Stihl Trimmer Does Not Work Fuel Booster

Despite the simplicity of the design of the chainsaw, in case of interruptions in its operation, and sometimes with a complete failure of the unit, it is quite difficult to find the cause of the problem. Of course, an experienced master will be able to immediately determine what led to this or that failure. But an ordinary user, in order to find a chainsaw malfunction and do it yourself, will need to study the symptoms that are inherent in a particular breakdown.

Chainsaw engine malfunctions

The engine is the main unit of the chainsaw, and most of the breakdowns that occur in it are associated with a gasoline drive. Correct diagnostics can determine the causes and remedies even for an untrained user.

The main problems with starting the engine can be the following:

• The engine does not start;
• Unstable;
• There is a start, after which the unit immediately stalls;
• Stalls under load.

Malfunction of the ignition system

First of all, the reason that the chainsaw does not start should be sought in the ignition system of the unit. You need to start with checking candles, since there is a possibility that the spark disappeared.

According to the state of the twisted out candle, you can determine how the fuel system works. The candle is twisted with a special key.

The following figure shows 3 options for the condition of the spark plug.

Fuel splashed candle speaks of its excess in the cylinder. If the candle is poured, then most likely the carburetor is incorrectly adjusted, or the rules for starting the engine have been violated. The candle must be wiped well and dried. Also, dry the combustion chamber:

• Shut off the fuel supply;
• When the candle is unscrewed, pull the starter several times so that all gasoline is removed from the cylinder:
• Reinstall the spark plug and adjust the carburetor according to the instructions.

A large amount of soot on a candle caused by the wrong ratio between oil and gasoline during the preparation of the fuel mixture, as well as malfunctions in the fuel supply system. If the mixture is prepared correctly, using high-quality oil, then the carburetor should be adjusted. A candle with carbon must be cleaned by washing in gasoline. After that, it needs to be wiped dry, with a needle to remove the remains of burning and to clean the electrodes with fine sandpaper.

You should also check the candle for the correct gap between the electrodes. Normally, the clearance of the candle should be in the range from 0.5 to 0.65 mm.

If dry candle, it is required to check for a spark on its electrodes in order to eliminate a malfunction in the ignition system.

1. Put a cap with a high-voltage cable on the candle.
2. Holding the cap, attach the thread of the candle to the cylinder.
3. Pull the starter handle several times and see if a spark jumps between the electrodes. Normally, the spark should be bright. A weak spark indicates a possible malfunction in the ignition coil or in the candle itself.

If there is a spark, then the problem must be sought in the fuel system. No spark. The cause may lie in the candle itself (needs to be replaced) or the ignition system. The absence of a spark can cause a damaged cable, which should be checked by “ringing” the tester. With a good wire, you need to move on. Check the ignition module. A malfunction of the ignition coil or an incorrectly set gap between it and the magnet can also cause the fact that the spark disappeared.

Ignition on a chainsaw is simple: a permanent magnet is fixed to the engine shaft. A coil is fixed near it under a certain gap. When the magnet rotates, an electric current is generated in the coil, which is supplied to the electrodes of the candle. In the next photo, the arrow shows in which place correct clearance between coil and magnet.

The gap between these parts should be 0.2-0.4 mm. The walls of an ordinary plastic bottle have such thickness, and a template (probe) can be made of it by cutting off a small strip.

The clearance is set as follows:

• Unscrew the screws holding the coil;
• Lay a pattern between the magnet and the coil;
• Lightly press the coil to the magnet;
• Tighten the coil fixing screws and remove the template.

Fuel system malfunctions

If the chainsaw starts up poorly and the ignition system is OK, then check the entire fuel system of the unit. First of all, required adjust the fuel supply into the engine cylinder through the carburetor, setting it correctly.

Next, you need to observe how the chainsaw behaves.

1. The device stalls after starting. If the fuel mixture is not prepared correctly, adding more oil to it than it should be, then the unit will immediately stall or only work on the choke.
2. The engine stalls idling. This is a sign of a muffler clogged with soot (it is necessary to remove soot), a clogged air filter (you need to wash it), incorrect carburetor settings.
3. The unit stalls at maximum speed. The fuel or air filter is dirty and needs to be cleaned well. Often this behavior of the engine can cause a clogged gas tank breather. It is cleaned with a regular needle. In addition, a malfunction of the membrane acting as a fuel pump may also prevent the engine from gaining maximum speed. You will need to disassemble the carburetor and replace the membrane if it has lost elasticity.
4. Chainsaw stops working under load. This is a sign of incorrect carburetor adjustment, improperly prepared mixture or a dirty air filter.
5. Fuel pumping does not work. If the primer does not pump gas, and this happens most often after a long break in the operation of the unit, then you need to check the carburetor. How it looks and where the primer is located on the Husqvarna chainsaw is shown in the following photo. Inside the carburetor there is a spray valve that can stick when the fuel is around for a long time. To eliminate the malfunction, it is necessary to rinse the carburetor well with gasoline or flushing liquid, and then blow all openings with compressed air.
6. Chainsaw doesn’t start up hot. If you, having drowned out a chainsaw, after a short period of time unsuccessfully try to start it, then in most cases this is caused by loss of compression in the piston group.

Compression is checked by a compressor that is screwed into the cylinder instead of the spark plug. Next, you need to pull on the starter and observe the readings of the device. Normally, a new chainsaw shows compression ranging from 8 to 12 atmospheres. Below 8 atmospheres, the engine will not work.

Compression may disappear due to scratches on the inside of the cylinder and on the side of the piston. In this case, it is necessary to change the entire piston group.

Chainsaw Chain Problems

In addition to problems with the engine, a chainsaw may have problems in operation due to a malfunction of the cutting (sawing) assembly consisting of an oil pump, a tire and a saw chain.

No oil enters the tire

Usually, if oil does not enter the chain of the chainsaw, it is necessary to check the channels through which the oil is supplied to the tire and clean them of contaminants. If the previous steps did not find the cause of the problem, you will have to check the oil pump. To do this, you need:

• Remove part of the chainsaw casing;
• Remove the coupling;
• Having unscrewed 3 screws, remove the cover hiding the pump;
• Get to the gears of the worm gear that rotates the pump shaft.

If the thread on it is worn, the shaft does not rotate, the pump does not work, the chain is not lubricated. The worn gear needs to be replaced. You can also pull out the oil pump itself and manually try to pump oil through it. If it does not pump, replace the pump.

Chainsaw Oil Filter

Remember to remove the oil filter from the tank and clean it if necessary.

Also, a lack of lubrication may be due to cause her leak. You should check how tightly connected the pipes coming from the oil pump are. If the tightness is broken, the tubes are replaced with new ones.

The chain is breaking

If the chain broke during the operation of the chainsaw, then this could happen if it fell on a solid object, for example, on a nail. If the chain is constantly breaking, then the reasons may be as follows.

1. Low quality metal, from which the chain is made. You need to buy saws for gas cutters from well-known brands.
2. Circuit overheating due to poor lubrication. As a result, the saw overheats, the properties of the metal change, and it breaks under load. Verification of the entire chainsaw lubrication system (discussed above) is required.

You can also learn about the causes of frequent open circuits from this.

The chain is not spinning

This nuisance often haunts inexperienced chainsaw owners. They forget after starting the engine remove the brake. As a result, the chain does not spin, the brake system overheats, and the clutch mechanism fails. The problem is solved by removing the saw from the brake. If the clutch does not “burn out”, you will notice chain rotation. Otherwise, clutch replacement is required.

The chain is dull quickly

The chain does not stop

If during operation with a chainsaw you notice that the saw chain does not stop at the right time, then this breakdown can have 2 options.

1. Brake band is dirty. When the saw is working, dirt, sawdust, dust, etc. Can get under the tape. As a result, the brake mechanism is locked and the circuit does not stop when the gas is released. The problem of cleaning this node is fixed.
2. Brake band worn. It is necessary to replace this element of the brake system.

Chain wedges

This happens when the drive or driven sprocket wears out. The chain usually begins to wedge under load. But without load, the saw can rotate. The photo below shows a worn out chainsaw sprocket.

The following photo shows that the reason why the chain wedges must be sought at the location of the driven sprocket.

But what if the chainsaw is completely jammed and all attempts to pull the starter to no avail? Such a malfunction is sometimes found on Chinese-made chainsaws. It is caused by bolts that have been loosened by vibration, which screw the engine to the plastic casing of the unit. These bolts are located directly under the flywheel (magneto). In the photo below, the arrows show the location of the problem bolts.

Twisting, they begin to rub on the flywheel and can completely jam the chainsaw. The following photo shows a flywheel with existing scuffs from bolts.

To eliminate the malfunction, you will need to remove the flywheel from the motor shaft and tighten the bolts.

Chainsaw crookedly sawing

This problem may occur if the chain is dull or improperly sharpened. This, to a greater extent, applies to new chainsaws. But if tire is worn out, then even after replacing the chain you will notice that the saw leads away. Tire wear can be easily determined if you put it on a flat table and attach a square to it, as shown in the following photo.

In this case, you can see that there is a gap of about 2 mm between the tire and the corner. It is because of this one-sided tire wear that the chainsaw is sawing crookedly. The problem is solved only by replacing the tire with a new one.

Important: in order to extend the service life of the chainsaw tire, it is necessary to remove and turn it over from time to time. Due to this, the tire will wear out more evenly and will not cause chain skew.

Why is a chainsaw heated

The new chainsaw is warming up because all the details of the piston group have not yet been rubbed. Therefore, the unit must be run-in during which the engine must not be allowed to overheat. If the unit is already run-in, then overheating of the engine may cause late ignition, of course, provided that the combustible mixture was prepared without violating the proportions. To fix the problem, you need to adjust the ignition system of the device.

Why is oil flowing

Many chainsaw owners are faced with a problem such as oil leakage from under the unit. Most often, oil flows due to damage to the oil hose connected to the oil pump. The photo below shows exactly the case when the end of the hose is torn and does not fit tightly on the pump nozzle.

But to get to this place, you will need to remove the clutch mechanism from the shaft. In some chainsaw models, oil may leak out at the junction of the oil pump with the oil tank hose (indicated by arrow in the photo).

To eliminate the leakage of lubricant, you will need to pull this hose from the place of landing. To do this, you can use pliers by pulling on its outer part. At the end of the hose you will see rubber stopper, which is the cause of oil leakage. This cork needs to be wiped well to remove the remaining oil, after which its seat needs to be sealed with something. You can use car sealant or fum tape, as shown in the following photo.

Next, insert the hose into the hole, reinstall the plug and seal it using a flat screwdriver. On this, the operation to eliminate oil leakage can be considered completed.