Do Not Start Saw Stihl 250
Chainsaws are simple in design and reliable in operation.
When properly handled, breakdowns rarely occur and are quickly eliminated if the owner knows where to look for the cause.
And yet, the question of why the chainsaw does not start cannot be answered unequivocally. This tool is basically a conventional two-stroke internal combustion engine. For its normal operation, four conditions are necessary: fuel, air, spark and lubrication.
The carburetor is responsible for preparing the air-fuel mixture, the air cleans the filter from dust, the spark is created by the ignition unit and the spark plug, and the lubricant is in gasoline.
Reasons why a chainsaw refuses to start, you need to search sequentially, starting from simple and moving to more complex ones. Anyone who immediately rushes to disassemble the carburetor when the chainsaw starts poorly on a hot one is at a great risk. This unit is better to repair and adjust in a specialized workshop, and not on the knee.
By the way, some manufacturers of chainsaws so that users do not climb into the carburetor to change the composition of the fuel mixture, make the jets unregulated.
For trouble-free operation of the chainsaw, special attention must be paid to fuel. If the fuel mixture is improperly prepared, even a reliable Husqvarna will not start. In this case, the owner will begin to search for the cause of the malfunction anywhere, but not in the fuel. To eliminate this factor, you must always prepare the fuel mixture from high-quality gasoline and the type of oil that is indicated in the instructions.
You need to do it in such a quantity that in 1-2 weeks you can fully work out. If you keep her for a month in a canister, then gasoline will lose its octane qualities and problems with the saw are guaranteed.
Quite often, chainsaw malfunctions arise due to the filling of a candle gasoline at the time of launch. This problem is eliminated by twisting and drying the candle (without calcining!). Excess fuel is poured out through the candle hole, after which a 20-30 minute break is made, then the candle is put in place and the start is repeated. A good owner always has new candles in stock to exclude this item from the list of suspects when troubleshooting.
The absence of sparks is often caused not only by candle failure, but also poor contact between its tip and the high-voltage wire. If this connection does not raise suspicions during testing, but the spark does not appear when the starter is turned on, the electronic ignition unit is to blame. This unit is not being repaired, but is being replaced by a new one.
Remember to inspect the spark plug for important information. If it is dry, it means that no fuel enters the cylinder and you need to check the entire supply chain, starting from the carburetor. Black soot indicates improper adjustment of the carburetor, which feeds too much fuel into the mixture, or that the oil is overloaded with gasoline.
Video: Do Not Start Saw Stihl 250
If the chainsaw starts and stalls when you press the gas, this indicates a poor flow of fuel. The cause may be a clogged fuel filter or carburetor jet. The first unit can be checked and cleaned very quickly, but in the second case it is better to trust the specialists.
Dismantling and cleaning the chainsaw carburetor requires experience and accuracy. Therefore, it is usually taken only by those owners who have already repeatedly and successfully performed this procedure.
The air filter should also be considered., so as not to look for the cause of malfunctions in the chainsaw in the wrong direction. If it is clogged with dust, then you can not count on easy start-up and stable operation.
This valve equalizes the pressure in the gas tank as fuel consumption. When it becomes clogged, a vacuum forms in the tank and the fuel stops entering the carburetor. This disease is treated with a breather using a regular sewing needle.
It’s easy to remove the breather from the list of suspects. To do this, disconnect the fuel hose from the carburetor and see if fuel leaks from it. When gasoline flows in full flow. the breather is clean, if the fuel does not flow from the gas pipeline or flows out very slowly, the cause of the malfunction is established.
Many owners of new Stihl chainsaws are frightened by the increase in idle speed after the development of the first tanks of gasoline. Experts consider this behavior of the saw normal and indicating that the running-in of the engine and carburetor is normal. Therefore, do not rush to contact the service, but just slightly reduce the engine speed with the idle screw of the carburetor.
If the power drops and the chainsaw stalls idling, Remember to check the muffler, which may be clogged with tarry exhaust deposits. Cleaning the exhaust duct and silencer eliminates these problems.
It’s especially unpleasant for the owner, when all possible reasons seem to be eliminated: a new working spark plug is installed, the carburetor is neatly and correctly cleaned, the fuel is normal, but the chainsaw still does not want to start.
In this case, you need to look into the cylinder-piston group. A visual inspection of the cylinder and piston in this case helps to find the cause. If chips or badges are noticeable on them, then the saw will work normally only after replacing these nodes. You can fix this problem by boring the cylinder under a new piston of a repair size.
If there are no visible defects on the cylinder and piston, then the piston rings are checked. To do this, the piston is inserted into the cylinder and swing it slightly by the connecting rod. If there is play, then the rings are worn out and need to be replaced.
Chainsaws often fail due to insufficient chain lubrication due to oil leakage and clogged channels. Therefore, if the chain has become dry, urgently need to clean the channels that feed oil to the tire. Then, an inspection is made of the joints of the tubes with the oil pump fittings. If a strong oil leak from contact points or cracks in the oil line is detected, the tubes are changed, and the joints are sealed with a high-quality sealant.
Some parts of chainsaws must be changed upon expiration of the passport service life. Therefore, do not forget to look at the instructions, where they are clearly stated. Such details include the tire, drive sprocket, chain, parts of the anti-vibration system.
If the replacement is not done on time, the wear of these components will adversely affect the serviceable parts of the chainsaw. For example, a long delay in replacing the drive sprocket leads to an increase in vibration, which quickly breaks the crankshaft bearings.
Therefore, it is necessary to regularly check the depth of tooth extraction, which should not exceed 0.5 mm. The resource of the tire is usually enough for 3-4 chains, after which it also needs to be replaced.
Useful video on the correct operation of the chainsaw: