The heart of any chainsaw is the internal combustion engine, which drives the working element - the sawing chain. During the operation of a garden tool, it becomes necessary to disassemble the engine. This could be scheduled maintenance, cleaning from carbon deposits and soot, troubleshooting or replacing components. If you take the chainsaw to a service center for this, then you will not have any questions. However, when independently servicing a gasoline engine of a garden tool, the question often arises: how to correctly install the pistons back and where the arrow points to them.
What is a piston in an internal combustion engine
A piston is an element of a piston internal combustion engine designed to convert the energy of changes in the pressure of compressed gas in the cylinder into the energy of translational motion. Next, the energy is converted into rotational motion using the crankshaft and connecting rods.
When disassembling the chainsaw engine, be sure to remember or mark how you removed the pistons from the cylinders. Important information is usually indicated on the surface of the piston ring heads, which can be seen by removing soot deposits.
Fault detection algorithm
The cause of saw failure or deterioration in its performance may be:
- clogged fuel tank cap breather;
- air leakage from the carburetor due to the destruction of the gasket or loosening of the threaded fasteners;
- mechanical jamming of removable saw equipment and other minor defects.
Before you begin disassembly, you should make sure that more extensive repairs are necessary.
It will most likely not be possible to independently assemble a new chainsaw after repair with the original quality. The design of modern chainsaws often uses press fits of mating parts, which have minimal repairability.
Even partial disassembly of a chainsaw using improvised tools can lead to undesirable consequences. In most cases, to eliminate a malfunction, you can limit yourself to dismantling a separate unit or system.
This list includes:
- connecting rod and piston group;
- carburetor;
- clutch mechanism;
- saw chain drive sprocket.
Boats and motors in questions and answers
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| Moscow time 10:04:27 | Your local time | Vladivostok time 17:04:27 |
| Author: Dima X (—.pool-123.spbnit.ru) Date: 15-08-02 06:17 Same as on the second or in the opposite direction? |
| Author: SerG (—.dial-up.kraft-s.ru) Date: 15-08-02 06:29 Dima X writes: > > In the same way as on the second or in the opposite direction? The arrow on the piston points towards the exhaust port of a particular cylinder |
| Author: SerG (—.dial-up.kraft-s.ru) Date: 15-08-02 06:31 Yes, by the way - I’m on ICQ almost all day long, if anything happens - go online, I’ll help And apparently I'm not the only one here my UIN is 118014806 |
| Author: Dima X (—.pool-123.spbnit.ru) Date: 15-08-02 07:13 SerG thanks, but I’m not very good at computers, and I don’t know how to go online :-)) If something happens, I’ll be here ask, okay? |
| Author: Dima X (—.pool-123.spbnit.ru) Date: 08/15/02 07:25 Yeah, that means they should be looking in opposite directions. And the new bearing sat on the journal with a slight interference, and the old one was completely loose. And in my opinion, I found the reason for the failure of one cylinder: the cam stuck in the ignition and moved very tightly, apparently it opened and stuck in this position, which is why the cylinder did not work. Is it really not recommended to seal the head gasket with sealant? Do you need to lubricate with lithol? |
| Author: SerG (—.dial-up.kraft-s.ru) Date: 15-08-02 08:01 > Is it really not recommended to seal the head gasket > with sealant? Do you need to lubricate with lithol? For regular sealant – not recommended on a special high-temperature, smeared with a THIN layer |
| Author: Yura (—.primorye.ru) Date: 08/15/02 08:58 Yeah, that means they should be looking in opposite directions. -What kind of engine do you have? Are you confusing the exhaust with the intake windows? On the Whirlwinds the arrows point towards the exhaust manifold. |
| Author: Ivan (—.vladivostok.ru) Date: 08/15/02 09:36 This is “Neptune-23”, it has cylinder exhaust windows on different sides of the block. |
| Author: DENis (Belovo Kuzbass) (—.kuzbassenergo.ru) Date: 15-08-02 11:46 if the gasket is new, then it is better to lubricate it with graphite lubricant, and if used, then they sell it at car markets for high-temperature lubricant, I think it's red, just like the tube. |
| Author: Yura (—.primorye.ru) Date: 15-08-02 13:05 I’m not confusing, I clarified, as in VORTEX. I was just surprised that I was used to B30. I apologize if I confused you. |
| Author: Alexander (194.186.125.—) Date: 08/15/02 16:33 I’ve been installing new gaskets all my life, and no problems. Place old ones, pressed on with paint or sealant - only if in camping conditions. It’s better to buy new ones, since the entire engine is disassembled anyway! |
| Author: Dima X (—.peterlink.ru) Date: 15-08-02 17:09 Well, I put it on red sealant, but I’m not sure about the thin layer, I think I coated them well :-)) Damn, at 3 am It turned out that the top gasket was missing (the bastard seller said that he put all the gaskets) which is in the form of a figure eight, so I had to install an old one heavily coated with sealant. Another washer disappeared somewhere... it seems to me that I dropped it inside the engine. |
| Author: Alexander (194.186.125.—) Date: 15-08-02 17:47 As my old friend says to this day, “...A good knock will show itself!” Are you sure that this washer was there at all and you didn’t put it in another place where it might be missing? Now you won't be forced to go through the engine to make sure whether the puck fell there or not!!! Therefore, the question is removed from the discussion by itself - if you bring it up, you will find out. Before starting, spit three times!!! Good luck. |
| Author: Dima X (—.peterlink.ru) Date: 15-08-02 19:31 The puck was there for sure, but I didn’t want to take it apart, and there was no time. On Ladoga, the ide is rushing to the turntables. I want to rush tomorrow. |
| Author: Bas (—.DSI.ru) Date: 16-08-02 11:47 If you haven’t put the head on the pan yet, unscrew the carb, grab the flywheel, and shake it, it should rattle, the washer is a piece of iron, if it gets sucked into the chamber combustion is that the bottom of the piston will be beaten by hell, but if it successfully hooks, the whole piston, rings, grooves may come under attack and lift up the cylinder mirror, and this is a major blow to the headstock. And don’t be too lazy, remove the mufflers and turn the crankshaft, they are not a power element like the cylinder head, although they are no simpler. if the search is unsuccessful, see Alexander’s previous advice. Good luck. |
| Author: Dima X (—.pool-113.spbnit.ru) Date: 19-08-02 09:31 Found the puck, hurray! She fell inside her leg. |
What is a fuel mixture and how to prepare it?
Although many people simply pour gasoline into the tank first, and then oil, and lightly shake the mower, we will do everything right for the new unit. To prepare the fuel mixture for the Fubag lawn mower, 92-octane gasoline and a special semi-synthetic motor oil designed for 2-stroke air-cooled engines are used.
Please note that oil for water-cooled engines (boat engines) and oil for 4-stroke engines are not suitable here - they form carbon deposits on the spark plug, clog the exhaust port and damage the piston. For our engines, we recommend Fubag 2T Extra semi-synthetic oil - an optimally selected high-quality composition.
The recommended proportional ratio of oil to fuel mixture is 1:40, that is, for 1 liter of gasoline you need approximately 25 grams of oil, this can be exactly the volume of a standard cap from an oil container. In the case of a fuel mixture, oil can ruin the porridge, because... excess slightly increases the smokiness of the mixture during operation, and therefore carbon deposits.
Not adding oil is also not good, because... Lack of lubrication critically affects the service life of 2-stroke engines.
Before refueling the Fubag gas trimmer. This mixture must be thoroughly mixed in a separate canister, and only then poured into the gas tank. The quality of mixture preparation directly affects the engine life of a gasoline trimmer. Therefore, do not use fuel mixture prepared more than two weeks ago. This may lead to premature failure of the unit.
Pour the mixture into the gas tank, it is advisable to fill it no more than 80%.
On our trimmer, the tank is translucent, which makes it possible to monitor the amount of mixture by eye. it is very comfortable!
By the way, there is a reminder on the fuel tank - so you won’t forget.
EXPERT TIP: Under no circumstances should you store gasoline in a plastic water container. When mixing the fuel mixture, a static charge accumulates and a spark can be caught.
— Assembling the braid
So, first you need to properly assemble the lawn mower. It's very simple.
1) Connect the rod and the motor. To do this, we align the rod relative to the engine so that the spindle is located in the same plane with the engine fuel tank.
2) Install the rod flange into the engine and secure it with 4 screws.
To do this, you need to unscrew the thumbscrew on the top cover of the fastener. And remove the top cover. Next, insert the handle into the fastener, install the cover, and tighten the screw. We put the control handle on the pipe and fix it with a screw. On this trimmer, the adjusting screw allows you to adjust the handle to suit the user: you just need to loosen the “thumb” and move it to the required distance, and then secure it.
READ Can the trimmer be stored vertically?
Connect the throttle cable to the engine and insert its end into the throttle joint. Connect the red wire of the control handle to the red wire of the engine, and the black wire to the black wire.
9) Holding the rod, twist the spool of fishing line counterclockwise until it stops. All that remains is to install the two-shoulder belt. Attach the shoulder strap carabiner to the shoulder strap attachment ring. We adjust the position of the ring on the rod of the product and fix it with the fastening screw. Adjust the length of the shoulder strap.
What is the difference between a good trimmer and a bad one?
The main difference: the level of assembly and manufacturability. To do this you need to disassemble the engine. In the figure we see that there is a grid on the engine cylinder mirror. The mirror is finished with final honing. We see a network of small grooves that retain oil, which creates ideal conditions for lubrication of the piston and removal of excess heat.
The cylinder mirror is chrome-plated - this application strengthens the surface layer of the cylinder mirror made of porous chromium, which increases wear resistance and service life, reduces friction and increases the specific power of the engine. Therefore, this particular engine will last a long time even under intense load.
Where does the arrow on the piston point?
Due to the fact that the pistons have the correct cylindrical shape, after removal, many inexperienced craftsmen are confused about how to properly return them to their place.
- Remember the main rule: the arrow on the chainsaw piston points in the direction of the exhaust towards the exhaust hole of the cylinder.
The pistons in the cylinders in modern internal combustion engines have a very strict position, so the arrow always points in the direction where the exhaust gases move. If you still have questions, the garden tool has an instruction manual. Even if it is in English, it will not be difficult to translate it.
Replacing the piston group in a chainsaw or trimmer
Repairs of this level must always be balanced. In such small engines operating at high speeds, replacing the first piston, which is burned out or jammed, does not give a long result and, if necessary, you need to change the entire piston group. » How to position it in a chainsaw or trimmer. Making sure the piston sits on. Therefore, you need to consider whether to continue to use this saw or purchase a new saw.
If this is a professional model, then such repairs are worth carrying out, but if it is an ancient household model like the Husqvarna 40 and it has worked for more than 10 or 12 years, it is unprofitable to repair it. Therefore, how much will it cost to repair it? the same as purchasing a new saw, albeit not a Husqvarna, but a PARTNER P350XT CHROME, at a price of 165 will definitely be enough. Moreover, such saws are sold by Husqvarna, since PARTNER is its subsidiary.
But if you still decide to repair a chainsaw or trimmer , then you need unique spare parts that are not cheap. If the engine is used correctly, the first repair may not occur soon and only the piston ring or rings will have to be replaced, depending on the model. But if the saw jams, then you need to change the entire piston group - the cylinder, piston and rings.
You need to see that Husqvarna 136/141 chainsaws have approximately a service life of 500-600 hours, Husqvarna 340/350. 1000-1200 operating hours, professional chainsaws more than 2000-2500 operating hours, subject to strict adherence to the operating instructions. In fact, you cannot rely on these numbers, because the real resource can differ significantly, both hugely and minimally.
Naturally, nothing is endless, but it’s one thing if you change the piston group, after many years of operation and it has worked its hours, it has completely paid for itself, and another thing is that this saw was filled with, for example, only gasoline, without oil, and it jammed. Such a saw has to be repaired, because all other parts are ordinary.
Many companies deliberately inflate the price of spare parts so that new models can be purchased. For chainsaws and trimmers, for example, from the STIHL office, spare parts are available in a larger assortment than for Husqvarna. Therefore, when choosing a specific model, find out how things are with spare parts. RVT
How to correctly install rings on a two-stroke scooter piston
There is nothing complicated about installing rings on the piston of a two-stroke scooter, just like a four-stroke scooter, and many people understand this. But most scooter riders who only recently acquired similar equipment do not even have an idea of how to change the piston on a scooter, how to correctly install the rings on the piston, where the arrow should point , and almost everything else.
READ Gasoline trimmer does not develop speed cause Husqvarna
In this lesson, I will tell you how to correctly put the rings on the piston and assemble the piston in place. Because we have already talked about four-stroke engines, here we will only talk about two-stroke engines. So, our piston is worn out and requires replacement.
Pridonok shows and tells how to correctly install the piston into the cylinder on a scooter and motorcycle. How to install a piston on a lawn mower in this lesson, I will tell you how to correctly put the rings on the piston and assemble the piston in place. The rings wear out first.
The rings and piston wear out first, and usually only those need to be replaced. If the piston is severely worn, it is necessary to bore the cylinder. It is also bored when the piston jams in the cylinder, forming deep scratches on the walls of the latter.
There is nothing wrong with this, and if your new cylinder has been properly bored (which will only cost about 10), it will need a repair set of rings with a new piston. Such rings are marked 0.25. The second boring is 0.5, respectively, etc. to one.
What can result from incorrect piston installation?
Incorrect installation of the piston ring in the chainsaw engine will lead to the fact that it will work strained and intermittently, and may stall. Eventually, at best, the piston or cylinder will be damaged. In the worst case, the engine itself will fail and require expensive repairs.
If your chainsaw needs repair or maintenance, take it immediately to a specialized service center. It is better to pay a specialist than to buy new garden tools.
Photo report: Installing a piston on a two-stroke scooter engine
Learning to install a new piston, today we will be using the most ordinary Chinese two-stroke Forsage scooter with a 1E43QMB engine. Scooters equipped with this engine are found on our roads less and less often, due to their ancient and extremely unsuccessful design, which in modern realities does not withstand even the slightest criticism...
A few words about choosing a piston group: The piston (43mm 65CC) shown in the photo below is simply of disgusting quality, so there is no point in buying it, much less putting it on a scooter. It’s better to drink the 1200 rubles it costs in the first tavern you come across than to give it away for this bullshit.
If possible, then it is worth looking for a piston from the manufacturer presented below (41mm 50CC), although it is of a smaller volume, the quality is much superior to the first sample, and its price is noticeably lower.
Work on the implantation of our piston should always begin with the correct installation of the piston rings, and only then move on to other “things”.
We take one retaining ring from the kit and insert it into any groove of the piston (it is most convenient to install retaining rings with round nose pliers).
The retaining ring must lie tightly in the groove, evenly fitting around the entire circumference, and at the same time rotate freely in it.
Lubricate the mounting holes for the piston pin with motor oil, preferably for 2T engines, for more information about motor oils, read the article: Motor oil for scooters
It is best to lubricate this kind of parts using a regular medical syringe, in this way it is possible to protect the engine parts from dirt getting on their surface, plus everything: it is very convenient to rub the oil over the surface of the parts with the syringe needle.
After applying the oil, rub it evenly over the surface of the parts.
We take the piston pin from the kit and insert it so that it extends slightly from the mounting hole into the piston.
How to extend the life cycle of CPG
It is not recommended to drive the scooter at high speed for long periods of time (especially in hot weather). This can lead to thermal seizure, which leads to deformation of individual parts of the CPG. Ultimately, the highest speed will be unattainable due to the loss of pressure inside. When disassembling the structure, the sticking is simply determined by the presence of burnt parts in the form of tongues. The carburetor will need to be adjusted to prevent the formation of deposits in the muffler and combustion chamber and a general loss of power.
You need to fill in high-quality motor oil that gives a beneficial effect:
- no noise from the motor;
- no overheating of the motor during long-term operation;
- relatively clean exhaust and a pipe for the exit of gases.
READ How to Correctly Wind Line on a Trimmer
The ideal option is synthetic oil, which has the advantage of efficiency, the absence of carbon deposits in bearings, deposits on the piston bottom and other unpleasant consequences. Similarly, you need to carefully approach the choice of fuel for a scooter. Gasoline should be taken 95 type, which does not lead to detonation inside the combustion chamber, increasing the temperature of the engine.
After replacing the piston on the scooter, you can begin other types of work such as painting or changing other internals. Be sure to drive several hundred meters to ensure the reliability of the work done.
Square chainsaw Partner how to correctly install the piston
Cylinder-piston group of chainsaws Partner 350-371 (Vityaz)
The cylinder-piston group of the Vityaz office has shiny cylinder walls, a 2-ring piston with a diameter of 41 mm. Suitable for chainsaws of the Partner (Partner) 350, Partner (Partner) 351, Partner (Partner) 352, Partner (Partner) 371 type.
Set contents: Cylinder - 1 pc., Piston - 1 pc., Pin - 1 pc., Piston rings - 2 pcs., Retaining rings - 2 pcs.
Article: 41041 Manufacturer: Vityaz (Belarus)
Together with the cylinder-piston group, we recommend replacing: a set of gaskets for the Partner (Partner) 350 chainsaw. Partner 371 chainsaw. Replacement of the piston group. Replacement of the PISTON, Chainsaw Partner 350,351. Replacement PISTON, Chainsaw Partner 350,351. Replacement. Chainsaw Partner 371. Replacing the piston group. the chainsaw through them
will not work correctly.
