In detail: do-it-yourself piran chainsaw repair from a real master for the site my.housecope.com.
A chainsaw is a worthy replacement for hand saws and axes. Today, this tool is available in almost every household - it is indispensable for arranging a personal plot, construction and repair work. Intensive use and improper care of the tool can lead to premature tool failure. However, it is not at all necessary for the owner of a chainsaw to immediately contact the workshop - many of the malfunctions that can happen to it during operation can be eliminated on their own.
The main condition for a successful repair is the correct diagnosis. Therefore, in order to determine why the chainsaw failed and, most importantly, how to make it work again, you first need to know the features of its design.
It should be noted that it does not differ in particular complexity, since it includes:
- engine (two-stroke gasoline);
- functional part (saw bar and chain);
- systems that ensure the joint operation of these two components (ignition, filtration, lubrication, etc.), that is, the tool as a whole.
In order to simplify the diagnosis of faults, it is customary to distinguish them into two main categories:
- engine malfunctions;
- malfunctions of other components of the chainsaw.
Most often, failures occur in engine systems, however, other parts of the tool, due to intensive use or improper care, can fail at any time. How to determine exactly where the breakdown occurred? Simple logic will help us with this.
If the problem is in the engine, it will:
Video (click to play). |
- do not start;
- go deaf;
- unsteady work;
- overheat;
- smoke;
- develop insufficient power.
As for all other malfunctions, as a rule they manifest themselves with a normally running motor.
If the chainsaw won't start, the first thing to do is to check the fuel mixture in the tank. By the way, it must be prepared in the proportions specified by the engine manufacturer, otherwise the tool simply will not start.
After making sure that the fuel mixture is correct and available, the ignition system should be checked. To do this, inspect the spark plug.
Her condition can say a lot:
indicates that the fuel mixture does not enter the carburetor, which means that the problem is not in the ignition;
is the result of an excess of the fuel mixture, which lies either in a violation of the engine start algorithm, or in improper carburetor adjustment;
this is a signal about the presence of low-quality oil in the engine lubrication system, incorrect carburetor settings, or an incorrectly prepared fuel mixture.
If the spark plug is splashed with fuel, wipe it thoroughly after removing it. You should also clean the fuel supply system. To do this, it overlaps, after which the starter is turned on. A carbon-covered candle must be carefully cleaned with an awl and emery.
When checking candles, attention should be paid to the distance between the electrodes (the normal gap is 0.5-0.65 mm), as well as the condition of the gasket and the presence of a spark. A damaged or worn gasket will have to be replaced, and the spark can be checked by putting on the ignition cable, connecting the cylinder and spark plug nut, and cranking the starter.
If the discharge does not occur, the candle must be replaced. In the event that a spark does not appear with a new candle, then the problem is in the connection with the high-voltage wire or in itself.
If the fuel mixture does not enter the cylinder, but the spark plug is working properly, this may mean that:
- The fuel filter is clogged.
To clean this assembly, remove the fuel hose and check the jet. If it is weak, the filter must be removed through the filler hole of the fuel tank and cleaned or replaced in case of complete wear.
As a preventive measure, it is recommended to replace the fuel filter at least once every 3 months.
This is nothing more than a hole in the fuel tank cap, which is cleaned with an awl.
- The fuel mixture is not supplied or supplied in insufficient quantity.
There may be several reasons for this:
- the air filter is clogged (in this case, it must be removed, rinsed with water, dried and put back in place);
- the carburetor settings have gone astray (which means this assembly must be re-adjusted);
- the integrity of the carburetor membrane is broken (it must be replaced);
- the carburetor channels are clogged (it must be disassembled and cleaned of all parts and assemblies).
If the chainsaw motor works fine at low speeds, but starts to stall and smoke at high speeds, the problem may be hiding in the muffler.
To check the quality of its work, do the following:
- dismantling (with obligatory closing of the outlet);
- disassembly (if the muffler is collapsible);
- cleaning from carbon deposits using special detergents or by dry method;
- drying (using a hair dryer);
- reassembly and installation.
Dry cleaning without respiratory protection is not recommended. The carcinogens present in soot will be released into the surrounding atmosphere in the form of dust, the inhalation of which is extremely dangerous to health.
To prevent clogging of the muffler during the operation of the chainsaw, you should carefully monitor the composition of the fuel mixture and the quality of its components.
If the chainsaw engine does not start or cannot develop normal power, it is likely that there is not enough pressure in the engine cylinder to burn the fuel mixture. The reason for this may be the wear of the elements of the cylinder-piston group - piston, rings, bearings, etc. In order to assess the condition of this assembly, it is necessary to conduct a visual inspection of it, after removing the muffler.
For a more complete diagnosis, a compression gauge is placed in the spark plug hole of a two-stroke chainsaw engine. It measures the compression in the engine. Based on the results of the check, one can judge the state of the CPG, however, accurate facts can only be obtained with a complete disassembly of the assembly.
If there are chips or scratches on the piston, it is obvious that it will have to be replaced. The same applies to deformed or broken piston rings - for normal engine operation, they must be fully functional and clean from carbon deposits.
A properly working carburetor guarantees maximum efficiency of the chainsaw, that is, it is possible to develop full power with the most economical consumption of the fuel mixture. The adjustment of this unit is usually carried out by the manufacturer, however, its design provides for the possibility of adjustment during operation.
The fact that such a setting will have to be performed by the owner of the chainsaw is evidenced by:
- Strong vibrations or damage to the protective cap.
- Depreciation of the CPG.
- Clogged carburetor.
- Inability to start the engine or its spontaneous stops after starting.
- Increased fuel consumption and emissions while reducing engine power.
The chainsaw carburetor is adjusted in strict accordance with the manufacturer's instructions using three special screws that are responsible for the maximum ("M") and minimum ("L") revolutions, as well as idling the engine ("T").In order to exclude unwanted interference by an inexperienced user in the operation of the carburetor, some manufacturers install only one idle screw.
Carburetor adjustment is carried out in two stages:
- Basic (carried out with the engine off).
- Finishing (carried out with a running, preheated engine).
For basic adjustment it is necessary to tighten the screws H and L until they stop and turn them back 1.5 turns. Finishing adjustment requires that the engine be warmed up for 5-10 minutes at low speeds.
The final calibration is carried out by turning the idle screw until the minimum engine speed is reached (its operation must be stable and the chain must be stationary). If the engine stops idling, the screw must be turned back, and if the saw chain is still driven, continue to turn it counterclockwise.
Calibration check is done by test:
- Accelerations (when you gently press the accelerator, the engine should quickly gain momentum to the maximum rate).
- Maximum speed (if there is a misfire, screw H should be slightly loosened).
- Idle operation (the chain should not move, and the engine should pick up speed as quickly as possible).
If the owner of the chainsaw is not familiar with the carburetor device and does not have the tool necessary to calibrate it, you should contact a specialist. The carburetor is a very complex unit, so any wrong action can lead to irreversible consequences, such as complete failure of the engine.
If the diagnostics showed that everything is in order with the engine and its systems, then the cause of the malfunction should be sought in other components of the chainsaw. The most common problems are:
- starter failure;
- improper operation of the lubrication system;
- incorrect operation of the chain brake;
- saw chain wear, etc.
If the cause of tool failure is not visible to the naked eye, as is the case with an engine, a thorough fault diagnosis must be made and corrected in accordance with the manufacturer's recommendations and safety regulations.
It would seem, why would a summer resident who grows vegetables and fruits need a chainsaw, or an owner of a country house with a small garden and several flower beds? The question disappears when there is a desire to build a bathhouse, renew a greenhouse, knock down an old business, or simply make a bench for relaxation. Unfortunately, any mechanism periodically needs maintenance and replacement of spare parts, and for this you need to be well versed in the design of the product, in addition, repairing a chainsaw with your own hands will save time and money.
- Structural components of a chainsaw
- Checking the ignition system
- Repair of the fuel supply system
- Dismantling and cleaning the muffler
- Assessment of the state of the cylinder-piston group
- Repairing the chain lubrication system
- Chain brake adjustment
All chainsaws are similar in their structure, regardless of whether they are made in Europe (ECHO, Stihl, Husqvarna) or domestic (Kedr, Ural). Inside the body are the main elements - a fuel tank and an engine, and outside the starter, a handle, a saw part (tire) with a chain. A sharp jerk of the cable starts the engine, and that - the saw blade.
To get started, we suggest that you familiarize yourself with the video clips that show how the chainsaw is arranged and how it works:
From time to time, malfunctions occur in the operation of the saw, which require disassembly to eliminate. What can happen to such a simple mechanism as a chainsaw? At least the following:
- Stops starting;
- Starts, but soon stops;
- Ceases to function in the cut;
- Loses its power;
Most of the problems are associated either with interruptions in the operation of the engine (fuel supply system, exhaust system, ignition, cylinder-piston part), or with malfunctions of other systems and components (clutch, chain brake, tire, lubrication system). Consider the most common breakdowns and methods for their elimination.
A serviceable chainsaw starts with one jerk and does not fail in cutting
The first thing to do when a chainsaw breaks down is to inspect the spark plug by disconnecting the wire and carefully turning it out with a special key.
Components of the chainsaw ignition system: 1 - flywheel with magnets, 2 - ignition module, 3 - candle, 4 - high voltage wire
The spark plug is unscrewed to check its condition.
Her appearance says a lot:
- Dry. Most likely, the fuel mixture does not enter the cylinder. It's not the ignition system, so the candle is twisted back.
- Heavily splashed with fuel. The reason for the excess fuel mixture lies either in violation of the rules for starting, or in improper adjustment of the carburetor. The candle is thoroughly wiped, the fuel supply is turned off and the starter is turned on - to remove excess fuel and ventilate the combustion chamber. Then the candle is placed in place and the mechanism is started again.
- Covered with black soot. This may indicate the use of low-quality oil, an incorrectly adjusted carburetor, or an incorrectly calculated ratio of gasoline and oil. The candle should be washed, cleaned of soot with a sharp object (awl or needle), wipe the electrodes with a sandpaper and place in place.
When checking the candle, you need to pay attention to the gap between the electrodes: from 0.5 to 0.65 mm is considered normal. A damaged or worn gasket must be replaced.
A large amount of black soot on the spark plug indicates a malfunction in the engine
To be completely sure, you should also check for the presence of a spark. To do this, put an ignition cable on the spark plug, connect the spark plug nut and the cylinder with pliers, start the starter and watch for a spark. If it is missing, the spark plug needs to be replaced. If the new spark plug doesn't spark either, the problem is with the high-voltage wire or a loose connection to the spark plug.
Fuel may not enter the cylinder for the following reasons:
- Fuel filter dirty. Remove the fuel hose and check how the fuel flows. If the jet is weak, the filter may need to be cleaned. It is taken out through the filler hole of the fuel tank and cleaned; in case of severe contamination, it is replaced with a new one. As a preventive measure, it is recommended to replace the fuel filter every three months.
- Clogged breather (holes in the fuel tank cap). They also check by disconnecting the hose, in case of blockage, clean with a needle.
- No or insufficient fuel. There may be several reasons for the failure. The first reason is a clogged air filter. The air stops flowing into the carburetor in the right amount, in connection with this, due to an overly enriched fuel mixture, engine operation is disrupted. The dirty filter is carefully removed, cleaned and washed in water, then dried and replaced.
Another reason is the incorrect adjustment of the carburetor. Adjustment is made with three screws.
Timely replacement of the fuel filter guarantees a full supply of fuel
The fuel hose and the air damper actuator must fit snugly against the fittings
Throttle lever cable must be in place
During operation, you must use the instructions, otherwise you can only make things worse.
Related article: Chainsaw carburetor adjustment: technical nuances
And the last reason is a violation of the integrity of the membrane or clogging of the carburetor channels.
To repair the carburetor yourself, you need to get acquainted with all its details
All parts must be clean, dry and in good condition.
If the engine runs fine at low speeds, but starts to stall at high speeds, the reason may lie in the muffler spark arrester, clogged with combustion products.
- remove muffler;
- disassemble (there are also non-separable models);
- clean from soot using detergents;
- dry with a hair dryer;
- put in place.
Dry cleaning is unacceptable, as carbon deposits contain carcinogens, the inhalation of which is dangerous to health. After removing the muffler, cover the outlet with a clean cloth.
Interruptions in the operation of the chainsaw signal a possible clogged muffler
To prevent clogging of the muffler, it is necessary to monitor the composition of the fuel mixture. The amount of oil should not exceed the norms recommended by the manufacturer. Poor oil quality also negatively affects engine performance.
Often the engine does not start or does not run at full capacity due to low cylinder pressure. It can be caused by worn pistons or cylinders, slipped piston rings, or worn bearings. You can partially examine the state of the cylinder-piston group (CPG) by removing the muffler and looking into the opened hole.
A compression gauge placed in the spark plug hole will help measure the compression in the engine - based on the results of the measurement, one can also talk about the state of the CPG. Accurate data is obtained only after the complete disassembly of the mechanism. If the piston has chips or scratches, it must be replaced. The piston ring must be clean, free of carbon deposits, and in exactly the right place.
Wear of the piston and crank mechanism is considered a serious problem
Based on the results of measuring compression, one can judge the condition of parts of the CPG
Consider three main faults:
- Oil leakage. It should be checked whether the tubes are hermetically attached to the pump fittings and whether they are cracked. Problematic tubes are sealed with sealant or changed.
- Insufficient oil supply. Most likely, the lubrication channels are clogged.
- The occurrence of cracks in the oil pump housing. A part needs to be replaced.
Here is how the lubrication system is diagnosed:
The chain brake often does not work due to grease or sawdust clogging the brake band and the space under the cover. All parts must be cleared of blockages. Perhaps the tape is simply worn out, then it needs to be replaced.
The operation of the chain brake is restored by mechanical cleaning
Some chainsaw parts wear out faster than others. These include the drive sprocket, tire, chain, anti-vibration elements. For quick replacement of spare parts, it is better to always have at hand. Do not neglect the sharpening of the chain.
The chainsaw has become such a familiar and necessary tool in the hands of a skilled man that if it fails, we begin to feel uncomfortable. But the design of this unit is so simple that we can make almost any repair of its components ourselves. But what do you need and how do you repair a chainsaw with your own hands?
You need to have a very small set of tools for this:
- a set of keys (including a special key for spark plugs);
- chainsaw device diagram (usually it is included in the package).
You also cannot do without elementary knowledge from the course of physics. Add to this the ability to reason logically, and you are almost ready to repair a chainsaw.
We will start the repair with a "diagnosis" - the definition of a malfunction. First you need to unscrew the candle and carefully examine it. Possible problems are listed below.
Types of spark plugs for chainsaws.
The candle is wet. We draw a logical conclusion that the fuel mixture inside the combustion chamber does not ignite. The second reason could be water getting into the cylinder.In any case, you need to dry the candle, blow out the cylinder. We do the same steps as when winding a chainsaw. The only difference is that the fuel supply valve must be closed and the throttle valve fully open. After that, we put a cradle from the wire on the candle and check for a spark by pressing the candle against the cylinder body and trying to start the engine. If the spark is good, then the cause may be fuel - it needs to be replaced. If the spark does not appear or appears unevenly, then the cause of the malfunction should be sought in the ignition system. Perhaps there is a breakdown of the high-voltage wire or damage to the candle itself. It is enough to try to use a spare candle to make sure that the first candle can still be used. If the spare spark plug does not respond to the start test, then the ignition system should be more thoroughly examined.
The candle is dry, but heavily covered with soot. This fact indicates that the balance between fuel and oil is disturbed (too much oil!) Or one of the filters is clogged (fuel or air). Clogged filters lead first to a loss of power of the chainsaw, and then to a complete stop. Dust that gets inside the cylinder cannot burn out completely and settles on the inside of the cylinder in the form of a dense layer of soot.
Chainsaw fuel system: 1 - fuel filter, 2 - carburetor, 3 - manual pre-priming pump.
This drawback is eliminated as follows: the fuel is replaced, the fuel filter is cleaned (according to the instructions), the air filter is washed and dried. The candle itself is mechanically cleaned of soot with an awl, its contacts are cleaned with fine sandpaper.
The candle is dry and clean. Apparently no fuel is getting into the cylinder at all. The cause may be either a clogged conductive tube, or problems with the carburetor. It is necessary to clean the fuel line of the chainsaw and check the operation of the fuel pump and carburetor. Repair of these chainsaw components at home is almost impossible, so they are simply replaced.
Regarding the chainsaw carburetor, it is still necessary to clarify a few important points: manufacturers minimize the possibility of adjusting it, leaving access only to idle adjustment. But even such a small amount makes it possible to achieve maximum power from the chainsaw.
By properly adjusting the idle speed, you will notice that the engine has become more reliable.
But it is better to entrust the repair of the carburetor to the service specialists, since it can be done independently only if you have extensive experience and certain knowledge.
Scheme of a two-stroke chainsaw engine.
We will assume that you were able to do everything exactly and your chainsaw began to show signs of life, but there are problems with power. It happens very often that the engine runs well at idle, but the chain speed increases very slowly when the accelerator lever is pressed, or the chainsaw simply stalls. The problem may be that the hole for exhaust gases is clogged. It is not difficult to eliminate this shortcoming.
First you need to unscrew the muffler. The piston must be set to its highest position so that it blocks the channel and excludes the possibility of soot entering the cylinder. And now the soot must be carefully scraped off the walls. You can use both a screwdriver and a thin chisel for these purposes. When cleaning, we try not to make great efforts, as you can easily mechanically damage the cylinder or piston. After removing the plaque, we wipe the cleaned surface with diesel fuel or gasoline, and the muffler can already be screwed on. Before this, the non-separable muffler should be washed with diesel fuel or low-octane gasoline and dried. Removing soot will increase power.
It is possible that none of the home repair methods described have led to the desired result and the chainsaw is still not working. Most likely, you have a malfunction in the ignition system. It turns out that the fuel is supplied, and the spark on the candle is excellent, but the engine refuses to work.