Can 1 Use 50:1 In A 40:1 Weedeater? [Guide]

Can 1 Use 50:1 In A 40:1 Weedeater? [Guide]

A weedeater is one of the essential pieces of equipment in a gardener’s arsenal. It takes care of the weeding part of their job, which is the most tasking of all their chores. There are different kinds of weedeaters with their individual needs and requirements, especially in terms of gas and oil.

Different engines require a specific combination of gas to oil, and the most common are the 50: 1 and the 40:1. You cannot use a 50:1 ratio for a weedeater that is designated as a 40:1. The implication is that the lubrication of the engine will be inadequate which can damage the weedeater.

What Exactly Does 50:1 and 40:1 Mean

All electrical and mechanical appliances have engines, which differ from one appliance to another. For instance, the engine in your car is different from the one that powers your weedeater, which means that their requirements will also be different.

Now, for your weedeater, there are two main types of engines: two-stroke and four-stroke. Without getting too technical, the main distinguishing difference between a two-stroke and four-stroke engine is that four-stroke engines have a separate oil fill tube, so you do not have to mix the oil with the gas.

They both have different compartments. Exception for the auto-injection engines, as you have in two-stroke motorcycles and ATVs, which hold two-stroke oil in a separate reservoir, all other two-stroke engines combine oil and gas.

Generally, a two-stroke engine manufacturer will specify the amount of oil that must be mixed into a given quantity of gas for the engine to work well, which is usually depicted as a ratio. Read also Is a 4-cycle Weed Eater Better Than a 2-cycle?

So for a weedeater that requires a 40:1 ratio, it means that for every 40 parts of water, you will need 1 part oil. So, for instance, if you want to mix 40 liters of gas, you will need 1 liter of oil to go with it.

For an engine that has the ratio 50:1, what it means is that you need to mix 1 part oil into 50 part gas. So if you want to mix 50 liters of gas, add 1 liter of oil. If you are mixing smaller quantities, you only need to reduce the quantity of gas and oil following the same ratio.

It is very critical to know the ratio of gas to oil your engine requires if you want it to function optimally for a long time.

Can 1 Use 50:1 In A 40:1 Weedeater? [Guide]

Can 1 Use 50:1 In A 40:1 Weedeater? [Guide]

You shouldn’t use a 50:1 in a weedeater designed to use a 40:1 gas-to-oil mixture. It is because it can ruin the engine of the weedeater. The reason why many people go ahead to use any ratio of gas to oil for their weedeater is that the effect of this improper use is not immediate, it is gradual, and in most cars, when you are least prepared for it, the weedeater packs up, meaning you have to spend an excess of money to fix it or even replacing it.

Another problem with using a 50:1 ratio on 40:1 is that the weedeater might have a problem starting, or it will die even when it starts, and the throttle is engaged. This problem will eventually lead to the engine getting damaged.

Using a 50:1 ratio on a 40:1 means that the engine of the weedeater gets less oil than it requires, and when you press down the throttle, you will notice that the outer part of the engine is hot and it emits an odor that feels like metal rubbing against metal. It will lead to the weedeater going rancid.

Too little oil in a weedeater and any other appliance means that the moving internal engine parts are not well lubricated, which will cause wear, friction, and overheating of the system, which may damage the engine permanently.

How to Mix Gas And Oil For A Weedeater

How to Mix Gas And Oil For A Weedeater

Your weedeater needs the correct proportion of gas to oil to function optimally. It is how to make the mixture:

Finding the Correct Measurements and Materials

Step 1

The foremost thing you must do is find the correct gas-to-oil ratio for your weedeater. You will find this information in the manufacturer’s manual; if you have lost it, check online at the manufacturer’s website.

Step 2

Get a clean container like a Jerrycan to hold at least a gallon of gasoline. It should be 3.8L in volume. Ensure that you only mix gas in a container meant to hold gasoline.

Step 3

Here, you will have to do a little calculation. You have to convert gallons to fluid ounces by multiplying by 128. So for the 1 gallon, you will have:

1×128= 12 fl. oz.

You could use this calculation for any quantity of gas you want to calculate.

Step 4

Now divide 128 by 50 for a perfect 50:1 mixture, but if your weedeater’s ratio is 40:1, then you divide it by 40.

For 50:1,

128/50= 2.6 fl. oz

That means that for a 50:1 weedeater, you will need 2.6 fl. oz of oil to a gallon of gas.

For 40:1

128/40= 3.2 fl. oz

While for a 40:1 weedeater, you must mix it with 3.2 fl. oz of oil in a gallon of gas.

A Review Of Most Manufacturer’s Gas to Oil Recommendation For Their Products.

Different products have different gas-to-oil recommendations for their weedeater. While we cannot categorically say why one manufacturer recommends the ratio of gas to oil that should be used on their products, sticking to it will ensure that the weedeater lasts for longer.

These are the recommended gas-to-oil ratios for the most common weedeaters’ brands:


Gas to oil ratio













Most manufacturers recommend a 50:1 ratio for their two-stroke engine, including Stihl, Husqvarna, Ryobi, and ECHO, while McCulloch and Craftsman favor the 40:1 ratio. The older model of Husqvarna uses the 40:1 ratio, so you must discover the model you have to know which is best for your weedeater.

How To Tell If You Have The Proper Gas And Oil Mixture In Your Weedeater

How To Tell If You Have The Proper Gas And Oil Mixture In Your Weedeater

We have already established that the proper gas-to-oil mixture in your weed eater is essential in keeping the piston lubricated and the engine working perfectly. If the oil is too little, it will scar the piston.

If you fail to add oil to your weedeater, it will cause the engine to stop after a few minutes of starting the unit. That means you’ve some repairs on your hands.

If you are not sure if you have the correct ratio of gas to oil in your weedeater, then do the following:

1. Start the weedeater and let it run at the ideal speed to warm up.

2. Now engage the throttle and check how the engine reacts: if you notice blue smoke coming out of the exhaust or oil dripping from the exhaust, you have too much oil in your weedeater. All you have to do is turn off the unit, remove the gas, and replace it with the right mixture of gas and oil.

3. As you press down the throttle and you touch the outer part of the engine, if it is hot and gives off a funny metallic smell, it means you have little oil in the gas mixture. Stop the engine immediately and replace the fuel with a properly mixed ratio, so the unit is not damaged.

Tips For Mixing Gas And Oil For A Two-Cycle Weedeater

1. Ensure that you thoroughly but carefully shake the container of oil and gas mixture before each use to ensure it is mixed. It is to ensure that the two liquids do not separate.

2. Always check the manufacturer’s manual or website to ensure the recommended gas-to-oil ratio of their weedeater.

3. Never use straight gasoline on your two-cycle weedeater because it will cause the engine to seize immediately.

4. Ensure you use a two-cycle oil meant for a weedeater and never an automotive oil.

5. Try to avoid using gasoline that is more than six months s. It led to power loss in tour weedeater

6. You can protect our environment by never dumping gas or oil on the ground as it will seep into groundwater or run into nearby storm drains, contaminating the water bodies around you.


Gas-to-oil ratios vary from one manufacturer to the other. While 50:1 and 40:1 are the two common ratios, this does not mean you can use any of these ratios interchangeably for any weedeater. Sticking to the manufacturer’s recommendation is critical to prolonging the useful life of your weedeater.

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Using a 50:1 ratio on your 40:1 weedeater means that your unit will get less oil than it needs, which can damage your weedeater’s engine. You may also want to check out Weed Eater vs Weed Wacker.

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