Finding Reasons Why a Chainsaw Doesn’t Start
Amateur and professional chainsaws are complex devices. The engine life of their two-stroke engines, components and assemblies has its limitations. For this reason, quite reliable and expensive tools along with cheap Chinese units periodically fail and refuse to start. The situation when the chainsaw does not start or stalls is not very pleasant and sometimes confuses the user. How to identify and fix a malfunction by returning the instrument to working condition.
Identification and elimination of obvious malfunctions of the chainsaw.
To determine the reason why the chainsaw does not start up or stalls when starting, it is necessary to carry out a defect in the tool. The essence of the procedure is the sequential inspection of the state and operation of the main working elements of the saw engine. At this stage, we check:
- The presence of sparks on the spark plug;
- Fuel supply;
- State of filters;
- The operation of the breather of the stalling unit integrated in the fuel cap;
- The functioning of the exhaust channel.
Check spark on spark plug and eliminate causes.
The first step in finding the reasons why the gasoline saw does not start is to check the spark on the spark plug. There are many factors that influence the operation of this element. However, the main ones at the initial stage of instrument troubleshooting are:
- Incorrect carburetor adjustment;
- The presence of more than expected oil in gasoline;
- Clogged air filter.
All of them contribute to the formation of carbon deposits on the electrodes of the candle. In 50 cases out of 100, the saws do not start up cold due to the lack of spark due to deposits of carbon deposits on the electrodes and their corrosion. As a result, there is either a decrease in the gap or an increase in it.
Checking the spark plug for an idle chainsaw
Checking for a spark is pretty simple. This will require:
- Remove the tip of the high voltage wire;
- Unscrew the candle;
- Put the tip back;
- Lean the candle with the skirt against the cylinder;
- Start with starter.
If a good spark is observed between the electrodes at the moment of starting the chainsaw engine, then everything is in order with the ignition unit. If it is not there, then it is worth cleaning the element itself and checking the electrode gap. If necessary, use a special probe to adjust the distance between the contacts.
For candles of different manufacturers, the distance between the electrodes can fluctuate. In some, it can be equal to 0.5 mm. Others have 0.2 mm. Therefore, carefully read the manufacturer’s recommendations.
Sparks on the spark plug may not be for other reasons. Of the main malfunctions that affect the poor start of the chainsaw and the unstable operation of the internal combustion engine at idle, from which the tool can stall, the following can be attributed:
- Overfill of the candle channel with fuel;
- Lack of contact between the high-voltage cradle and the tip of the candle;
- Failure of the ignition unit.
How to start a cold chainsaw, if the candle channel is constantly filled with gasoline? To fix the problem at the time of starting the tool, you can use the following algorithm:
- Unscrew the candle with a special key;
- Wipe it with a clean and dry rag;
- Dry for 20. 30 minutes;
- Remove the soot with a file and adjust the gap between the electrodes;
- Drain the remaining fuel from the candle channel and dry it;
- Collect everything and try to start the mechanism.
As a rule, these measures are enough to start the chainsaw and do the work. However, this extreme measure does not eliminate the main reason why the engine does not start or stalls. The carburetor is not working properly, which needs to be finely tuned.
If there is no spark due to poor contact of the high-voltage cradle with the tip of the spark plug, check the connection. Verification can be carried out using a conventional tester. If a defect is found and corrected, the chainsaw should start without any problems.
If the check shows that the contact is reliable, and the saw does not start further, look for the cause in the ignition unit. As a rule, a faulty unit cannot be repaired or repaired. It will require a complete replacement.
We determine the availability of fuel and its supply.
First you need to make sure that in the tank of the chainsaw that does not want to start, there is a fuel mixture, and it regularly enters the carburetor. With a full tank, we check how the mixture is fed through a gas line. Disconnect the fuel system tube from the carburetor and try to pump up. In the case of a complete order, when pumping, gasoline will be supplied jerkily in accordance with the standards set by the manufacturer. Poor fuel supply or lack thereof may result:
- The fuel supply channel is clogged;
- Clogged fuel filter.
Often the cause of a poor start of the chainsaw can be too full a tank. In this case, it is worth paying attention to the presence of smudges under the cover of the saw case. If they are present, see the connection of the gasoline supply pipe to the carburetor. Most often, it is squeezed out by pressure when tightening the cap of the tank, tucked under the very neck, which prevents the engine from starting up.
The quality of the fuel mixture can also be one of the reasons why the chainsaw does not start. If, after completing the work, the gasoline residues are not drained and the instrument is left for long-term storage (more than 2 weeks), then resin formation and polymerization of the components will start inside the tank. What can cause carbon deposits on the piston, rings and cylinder liner. Therefore, always before cooking, prepare the mixture only in the required quantity.
Checking the condition of the fuel and air filters.
If everything is in order with the fuel quality, the chainsaw engine may not start because of clogged fuel and air filters. To diagnose these elements, a number of manipulations related to their dismantling will be required.
For fuel filter:
- Disconnect the gas supply channel from the carburetor;
- Pump up fuel.
If the pressure is low or absent, the filter should be disconnected. Before this, empty the tank from the mixture and remove the filter element itself. Dismantling is carried out by means of a wire hook. A clogged replacement cartridge that has caused poor engine start-ups can be cleaned, but it is best to replace it with a new one. When using the tool in dusty conditions, cleaning should be done on a regular basis.
A clogged air filter can cause the chainsaw engine to become unstable, causing it to stall or become difficult to start. Dust and dirt deposited on the absorbent material make it difficult for air to enter the system, make the fuel mixture so enriched that it can be difficult to start the tool.
Checking the air filter is one of the first steps in finding the causes of a poor start.
Removing the air filter should be done with caution, since dust accumulated during the operation of the saw on its surface can get into the carburetor. And this is fraught with more expensive repairs. After detaching the cartridge, thoroughly clean it of accumulated dirt and rinse with detergent. Dry the element and put it back in place as well.
Check the breather and clean it.
The breather is another element from the malfunction of which the chainsaw may not start or stall during sawing. This item is located on the fuel cap in the area of the air hole. This is a kind of valve that does not allow gasoline to flow out and equalizes the air pressure necessary for the free flow of fuel into the carburetor.
In case of contamination of the breather, the working chainsaw stalls, and at startup it refuses to start. The thing is that through the hole air stops flowing. As a result, a negative pressure (vacuum) is created inside the fuel tank, which prevents the flow of gasoline to the carburetor.
Identifying the problem is quite simple. Disconnect the fuel supply hose from the carburetor and see what happens to gasoline. If it flows smoothly with a good trickle, then the breather is all right. If it is absent or it flows weakly and intermittently, then the reason is identified. The breather is clogged with dirt. You can solve the problem by cleaning the air hole with a regular needle or a powerful jet of compressed air.
Checking the outlet of the chainsaw.
One of the reasons that the chainsaw starts poorly may be the clogging of the exhaust duct or its muffler. At the same time, a drop in power is observed in the process of sawing lumber and logs. Most often, this occurs due to tarry deposits on the spark catcher or the silencer channel, which are formed during the combustion of a poor-quality mixture of gasoline and oil, which interfere with the exhaust gases.
Clogged resonator can cause poor start of gasoline saw
To eliminate the cause of a poor start of the chainsaw, in this case, you can remove the accumulated combustion products. To do this, perform a series of manipulations:
- Remove the muffler by unscrewing the screws;
- Remove the cooling panel and gasket;
- Remove the spark arrester;
- Disassemble the resonator housing;
- Wash all elements from carbon deposits with detergent;
- Let them dry completely;
- Assemble everything in reverse order;
To prevent dust and sand from entering the cylinder when cleaning the muffler, close the exhaust duct of the chainsaw engine with a clean rag.
What to do if the chainsaw does not start further?
If the initial inspection did not give anything or the defects in the search process were eliminated, and the chainsaw does not start further, then you need to look for more serious reasons. It is best to identify and fix such breakdowns in the service center. However, if you have experience, you can find and eliminate them yourself. What to diagnose and check?
- Compression in the cylinder;
- Compression in the crankcase;
- Carburetor operation.
In the first case, checking the compression in the cylinder will determine the state of the cylinder-piston group (CPG) of the chainsaw that does not want to start up in the cold. To do this, you need a compressor. The device is screwed into place of the spark plug and the engine is idle. Measurement of testimony allows you to judge the state of the CPG. In the absence of a compressor, the compression in the cylinder can be determined offhand as follows:
- Put your finger on the candle hole;
- Try to start the chainsaw engine.
By putting a finger on the spark plug hole and pulling the starter, you can check the compression in the cylinder
If you feel that the finger pulls strongly into the candle channel, then the compression is all right. The lack of vacuum in the chamber indicates a malfunction. The cylinder-piston group needs a more detailed inspection, which will give an idea of the condition of the piston and cylinder, piston rings and bearings.
Do not start the chainsaw in the cold and may be due to the lack of compression in the crankcase. The main reason for this is damage to the gasket located between the cylinder and the crankcase. Detecting lack of compression is pretty easy:
- Disconnect the upper tube from the carburetor;
- Pour gasoline into an ordinary cork;
- We load the removed tube into the fuel;
- We pull the starter several times.
If the fuel from the cap is sucked up when the chainsaw starter is started, then the compression is all right. If not, see the gasket.
If the fuel is drawn in, then everything in the lock. The gasket is intact. Otherwise, you will have to purchase a repair kit and make a replacement. How to do this, watch the why the Chinese chainsaw does not start:
Starting the tool can be complicated by improper operation of the carburetor or its breakdown. It often happens that during sawing, the fastening screws loosen and air is sucked into the cylinder. Check that the carburetor is securely fastened. Inspect it for fuel leaks. The causes of the malfunction may be a mass. Accurately determine the malfunction, eliminate it and fine-tune the carburetor is possible only in the service center.
After a step-by-step troubleshooting of the chainsaw engine, you can find the malfunction, fix it yourself and successfully start your working tool. Do not take on those types of work in which you are not sure. Entrust troubleshooting to specialists from the service center.