What Is The Best Oil For A Ryobi 4-Cycle Weed Eater?

A weed eater is handy when it comes to keeping your garden free from stubborn weeds. If you have a Ryobi 4-cycle weed eater, and you're wondering what kind of oil you should use with it, don't worry. We've researched this question for you, and here's what we found.

Here are a few options you can choose from when selecting oil for your Ryobi 4-cycle weed eater.

  • SAE 20W-50 
  • SAE 30W
  • SAE 10W-30
  • SAE 10W-40

According to Ryobi, these oils are safe to use in your 4-cycle weed eater.  Since the weed eater operates on a 4-stroke engine, it's best to use oil meant for this type of engine. 

In this article, we'll be discussing the kinds of oil you can use in your Ryobi 4-cycle weed eater, how to check the oil, and when to change it. Keep reading to learn more about the factors you should consider when choosing oil for your Ryobi 4-cycle weed eater.

Four Oils To Use In A Ryobi 4-Cycle Weed Eater

man choices engine oil supermarket

The oil you use in your weed eater can impact its engine performance and service life. Because of this, Ryobi discourages using non-detergent or 2-stroke engine oils, as this can damage the engine of your Ryobi 4-cycle weed eater.

You should select an oil that's suited to the 4-stroke engine of your weed eater and check if the oil meets the standards of the American Petroleum Institute (API) under the SJ service category. This includes oils such as SAE 20W-50 and SAE 10W-40.

SAE 20W-50

This oil comes with your Ryobi 4-cycle Weed Eater upon purchase. Ryobi recommends that you continue using this oil if you want your weed eater to carry on with its best operating performance.

This oil is a good option if you're looking for a product that does well in warmer climates, as it does not thin in higher temperatures.

Click here to see this SAE 20W-50 oil on Amazon.


SAE 30W is a monograde oil, which means it performs in a smaller temperature spectrum than SAE 20W-50.

It is a thick motor oil used in small-engine equipment such as lawnmowers. This type of oil is suitable for warmer climates or spring and summer use. 

Click here to see this SAE 30W oil on Amazon.

SAE 10W-30

SAE 10w-30 is a multigrade oil. The 10W indicates that the oil flows well in cold climates, while the 30 means it shares the same thickness as SAE 30W once the engine is hot.

SAE 10W-30 is generally thinner than SAE 30W. This isn't necessarily bad unless you live in an area with high temperatures.

Because of its wide temperature range, this is a good option if you live in an area with varied temperatures, as it will perform well in both lower (-13°F) or higher (86°F) temperatures.

Click here to see this SAE 10W-30 oil on Amazon.

SAE 10W-40

SAE 10W-40 oil works similarly to SAE 10W-30 in colder temperatures. However, If you need an oil that will perform better in temperatures reaching 104°F, this is a good option for your weed eater.

How To Check The Oil Level In A Ryobi 4-Cycle Weed Eater

Before changing the oil, you'll want to check the oil level in your weed eater. Doing this is fairly simple. Just locate the oil cap, which can be found at the very top of the engine, and unscrew it to access the dipstick.

On the dipstick, you will see a hatched area. This area has three levels. If you remove the dipstick and find the oil only sits at the lowest level, this indicates that your Ryobi's engine is low on oil.

But if you find the oil sitting on all three levels of the dipstick, this shows that you have enough oil in your engine.

Why Change The Oil In A Ryobi 4-Cycle Weed Eater?

petrol trimmer mows green grass photography

It's essential to change the oil of an engine to ensure the surfaces within the engine are properly lubricated. Doing this allows the gears in your Ryobi weed eater to slide smoothly alongside each other, preventing harsh friction.

gasoline grass trimmer professional gardening tool, What Is The Best Oil For A Ryobi 4-Cycle Weed Eater?

For optimal use, Ryobi suggests changing the oil in your 4-cycle weed eater after every 25 hours of use. Regularly changing the oil extends the longevity of the machine and aids in decreasing fuel consumption.

It also aids in minimizing oil sludge. Oil Sludge is a thick, dark substance that can develop when you neglect to change the oil. It can damage your weed eater by blocking the gears in the engine. 

How To Change The Oil In A Ryobi 4-Cycle Weed Eater

mowing weeds grass very green and long grass

Changing the oil in your Ryobi 4-cycle weed eater can be challenging if you don't know where to start.

Before you begin, make sure you've turned off the weed eater and allowed its engine to cool. Wait until the engine is warm, and then get started. This will make the job easier, as a warm engine will allow the oil to drain completely.

You should have a funnel ready when refilling the oil. This will minimize spillage while draining the old oil or pouring in the new oil.

To complete the task, follow these simple steps.

1. Remove The Top And Bottom Covers

Take off the top and bottom engine covers by removing their screws

The green top cover has the 4 Cycle logo and is attached by one screw found at the top of the engine, while the bottom cover is black and attached by two screws located at the bottom of the engine.

Doing this will allow you to easily access the oil fill hole and prevent oil from leaking onto the engine cover.

2. Drain The Oil

Now that the top and bottom covers are out of the way, it's time to unscrew the oil cap and let the old oil drain. 

To do this, have a leak-proof container or can ready for the old oil to drain into. It'll make things easier for you if the container has a wide opening. If not, use a funnel if you're worried about spilling. 

Next, tilt your Ryobi weed eater over the empty container and keep it this way until you're sure you've emptied the oil out of the engine. 

To properly recycle the used oil, you can contact your local waste collectors for information on approved disposal sites near you. 

3. Add New Oil

When adding the new oil, you can reuse the SAE 20W-50 bottle that came with your Ryobi weed eater to measure how much oil you'll need for the engine. This is because the bottle holds the exact amount the engine needs: 2.2 ounces.

The Ryobi weed eater owner's manual tells users to add the whole bottle. However, if you no longer have the bottle, you can utilize the dipstick to gauge whether you need more or less oil.

Just check if the oil level is in the hatched area. Add more if the oil falls to the lowest hatch level, and remove oil if it exceeds the hatched area. 

4. Replace The Top and Bottom Covers

Once the engine is refilled with new oil, you can close the oil cap and replace the top and bottom engine covers by screwing them back on. Your Ryobi is now ready for use again!

In Summary

gasoline grass trimmer professional gardening tool

Choosing oil for your Ryobi 4-cycle weed eater depends on the weather you experience in your area. You can never go wrong with SAE 20W-50, the oil that comes with the weed eater.

The oil SAE 30W is great for all-around warm weather, while SAE 10W-30 and SAE 10W-40 are better options if you live in lower-temperature areas. 

Changing the oil in your weed eater is important. Neglecting to change it after 25 hours of use can lead to oil sludge, which can affect the performance of the machine and potentially cause damage. 

Made it to the end? Check out these related articles:

How To Use A Ryobi Edger [Step-By-Step Guide]

How To String A Kobalt Weed Eater [Step By Step Guide]

5 Best Lawn Mower and Weed Eater Combos

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