How to Start a Petrol Lawn Mower

We’ve all been there – repeatedly pulling on the start coil trying to persuade our petrol mower to jump into life. Petrol mowers can be a little tricky to get going, but if you follow these simple steps you’ll be able to start your petrol lawn mower first time, every time: 

Check the Oil 

First things first – make sure that your petrol lawn mower has enough oil. Too little will cause the engine to seize up, leaving you with problems that are expensive to fix; however, be aware that too much can also be damaging. 

There’ll be a dipstick attached to the oil cap on your mower. Pull this out and read the markings, adding more oil if necessary. 

Why not check out our article on what oil to use in a petrol mower.

Check the Petrol 

Stale petrol causes so many lawn mower issues. If the petrol in your lawn mower is older than 2-3 months, drain it out and replace it with fresh petrol. 

For this reason, it’s a good idea not to fully fill your lawn mower with petrol each time. Instead, only pour in the amount that you think you’ll use in the next week or so. If you fill your mower more than necessary, you’ll just end up wasting it in the long run as it will go stale again.

Stale fuel is one of the main causes of trouble starting a petrol lawn mower engine.

Check the Spark Plug 

Your lawn mower’s spark plug is what ignites the machine, which is why it’s usually located at the back of the engine.

Once you’ve found the spark plug, give it a quick clean to make sure that it isn’t dirty or wet – this can affect how it functions. 

Occasionally, the spark plug will need replacing. This generally needs to be done after every 25 hours of use.

Press the Primer Button 

Most lawn mowers have a primer button – you’ll need to press this to push fuel through the machine.

However, you should only press it 2-3 times, with a quick press each time. Pressing it too much or for too long will send excess fuel into the engine, which will cause it to flood. 

If you accidentally flood the engine with too much fuel, leave the mower to stand on a flat surface for 15 – 20 minutes.

Don’t worry if your lawn mower doesn’t have a primer button. It likely automatically draws the fuel in itself. 

Start the Mower 

After following all of the above steps, you’ll need to do two things to physically start the mower. Pull back on the throttle with one hand, and use your other hand to firmly pull the start cable. Some mowers will require a harder pull than others. Once the engine gets going, guide the start cable back into its holder. Don’t let go of the throttle with your other hand, as this will cause the engine to turn off. 

If you’re happy with getting your mower started, but it keeps cutting out, we’ve got another guide for petrol mowers that won’t stay on!

Clean the Carburettor

Sometimes, you might be doing everything right but still be struggling to start your petrol mower. In this case, it might need a more in-depth service.

One common reason that petrol engines have trouble starting, is a problem with the carburettor.

It may just need cleaning, or the gasket may need replacing. We’ve written a post about servicing your mower which covers this process in more detail. 

Alternatively: Have You Considered an Electric Start?

If you’re done with starting coils altogether, but still want a petrol mower, some modern petrol mowers come with an electric start.

Instead of using a pull cord to generate a spark, these mowers will electrically generate a spark and ignite the engine that way instead. These mowers generally require an additional battery to power the electric start. The best thing to do is choose a model that has both an electric start and a starting coil, just in case you forget to charge the battery (hey, I get it, these things happen).

You can take a look at our ultimate guide to petrol lawn mowers for more information on models with an electric start.

Now, it’s time to get mowing!

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