Can You Use Bar And Chain Oil In A Lawn Mower? (Explained)

Oil gauge

So you want to know can you use bar and chain oil in a lawn mower?

Maybe you have some engine oil left over from your chainsaw and your lawn mower needs a top-up before you can cut your grass.

Are the two compatible?

We take a closer look in this article.

So let’s get started…

Can You Use Bar And Chain Oil In A Lawn Mower?

Bar and chain oil is usually 2-stroke oil and as such will be suitable to use if you have a 2-stroke mower. However it should not be used in 4-stroke mowers as it will cause damage to the engine. Nearly all modern mowers have 4-stroke engines, and it is only very old mowers that have 2-stroke engines, so always double-check if you plan on using bar and chain oil in your mower.

Bar and Chain Oil: The Basics

Before we answer the question, let’s just take a quick look at what bar and chain oil is.

Essentially it is a lubricant that is designed to stick to the chain and bar of a chainsaw to reduce the friction you get from the metal-on-metal contact between these two components, hence the name.

Unlike the oil you get for your mower or your car it doesn’t come with a weight classification, instead it is just rated for summer or winter use.

It is typically made of one of two substances:

  • Petroleum
    Most bar and chain oil is petroleum-based, and a lot of the big brands such as Husqvarna and Stihl make bar and chain oil from petroleum. The downside is it is bad for the environment. Tiny droplets are released when the chainsaw is in use and can find their way onto trees and plants in the surrounding area.
  • Vegetable Oil
    Recognizing the negative effect that petroleum-based bar and chain oil can have has seen vegetable oil-based bar and chain oil becoming more common. It is recommended by the United States Forest Service as well. It can also be cheaper, although it is still harder to find than petroleum-based bar and chain oil.

Anyhow, we have dealt with the basics of bar and chain oil, but I know what you are really here to find out.

And that is whether bar and chain oil can be used in a lawn mower.

The short answer is it depends…

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Yes Bar and Chain Oil Can Be Used For 2-Stroke Engines

The likelihood is that the oil you use for your chainsaw is 2-stroke oil, which is made to be mixed with gas, usually at a ratio of 1:40 or 1:50.

If your lawn mower has a 2-stroke engine, then you can use the bar and chain oil in it mixed with the appropriate level of gas. 

This is because both engines are small and operate with a cooling system needed by the oil.

Two-stroke mowers are very old school, and quite unusual these days.

Two-stroke engines complete their combustion and exhaust cycle in two strokes (as the name suggests).

The oil works its way through the crankcase lubricating the relevant parts, enters the combustion chamber where it burns with the fuel and is then passed out of the exhaust.

So yes, if you have a 2-stroke mower you can use bar and chain oil in it as long as you mix it with fuel to the appropriate ratio.

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No Bar and Chain Oil Can’t Be Used for 4-Stroke Engines

Blue lawn mower on grass

Most lawn mowers these days have 4-stroke engines, and you should not use bar and chain oil in a 4-stroke mower as the engine operates in a completely different way to a 2-stroke engine.

Whereas 2-stroke oil is mixed with fuel and burnt and emitted through the exhaust, 4-stroke oil is not mixed with fuel and circulates continuously through the crankcase without being emitted.

If you were to put bar and chain oil (aka 2-stroke oil) in your fuel sump, then it would burn out very quickly so the engine would be operating without oil, which would likely cause engine failure.

That, at its most basic, is why it shouldn’t be used in a 4-stroke lawn mower, it has completely different properties to 4-stroke oil.

Bar and chain oil will also be much thinner and not lubricate the parts of the engine efficiently if used in a 4-stroke engine.

Instead, follow the manufacturer’s advice and use the appropriate oil, not bar and chain oil.

How Do You Know If You Have a 2-Stroke or 4-Stroke Mower?

There are a number of differences between 2-stroke mowers and 4-stroke mowers, but the easiest way to tell the difference (aside from reading the manual!) is:

  • 2-stroke engines: Have just a fuel tank (for a mix of gas and oil together), so only one tank.
  • 4-stroke engines: Have two tanks, one for oil and one for gas, both of which are clearly marked.

Aside from that 2-stroke engines are smaller, lighter, louder and produce more pollution.

Four-stroke engines are more fuel efficient, cleaner and easier to start.

Due to the fact they produce more pollution, 2-stroke engines are gradually being phased out, and the likelihood is, if you have a mower, it will have a 4-stroke engine, unless it is particularly old.

RELATED ===> What Happens If A Lawn Mower Has No Oil?

Final Thoughts

Can You Use Bar and Chain Oil in a Lawn Mower infographic

Bar and chain oil can be used in mowers that have 2-stroke engines, and can’t be used in mowers that have 4-stroke engines as outlined in the infographic above.

That is because bar and chain oil is nearly always 2-stroke oil, and 2-stroke oil has a very different makeup to the oil needed for 4-stroke engines.

It is much thinner and will burn up much quicker, so if used in a 4-stroke engine it won’t lubricate the engine parts sufficiently and it will burn out leaving the engine out of oil and causing it damage.

The vast majority of mowers these days have 4-stroke engines, so the likelihood is that you won’t be able to use bar and chain oil in it.

However if you have a much older mower it could use a 2-stroke engine, and you could use bar and chain oil in it.

Make sure you double-check first though.

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