out troubleshooting and replace damaged or worn parts. Next, the entire set should be washed with a special agent, dried and wiped with a dry, lint-free cloth. The jets and tubes of the assembly must be blown out with compressed air, or, in order to more thoroughly remove formations on their internal surfaces, they must be treated with ultrasound before that.
Reassembly of the carburetor is carried out only after complete cleaning, drying and blowing with compressed air. At the same time, do not forget that some gaskets and seals, even in the absence of damage, must be replaced.
You can start adjusting the carburetor, provided that it is properly troubleshooted, of high quality assembly and impeccable re-assembly on the engine.
Carburetor tuning principles:
screws H and L regulate the ratio of air and combustible mixture, i.e. throttle position. Tightening the screws clockwise leads to a lean mixture and the transition of the motor to low speeds. When unscrewing (counterclockwise), the mixture is enriched, and the engine speed increases;
screw T is responsible for adjusting the idle speed: turning it clockwise gives an increase in their number, against - a decrease;
screws are adjusted in L-H-T order. Chainsaw carburetor calibration
The general adjustment algorithm looks something like this:
First, the highest idle speed is found by turning the screw L, followed by a return of ¼ turn counterclockwise. If the chain rotates at idle, turn the screw T in the same direction until it stops completely.
With the engine warm and running at full speed, turn screw H ¼ turn to the left, then let the engine run for 10 seconds, check the maximum speed indicator using a tachometer. It must correspond to the figure indicated in the instrument's passport.
After calibrating with screws L and H, using screw T, the idle speed is adjusted. If everything is done correctly, the engine will run evenly in all its positions. Reminders for carburetor calibration on the chainsaw body
Upon completion of the adjustment, it remains to reinstall the chainsaw cover with an insulating gasket, after which you can begin the main work. If the settings are correct, the chainsaw engine will receive the optimal fuel mixture. This will ensure its normal efficiency, as well as the overall comfort and safety of working with the tool.
Among the huge selection of models on the modern construction market, the Partner 350 chainsaw stands out, which is produced by a subsidiary of Husqvarna.
General view of the chainsaw Partner 350
Simple and easy to use, reliable and unpretentious, this saw has gained wide popularity among summer residents and owners of country houses. Sawing firewood, pruning trees and branches - this is not the whole list of jobs that this model can handle without problems.Despite the well-thought-out design and layout of the units, over time, the power unit, transmission elements and fuel system wear out.
Experienced fellers know that a competent and accurate determination of the nature of the breakdown is half the repair work done. Based on many years of experience in repairing the partner 350 chainsaw, specialists have developed a special method for diagnosing problems.
The main breakdowns of the chainsaw Partner 350
It is worth starting from the simplest nodes and mechanisms, ending with more complex ones.
This allows you to significantly save time and avoid unnecessary operations. Troubleshooting is recommended in the following order:
Chainsaw spark test;
Ignition coil;
Diagnostics of the fuel supply system;
Inspection of crankshaft bearings.
To diagnose the presence of a spark, it is necessary to remove the spark plug and, without removing the high-voltage cable, make several jerks with the starter. If there is a discharge, you will need to set the gap between the central and side electrodes. Its value in Partner 350 should not exceed the limits from 0.7 to 1.2 mm.
Adjusting the spark plug gap with a feeler gauge
Lack of this distance can lead to incomplete combustion of the fuel mixture and, as a result, increased fuel consumption with a limited power unit. As a result of exceeding this parameter, there is an inconstancy in the occurrence of a spark and interruptions in the operation of the internal combustion engine.
If there is no spark on the electrodes, it is necessary to replace the candle and repeat the diagnostic manipulation described above.
If a discharge is also not observed on the replaceable candle, it is necessary to check the integrity of the high-voltage wire and, if necessary, replace it.
The absence of a bright blue spark in the plug may indicate the need to inspect the ignition module and adjust the gap. For these purposes, remove the plastic protective cover from the saw and check the condition of the coil. The wires leading to it must be firmly fixed with screws and must not hang out at the junction. Moisture must not be present on the flywheel of the input shaft, as it interferes with the electromagnetic field.
Flywheel and ignition module of the Partner 350 chainsaw
In the absence of such discrepancies, it is necessary to make sure that the gap between the module and the flywheel is correctly set. Its value should be no more and no less than 0.2 mm, and therefore, if it does not match the recommended distance, you must independently adjust the ignition of the Partner 350 chainsaw.
For the most accurate adjustment, you need a regular coin-shaped or flat probe, which you can buy in specialized or automotive stores.
After checking the ignition, we proceed to the diagnosis of the fuel supply system.
An important influence on the correct operation of the saw is played by the fuel system, consisting of a gas tank, pipes and a carburetor.
Carburetor Partner 350 disassembled
If the mixture does not come out of the tank, it is necessary to inspect the built-in filter and breather (hole in the lid). If the fuel filter is clogged, it will need to be replaced. To clean the breather, you can use an ordinary sharp needle, carefully removing the remaining dirt and sawdust from the valve. If the carburetor is clogged, it will need to be dismantled and thoroughly cleaned.
It must be remembered that the partner chainsaw carburetor is a complex assembly consisting of many small parts. Therefore, when dismantling, cleaning and assembling, maximum attention is required.
The carburetor is used to mix the fuel mixture (oil and gasoline) with air. His work begins with the moment the starter of the saw jerks, which forces the membrane to pump fuel. After that, a diaphragm-controlled needle valve delivers gasoline to the main chamber, through which it enters the cylinder. By means of the throttle valve, it is possible to “enrich” or “deplete” the fuel mixture with air. When it is closed, less air will enter the cylinder at the same fuel level.In this case, the consumption will be increased, coupled with a drop in engine power. Therefore, the adjustment of the Partner 350 chainsaw plays an important role in creating the optimal ratio of moderate fuel consumption with high tool performance.
It is recommended to make self-configuration only if you have special tools and skills.
Before starting adjustment work, it is necessary to clean the main fuel assembly from dust and dirt. To do this, you can use a compressed air compressor or a carpentry brush.
To adjust the carburetor, holes are provided on the left side of the power unit, however, for the convenience of determining their position, experts recommend dismantling the protective plastic casing. First, we tighten the screws for the quantity and quality of fuel clockwise to the stop, loosening them after 1/5 ... ¼ of a turn.
Partner 350 chainsaw carburetor with tuning screws
When the cover is dismantled, you need to know that the fuel mixture quality screw is on the right and, accordingly, the gasoline amount adjustment screw is located on the left. For convenience, the carburetor body under the bolts is marked:
- "L" - fuel amount screw (adjustment at low speeds);
- "H" - mixture amount screw (setting at maximum speed);
- "T" - idle adjustment bolt.
It must be remembered that the adjustment of the carburetor of the Partner 350 chainsaw must be carried out on a warm engine. At high temperatures, the metal expands linearly, as a result of which the throughput of the channels increases.
As soon as the cylinder becomes warm, we tighten the “L” screw until the internal combustion engine gives out the maximum speed of the crankshaft. Then twist it a quarter of a turn. It is worth noting that in this position the screw for the amount of mixture supply must maintain the engine at idle. If such a setting is not enough, then boldly unscrew the “T” bolt until the engine runs stably. Using the “H” screw, we correct the operation of the Partner chainsaw at maximum speed.