Difference Between 2 Cycle and 4 Cycle Weed Eater

Most common types of gas-powered weed eaters are 2-cycle and 4-cycle. Each model with a different price, size and performance. If you don’t know anything about gas engines, you’ll probably have problems to choose the most appropriate string trimmer for you. I just elaborate difference between 2 cycle and 4 cycle weed eater.

2-Cycle and 4-cycle gas engines aren’t as different as many believe. Both types use gasoline as fuel and a piston system to generate torque and motion. However, 4-cycle engines work in a more complex way than 2-cycle models.

In this article you’ll know each one of the features that make 2-cycle and 4-cycle motors so different. In addition, you’ll learn how each engine type works and how to choose the best model for you.

Difference Between 2 Cycle and 4 Cycle Weed Eater

What is 2 Cycle Weed Eater?

2-Cycle or 2-stroke engines generate torque and motion in a 2-step cycle. Here’s a detailed description of each one:

2 Cycle Weed Eater
  • Step 1 (Ignition/Compression)

New fuel enters the crankcase and existing fuel is compressed and then burned while the piston moves up.

  • Step 2 (Combustion/Exhaust)

The piston moves down and the gases of burned fuel are pushed out while more fuel is injected into the cylinder.

What is 4 Cycle Weed Eater?

4 Cycle Weed Eater

On the other hand, 4-stroke or 4-cycle engines use a 4-step cycle to generate torque and motion. This is how they work:

  • Step 1 (Intake)

The piston moves down to fill the cylinder with fuel and oxygen.

  • Step 2 (Compression)

The piston moves up to compress the fuel-oxygen mix.

  • Step 3 (Combustion)

The electric spark from the spark plug burns the fuel and pushes the piston down.

  • Step 4 (Exhaust)

The piston moves up to push the combustion gases out of the cylinder.

Step by Step Guide to Difference Between 2 Cycle and 4 Cycle Weed Eater

Step by Step Guide to Difference Between 2 Cycle and 4 Cycle Weed Eater

Now that you know what 2-stroke and 4-stroke engines are, it’s time to learn how to differentiate them. Just read carefully the information below.

Size and Weight

Usually 4-cycle engines are bigger and heavier than 2-cycle engines. 4-Cycle models include additional parts and are 50% heavier than their 2- cycle counterparts.

Storage Space

The less size and weight of 2-cycle trimmers also makes them easier to carry and store. On the other hand, 4-cycle trimmers may be a little more difficult to carry and require a bigger storage space.


4-Cycle engines can generate more horsepower by consuming the same amount of fuel as a 2-cycle engine. That means more cutting power and fewer passes to cut the hardest weed.

Torque and RPM

4-Cycle engines are designed to generate high torque with less RPM. 2-Cycle engines work in a totally different way, requiring more RPM to generate more torque.

In simple words, a 4-cycle trimmer will cut hard lawn at slow speed without trouble. On the other hand, a 2-cycle model will tend to get stuck at slow speed and will require turning faster to mow hard lawn.

Maintenance Frequency

2-Cycle engines tend to generate more friction and wear between the cylinder and the piston because they work at higher RPM. Therefore, 2-cycle trimmers need more frequent maintenance than 4 cycle models. That also means a higher money investment to keep your trimmer operational.

However, repairing a 2-cycle engine is much easier, faster, and cheaper than repairing a 4-cycle engine. To repair a 4-cycle motor, you’ll certainly need to buy more spare parts and spend more hours assembling and disassembling.

Fuel Consumption

2-Cycle trimmers tend to consume fuel faster than 4-cycle models. In addition, 4-cycle motors are friendly to the environment because they generate a lower concentration of polluting gases.

Also, 2-cycle engines are more difficult to set up, because you need to mix the gas with oil before pouring it into the fuel tank. In addition, you need to be precise with the mixing ratio in order to get the maximum efficiency of your trimmer.

On the other hand, 4-cycle engines have independent oil and fuel tanks and can automatically dose the required amount of oil.


4-Cycle motors generate much less noise than 2-cycle engines. Also, the sound they both make is completely different.


Certainly, 2-cycle and 4-cycle weed eaters may seem very similar on the outside, but they’re totally different in the inside. 4-Cycle models have a more complex functioning and include some additional parts that 2-cycle engines don’t have. They’re suitable for heavy duties, while 2-cycle models are better for light jobs.

Now that you ‘ know the main difference between 2-cycle and 4-cycle trimmers, it depends on you to choose the best option based on your requirements.

Also, read – Black & Decker Weed Eater Battery Charger Blinking Red.

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You certainly can’t believe everything the Internet tells you. Kelvin David knows this better than anyone. A few years ago, Kelvin decided to try online shopping for the first time. He was looking for a new electric drill he could use on his daily work as a contractor.