Difference between two stroke and four stroke engine. Disadvantages of two-stroke engines

What can be added to the tons of material written on this topic? Another banality?

Nevertheless, having stumbled upon another forum battle within the framework of the permanent war of "sharp-pointed and blunt-pointed", I decided to speak out and give some figures.

Let's try to figure it out quickly.

Advantages

What are the advantages of 4 and 2 stroke engines?

Advantages of two-stroke outboard motors

• less weight;
• better dynamics;
• lower price;
• ease of maintenance and repair (as a result of simplicity of design);
• b O Great reliability (also as a consequence of the simplicity of the design);

Advantages of 4-stroke outboard motors

• less noise during operation (especially on low revs);
• lower fuel consumption.

Not all 2-stroke engines need to pre-mix gasoline with oil. Therefore, the absence of this procedure during the operation of 4-stroke engines, I did not write them down as an advantage. I also do not give the traditional argument about the stunning resource of 4 cycles due to the lack of both solid evidence for this statement and the irrelevance of this problem for the vast majority of water motorists.

He also did not mention anything regarding the environmental friendliness of engines. It's irrelevant for now. Whether this is good or bad, but the question is not posed point-blank, and there is no reason to think that something will change here in the foreseeable future.

Dry residue

So, to the question why do we need to overpay for four cycles, we, it turns out, can answer: “It is quiet and economical.”

And now let's decide whether this "quiet and modest girl" is worth the cost of a wedding?

It is easy to talk about "silence" to a person who is not familiar with the subject of discussion. Yes, at low, up to 1000-1200 rpm, the four-stroke is quiet, and at idle it’s even almost inaudible - I remember a couple of times, at first, the already working engine tried to start with the key. 🙂

However, everyone who has operated both 2-ton and 4-ton PLM will tell you that starting from 4000 rpm. the difference in noise disappears and becomes insignificant towards the upper limit of the maximum.

Yes, if it is significant (there are “tractors” among 2-stroke engines), how long do we listen to the noise of our motor? Most of the rest / departure the engine is muffled.

But low noise has never been the decisive argument of the apologists of the four cycles. Economy has always been a reinforced concrete argument in a dispute with thinkers from the opposite camp.

The economy must be economical

Four-stroke engines consume less gasoline - and this is an indisputable fact. Less gasoline - less loading of the boat, less cost departure.

However, 4-stroke engines of the same horsepower tend to be heavier and more expensive than their 2-stroke counterparts. Thus, whatever one may say, we must know:

1. does the fuel economy pay for the high cost of the motor itself;
2. whether the difference in the weight of the required fuel compensates for the difference in the weight of the motors.

Yamaha, as well as some other manufacturers, publish reports with the results of evaluation of the performance of their PLA. This information is freely available online at http://yamahaoutboards.com/owner-resources/performance-bulletins

To evaluate the economic effect of using a four-stroke engine, I needed data on the consumption of a pair of 2-ton and 4-ton PLA with the same number of horses. I stopped the choice on two medium power engines:

1. 2-t: Yamaha 50TLR (we know it as Yamaha 50HETOL).
2. 4-t: Yamaha F50TLR (we have Yamaha F50HETL).

Two-stroke "fifty dollars" was tested on a boat Sundance FX 17 Flicker(length 5.21 m; width 1.98 m; total weight during testing 710 kg).

Four-stroke - by boat Key West 166SK(length 4.95 m; width 1.83 m; total weight during testing 623 kg).

Please note that the boat on which the two-stroke is installed (Sundance FX 17) is slightly longer and wider than the other and also heavier by 83 kg. But these are the closest in terms of parameters and type of watercraft that I was able to find for this power. Okay, let's give four bars a little head start. 🙂

Test results were these:

Yamaha 50TLR				Yamaha F50TLR
rpm	speed km/h	consumption l\h	consumption l\100 km	rpm	speed km/h	consumption l\h	consumption l\100 km
1000	6,28	1,89	30,16	1000	6,44	1,51	23,52
1500	8,53	3,41	39,94	1500	7,72	2,27	29,40
2000	10,94	4,54	41,51	2000	9,17	3,79	41,27
2500	12,07	6,44	53,32	2500	11,59	4,92	42,47
3000	19,31	7,95	41,16	3000	16,74	6,81	40,71
3500	29,29	9,46	32,31	3500	28,97	6,81	23,52
4000	37,82	10,98	29,03	4000	35,89	8,71	24,26
4500	44,42	11,73	26,42	4500	42,16	10,60	25,14
5000	51,98	16,28	31,31	5000	46,99	13,25	28,19
5500	57,78	21,58	37,35	5500	51,34	17,79	34,66
5600	58,26	21,96	37,69	5950	54,88	18,93	34,49

Let's slightly transform the table so that we can operate with both absolute and relative values:

rpm	consumption, l\h Yamaha 50	consumption, l\h Yamaha F50	difference in consumption, %
1000	1,89	1,51	25,00
1500	3,41	2,27	50,00
2000	4,54	3,79	20,00
2500	6,44	4,92	30,77
3000	7,95	6,81	16,67
3500	9,46	6,81	38,89
4000	10,98	8,71	26,09
4500	11,73	10,60	10,71
5000	16,28	13,25	22,86
5500	21,58	17,79	21,28

The RPM range from planing to ~5000 is preferred by the navigator who doesn't like to drag at half throttle, but doesn't intend to spend too much either. Golden mean. And in this range, the four-stroke, as you can calculate, consumes an average of 20.27% less than its two-stroke counterpart. In absolute terms, this savings will be approximately 2.65 l/h. By this amount, the F50 will consume less gasoline, operating in the optimal speed mode.

Let's count the money now. I will make a reservation right away, I do not take into account oil for 2 tons and oil and 2 filters for F50. The introduction of these variables into the calculation will not greatly affect the final result, but for F50, in this case, you will have to build a whole function graph.

So, consider gasoline. At the time of writing, the cost of the "participants" of the test was as follows: Yamaha 50HETOL - 346,000 rubles, Yamaha F50HETL - 423,000 rubles. A four-stroke costs 77,000 rubles. more expensive, but it saves gas.

So, we decide to bet on savings. Let's calculate when our "investments" will simply return to us for a start.

As already mentioned, for this pair of engines, gasoline savings are ~ 2.65 l / h in favor of the F50. The cost of the 92nd gasoline at the time of this writing is ~ 36 rubles / l. Let's convert liters into money: 2.65X36 \u003d 95.4. Thus, the average savings in rubles per hour will be 95.4 rubles.

Let's calculate how many hours we need to use the saved gasoline to return the money overpaid for a four-stroke engine:

77000:95,4=807,1.

807 engine hours! Do you feel the scope? That is how much F50 should work so that the overpayment upon purchase, in comparison with 50 2 tons, is completely returned to your pocket.

What is 807 m/h? I think you will not object that there are few people who roll more than 50 hours per season. And this is still quite optimistic - personally, I haven’t been gaining 40 lately ... We count the seasons: 807:50 = 16.14. Think about this figure: 16 years! So much time must pass for the difference in the cost of the pair of motors in question to pay off.

And it's an economical motor!?

I'll tell the truth about you such that it's worse than any lie

See what happens. We came to the store to buy a 50 hp motor. Having heard the manager's tales about a quiet, economical motor, we take "four cycles" instead of two. Those. from a light, dynamic motor, we refuse in favor of a heavier and more expensive motor. The main thing is that it consumes 20% less gasoline. Here it is, marketing in action.

Jokes, jokes, but this is how decisions are often made. The buyer of the forums read a lot, then the seller of the songs sang - and that's it, "the client is ripe."

Let's answer simple questions.

Is it more profitable for a motor manufacturer to sell which motor - simple and cheap or complex and expensive? Of course expensive!

Which motor has more parts: a simple 2-stroke or a more complex one? In difficult. Where is the most likely to break? In difficult. Is it profitable for the manufacturer to sell spare parts for repairs? Yes!

Another very interest Ask: why do most 2-stroke engines in terms of design look like awkward guests from the last century, like some kind of ugly ducklings, and all four-stroke engines are almost ultra-design? What, “kopeck pieces” cannot at least make normal caps? It's not clear, at least not clear.

Well, and finally, to the dealer and everyone he feeds, which one is more profitable for you to sell an expensive or not very expensive motor?

And who benefits from the "4-stroke" philosophy? Answer: it is beneficial for everyone in the chain from the manufacturer to the cashier, but, alas, not for you.

conclusions

The four-stroke is sometimes preferred for some uses, and sometimes is the only alternative. For example, for known types of fishing at low speeds, a 4-stroke engine is more suitable (although there is something to argue about). For constant many hours of movement on the water, whether it is a pensioner who does not care to do more in life, or a fisherman who fishes for days, from last ice to the first - these people may also find 4 measures more convenient. And, of course, we shouldn't forget about professional passenger carriers - that's who care about both resource and savings.

But what will "four strokes" give to an ordinary poor motorboat, resting on the river on a serene, quiet weekend, having a watercraft designed for engines of 30-60 hp? Nothing but a feeling of lightening the pocket from extra money. No matter how stylish and prestigious the “economical-expensive” purchase looks on the transom.

Thus, the choice of a 4-stroke outboard motor for small seasonal runs, if it is much more expensive than a 2-stroke of the same power, looks unprofitable and irrational. At least for those who count money.

When buying a new scooter, people often ask questions like " Which is better 2 stroke or 4 stroke". There is no single answer to this question. Each motorist will find both disadvantages and advantages in both types of engines. To figure it out for yourself which scooter is better 2 stroke or 4 stroke, you should first find out What is the difference between 2 stroke and 4 stroke engine.

The difference between a two-stroke and a four-stroke

Main differences between two-stroke and four-stroke engines is due to the difference in their gas exchange devices - the supply of a fuel-air mixture to the cylinder and the removal of exhaust gases. IN 4t engine the processes of cleaning and filling the cylinder are carried out using a special gas distribution mechanism (GRM), which closes and opens the intake and Exhaust valve s. IN engine 2t filling and cleaning of the cylinder are carried out in parallel with the compression and expansion strokes - at a time when the piston is located near BDC (bottom dead center). To do this, there are two holes in the walls of the cylinder - inlet (purge) and outlet, through which fuel mixture and exhaust gases. The two-stroke engine does not have a valve timing mechanism, which makes it much lighter and simpler.

Which engine is more powerful 2 stroke or 4 stroke

Unlike a 4 ton engine, in which one stroke occurs for two revolutions of the crankshaft, in a 2 ton engine, a stroke occurs with each revolution of the crankshaft. This means that a two-stroke engine must have (in theory) twice as much liter capacity (the ratio of power to engine volume) as a four-stroke. But in practice, the predominance is only 1.5 - 1.8 times. This happens due to inadequate use of the piston stroke during expansion, the worst mechanism for ridding the cylinder of exhaust gases, the cost of a share of power for purge and other phenomena associated with hallmarks gas exchange of 2 stroke engines.

Fuel consumption 2t and 4t

Surpassing the four-stroke engine in liter and power density, two stroke engine inferior to him in economy. The expulsion of exhaust gases is performed in it fuel-air mixture arriving in the cylinder from the crank chamber. In this case, part of the fuel mixture ends up in the exhaust channels, being removed together with the exhaust gases and not producing useful work.

Grease 4 t and 2 t

Two-stroke and four-stroke engines have a different design and principle of operation of the engine lubrication system. In 2 stroke scooters it is carried out by mixing in established proportions (usually 1:25 ... 1:50) engine oil with fuel. The fuel-air-oil mixture, circulating in the crank and piston chambers, lubricates the connecting rod and crankshaft bearings, as well as the cylinder mirror. When the fuel mixture ignites, the oil burns together with gasoline. The products of its combustion are removed together with the exhaust gases.

There are 2 methods of mixing oil with gasoline. Conventional mixing before pouring fuel into the tank and a separate supply, in which the fuel-oil mixture is formed in the inlet pipe located between the carburetor and the cylinder.

Separate lubrication system for two-stroke engine

1. oil tank
2. carburetor
3. throttle cable separator
4. throttle stick
5. oil control cable
6. plunger dosing pump
7. oil inlet hose

All modern 2t scooters use separate oil supply(we fill in 2t oil separately from gasoline). IN two stroke scooter the engine has an oil tank, the pipeline of which is connected to an oil pump that supplies oil to the inlet pipe in the amount that is necessary depending on the amount of air-gasoline mixture. The productivity of the pump depends on the position of the "gas" knob. The more fuel is supplied, the more oil is supplied, and vice versa. A separate lubrication system for two-stroke engines is considered more flawless. With it, the ratio of oil to gasoline at light loads can reach 1:200, which leads to a reduction in smoke, a decrease in carbon deposits and oil consumption. This design is used on modern scooters with two-stroke engines.

In a four stroke engine oil does not mix with fuel and served separately. To do this, the engines are equipped traditional system grease made up of oil pump, filters, valves, pipelines. The role of the oil tank can be performed by the engine crankcase (wet sump lubrication system) or a separate tank (dry sump system).

Lubrication system of a four-stroke engine with a wet and dry sump

1. sump
2. oil intake
3. oil pump
4. oil filter
5. safety valve

When lubricating with a “wet” crankcase, pump 3 takes oil from the sump, pumps it into the outlet cavity and then delivers it through the channels to the crankshaft bearings, crankshaft and timing parts. When lubricating with a “dry” sump, oil is poured into the tank, from where it is pumped to the rubbing planes. That part of the oil that flows into the crankcase is pumped out by an auxiliary pump, which gives it back to the reservoir. There is a filter to clean the oil from wear products of engine parts. If necessary, a cooling radiator is also installed, since during operation the oil temperature can rise to high temperatures.

It is a converter of energy of thermal expansion of fuel into energy. mechanical movement shaft. Its meaning is that in some closed space fuel enters, which burns there, and due to the fact that when liquids and gases are heated, they increase in volume, this fuel moves one of the movable walls of this space, or a piston. This is the point ICE operation-ov

The first such engine was created at the beginning of the nineteenth century by the Frenchman Lenoir, and its power was equal to twelve horsepower. It was very weak with low efficiency (only about 5 percent), but despite this, for that time it was a big step forward. The Lenoir engine could not be used almost anywhere, as it was quite bulky, although it consisted of only one cylinder, but at the same time it produced very low useful power. However, it was used on ships for some time.

In the future, ICE technology improved, and soon more efficient and practical models appeared, as a result of which, today, 90 percent of all land transport works on engines internal combustion. Exceptions are trolleybuses, trams, trains and electric vehicles that are very fashionable today, which, although less convenient than cars, are much more environmentally friendly.

Why are internal combustion engines divided into 2-stroke and 4-stroke?

As we have already said, the main feature of the internal combustion engine is filling the volume of the cylinder with fuel. But the fact is that this filling can be done in two ways - you can make separate strokes for the introduction and removal of gasoline, as is done in a 4-stroke engine, or you can inject it at the end of the second stroke, and at the same time, the new fuel itself expel the exhaust gas. This principle takes place in a 2-stroke internal combustion engine.

Let's start with the 4-stroke, as it is easier to understand. So, the whole cycle of its work is divided into 4 parts. A cycle is when the fuel ignites once. If the fuel has ignited twice, it is said that two working cycles have passed. So the 4 parts of the loop are:

1. By opening the valve with gasoline pressure, it is injected into the cylinder. The piston under the pressure of gasoline moves down During this time crankshaft makes a 180 degree turn.
2. The crankshaft rotates another 180 degrees, and drags the piston with it, which is now starting to move up. As soon as it reaches the extreme point at the top, a lighter flares up, or as it is also called, a candle that ignites the fuel, which, when compressed, gives more thermal expansion energy.
3. The flash of a candle, and the subsequent ignition of gasoline in the cylinder, causes the piston to be pushed back down to dead center. This movement is the main impetus that ensures the rotation of the wheels of the car, that is, you need to understand that the car is moving thanks to this third phase of the work cycle. The crankshaft rotates another 180 degrees.
4. And the last stage is the removal of fuel combustion products from the cylinder, which are no longer good for anything. They are removed using a special valve. As you probably already guessed, two different valves, gasoline enters through one, and leaves through the second. Further, after the end of the output, the first stage begins again.

This method of implementing fuel injection into the cylinder assumes that the change of the working medium (i.e. gasoline) is not assigned in a separate cycle, but the input is carried out in a short period of time when the piston is at its very far distance from the opposite edge of the cylinder, at the dead center. Simultaneously with the input, the output of combustion products occurs. That is, the procedure for changing the working medium occurs at the end of the second cycle, and is called purge.

Purge does not occur through valves, but through special holes that are located at the bottom of the cylinder, and the piston closes them almost all the time. But when the piston goes dead center, the artificially created vacuum draws in the spent fuel, and under the influence of the pressure difference, fresh gasoline enters the working volume.

Each of these two types of internal combustion engines has certain advantages over each other, which we will now discuss in detail.

The main differences between these two types of engines

1. Engine weight. The first difference is that 2-stroke engines are lighter (have less weight) than 4-stroke ones. This means that if you want to reduce the weight of the car as much as possible, which is very important, for example, for racing cars, then it is more profitable to use two-stroke.
2. Engine cost. Two-stroke is cheaper, so in budget options cars, as a rule, are worth it.
3. Noisy work. Four strokes are quieter and almost inaudible during operation. This is one of the reasons why they are put in expensive cars.
4. Environmental friendliness. Four-stroke is more environmentally friendly, as their duty cycle produces less combustion products, and therefore less smoke.
5. Grease consumption. Two-stroke internal combustion engines consume more machine oil, since it has to be diluted with gasoline, while 4-strokes have a separate system for this.
6. Manufacturing complexity. Do two-stroke internal combustion engine much simpler, and this is due to its cheapness.
7. Acceleration speed. Two-strokes accelerate faster, which is why they are used in sports and racing cars.
8. Exploitation. 4-strokes are harder to maintain and repair as they are more complex and have many additional systems, which are absent in two-stroke.
9. Life time. 4 strokes last much longer.

These are the main differences between them, but if you dig into the topic and understand it well, you will certainly find a whole bunch of other differences.

Engines are classified according to the way the operating cycle is carried out, two-stroke and four-stroke, consider them.

Two stroke engine

The working cycle occurs during one revolution of the crankshaft, only compression and expansion work. Instead of intake and exhaust, scavenging occurs near the piston, while fresh working mixture pushes exhaust gases out of the cylinder
The piston goes up, the working mixture in the cylinder is compressed, the valve opens intake manifold and a fresh portion of the working mixture is sucked into the crank chamber.
Compared with four stroke engine two-stroke has almost twice the power with the same volume. But the power is not fully realized, due to insufficient purge.
Also, a two-stroke engine has such an advantage as the absence of a bulky valve system and camshaft, as a result, equipment with a 2-stroke engine is cheaper.
Other advantages of a two-stroke engine:
The absence of bulky lubrication and gas distribution systems for gasoline options.
Higher power in terms of 1 liter of working volume.
Easier and cheaper to manufacture and maintain.

Four stroke engine

The working cycle of the engine consists of 4 stages (strokes):
a) Inlet, the piston descends to the bottom dead center, at this time a fresh air-fuel mixture enters the cylinder.
b) Compression, the piston rises to top dead center, compressing the working mixture.
c) Combustion and expansion, piston stroke Shortly before the end of the compression cycle air-fuel mixture ignited by a spark from a spark plug. During the journey of the piston from TDC to BDC, the fuel burns out, and under the influence of the heat of the burnt fuel, the working mixture expands, pushing the piston. The degree of "non-rotation" crankshaft engine to TDC when the mixture is ignited is called the ignition timing. The ignition advance is necessary so that the combustion of the fuel has time to completely end by the time the piston reaches bottom dead center.
d) Exhaust, after the bottom dead center of the working cycle, the exhaust valve opens, and the upward moving piston displaces the exhaust gases from the engine cylinder. When the piston reaches top dead center, the exhaust valve closes and the cycle starts over.

Pros of a 4-stroke engine:
Greater resource.
Higher economy.
Cleaner exhaust.
No complex exhaust system required.
Less noise
No need to pre-mix oil with gasoline

• To complete the comparison of two-stroke and four-stroke engines, we note the following:
• Two-stroke engines have more power per unit volume, but lower efficiency. For this reason, two-stroke engines are used where small size is very important, but fuel efficiency is relatively unimportant, for example, on motorcycles, small motor boats, chainsaws and motorized tools.
• Four-stroke engines are installed on the vast majority of the rest Vehicle including motorcycles.

Many sites may convince you that a four-stroke engine is better. In some articles you can read the opposite - they say, buy 2 cycles and forget about four altogether. But still, which outboard motor is better? We confidently intend to say that the best engine is the one that best suits your goals. For example, according to rumors and unverified data, since 2006, the sale of two-stroke engines has been banned in the EU and the USA due to increased environmental standards. But on the other hand, how many of you are going to the United States on a motorboat?

In general, unambiguously answer for you which outboard motor is better only you can. We, in turn, will try to describe the comparison as fully as possible. two-stroke engines with four strokes.

So, ecological norms and morality. Where is the truth, and where is the fiction?

Essence. Due to the design features in a two-stroke internal combustion engine, the oil that lubricates the crankshaft enters the combustion chamber. As planned by the designer, it burns there together with gasoline and the waste comes out as exhaust. The saddest thing for the environment is that not everything fits in with the plans of the designer. In fact, the injection of new fuel into the combustion chamber occurs almost simultaneously (with a small error) with the withdrawal of the spent mixture, which leads to the ingress of a certain amount of unburned or partially burned mixture into the exhaust. It is unlikely that this will lead to a mutation of tadpoles, but it is quite possible to toxic poisoning of the inhabitants of the reservoir. Although, to be honest, for a quickly noticeable effect of pollution, you need about one motorboat to be on one square kilometer, which happens quite rarely.

Now for the rules and regulations. There are various rumors about the ban on two-stroke engines in the countries of the European Union and the USA. Some eyewitnesses say that only sales are prohibited in Finland, and everyone who managed to buy a two-stroke for themselves swims with it without bothering. Others say they saw two-strokes for sale in Germany, only the prices were too high. Presumably, these were two-stroke engines designed taking into account environmental standards. Hence the price and permission to sell. In general, how many countries, so many rules, and if you are going fishing in a particular country, then check it there. And if you want to go under the motor all over Europe, then buy four cycles. So far, no such laws have been adopted in Russia, which means that Russian Federation you can safely row in two cycles. If you think that environment you need to protect as much as possible, it is important for you what will be on the planet in five hundred years and think about how which outboard motor is better, then for you the answer is unambiguous: four cycles.

Another important aspect of the issue can be considered weight.

Every second cycle is a worker. In four-stroke, as you might guess, every fourth. That is, in theory it can be assumed that with the same combustion chamber, two-stroke engines are twice as powerful as four-stroke ones. Due to many shortcomings (for example, the ingress of an unused mixture into the exhaust and a used mixture into a fresh one), practice differs slightly from theory and in reality this figure is slightly lower - usually the difference is somewhere in 1.6-1.7 times. This means that in order to obtain the same power on the shaft (in principle, this is where it is most interesting to us), a two-stroke engine needs a smaller size than a four-stroke one. Smaller size equals less weight. That is, if, when solving a problem, which outboard motor is better Consider mass as the main parameter, then preference will strongly lean towards two-stroke.

Now, exactly, where does it matter? After all, it is quite possible that your boat is in the garage in the country and you do not care what weight the motor has. Let's look at this issue in more detail. Here the main thing to consider is what kind of boat you have and how far it is from the body of water most of the time.

If you have an inflatable boat and you go fishing in a jeep or in a passenger car with a trailer and constantly take off and put on the motor, then its weight will probably be a significant factor for you. If you have a hard hull boat and you can hang the motor on the transom forever, then what difference does it make to you how much it weighs?

The longer your boat, the less weight at the stern matters. Conversely, with a short boat, you will have to constantly additional load the bow as soon as you want to approach the motor.

If you have a large inflatable boat and you put, for example, 15 horses on it, then a difference of 20 kg will be noticeable - 30 kg can be hooked on the transom yourself with some effort, but 50 ... for this you need to swing in advance or call friends for help... If you are just fishing in quiet places and your motor has a mass of up to 20-25 kg, then you may not notice much difference when carrying. Here you yourself correlate your forces with the mass of the motor and decide which outboard motor is better just for your collection. If the PLA lives on the transom, then the weight does not matter.

Profitability. Myths and reality.

Let's start with the cost.

Due to the more complex design, the cost four-stroke motors exceeds two-stroke analogues. In some cases, this difference is only 10%, and in some cases even 50%. In any case, for one horsepower, two cycles will be cheaper.

Fuel consumption.

At first glance, it may seem that four-stroke outboard motors consume less gasoline, oil and generally have a higher ratio useful action. What is there to hide, the way it is ... One of the main reasons is, of course, the ingress of unspent fuel into the exhaust. The second is provided by the design of a two-stroke engine initially - the oil not only lubricates, but also burns. I don’t know how in your reality, but in my cost good oil for an internal combustion engine outweighs the cost good gasoline several times. And the third more or less significant reason is the combination of the working cycle with the exhaust. In four-stroke engines, the spent mixture begins to be removed only after the cylinder head has dropped to its lowest position, and in two-stroke engines, about halfway through (plus or minus, depending on the specific model).

Now on business. When is it important? After all, for example, at races, no one thinks about economy - the main thing is to come first, and when traveling over long distances ... The truth is that if you go swimming only in July and then once a week, then, quite possibly, your grandchildren will pay off price difference. And if you think about it, which outboard motor is better for you, then fuel consumption will play an insignificant role. And if you earn your living by doing this and the outboard motor rests only when there is ice on the river, then you should seriously think about the cost of feeding your pet ...

Motor resource.

Rumor has it that a four-stroke will last much longer than its two-stroke counterpart. But, as they say, in reality, everything is not as it really is. The reality is that all these statements are too theorized. Let's say the declared motor resource of some engine is 2000 hours. In order to test this in practice, you need to ride a boat around the clock for the whole season. Or 3 seasons for 8 hours a day. Every day. No weekends or passes. Regardless weather conditions. And keep in mind that in order to compare, you need to check 2 outboard boat motors. Can you imagine the cost of such a check? And who can afford to spend a year of his life on this? I'm with full confidence I declare that not a single private person has been engaged in such a check and will not be. In practice, if such tests were carried out (which I personally doubt), then they were sponsored by the manufacturers of the PLA and, of course, biased in someone's favor. And if you consider that the engines will be repaired? How then to calculate the motor resource? Everyone knows that some grandpas ride motorcycles from the 70s, just replacing the cylinder head. What can be said about motor resources? In general, here we can say that the data on the motor resource of outboard outboard motors are calculated only on paper (or on a computer) and may be far from reality, so it's hard to say here which outboard motor is better.

Repair and service.

Engines of all makes and for all purposes can experience breakdowns from time to time. And everyone understands that the more expensive the engine, the more expensive the parts for it. For example, instead of fixing a Porsche, you can buy yourself a Zhiguli. It's the same with outboard motors - the cheaper the engine, the cheaper service and repair. If you live in St. Petersburg, then it will be easier for you to make tinctures, repairs, adjustments and other useful things with us and say here which outboard motor is better difficult. Contact our dealers and they will give you necessary information. If you are planning to do an engine overhaul. on their own or by the forces of acquaintances, then most likely you should buy a two-stroke - they are simpler, longer produced and there are more specialists on them. Some craftsmen can tune their two bars right on the water very well ... But with four things are more complicated. Although in any case, the initial setup is strongly recommended to be carried out in our workshop or with our master on the road.

Other nuances

Noise. At full speed, two-stroke engines scream louder than their four-stroke competitors. According to many users, at lower speeds, this difference is much less noticeable. And yet, if you are going to troll a shy fish, you should seriously think about extra decibels.

Smoke. Due to the presence of oil in the fuel mixture, two-stroke PLAs smoke noticeably more strongly. If you're using a motor to get from point A to point B, then smoke doesn't matter. And if one day you want to troll with a fair wind, then you will quickly decide for yourself which outboard motor is better. Unless, of course, weight and price play a key role.

Transportation. There is an opinion that outboard motors with a duty cycle of 4 strokes need to be transported only in certain positions, and two-stroke motors can be transported in any way. And this opinion is correct. A certain position of the PLA when transporting four-stroke engines is necessary so that oil does not flow out of the crankcase. Many two-stroke promoters use this as a strong selling point. In fact, I don’t remember that the owners of fours complained about such a trifle. In general, this is a problem in the minds, not in reality.

Oil mixing and non-mixing. Everyone knows that a mixture of gasoline and oil is fed into the combustion chamber of a two-stroke engine, and pure gasoline is fed into a four-stroke engine. And many, when thinking about the topic which outboard motor is better they begin to complain, they say, it is necessary to constantly mix the oil, and even in the right proportions ... The same trifle as transporting on its side from the previous paragraph. Any owner of two cycles knows very well that for running in the majority of LLMs, the proportions are 1 to 25, and when driving 1 to 50 (although some experienced ones recommend 1 to 25 when driving). Who can't divide a liter by 25? Or 50? For whom is it difficult to pour a stack of oil into a canister? Many people pick up a canister of gasoline at a gas station, pour oil in the same place, and by the time they reach the boat, it is mixed. On the waves, mixing continues and is maintained. And even now, most of the oils that are produced for these purposes are self-mixing ... In short, the owners of two-stroke engines do not complain about this.

Exit to planing mode. To enter planing mode, the first thing you need is the presence of an appropriate boat. If the boat was originally designed to sail in a displacement mode, then trying to bring it to gliding is tantamount to trying to bring an aircraft carrier to gliding. If you have a punt, then, depending on its deadrise, you will need about one horse under the hood for every 20-30 kg of total weight. Since the weight of the outboard motor is also included in the total, the lighter the motor, the less horses are needed. On the other hand, the lighter the engine, the less it produces the same horses. According to rough calculations, we can say that if you are the owner of a small vessel and are going to harness your carriage with five horses, then take two-stroke horses - they are lighter. If the question is about fifteen forces, or at least ten, then here the weight of the engine already plays an insignificant role and bother about which outboard motor is better not worth it.

If you have any questions about outboard motors, their selection, operation, maintenance, etc., feel free to contact our dealers. We will be glad to you