You just bought a new lawnmower and you are happy about it. You are eager to mow your lawn for the first time but there is no gas in the gas tank.
You are not sure the fuel you have is the right kind of fuel for the engine. First, you have to find out the kind of engine in the mower, to know the kind of fuel you require.
One of the questions you should ask is, how do I know if my lawnmower is 2 or 4-Stroke? If you can answer this question, you can handle the mower without hassle.
How do I know if my lawnmower is 2 or 4-stroke? If this is the challenge you are facing, do not worry.
In this article, you will learn everything you are supposed to know about 2-stroke and 4-stroke engines. You will learn how to differentiate between the two.
How do I know if my lawnmower is 2 or 4-stroke?
Many lawnmowers are 2-stroke engines. Nowadays, people are going for 4-stroke engine lawnmowers because of their environmental friendliness.
If you check the fuel tank of your lawnmower, you will know the type of engine it has. 2-stroke engines have one port for oil and gas. 4-stroke engines have two ports for oil and gas. You will learn more of this in the article.
How to Check the Type of Engine:
Fuelling is the major difference between 2-stroke and 4-stroke engines. Check your lawn mower’s fuel tank. If it has just an intake port, know it is a 2-stroke engine. You have to mix oil and gas, that is the reason it has just a port.
When it comes to 4-stroke engines, you will see two different ports. One is for oil and the other is for gas. Therefore, an examination of your lawn mower’s fuel tank tells you if it is a 2-stroke engine or a 4-stroke engine.
Another way you can differentiate the two is their noise. 2-stroke engines produce thunderous noise. The noise produced by the 4-stroke engine is normal and bearable.
Check the quantity of smoke your lawnmower exhaust emits. 2-stroke engines emit much smoke while the smoke emission of the 4-stroke engine is low.
There must be fuel in your lawnmower for you to apply this method. Your lawnmower should be running well too. Where there is no fuel in your lawn mower’s tank, you have to use the first method.
What is a Stroke?
During an engine’s combustion cycle, the piston moves up and down in the cylinder. Top Dead Centre (TDC) describes the position of the piston nearest to the values.
Bottom Dead Centre (BDC) describes the position of the piston farthest from them. The movement of the piston from the Top Dead Centre to the Bottom Dead Centre is known as stroke.
The movement of the piston from the Bottom Dead Centre back to the Top Dead Centre is also known as stroke.
The total process of what takes place in the engine is known as the combustion cycle. We have to have a clear understanding of the combustion cycle before we move on to 2-stroke and 4-stroke engines. The following make up the combustion circle.
- Intake: As the piston moves down the cylinder, a mixture of air and fuel is drawn in.
- Compression: As the piston moves down, a mixture of air and fuel is compressed.
- Combustion: A spark that ignites the gas is produced by the spark plug. This will cause an explosion and the piston is pushed down by the explosion.
- Exhaust: The burned gas is pushed out of the engine as the piston moves upwards.
2-stroke Engine:
This kind of engine has but two strokes, which are, compression stroke and power stroke.
For the engine to work, it combines multiple functions into a piston movement. When fuel and air are pulled into the cylinder, it is known as a compression stroke.
The piston is pushed downs by an explosion caused by the spark plug. The push down of the piston uncovers the exhaust port.
Pressure from the cylinder then drives the exhaust out of the port. As the piston is pushed down even further, new fuel and air will be drawn. This exposes the intake port. A combination of these three processes makes up the power stroke.
In a 2-stroke engine, the exhaust port and intake port are the same. It is known as power stroke because these processes produce the actual explosion that in turn creates the power. Concluding, in a 2-stroke engine, a complete cycle demands for double piston strokes.
2-stroke engines are straightforward. They do not have valve. Their weight is small because they have few working parts.
Their fuel tank is one. You mix fuel and oil before you put them in the tank. You should mix the fuel and oil very well before filling the tank.
If you do not, it will spoil the engine. The mixture should be in accordance with the oil/gas ratio as directed in the machine’s manual.
Applications:
2-stroke engines are commonly used in small machines, such as weed eaters and chainsaws.
They are racers’ choice of engine. The reason is that they are able to generate more power, because of their lightweight.
They have the ability to run, their position notwithstanding. They dominated the old lawnmowers. Even presently, it is still the choice of many people, because its power output is high.
Advantages of 2-stroke Engines:
- Their design is simple because they do not have a valve.
- They are not costly to manufacture because their weight is light.
- Their maintenance cost is low.
- They have double the power of a 4-stroke engine that is of the same size and,
- Their power output is higher than that of a 4-stroke engine because it fires once on each revolution.
- They are good for small equipment.
Disadvantages of 2-stroke engines :
- Their pollution rate is high when compared to 4-stroke engines.
- They produce much smoke and oil/gas sometimes leaks out of the exhaust port.
- A mixture of oil and gas is costly.
- They are less durable than 4-stroke engines.
- Their efficiency is less than that of 4-stroke engines.
- A little mistake in the oil mixture can spoil the engine.
- They are very noisy.
- They do not work well in bigger equipment.
- Its popularity is decreasing by the day, because of its environmental hazards.
4-stroke Engines
True to its name, this engine operates on four strokes. They are compression stroke, power stroke, exhaust stroke, and intake stroke.
When a mixture of air and fuel is compressed on a piston, as it is moving up, it is called a compression stroke. As the spark plug produces a spark, the gas is ignited and there is an explosion. This is called combustion stroke.
The explosion will push down the piston. As the piston moves upwards, it pushes the burned gas out.
This is known as the exhaust stroke. As the piston moves down the cylinder, a mixture of air and fuel is drawn in.
This is known as an intake system. Finally, in every two revolutions, power is produced once. All of these are known as 4-strokes.
In a 4-stroke engine, the oil that lubricates various parts of the engine is not consumed. It flows back to the crankcase.
Valve train is well protected in the 4-stroke engine and the engine is kept clean. The oil is retained in the crankcase.
You have to change the oil after a number of hours. Do not forget to check the oil level regularly. Port for oil and gas are separate.
You have no need to mix the oil and gas before you fill the tank. You will see the ports on the machine and pure the fuel.
Their weight is big because so many functions take place in them. In view of the system of oil flow in them, they can only operate in their upright position.
Their environmental friendliness has earned them popularity these days. A lot of modern lawnmowers make use of 4-stroke engines a lot.
Advantages:
- They exhaust little smoke.
- Their noise level is low and they are reliable.
- They are better than a 2-stroke engine and last longer.
- You do not need to mix oil and gas, therefore it does not easily spoil as the 2-stroke engine.
- Running cost is reduced because oil and gas is not mixed.
- Their pollution rate is low.
- Their running is smoother than that of 2-stroke engines.
Disadvantages:
- They have complicated designs and they have valves.
- They are hard to produce and repair.
- Their power is less than that of 2-stroke engines because they have less stroke fire per revolution.
- They are far heavier than 2-stroke engines.
- They are costly.
- They are hard to maintain because they have complex design.
Which Engine is Better for Lawnmowers?
A customer’s need determines the engine that should be used in a lawnmower. A 2-stroke lawnmower engine is recommended for customers who want an engine with more power.
A 4-stroke lawnmower engine is recommended for customers who want an engine with more efficiency.
The 2-stroke lawnmower engine was very popular back in the day. Today, the 4-stroke lawnmower engine is dominating the market.
Owing to its environmental friendliness, most customers are going for a 4-stroke lawnmower engine. As environmental pollution increases, people do not want the machines they use to contribute to it.
It depends on the kind of function you need to get from the engine. What you need determines the one you buy.
Is a 4-stroke engine more powerful?
There is no single answer to this question. The size of 4-stroke engines is always bigger than the size of 2-stroke engines, therefore, their power is greater.
However, a 2-stroke engine is more powerful than a 4-stroke engine of its size and weight. In summary, the power-to-weight ratio of 2-stroke engines is better.
Can you use diesel in a 4-stroke gasoline engine?
The answer is no. Do not try it. Diesel is a fuel that ignites itself. You will incur great damage if you use diesel in a gasoline engine.
What is a four-stroke lawn mower?
A 4-stroke engine has a cycle that consists of 4 strokes, in those 4-strokes, the piston goes around twice in the engine, so the spark plug fires every other rotation. There are two separate valves in this kind of engine, one for intake and one for exhaust, unlike the 2-stroke engine.
How can you tell the difference between 2-stroke and 4-stroke fuel?
You can easily tell apart a 2-stroke and 4-stroke engine. First, a two-stroke engine needs a combination of oil and fuel that ignites when the engine is in operation.
It will continually consume the oil. Second, a four-stroke engine allows oil to flow back to the crankcase after lubricating the different engine parts.
Also, if you have a 2-cycle engine, it comes with one fill port with a cap that has a fuel pump and oil can icon.
Meanwhile, the cap states the oil to fuel mix ratio, while a 4-cycle engine comes with two fill ports with each cap that separately identifies the fuel tank from the oil sump.
What happens if you put 2-cycle oil in a 4-cycle engine?
You should not worry about the values getting a little lubrication because there would not be an issue with your four-stroke mower if you use two-stroke oil. In a four-stroke engine, it can use a 1:500 ratio.
Are lawn mowers 2-cycle?
You should know that the 2 cycle mowers have been phased out in the United States. Hence, most lawn mowers are now 4 cycles.
In a 2 stroke engine, the gasoline and oil must be mixed. For a 4-stroke engine, the oil and the gasoline are separated, in two different tanks.
Lastly, we believe that this article can help you differentiate between a two and four-stroke. If you are in the United States, you can mostly use the four-stroke engine for your activities.
However, this does not mean that you would not see the two-stroke engines. The good thing is that you can use the engine on your four-stroke mower.
We hope that this article helped you understand more about the lawn mower’s engines.