Why Does My Petrol Strimmer Keep Cutting Out?

Petrol Strimmers are super handy little contraptions, but they also take quite a bit of maintenance to ensure they’re healthy. If you’re struggling with your strimmer, though, you’re in luck! We figured it was about time to answer a couple of questions, namely: why does my petrol strimmer keep cutting out, and how much 2-stroke oil for a trimmer?

Today’s Topics Include:

With that said, let’s just get going, shall we?

Troubleshooting Petrol Strimmers

Now without further ado, let’s discuss the major causes of a petrol strimmer continuously cutting out. Among the most common issues you’ll find are broken or corroded parts (poor maintenance), dirty bits and bobs (poor maintenance), and improper oiling (poor maintenance), are you getting the drift?

In short, if your petrol strimmer continuously cuts out, the most likely cause is that it’s because the trimmer hasn’t been maintained properly. While there are exceptions to this, the likely answer is that you simply didn’t take proper care of the trimmer. With that said, let’s get into things, yeah?

Why Does My Petrol Strimmer Keep Cutting Out?

open strimmer for maintenance

This is an answer that’s surprisingly simple. There are four primary things to keep an eye out for if your petrol strimmer keeps cutting out:


This is super common in trimmers that are stored outside. While there’s no super easy fix, it’s always worth inspecting the interior of your strimmer for corrosion. If you notice rust on anything, scrub it gently off with steel wool and vinegar and look for a replacement part.

Broken Part

This is the least likely cause, but it’s possible that something has physically snapped inside. Strimmers aren’t the most durable, but luckily, original parts are easy and affordable to come by for most brands.

One of the most common parts that will fail is gaskets – you know, the little rubber rings in pretty much everything mechanical? Luckily they’re cheap and easy to replace, so just keep an eye out for blown or stretched gaskets while cleaning out your strimmer.

Fuel Issues

This could mean that you have the wrong fuel in the strimmer or that it’s not being delivered properly. Start by replacing the fuel line, and then double-check you’re using the right fuel.

Air Intake

Check your carburettor. If it’s seeming a bit dirty or gross, clean it off and then see if this fixes the issue. Often, trimmers cut out because the carburettor is gunked up and can’t deliver enough oxygen for the engine to stay running.


Strimmer fuel filter

Most trimmers have two filters: a fuel filter and an air filter. Both of these require consistent (1-2 times a year, depending on use) replacement, and are often forgotten. So pull apart your strimmer and look at the filters – if they’re clearly dirty, worn out, or just plain old – replace them!

Both the fuel and air filters are quite affordable, so don’t let these be the end of your strimmer.

Spark Plugs

Check your coil wire and spark plug – for those who aren’t aware, the coil wire is attached to the spark plug. Ensure they’re not damaged, corroded, or dirty – if they are, clean or replace both. Something that’s often forgotten is that a dirty spark plug can’t spark, so if it’s super dirty or oily, there’s a strong chance that it’ll just… not work. Luckily, both the coil wire and spark plugs are also pretty cheap, so they shouldn’t prove an issue.

Spark Arrestor

Your second to last stop before throwing in the towel should be the spark arrestor. Unfortunately, these are pretty expensive when compared to other parts, so it’s preferable that they don’t need to be replaced. Check that the spark arrestor isn’t dirty – that is by far the most common cause of issues with spark arrestors.

If it is, gently remove it and wipe it down with a rag and wire brush, then reinstall.

If your petrol strimmer keeps cutting out, ensure you’re using the proper fuel, that the carburettor is functioning and clean, and check for corrosion or broken parts. Should something need replacement, look for original parts from the manufacturer and the problem should resolve itself.

How Much 2-Stroke Oil For a Strimmer?

red petrol can for 2 stroke oil

And finally, the last (though not least important) question to address. If you’re new to strimmers, it’s likely that you’re a bit lost. One of the most common questions we get about them is exactly how much 2-stroke oil for a strimmer is appropriate. Also – what the hell is 2-stroke oil?

First off, what’s 2-stroke oil? In short, it’s a special blend of motor oil that’s common in smaller household combustion-powered devices. It generally consists of unleaded petrol and 2-stroke oil, mixed to a specific ratio on a by-engine basis.

Head here for a handy 2-stroke fuel mix calculator and then look in your manual – it should tell you exactly the ratio you need. Once that’s done, just plug that information into the link above and get your strimmer going again!

Just in case – let’s give an example really quick. Let’s say you need a 40:1 ratio of 2-stroke oil – that boils down to 25 mL oil per litre of petrol. Easy!

In short, I can’t answer how much 2-stroke oil for a strimmer without seeing the user manual. The two most common ratios are 50:1 or 40:1, both being a petrol:2-stroke oil ratio.


And that’s that! Petrol strimmers generally need consistent maintenance at least twice a year, depending on how often you use them. If you neglect your strimmer, you’ll have parts snap, corrode, and wear down faster than they should. And ignoring your strimmer’s 2-stroke oil needs is a great way to find it ruined. So just remember to keep strimmer maintenance a regular occurrence, and you should be fine.

If you’re still having issues with your strimmer, head to our strimmer wire troubleshooting article.