Mowing grass for each owner of a country or private house is an important process, it allows you to give your site an aesthetic appearance. Usually, a thing such as a four-stroke gasoline trimmer is used for this. Let's try to figure out what kind of devices are and how justified their use is.
The main feature of such a motor is that here the work cycle is carried out in 4 cycles - 2 crankshaft turns. Here the piston simply descends from the dead point from top to bottom. At this point, the intake valve is opened thanks to the camshaft cams. It is through the said valve that fuel is sucked in. With a reciprocating piston stroke, fuel is compressed, which is accompanied by an increase in its temperature.
Before the end of the compression, a spark ignites fuel between the spark plug electrodes. During combustion in this case, combustible gases are formed that push the piston to the lower position. The working course is carried out. The piston of the engine of the brushcutter at the lower point opens the intake valve, which allows the piston, which moves up, to push out gases that have already been exhausted from the cylinder. When the piston is in the upper position, the valve closes and everything repeats again.
Comparison with push-pull
If we compare the two-stroke and four-stroke engines for scythes, then we should start with the fact that the device of the two-stroke model does not provide for gas distribution with valves, which greatly simplifies its mechanism. Another important comparison criterion is liter power. In the two-stroke model, the working stroke occurs at each revolution of the crankshaft, and in the considered one - by 2 turns. In practice, this indicates a higher liter power - about 1.6-1.8 times in the push-pull model.
In terms of fuel consumption, the four-stroke analogue is inferior to the two-stroke one in terms of efficiency due to the fact that part of it during operation falls into the exhaust channels and is removed together with the gases without performing useful work.
These motors also have an excellent lubrication principle. Two-stroke - by mixing engine oil with gasoline. In a four stroke gasoline and oil are served separately. They have a classic lubrication system consisting of a filter, valves, an oil pump and a pipe line.
The main parameters of these devices are as follows:
- liter power in two-stroke engines is almost 2 times higher;
- their specific power is also higher;
- in terms of fuel supply and cylinder cleaning, four-stroke ones have a special gas distribution mechanism that the two-stroke model does not have;
- In terms of efficiency, four-stroke engines are better, because the consumption here will be lower by 25-30 percent.
Now we’ll go directly to a review of manufacturers of gas trimmers and try to make a small rating of the best companies that produce similar products. It must be said that the undisputed leaders in the production of this category of equipment are Makita, Hitachi, Echo, Stihl, Husqvarna. Trimmer models from these companies have such characteristics as:
- excellent functionality;
- high reliability;
- ergonomic design.
It is because of these factors that the trimmer models from these manufacturers are considered the best. And the technical qualities here will also be on top. Amateur devices of these firms are not very expensive. Therefore, it can already be argued that in terms of price and quality, they will be the best trimmers on the market.
If we talk about domestic manufacturing companies such as Energomash or Interskol , their products are notable for quite good power and a high technical level. If you conduct competent maintenance of this equipment and carefully operate it, then the trimmers of domestic manufacturers will be inferior in many ways to their foreign counterparts.
If we talk about Chinese companies, then for all their shortcomings, they have their customers because of the significantly lower cost of production. The fact is that consumers in this case usually think that they will only use a couple of times with a trimmer in the country for the whole summer, so it makes no sense to purchase a high-quality, but more expensive brushcutter from a well-known manufacturer. In general, this opinion has the right to life in the context of the fact that if the operation is as sparing as possible, then even a not too high-quality trimmer can last 1-2 years without breakdowns.
And let's say a little about specific models of lawn mowers that really deserve attention. One of them is Stihl FS 38 . A distinctive feature of this model is its low weight. Without fuel, it is just over 4 kilograms. And with fuel - about 4.5 kilograms, because the gas tank here has a volume of only 330 milliliters. But this does not mean that you have to constantly refuel the trimmer. The manufacturer tried to minimize gasoline consumption, so that even with a small supply of fuel, the model can work for a long time.
High-quality rotation of the working mechanism provides cutting the grass the first time . And on the protective shield there is a special knife that removes excess fishing line and brings it to its working length. The main drawback of the model and, perhaps, the only one, is a rather narrow fishing line in the kit. Therefore, it is better to immediately replace it with a thicker one.
Another noteworthy model is the Husqvarna 128R. It features a fairly high power. She will perfectly cope even with serious loads. The device includes a fishing line, as well as a blade knife. This allows you to adapt to various conditions. The considered model is very easy to use not only in terms of mowing grass, but also when cutting overgrown bushes or tree shoots. The model is equipped with a simple control system that allows even an inexperienced person to easily use this motokosa. The handle is also adjustable and there is a belt snap. The mass of this model is relatively small and is only 5 kilograms.
Separately, it should be noted the presence of a fairly high-tech engine, which is equipped with a special system called E-Tech. It can significantly reduce the harmfulness of exhaust gases and their amount, as well as save fuel.
In addition, the model has a very low noise level, which will allow you to work even in the evening, without creating discomfort for others.
Criterias of choice
First you need to decide how often the brushcutter will be used and how difficult it is planned to carry out work. The power and performance of the braid will depend on these points. And the service life of any equipment is determined by how its power corresponds to the tasks that it faces. If the loads are small, then there will not be any special difference between a professional trimmer and an amateur device.
But if you have to work 8 hours a day, then you need a powerful professional trimmer, the cost of which will be appropriate. And a small number of breakdowns, a long operating time, high reliability will justify the high price. You should also take into account the variety of grass that grows on the site, the size of the area to be cultivated, as well as the terrain.
Another important selection criterion is the mass of the tool. It is difficult to overestimate the role of this criterion, because even a physically developed person will find it difficult to work with a heavy tool all day. And if we are talking about a girl or a woman, then the mass factor becomes almost a priority. The net weight of the trimmer can reach 10 kilograms. But here it will also be important whether the model is equipped with a so-called backpack suspension. If it comes to periodic use, then simple straps, which are equipped with almost every model, are enough.
In addition, it is necessary to take into account such physical parameters as the type of rod, what type of shaft the rotation is transmitted - all-metal or flexible, the category of the cutting tool, as well as the equipment of the device. In addition, it is necessary to pay attention to the noise level during operation. If the device is too loud, then it will be extremely difficult to use it in the evening and in the morning, so as not to disturb anyone.
Another criterion is the degree of vibration. Comfort of work greatly depends on it. In most of the devices on the market there are special mechanisms to reduce vibration during operation. Also, balancing will be extremely important, because the advantage of one side will greatly affect the work - this will be very noticeable during grass mowing. Equally important will be the easy launch of the device. If you have to spend a lot of time trying to start a brushcutter, then you should think about whether it is needed at all.
By the way, the startup mechanism is one of the most vulnerable systems of such devices that have a low cost. And therefore, it may be worthwhile to make a choice in favor of a slightly more expensive model, where there will not be such a problem.
When working with such equipment, it is necessary to use only high-quality and special motor oils, which allows to ensure high efficiency of the devices in question. Otherwise, there is a high probability of damage to the device. The same goes for gasoline. It’s better to overpay a little, but use high-quality fuel, which will really allow the trimmer to perform its functions well.
Another important point - you should not neglect to read the instructions for use, because there you can find a lot of tips on working with a specific trimmer model. This will significantly improve the effectiveness of its application. Another aspect - during long-term operation, even an expensive model should be given a certain respite in order to reduce the likelihood of overheating of the engine and its subsequent failure.
In addition, it is necessary to carry out maintenance of the device from time to time, which will maintain its performance at a high level.
For a better trimmer, push-pull or four-stroke, see the next video.