2-Stroke VS 4-Stroke Generators – Which One is Better and Why

Generators come in different shapes and sizes. One variation based on the engine specification is the choice of a 2-stroke or 4-stroke engine. There are different pros and cons of each engine type and it is very important to know about their working, advantages, disadvantages, and power production capacity so that you can make the best decision.

In this article, we will discuss the working of 2-stroke engines as compared to 4-stroke engines, pros and cons, and which one is better and why. We have put in a lot of effort into doing research on this and want you to make the best possible decision while buying your next generator.

2-Stroke VS 4-Stroke Generator

In order to understand the difference between a 2-stroke and a 4-stroke generator, you need to have a basic understanding of the definition of a stroke. A stroke is defined as the phase of an engine cycle during which the piston travels from the top to the bottom or vice versa. Usually, the mechanical stroke is defined in very complex ways; we want to keep things easy and understandable for you!

Interesting read: How Does an Electric Generator Work? Parts, Mechanism and more

2-Stroke Generator

features of 2-stroke generator

As the name implies, a 2-stroke engine completes a power cycle with two strokes of the engine’s pistons. The end and the beginning of the combustion happen at the same time. The intake and exhaust of air take place simultaneously as well. In a 2-stroke engine, you need to add oil with the fuel as a basic requirement. Generators that have a 2-stroke engine are lightweight as compared to generators with 4-stroke engines.

2-stroke generators are designed for places where you need a small power range. Most 2-stroke generators are found in 500 watts to 800 watts and may go up to 1200 watts.

Pros of 2-Stroke Generators

Following are the pros of a 2-stroke generator:

Simple Design – The design of the 2-stroke engine is simple and easy to understand. In case your 2-stroke generator breaks down, you will be spending very little on maintenance.

Size and Portability – 2-stroke generators are small and less in weight. This feature makes them highly portable and easy to carry around. If you are an avid traveler and like to camp in the open, then a 2-stroke generator can easily meet your electricity needs in the open. You can easily charge your phone, laptop, and other on the go small devices.

No Separate Oil – You do not need to keep a record of your generator’s working hours. Lubrication needed for engine parts is provided by the oil mixed in the standard fuel. The oil which you are going to add is very low. Most 2-stroke generators work at a ratio of 32:1 to gas to oil.

Optimal Power – 2-stroke generators deliver more Power because in a 2-stroke engine, every alternate stroke provides Power compared to a 4-stroke engine that returns Power after four strokes. This feature allows the generator to deliver more Power at a small size.

Cons of 2-Stroke Generators

A 2-stroke engine has the following drawbacks:

Limited Power – 2-stroke generators have a little power range. It is their main limitation that you cannot use them to Power large spaces.

Time-Consuming – Starting this generator is time-consuming. It has a very small tank, and if you are planning to run it for a long duration, you will have to fill in the tank often. You will also have to mix oil with gas; this will consume a lot of time. It is also difficult to start it by pulling the starting-rope with your hands.

Wastage – If you have mixed oil and gas and you do not need a generator anymore for some time, the mixed oil and gas will be wasted as you cannot use them elsewhere.

Expensive – if you run your generator for long periods, oil addition can be costly. Further, fuel is also wasted during the starting of the generator.

High Maintenance – We agree that the maintenance price is less, but it is required more frequently. Spark plugs and filters need to be cleaned and replaced much more often than a 4-stroke engine.

Emission Sound – 2-stroke generators produce a lot of sound while running. It would help if you got an additional muffler to reduce their exhaust sound.

Pollution – 2-stroke generators produce a lot of pollution. They let out gases that can be harmful to human beings.

4-Stroke Generator

features of 4-stroke generator

4-stroke engines are in vogue nowadays and almost all the generators you will find will have a 4-stroke engine installed in them. In a 4-stroke engine, the intake and exhaust of air are separate. Compression and combustion also take place separately. The power is produced after every 4 strokes of the piston.

The engine design in a 4-stroke generator is more complicated as compared to a 2-stroke generator engine. You do not need to add any additional oil along with the standard fuel apart from the separate engine oil which needs to be changed at the prescribed limit of working of the generator. The 4-stroke engine is heavy and as a result, the overall weight of the generator is also more. These generators could be found in with a larger wattage i.e 2000, 3000, 4000, 5000 and above.

Enhance your knowledge with this guide –> What is Generator Load Bank Testing? (A Guide to Perform it)

Advantages of 4-Stroke Generators

With a generator having a 4-stroke engine, you can enjoy the following benefits

Fuel Efficiency – 4-stroke generators are more fuel-efficient as compared to 2-stroke generators. They are easy on your pocket. They consume the fuel on every 4th cycle; hence they save the extra usage of fuel.

Durability – 4-Stroke engines are more durable than 2-stroke engines. A 2-stroke engine works more as compared to a 4 stroke engine for a specific time. It is evident from the fact that a 2-stroke engine produces more heat and more exhaust in one hour as compared to a 4-stroke engine.

Less Sound & Pollution – A 4-stroke engine produces less sound and makes less pollution. It is safe for the environment. This is due to the fact that you do not have to add oil to the gas and hence no oil is burned during the combustion process.

No Extra Oil in Fuel – There is no need to add extra oil along with the fuel in the fuel tank. Separate engine oil is used which needs to be replaced after every 500 hours of activity.

Disadvantages of 4-Stroke Generator

With the benefits of a 4-stroke generator, come the following disadvantages

Complex Design – The design of the 4-stroke engine is complex, hence it makes the overall design of the generator complex and difficult to understand.

Expensive – A 4-stroke generator is expensive to buy and also expensive to maintain and repair. Its frequency of breaking down is usually low but when it goes rogue, its repairing is expensive.

Less Powerful – A 4-stroke engine is less powerful as compared to a 2-stroke engine because it delivers power on every 4 strokes.

Conclusion: Which is better and why?

Which generator is best for you, the answer to this question really depends on your needs. If you are looking for a generator under the power of 1000 watts, is portable, lightweight, then a 2-stroke generator is your go-to option. Mixing the oil/gas can be a little difficult in the beginning, but once you do it a few times, you will manage it very well. If you travel a lot and like to go camping in the mountains and forest, then this is the generator for you.

If you want a standard generator for your house or generator then you must choose a 4-stroke generator. First of all, you will not find a 2-stroke generator large enough to support your needs for your home or office. Secondly, 4-stroke generators are fuel-efficient; hence they will save you a lot of money while running for long periods of time. Their exhaust is less harmful and they produce less sound while running.

Similar Guide: Single Phase VS Three-Phase Generators – Which One is Better and Why

We are sure that now you have a clear picture in your mind that which generator is better and which one you should buy.

6 thoughts on “2-Stroke VS 4-Stroke Generators – Which One is Better and Why”

  1. I have a power wheelchair and I was wondering if 2 stroke power generator will suffice to provide power if I plan to make a long distance like go downtown and back about 10 kilometres round trip?

    • I have been using my 2 stroke power generator to power my house during power outage for years.

      It’s 700w nominal, surge maybe 900w max. I could run my 200+ liter freezer about 100w when compressor kicks in, washing machine (no heating of water & max spin set at 1000rpm), whole house lightings estimated less than 200w, one exhaust fan about 35w, one wall fan about 50w, phone charger, CCTV with 4 cameras and a dozen online of devices.

      So I really think powering your wheel chair is not a issue at all.

  2. We need a 2000-watt generator for our house which will be used very seldomly (only when there is power outage). Which is better for this application, 2-stroke or 4-stroke engine generator?

    Thank you.

    • Hey Jerry!

      We recommend that you buy a 4-stroke generator. 2-stroke generators will not give you enough power
      to run major applications of your home as they usually come in a size of 1000-watt. A 4-stroke generator
      is a bit expensive than a 2-stroke generator, but it is durable, fuel-efficient, and is safe for the
      environment. A 4-stroke generator also frees you from the hassle of mixing oil and fuel. Here you can check our guide for 2000-watt generators to pick one for you: http://voltagehero.com/best-2000-watt-generators/

      Let me know if you need anything else.

  3. Live alone in single wide mobile home in country. Power goes off often during storms due to wind & excessive trees. Sometimes it is out for hours or days. Looking for right generator to power bare minimum. Maybe just fridge & 5 cubic freezer. What do you suggest?
    Thanks for your help.

  4. Angela,
    Get all the equipment you want to power during a outage their power requirements, list them down. For compressor type equipment, you need the start up power requirements which maybe 6x the normal running requirements. Add all power requirements together, then you add at least 20%.

    Most probably you will need a 4 stroke generator.

    If cost savings is important and you don’t mind scheduling your freezer to be powered every 4~6hrs, you can cut down your power requirements.

    I have been able to get by on a 700w(surge 900w) 2 stroke generator. It serve my 200l fridge, lightings less than 200w and some essential stuff well. I switch off my bigger deep freezer during outage.


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