Why the chainsaw does not rev up and how to fix it
Stable operation of the internal combustion engine depends not only on the condition of the internal components of the CPG, but also on the external devices with which it interacts. The disturbance of the rhythm entails various problems, one of which is manifested in a complete stop of the mechanism when trying to increase revolutions. Causing such a malfunction, can reduce the efficiency of some nodes. How to identify a defective element and fix a malfunction, told and shown in this article.
The impressive construction of the system, includes many indispensable components, the defect of each of which has a direct impact on the behavior of the tool. Unintentional engine stall when trying to increase RPM, most likely due to insufficient supply of combustibles. Air-fuel passages, get clogged during operation, their flow capacity decreases and the chain saw does not develop full power, because the engine does not have enough “nutrients.
In addition to a constant supply of fuel and air, the engine needs an open channel for the exhaust. The caustic substances burn off and slowly reduce the gas passages, and the chainsaw doesn’t make enough power. The cause is in the muffler and it is not visible on the surface. The problem becomes visible after several tens of hours of use (time depends on the quality of the fuel).
If the valve (breather) in the fuel tank is clogged, it will create negative pressure until the pump stops pumping at all, interrupting engine operation. The problem is not limited to high rpm, but it is particularly quick when you step on the gas. Also, with a clogged breather valve, the chainsaw does not hold idle speed and shuts down within seconds after starting. To check the valve capacity, it is sufficient to unscrew the fuel tank cap immediately after an unintentional stop. If when unscrewing it, air is sucked in sharply, it means that there is a vacuum and the breather requires cleaning.
The carburetor and the hoses connected to it play a major role in pumping fuel. The first thing to do is to check the hoses for leaks and cracks. If the fuel pipe is fine, you can adjust the carburetor or clean its filter. All stages of this process are visually described below.
A decrease in engine compression, due to the destruction of compression rings or the formation of burrs, breaks the operating cycle and muffles the system when revs are increased. A quick visual check of this assumption may be made through the exhaust port by removing the muffler. Ideally, you should use a compressometer by screwing it into the spark plug hole and pulling the starter handle a few times. Depending on the engine displacement the compression varies between 160 and 180 PSI. To be absolutely sure, it is better to get this value from the data sheet, or from the dealer or the manufacturer of your saw model.
Lack of timely sparking and ignition, leads to refilling the chamber with a new portion of fuel in addition to the already available. For overfilling, 3 or 4 “idle feeds” are enough, as a consequence of which the plug contacts will be flooded and the instrument will not work (until they are dried out). This problem is often seen in overheating, when the resistance of the defective coil is increased and at high speeds there is a greater chance of flooding. Also, soiling or improper gap of the spark plug pins may be the cause.
Check ignition module operability immediately after an unexpected hot stop and after it has completely cooled down. Simply unscrew the spark plug from the socket, connect the cap with a high-voltage wire, touch the contacts on the metal surface of the engine and yank the starter. If the frequency of hot and cold spark formation is very different then the coil is defective and must be replaced.
The engine started, but the chainsaw stalls at idle or under load. In this case, most often the same actions as described above should be performed.
How to adjust the chainsaw depends on exactly when the problems start:
Stops right after starting:
- The fuel mixture is not mixed properly, there is too much oil in it so the octane rating is lower than it should be and the chain saw only runs on the breather or shuts down right away.
- There is soot on the spark plug or the gap between the spark plug and the wire is not correct.
Stops and won’t run at idle:
- Muffler is clogged. Carburettor sludge must be decalcified.
- The carburetor settings are faulty. You need to adjust the idle speed on your chain saw. Adjustment is accomplished with L and H alignment bolts. To adjust the idle speed, see the article on carburetor adjustment.
Stalls at maximum rpm and runs on suction only
- Air or fuel filter is blocked. Clean and check the seals.
- The breather plug is clogged, which prevents fuel flow and gasoline pumping on the chain saw. Take a needle and gently clean the breather plug.
- Gasoline pump malfunction. Remove the pump and check for gasoline leakage. If it is, check and replace gasket or pump.
Chainsaw will not cut under load and stops
- Clogged air filter. You need to take out the filter, clean it well or even rinse it, dry it and put it back.
- Incorrect petrol/oil mixture ratio. Drain fuel and re-mix oil and gasoline in the correct proportion.
Checking and Adjusting the Carburetor
Have your carburetor adjusted with special equipment at a service center. The adjustment screws have different angles of rotation for each saw (these are listed in the instruction manual). The need to adjust the carburetor does not arise very often, especially if the saw has been purchased from a trusted retailer. All of our Husqvarna saws are sent to a service center before sale, where specialists adjust the revs.
However, misalignment of the adjusting screws sometimes happens.
Causes of improper adjustment of the chainsaw carburetor:
- Severe wear of the engine (pistons). In this case, more care must be taken to fix the engine, but adjusting the carburetor may improve the functionality of the saw for a while.
- Clogging of the carburetor due to a damaged air filter, the use of gasoline of poor quality and the formation of scale.In such a situation, besides the adjustment of the carburetor, you also need to wash it.
- Severe vibration of the saw or damage to the protective cap. This is very rare, but does occur.
Signs that indicate the need to adjust the carburetor of a chainsaw:
- The engine either does not start or starts and immediately shuts down. This is due to the use of a bad fuel mixture.
- A considerable increase in fuel consumption and emissions. Increased exhaust fumes indicate that the fuel does not burn completely. Overcharging with too much fuel may be the reason.
The scheme of adjusting the carburetor is different for different chainsaw models and is described in the instruction manual. But the general principle is the same: you have to change the quantity and quality of the fuel mixture that goes into the engine cylinder.
There are three screws to help us adjust the carburetor:
- “L”. low, for low rpm setting
- “H” is high, for the upper rpm setting
- “T” (“LA”, “S”). for adjusting the idle speed (models that have only one screw have the “T” screw)
When adjusting the chainsaw carburetor, the following guidelines should be followed:
- Make sure the saw chain is facing in the opposite direction from you
- Place the saw on a stable, level surface and make sure the cutting attachment does not touch any objects.
Please note: the instructions give you the exact angle at which you turn the adjusting screws. If you follow the instructions carefully, it is very important to avoid damage to the engine.
There are two points in the carburetor adjustment procedure: the basic one (with the engine stopped) and the final one (with the engine warmed up).
The chain saw cuts out under load
The problem with the engine stopping while sawing has similar causes to the above described situation of the tool stopping when the throttle is depressed. As in the latter case, the fuel-air mixture and combustion exhaust ducts can be clogged, but there are other reasons, characteristic exclusively disconnection at work. Specifically, the problem may be due to improper carburetor settings. It is also possible that the chain teeth are blunted or the size of the material to be cut exceeds the power capabilities of the tool.
To find the cause of stoppage under load, it is necessary to go from the simple to the complex. First of all, it is worth checking the performance on small diameter boards / branches. If on a smaller friction area the machine runs well, then the chain should be checked for sharpening. The saw should be cutting at its own weight, without any additional pressure.
If using the machine for more than 50 hours, it is advisable to check the air/fuel filter and the exhaust system. The details and nuances are described above.
If the elements of the system described above are still working, but the chainsaw keeps stalling on loading, it is necessary to pay attention to the high RPM adjustment. The screw H, which is responsible for this setting, has a correct thread (screwed clockwise). We simply tighten the screw to the full (without tightening), noting the number of turns, and then unscrew half a turn, periodically checking the work of the tool.
The process of adjusting the carburetor is relatively simple, but requires some skill. If you are inexperienced, you must be very attentive and careful. If you have no desire or confidence in your actions, it is better to take the saw to a carburetor service (the service is extremely fast and budget-friendly).
The main causes of chainsaw failure are
Although the chainsaw is not a complicated machine, it does occasionally have problems that can only be corrected by disassembly. Examples of the following malfunctions are:
- The chain saw does not pick up speed;
- The chainsaw stops functioning in the cut;
- The chain saw fires and stops;
- The chainsaw loses its power;
- Chainsaw stalls when pressed.
Most often the malfunctions are related to malfunctions in the motor, as well as malfunctions in other systems and assemblies. It is important to handle the machine correctly. If all the rules of use are followed, problems are likely to be the most obvious. When troubleshooting, it is best to start with the simplest part and end with the most complex part.
Faulty chain lubrication system in a chainsaw
What are the breakdowns in the chain lubrication system:
If there is a lot of oil leakage (small oil leakage is normal for all gasoline powered saws) you should check the tightness of the tubes and the oil pump connections. Tubing can be loose or even cracked. If the tubes are leaking, they can be repaired by replacing them or sealing.
As for the oil pumps, different chainsaw models have different constructions, and the drive is also done differently (as a rule, the drive sprocket or a special gear on the crankshaft). If the problem is with the oil pump, then most often it is not necessary to replace this entire unit, it will be enough to replace its moving part (plunger), it often fails due to ingress of large amounts of dirt and sawdust.
The most serious damage was a crack in the oil pump housing. In that case, it would have to be replaced completely.
What’s the Reason Your Saw Starts, Stops or Goes Flat?
Saw came in for repair and the problem is going out of order. Chainsaw starts up and shuts down. We are trying to find the reason why the chain saw starts and stops. A man explains the chainsaw malfunction situation. First thing we noticed. The chainsaw is on the fritz. The man couldn’t turn it off even after removing the spark plug cap. The chain saw breaks down when the ignition is off. When I check the chainsaw, it starts and stops. The cause became clear, an air leak. When we filled up the oil tank we were surprised. You can see what came out of it in the video.
Preventive maintenance to extend service life
Regular wear and tear on the saw head is an essential part of the job, but the service life can vary considerably with different approaches to the process. If you follow a small list of recommendations, you can significantly prolong the effective use of components, saving nerves and budget. Let’s start with the simple steps that should be performed regularly, and move smoothly to the more thorough ones. maintenance.
Chain tensioning has a direct effect on the sprockets (master and slave) and an equally pronounced effect on the tire. Excessive tension impedes rotation and increases friction between components, accelerating wear and tear. When loose, the shanks can slip over the sprocket, licking the ends of the sprocket, which reduces productivity and increases the chance of the sprocket slipping off the guide bar.
If the tension is optimal, the chain does not sag, and if you take it in the central, upper part of the bar and with a little effort pull it out of the groove, the ends of the 3 shanks will be visible. The links tend to expand as a result of heat, so retighten them periodically, and before you start the engine, manually check for smooth running, which should be easy.
Lubricating the chain reduces the friction of the links against the bar groove faces, which reduces heat and wear severity. Oil supply is absolutely essential and must be provided without interruption. Check regularly that the reservoir is full. When using the exhaust, filter it carefully through a cloth to eliminate the possibility of dirt getting between the rubbing parts.
Uneven sharpening of cutting teeth, distributes the workload on both the chain and the bar. Then wear is symmetrical and the rate of abrasion is much lower. Teach a simple technique and periodically sharpen the chain with a fine file. If you do not start the condition, the procedure takes about 2 minutes (if the hand is trained).
The condition of the drive sprocket determines how smoothly the saw blade moves over the guide bar. As the sprocket teeth wear out, cavities form in the sprocket teeth and the shanks occasionally drop into them. In this type of operation, the chain tension is constantly changing, and it’s not uncommon for the. How to determine deformation and replace a chainsaw sprocket is described in detail in a separate topic.
Follow these simple guidelines, don’t cut nails/ground, and your tool will retain its factory accuracy for a long time. Write your questions, criticisms, explanations, in the Комментарии и мнения владельцев below this publication.