Last Updated on March 5, 2021 by Duncan

Imagine this. Your lawnmower needs oil, so you rush to the garage and grab the oil bottle sitting near where the lawnmower sits, and without looking, you drown it to your lawnmower.

When you are done, you realize it was the 2-stroke oil you use on your weed eater.

Imagine another scenario. You check the oil level on your lawnmower with a dipstick, and you find out it’s abnormally low.

After rummaging in the garage, there is no 4-cycle oil you often use on your lawnmower—you only have 2-cycle oil. Can you use 2 cycle oil in a lawnmower? You wonder.

The answer to this question is no, you shouldn’t use 2-cycle oil in a 4-cycle lawnmower engine as the oil is too thin.

While the 2 cycle oil might work for the short term, it might lead to permanent damage to your engine when you repeatedly use it.

The difference between 2 cycle and 4 cycle oil

Most modern lawnmowers are 4-stroke, so they run on four-cycle oil that is often thick and not designed to burn.

2-cycle oil is mixed with fuel (in the 40:1 ratio), so it’s designed to burn with the fuel.

This means it’s more refined and contains many additives that include detergents to clear varnishes and carbon deposits from the combustion ports, antioxidants, and anti-wear agents to protect the moving parts biodegradability components.

In the same way, you shouldn’t use 2-cycle oil on your lawnmower, you shouldn’t try to run a 2-cycle engine by adding 4 cycle oil to the gas as you will damage the engine and shorten the appliance’s life.

What should you do after you have poured 2 cycle oil into your lawnmower?

If you poured just a little of it, you can top it off with SAE 30W oil or any other oil recommended by the manufacturer and go on with mowing.

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The 2-stroke oil will burn off from the lawnmower heat, and in no time, you will only have regular oil in the crankcase.

However, if you had poured a lot of 2-cycle oil in the lawnmower (1/2 liter or more), don’t put your lawnmower at risk and mow. Instead, drain the lawnmower and replace it with the manufacturer’s recommended oil.

How to drain oil from a lawnmower

If you put the wrong oil in a riding mower, park the mower on a flat, level surface and after securing it in place with a parking brake and gear, locate the oil drainpipe on the side of the mower near the bottom of the mower engine.

Position a container on the ground to collect the old oil, then loosen the cap on the drainpipe with an adjustable wrench.

Depending on the type of lawnmower, remove the cap to allow the oil to drain from the mower engine and into the container on the ground, or turn a valve cap on the end of the drainpipe to allow the oil to drain from the mower engine.

Give the lawnmower enough time to drain as much oil as possible, then place the cap back on the drainpipe and secure it with an adjustable wrench. You can also turn the drain valve to close the drain pipe.

If you have a walk-behind lawnmower, position it on a level surface, then place a container to collect oil on the ground beside the lawnmower. Position the lawnmower in such a way that it’s on the same side as the oil fill tube.

Remove the dipstick from the oil fill tube, then tilt the mower towards the container until oil drains from the top of the oil fill tube and into the container.

Be cautious when tilting the lawnmower so that you don’t tilt it so much that the carburetor is at the bottom, as this will cause the carburetor to flood and damage the engine.

Hold the mower in the slightly tilted position and drain as much oil as possible. After all the oil has drained, lower the lawnmower back to the ground and add the correct oil.

Can You Use 2-Cycle Oil In A Lawn Mower?

As mentioned above, 2-cycle oil is thinner and more refined, so it will ruin your lawnmower, especially when you repeatedly use it.

So if you have mistakenly added a lot to your lawnmower, don’t risk the life of your lawnmower—drain the wrong oil.