Unfortunately chain saws. just like other machines. can be at fault. With at least a little knowledge of how the saw works, most faults can be repaired with your own hands. The difficulty of repair is not so much in the work itself, but in correctly determining the cause of the breakdown.
For example, there are several possible causes for a chain saw not starting, so it is not a good idea to immediately disassemble it. First analyze the causes of failure, which are divided into 2 groups:
- Trouble with the engine, ignition, fuel supply or exhaust system. This also includes malfunctions of the cylinder. piston group.
- Malfunctions in the lubrication assembly, chain brake, clutch or tire, as well as a number of other problems.
Indicators of engine malfunction
Engine malfunction can be judged by the following occurring problems:
- It is impossible to start the engine;
- engine starts, but then immediately, stalls;
- The engine is running erratically;
- At idle rpm it runs normally, but at load it loses power or stalls.
All of these malfunctions can indicate a malfunction in the ignition system.
Checking the ignition system
You should start checking the system by looking at the spark plug. Dry, it tells you that no fuel mixture is getting into the cylinder and so the ignition has nothing to do with it. If the spark plug is too full of fuel mixture, then the saw was not started correctly or the carburetor is not properly adjusted.
Hamster Cancer. Go and get lost:
I have a Husqvarna 268 saw in repair right now. Compression is 5.5 atm. Motor also runs (starts). But once you start driving the canvas in the wood. it will come out. The result of the diagnosis is scuffing on the working surface of the piston and cylinder.
I have no experience of using this tool, if you could share your experience (I think that site visitors would be very grateful to you.
pictures of scuffing. of course you can. Stay tuned, there is already an article about disassembling the Husqvarna 268.
If I am not mistaken this preparation is called HADO gel-revitalizant for gasoline engines?
10 kPa Calm ms180 no compression measured after running the chainsaw
A chainsaw is a simple device that, with proper care, can last for a long time. And the saw is a tool, subjected to different loads and, consequently, breakdowns still occur. About what caused a particular fault and how to fix it you will learn from this article.
How much compression should a Husqvarna chainsaw have?
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Today we will measure compression. For this purpose, we need an electric drill with reverse and the maximum speed of about 2500-3000 rpm, a car compressometer, a flexible shaft to transfer the rotation from the drill to the crankshaft of chain saw, and, actually, the samples of chainsaws STIHL MS180 and Poulan 2250.
It is worth mentioning that the STIHL is fully operational saw (in the repair shop for the replacement of the starter cord), and here is a Poulan with a known crushed piston.
On both chainsaws for accuracy of measurement the carburetors are dismantled (the resistance on the inlet should be as little as possible), the starter caps are removed (in order to be able to put a flexible shaft with a head on “13” on the nuts that fasten the flywheel), the spark plugs are unscrewed and the shutoff keys are in the “off” position.”
Compressometer with its shank is inserted into the spark plug hole, a drill with a flexible shaft and a head is put on the flywheel nut. We turn on the el. Drill with counterclockwise rotation. 3-4 seconds and the measurement is done.
Now it’s turn for the STIHL MS 180. The procedure is the same.
This issue of the newsletter is not educational and does not explain. I would say that in it we stated the fact: at 5 does not work, at 9.5 WORKS. Conclusions, as they say, do it yourself!
Hamster Heaven. Get away and get lost:
I currently have a Husqvarna 268 saw in repair. Compression 5.5 atm. The motor also “works” (starts). But as soon as I drive the blade into the wood, it “goes out”. Diagnostic results scuffing on the work surface of the piston and cylinder.
I have no experience using this tool, if you share your (experience), I think that visitors will be very grateful to you.
“pictures of the scuffing” of course you can. Stay tuned, an article about taking Husqvarna 268 apart is in the works.
If I’m not mistaken, this preparation is called “Hado gel-revitalizant for gasoline engine”?
This leaves the last option the crankshaft oil seals.
Checking engine compression. measurement results
What is engine compression?
Compression refers to the value of the highest pressure in a cylinder, created during idle cranking of the engine by the starter (for example, when switching off the spark plug). The compression of an engine should not be confused with the compression ratio.к. These are different concepts.
What is the compression of the engine, you need to replace the spark plug set the compressometer. This device is a pressure gauge connected by a hose with a nozzle and a check valve. the rotation of the engine crankshaft presses air into the hose until the pressure in the hose is equal to the maximum pressure in the cylinder. The pressure gauge records the pressure.
How to check the engine compression correctly?
When measuring compression, the following rules should be observed:
- The engine must be “warm. The fuel supply must be shut off. You can, for example, disconnect the gasoline pump, the injectors or use other means to prevent large quantities of fuel from entering the cylinders;
- all spark plugs must be removed. Selective dismantling of plugs, practiced in some service stations, is unacceptable, as it increases the resistance to rotation and randomly reduces the speed when cranking the engine starter;
- the battery must be fully charged and the starter must be in good condition.
Compression is measured both with open and closed throttle. Each method gives different results and allows to determine its own defects. Thus, when the valve is closed, little air will obviously enter the cylinders, and therefore the compression will be low and will be about 0.6-0.8 MPa. The air leakage in this case is comparable with its ingress in the cylinder. This makes the compression especially leak-sensitive. even for small leaks, its value drops by several times.