You took your lawn mower out of your garden shed, you tried to start it, but nothing happened?
Don’t panic, it happens to a lot of people!
But you have landed on the right page and I’m trying to help you with your problem in the best possible way.
Do you have a petrol lawn mower and it won’t start?
In fact, most petrol lawnmowers are all constructed in the same way and have been for decades.
The principle of a petrol lawn mower does not actually change.
Although something is always improved from manufacturer to manufacturer, not much has changed in the basic principle.
Regular inspection of the lawn mower
It is important that you check your lawnmower regularly and keep it in good condition.
You can do this by cleaning it regularly, changing the oil, cleaning the air filter or replacing the spark plugs.
This is actually the most important thing you can do to rule out major defects.
But that’s not the case now, after all, you have a problem NOW;)
I have divided this article into different tasks that you can easily work through.
Now let’s find out why your petrol lawn mower won’t start.
I now recommend that you have a few tools and aids ready.
What we absolutely need is a well-equipped tool case, multi-oil such as WD-40 or similar,
Brake cleaner and some cleaning cloths.
When you have the opportunity to quickly get spare parts or the spare parts in your basement or in your garden shed it is of course the best. I recommend the following parts for a perfect inspection
ready to have; new engine oil, new spark plugs, a new air filter.
It is also very helpful if you have the operating instructions for your lawnmower to hand, so you can read where which part is installed and how exactly you dismantle or check the respective part.
Find out why your lawnmower won’t start.
Basically, a motor has a very simple structure and you can process all of the things very quickly.
An engine first needs air, then an engine needs gasoline and finally an engine needs an ignition spark that causes the gasoline-air mixture to explode. That was what a motor needs, nothing more.
Let’s start with the easiest one first!
The air filter
In many cases, the engine simply does not start because there is no or not enough air for combustion.
Every petrol lawn mower has an air filter. I am now assuming that you have found the air filter box.
Please open this box and take out the filter material and look at it.
How does it look like? Is it very dirty?
Then you now have a few options to clean the air filter.
Blow it out with compressed air. That is probably the easiest and fastest thing you can do.
You can also wash the air filter with gasoline. But please let the air filter dry well for a few hours afterwards before reinstalling it.
Please also have a look in the air filter box to see if there is any dirt deposited there.
The air filter box should be absolutely clean!
When you have cleaned the filter and the housing, please reassemble everything and we can move on to the next step.
Check the spark plugs.
The spark plug is of course a very important part of your lawnmower!
Now find out where your spark plug is installed.
Most of the time the spark plug is on top.
What also happens frequently is that the spark plug connector loosens from the spark plug and so the engine does not start.
First check whether the plug is firmly seated on the spark plug or whether there is water in the spark plug connector
has formed. Try if it starts … no? Ok let’s keep looking!
Turn out the spark plug alone and take a look at it.
What does she look like?
Is it all black? That indicates too much gasoline. Is she very white? That indicates too much air and too little gasoline.
It is best if the spark plug has a fawn color. That would be ideal.
Is the spark plug wet and full of gasoline? This indicates that the petrol arrives but is not burned.
This can be due to a defective spark plug that simply no longer produces a spark.
Is the distance between the electrodes ok? The distance should be about 1mm.
You can also clean the spark plug with a wire brush or blow it out with compressed air.
Now let’s test if we get a spark …
To do this, pull the spark plug out of the engine and insert it into the spark plug connector.
Place the spark plug on a metal part of the lawn mower so that it is grounded.
The best thing to do now is to do it with two people.
One tries to start the engine with the spark plug removed and the other observes the spark plug to see if there is a strong spark
Do we have a spark? Perfect, then it’s not the spark plug.
Don’t we have a spark? Ok, then let’s replace the spark plug with a new one and try again.
The ignition spark is essential for an engine, so we need a powerful spark!
Check the ignition.
In some cases it can also happen that the ignition components break or the cable loosens.
Please check all cables that go from the ignition unit to the spark plug.
It can also be that the deck or grass residues have settled on the ignition, please check everything there and clean
Thoroughly clean the ignition unit with compressed air or a brake cleaner.
Clean the carburetor.
Does the engine still not start? Now it can of course be the case that the carburetor on your lawnmower is dirty.
We have to clean it now. The best way to do this is to pull the gasoline hose off the carburetor and blow it in with compressed air.
That is actually the only thing we can do on the carburetor in a hurry.
If you want to clean the carburetor properly, you have to completely dismantle and disassemble it and clean it properly with gasoline or brake cleaner.
I can only recommend this to you if you are familiar with carburetors.
Check the gasoline.
Of course, petrol is also very important for proper combustion.
Please check whether there is still enough gasoline in there!
How old is the gasoline? If the petrol has been in the tank for a long time, it can of course be that it has attracted water and as we all know,
water doesn’t burn very well.
It’s best to change the gasoline for something new from the gas station.
Now shine a flashlight into the tank. How does it look in there? Is everything clean?
Or do you see a lot of dirt particles in the gasoline or on the bottom of the tank?
If so, then please empty the tank and rinse the tank well and clean it.
Clean the petrol filter.
The petrol filter also plays a major role! It cleans the gasoline from dirt particles before the gasoline gets into the carburetor. If the petrol filter is clogged or dirty, not enough petrol can get to the engine.
Take a look at the petrol filter. Is it all brown or do you see dirt particles?
Then please exchange it.
You can also remove the filter and blow into it, is it easy to blow or is it very difficult?
If it is very difficult, it may well be that the filter is clogged and you have to replace it!
You don’t have to use an original filter either, a simple universal petrol filter from the accessories that has the right connections is sufficient!
Check the engine oil.
Now let’s take a look at the engine oil. You have a stick somewhere with which you can check the level of the engine oil.
Look to see if there is still enough oil in it. If there is not enough oil in the engine, please fill it up again or you can also change the oil completely, including a new oil filter, if the oil is already very old.
I recommend changing the engine oil every two years if you use it constantly.
Don’t forget to install new seals when changing the oil.
Also check the operating instructions for your lawnmower or the manufacturer’s website to find out which type of oil you have to use.
But the oil is not so important for starting the engine, even without oil an engine starts … only then it doesn’t last long;)
Check all cables
Finally, please check all cables on your lawnmower.
It can happen that over the years a cable has loosened or a cable is frayed or torn.
We have now checked everything on the lawn mower and it should start again. If it still doesn’t start, write to me in the comments and I’ll try to help you!