Carver chainsaw Carburetor adjustment
Gasoline engine works by burning a previously prepared mixture of air, oil, and gasoline. Adjusting the chainsaw carburetor is necessary to prepare the mixture in the right proportion. The performance of the carburetor determines whether the engine will run with the declared power or stall.
Principle of operation of a carburetor
Regardless of the manufacturer’s company, the principle and operation of the carburetor of internal combustion engines is similar. To mix air and fuel, the carburetor is a device that includes:
The air under atmospheric pressure, after passing through the air cleaner, is fed into the restriction area, where its flow rate is regulated by the overlapping flat flap. After the contraction there is a vacuum in the pipe. As a result, the vacuum sucks the fuel from the fuel supply tube, the output of which is regulated by the fuel needle, connected to the float chamber by the nozzle. The structure of the carburetor of a chainsaw does not differ in principle from other fuel mixers of internal combustion engines.
The principle of mixing is to regulate the air damper, the level of the float, depending on the degree of rarefaction. We open the air. more fuel comes in, the engine increases the rpm. The correct mixture ratio depends on accurate adjustment of the chainsaw carburetor. If there is a lot of air in the fuel, the power goes down, the mixture is called lean. Lack of air leads to high consumption of fuel, incomplete combustion, soot on the cylinder and exhaust of unburned fuel. This tells you that the mixture is oversaturated.
The Ural chainsaw is instructed to run-in with an enriched fuel mixture. That’s why the carburetor comes from the factory with a running-in period setting. When you change to working mode, you have to readjust the settings.
Signs of a chainsaw carburetor working well:
When the carburetor needs adjustment
New chain saw is regulated for recommended mixture. Only a fine tune with three screws will be needed, no need to disassemble the carburetor. Setting the adjustment screws:
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- L regulates the fuel supply at low rpm;
- H is needed to regulate the maximum fuel supply;
- T idle speed regulator.
Because adjustment of the carburetor is done by ear with the engine running, safety precautions must be observed. The saw must be positioned steadily with the cutters pointing in a direction that is safe for those present.
Before beginning manipulation, you should mark the original position of the screws with paint or marker. The exact values for adjusting the carburetor of a chainsaw for each model are in the instruction manual.
However, more often a carburetor tune-up is needed after a tool malfunction has been corrected. The causes may be:
- violation of the protective cap and unbalanced screws;
- engine piston wear that requires a different mixture to operate;
- The carburetor itself does not work well.
How to adjust the carburetor on a particular model chainsaw? Perform the operations sequentially, following the instructions. Here is algorithm, general sequence of actions.
The basic setting is made only for fuel screws at low and high revolutions. Slowly close the throttle all the way to the stop. Also gently open counterclockwise both screws for 1.5 turns. After that, start the engine and warm it up for 10 minutes.
How to adjust the carburetor on the chainsaw when the engine is on:
- Adjust the idle speed with the screw T, turning counterclockwise until the engine operates steadily at idle speed;
- check the speed of revving, in case of slow revving turn the screw L by 1/8 of a turn additionally;
- Set the highest rotational speed by the tachometer with the screw H;
- Check the operation of the carburetor at idle finally.
How to find the carburetor failure
However, adjustment may be preceded by repair of the carburetor itself when it fails to perform its function as a fuel mixer.
If the fuel for some reason does not come into the engine, it is necessary to check the condition of the fuel supply unit. Often the reason is the supply of low-quality gasoline, as a result the fuel passages get clogged.
If the fuel mixture has been idle for a long time, the additives have deteriorated, the mixture can clog the passages, the grill with sludge. In this case, a long flushing is required, which is done with solvents in the service shop.
Troubleshooting by yourself
If troubleshooting is carried out with your own hands, you need to make room and spread out small parts. A tool will be needed:
The main thing is to properly release the assembly from the place of installation, cleaning it from the outside of the dirt. Remove the air intake, opening access to the carburetor and suction rod. Remove the gas pedal lever by lowering the carburetor choke. Release the part by removing the choke lever, lifting the wire along with the lever, hooking it to the left.
Chainsaw Carburetor Adjustment | How to Tune ‘Correctly’. by Craig Kirkman
Flush the freed carburetor in gasoline, blow it out with air, clean the grill by injecting with a fine needle.
Reassembling the assembly in reverse order, make sure that the spring under the needle lever is in place. If it is forgotten, fuel fails to cut off and the spark plug is damp or gives out no spark.
The throttle trigger on STIHL saw can sometimes get a little wedged. In this case the throttle must be cleaned. It is necessary to protect the flap after cleaning by tinning.
After assembling the carburetor, installing it in place, make adjustments, as written above.
When adjustment is needed at all?
In particular, it is rarely necessary to adjust the carburetor of a chainsaw, more often there are problems related to fuel consumption or wear and tear of parts. But sometimes the “symptoms” show that you need to adjust the mechanism. Here are some signs:
- When the engine starts, it immediately stops. Alternatively, it will not start at all. The reason is excessive air and lack of fuel.
- Fuel consumption increases and as a result. High volume of exhaust fumes. This is due to a reverse process. Fuel oversaturation.
Causes of failure may be mechanical:
- Due to heavy vibration, the protective cap is damaged, causing all three bolts to lose their set hold.
- Wear of the engine piston. In this case, adjusting the carburetor of a chainsaw will help only temporarily, it is better to replace the worn part.
- Due to clogging caused by poor-quality fuel, dross, or a damaged filter. Carburetor requires complete disassembly, flushing and adjustment.
If your chainsaw suddenly stops working, you need to take it apart to find out why.
How to adjust the carburetor on your Carver chain saw
T screw idle adjustment is always separate. If the Carver chainsaw engine stops idling, the cause could be:
- Poor spark plug performance;
- Loss of compression due to critical wear on piston system;
- Bad fuel;
- Low carburetor performance unrelated to regulation;
- Filters in the tank and carburetor clogged with paraffin.
For the same reasons, the Carver chainsaw engine may not run well, not only at idle speed, but in general. It doesn’t pull, doesn’t develop speed, lags when the throttle is depressed, etc. Д. Therefore, it is necessary to first try to deal with these causes. Last but not least, if the problem is not solved, you can try to increase the idle speed by turning the T screw clockwise.
- If the engine does not start at all at idle due to improper registration, the T screw turns 1/2 or 3/4 turn and the engine starts.
- Then adjust by ear with engine running, taking all precautions. (A sudden increase in speed could cause the chainsaw chain to spin, which is dangerous.).
- If the chain is idling, the screw T is unscrewed back to the position where the engine is idling, is not held back and the chain does not rotate.
Then check that the chainsaw engine is running in all conditions. If it runs steadily at idle but stops when the throttle is compressed, this is a sure sign of insufficient fuel supply to the combustion chamber. If all systems, clean filters and injectors are working properly, the cause is most likely a faulty adjustment of the L screw.
Carver saw carburetor repair: possible malfunctions and troubleshooting
After the chainsaw has produced 50-70 liters or more of gasoline, the filters and nozzles can become clogged.
The assembly is disassembled, rinsed, blown with compressed air, and returned to operation.
Much of the mechanical damage to the Carver carburetor is caused by the elastic diaphragm becoming rough over time and failing to work properly.
You can disassemble the carburetor and replace the diaphragm if you can find such a part. However, such components are of little use for repair, and it is easier to replace the entire carburetor of a “Carver” chainsaw, and sometimes all used chainsaws.
To adjust the carburetor of a “Carver” chainsaw, it is enough to know the device and the principle of operation. Knowing them, using simple tools and following the adjustment algorithm described in the article, you can easily adjust it at home. It is important to understand that adjustment is still a serious process, and if you are not confident in your abilities, it is better to return the chainsaw to the shop.
Countryside construction and repair is not without the use of chainsaws, as well as gardening. Due to the malfunction of the tool, all work can stop, so it is important to be able to disassemble it yourself, find the problems and fix them. With enough experience and dexterity, you can even adjust a chainsaw carburetor. The procedure is complicated, more precisely. Jewel. How to conduct corrective procedures, we suggest divorcing today.
When a carburetor adjustment is needed?
In a newly acquired chainsaw adjustment screws should not be touched in order not to disrupt the factory settings, providing an optimal flow of fuel and air into the combustion chamber and, accordingly, the values specified in the passport RPM at idle and under load.
The chainsaw should be run-in if this is specified in the instruction manual. If there is no such a requirement, still the first 3-4 hours of work, you should not use the tool at maximum loads.
Signs when it makes sense to make adjustment operations:
You should, before you sin on improperly set clearances and twist the adjustment screws, clean the carburetor from the outside and check the tightness of connections. In some models of chainsaws, vibration loosens the screws that fix the cap or feed tube, which leads to air suction through the holes not provided by the design.
Carburetors that are used on Chinese chainsaws
Well-known brands develop the best models, which are almost impossible to copy, so most Chinese manufacturers make the most popular models. Some remain nameless and unmarked, others receive names of popular brands.
The peculiarity of the carburetor, depends on the model and power. Due to this, the size of the carburetor and their design differ from each other.
Most of the copies are similar in design to originals, but alas quality is rare. To date, not all products made in China can be considered junk.
According to the quality of the carburetor, can be divided into three types:
Cheap ones, most often made of low-grade materials that often break, do not fit together, crumble, the size of holes does not agree with the calibration, torn off the thread. Such carburetors are hard to even call disposable. Buying such a carburetor, give yourself a report that you just threw your money in the wind, because such a purchase does not even have the markings and the name of the model.
Mid-priced carburetors are ideal for factory-assembled, good quality. They will probably last longer than the chainsaw itself.
Branded carburetors are made in China, but they differ from Chinese only in that they have a name and their brand. The companies that make these carburetors value their reputation and invest in manufacturing power.
Carver chain saw carburetor adjustment and structure
Carver chain saw carburetor is responsible for supplying a properly dosed fuel-air mixture. Increasing the mixture input increases the engine speed when the throttle trigger is held down. Consistent idle speed also depends on a properly functioning carburetor. This is an important chain saw system and you need to have an understanding of how it works, know the basics of diagnostics, and know how to adjust and repair.
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When adjustment is needed
Modern three-screw carburetors of Carver chainsaws are practically not designed for manual adjustment at home. The screws are factory-set, securely locked against rotation from vibration by tenacious springs and do not arbitrarily change their position.
adjusting the carburetor on a chinese chainsaw
But the screws on the Carver chain saw carburetors can be adjusted with a normal screwdriver through the adjustment holes without removing the cover. This suggests that these models are structurally in need of carburetor adjustment from time to time.
The reason for this from a technical point of view can not be accurately named. Only versions are possible:
- Carver chainsaw carburetor is in an area of high vibration, causing the screws to spontaneously unscrew.
- A coarse spring is installed, which can not fix the screw, as on other models.
- Periodic adjustment is required because of the technical features of the carburetor and the Carver chainsaw engine as a whole.
Design and principle of operation
Carburetor. is a device in which fuel (gasoline) and air are mixed in given proportions with the next supply of the finished consistency into the engine cylinder. Virtually all chainsaw models are equipped with a carburetor of the same type, so the device and mechanism of operation are similar.
The carburetor’s primary components are:
- body, which is cast from aluminum to reduce weight. Chainsaws routinely have to be moved from place to place, they are held by hands when working, so reducing the weight of the tool is the primary goal of manufacturers;
- Diffuser with an air damper, which are placed at the entrance;
- jets, which are the valves for accounting the fuel supply;
- spray, ensuring that gasoline is injected into the chamber (in the diagrams it is marked as the main flow)
- fuel (float chamber).
Figure one Diagram of a chainsaw carburetor
The principle of operation of the carburetor can be described as a cycle consisting of the following stages:
- The air damper opens when the engine is started.
- the piston stroke creates vacuum in the air duct, due to which the air flows into the diffuser, the amount of which is regulated by the position of the air flap.
- Gasoline flows from the gasoline tank into the float (fuel) chamber. The rate at which it is received is regulated by the jets.
- Gasoline and air mix in the diffuser, resulting in a fuel-air mixture, which then enters the engine cylinder. The more the mixture enters the combustion chamber of the cylinder, the higher the power and speed on the engine shaft.
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The maximum H and minimum L rpm setting screws should be slowly turned clockwise as far as they will go and then turn them back two turns
Find the highest idle speed
, to do this slowly turn the screw L in different directions. After having found the position of the highest motor rotation turn the screw L a quarter of a turn anticlockwise. If the chain is still rotating when idling, turn the T or (S) screw clockwise until it stops.
Checking and adjusting the maximum rpm.
Change the maximum rpm with the H screw. turning it in (clockwise rotation) will increase the rpm, turning it out will decrease the rpm. Chainsaw engines have the highest idle speed from 11500 rpm. to 15000 rpm. A higher speed is not provided by the ignition, besides it becomes dangerous for the engine. The rpm limit can be determined by the ignition interruption. If they are coming in, turn the H screw a little anticlockwise
If the operation of the engine is not checked for acceleration and maximum rpm then the adjustment of the chainsaw cannot be considered complete.
When you squeeze the throttle trigger gently, the engine should go from no-load to maximum rpm (2,800 rpm to 11,500-15,000 rpm) quickly and surely.to 11500-15000 rpm depending on the unit). If the RPM is slow and sluggish then the L screw should be turned slowly anticlockwise
After having adjusted acceleration and maximum rpm check again the idling of the saw. the engine should run steadily and the chain should not move. Chainsaw adjustment must be repeated if this condition is not met but except for the basic adjustment step.
A chainsaw is a tool that will come in handy in any cottage economy, even for amateurs, not to mention professional workers. But like any other device, the chainsaw needs constant care and preventive maintenance. One of the most common procedures is adjusting a chainsaw’s carburetor due to improper settings in the past.