Lawn mowers are expensive items, and it’s natural for you to want to keep yours in good condition and working well for as long as possible. You can extend a lawn mower’s working life by giving it a systematic service each year in the spring before the growing season starts. This is the time to change the oil, sharpen the blades and generally make sure it’s ready for another year.
However, despite everything you can do and all the careful attention you can give a mower, things can eventually go wrong. One problem you may face is that it starts screeching – something that can be quite worrying. There is no single cause for this, so here, we’ll look at what you can do if a lawn mower makes a screeching noise.
Here’s a video to give you an idea of what kind of problems you might face.
Several different causes
There are quite a few reasons why a lawnmower can start making a screeching noise. Let’s have a look at them one by one to see how to identify the cause and also what you should do if the problem occurs.
Here we are mainly focusing on walk-behind mowers rather than riding lawn mowers. Most of these issues are related to gas-powered lawnmowers, but some could equally apply to an electric cordless lawn mower or other types.
· Loose belt
If your mower starts making a loud screeching noise when you start the engine or when you are cutting the grass, the most likely culprit is the drive belt.
This is the most common cause of such noises, and if this is what is happening, it’s also good news since this is one of the easiest problems to fix.
Basically, what may have happened is that the belt connecting the engine to the mower deck that causes the blades to spin has come loose and has become stuck between the guides.
If your mower starts screeching, this is the first thing to check. If you see that the drive belt has slipped, it’s simply a case of putting it back where it belongs. Once this is done, the problem should disappear.
If this is the problem, make sure you don’t leave it unattended. If the belt is not aligned correctly between the guides, it will wear down and will eventually break and need replacing.
· Something caught around blade
Another problem that is easy to identify and easy to solve is if something has caught around one of your blades while you were mowing the lawn, something like a piece of rope or string.
If you mow over something on the lawn and it gets stuck on the blade, it may begin to make a loud screeching noise because the blades are spinning so fast.
To eliminate this possibility, simply check your blades to make sure they are clear of any debris. If you find something there, you have discovered the cause of the problem. Remove it and you should be good to go.
· Shaft bearings
Another cause could be that the shaft bearings simply need oiling. The way to test this theory is just to add oil and try again. If this solves the problem, you are lucky because it isn’t anything more complicated than the shaft bearings rubbing as the blade turns.
The shaft bearings are on the top part of the shaft – to oil them, remove the cover and add some oil to see if this fixes the screeching.
· Bent blade
Another reason your mower could be screeching is that a blade has become bent and is catching on the inside of the casing as it spins – this would certainly cause a high-pitched and highly unpleasant noise.
This is another one that is relatively easy to check and similarly simple to fix – just flip the mower on its side and have a look where the blades spin.
What you are looking for is an area of shiny, clean metal – this will be where the blades are hitting the housing with each spin.
If you find something like this, carefully move the blades round by hand to see if they make contact with the housing at that point. If they do, you have found the problem.
The solution is to remove the blade and hammer it back into shape. Once you have done this, put it back in place and try again to see if the problem is solved.
Another related problem is putting the blades back in the wrong way.
When you remove them at the start of spring to sharpen them, make sure you pay careful attention to how they are set before you detach them. Then, when you come to putting them back, make sure they go in the right way around.
It’s very easy to put blades in backwards, and this could also cause screeching.
If you are not entirely confident, a good tip is to take a photo on your cell phone before you remove the blades so you’ll have a reference when you put them back.
· Bad spindle bearing
If you have tried everything above and you still haven’t located the problem, you might have a bad spindle bearing. If this is the case, it’s not great news for you since this is more of a complicated problem to check and repair because you will have to remove the whole deck.
If you feel confident doing this, by all means, go ahead – but some people might prefer to call in a professional.
Don’t ignore it
If you check through all these suggestions and you still can’t find the problem, it may be best to call somebody in to look at it for you.
Although this will cost you money, if you ignore the problem, it will probably end up costing you a lot more because you might end up doing serious damage to your mower.
Above all, don’t leave the problem unresolved. If you do, you may find yourself needing to replace the engine or even the whole lawnmower.
A common problem – and many possibilities
Screeching noises are usually belt-related – and this means they are quite easy to fix. If your mower starts making this kind of noise, check the belt and resolve the problem as quickly as possible.
However, if it isn’t a belt-related problem – and it isn’t due to anything else we’ve mentioned here – the best solution is to have a professional look at it for you.