Surely you have experienced this situation before: You want to mow your lovingly laid out and carefully maintained lawn, but the lawnmower does not start. Serious problems can usually only be remedied in a specialist workshop, but numerous smaller, recurring difficulties can in fact be remedied very well yourself, so that nothing stands in the way of using the gardener’s favorite tool.
Table of Contents
electric or petrol?
It used to be relatively easy to troubleshoot a lawnmower that wasn’t working. The well-known petrol mowers are all very similar from a technical point of view, so that common errors could be found and corrected almost independently of the model. The first step in dealing with a malfunctioning mower is to determine whether it is an internal combustion engine mower or an electric mower. Of course, every hobby gardener knows his device and of course what drive it has. Still, the further steps differ significantly depending on this fundamental difference:
Electrically powered lawn mowers
In the case of an electric mower, the search for and elimination of causes is limited to very few points. Because as soon as the electrical installation itself is affected, non-experts should refrain from attempting repairs and visit a specialist workshop. The risk of injuries is too great, which can quickly turn out to be considerable in connection with electric current. So if you don’t happen to have training as an electrician or something similar, you should only take action in the following cases:
No energy
If the electric motor lacks the energy, i.e. the electric current, it cannot start despite the gardener’s best efforts.
For cordless devices:
- Cause: Battery empty or not inserted correctly
- Remedy: Remove battery, check charge, charge if necessary and reinsert correctly
For wired devices:
- Cause: Plug connections loose or not plugged in correctly
- Solution: Check all connections up to the socket
safety switch
Electric lawn mowers usually have a safety switch, which only makes contact when two switches, levers or buttons are pressed at the same time. On the other hand, if the specified order is not correct, the contact is not released and the lawn mower will not start.
- Cause: Circuit breaker switching sequence not adhered to, fuse not recognized and actuated
- Remedy: Consult the operating instructions and actuate the safety switch in the correct order
Internal combustion engine lawn mower
The causes of lawn mowers with combustion engines are far more varied and also easier to fix yourself. Even here, as a layman, you eventually reach the limit of what you can afford yourself, but in contrast to electric drives, not every failed attempt immediately poses a significant risk. Instead, unsuccessful repair attempts usually lead to the engine simply still not starting and, in the worst case, to a specialist workshop.
No petrol
As strange as it may sound, according to surveys by well-known lawnmower manufacturers, the third most common reason for unsuccessful starting is an empty tank. Logically, the lawn mower acknowledges this negligence immediately and does not start.
- Cause: Tank empty, fuel tap closed
- Remedy: Refuel, open the fuel tap
Fuel filter closed
Contaminated fuel, a rusting tank or foreign objects brought in from outside can lead to the fuel filter intended for retaining these substances becoming clogged and allowing little or no fuel to flow into the carburetor.
- Cause: Dirty filter, resulting in insufficient fuel flow
- Remedy: Close the petrol tap, open the filter, clean the filter insert with compressed air or replace it, then close the filter again and connect the fuel line
Spark plug problems
The heart of every combustion engine is the spark plug, which initiates the combustion process. If it is dirty or damaged, there is literally no spark.
- Cause: Contamination of the ignition head by contaminated fuel, damage or signs of wear on the spark plug
- Remedy: Pull off the ignition cap with power supply, unscrew the spark plug with a spark plug wrench, clean it and screw it back in, replace it with a new spark plug of the same type if it is damaged
Modern internal combustion engines are sometimes so heavily built in that the position of the spark plug is no longer easily recognizable. A look at the operating instructions helps and saves a sometimes tedious search!
air filter too
In addition to the fuel, in this case gasoline, oxygen is also required for every combustion. If it can no longer be supplied in sufficient quantity via a clogged air filter, ignition is not possible and the lawn mower engine will not start.
- Causes: Dirty filter from dust, leaves, grass and other items
- Remedy: Open the filter housing and remove the filter, clean it with compressed air and reinsert it, close the housing correctly, alternatively replace the filter if it is extremely dirty
The plastic materials used as filters age over time. It can therefore happen that the filters become clogged with their own loosening particles. Then it should be replaced!
Dirty carburetor
The carburetor mixes gasoline and oxygen in the intake air to form an explosive and therefore ignitable mixture. If it is dirty, the needle that regulates the injection timer can no longer work properly and the mixture is changed until it is no longer ignitable.
- Causes: Defective or missing air filter or fuel filter
- Remedy: Clean the affected filter as already described, open the carburetor and clean it with petrol and a brush, then reinstall it correctlyNote: Petrol is suitable for many cleaning jobs, especially in connection with the engine. However, since the substance also severely damages plants and the environment, this work should only be carried out in the workshop and in a suitable working environment!
Blockierte Messer
First of all, one may wonder why blocked mower blades cause the lawn mower not to start. However, if you realize that such a device does not have a clutch and the blades therefore always turn in the same way as the motor, the connection quickly becomes clear. For example, if the lawn mower is standing on a foreign object or the blades are not turning for other reasons, the cylinder in the engine cannot move either and the unit will not start.
- Causes: Mostly wedged foreign objects, possibly located over an undetected stone, piece of wood, etc.
- Remedy: Tilt the lawnmower to the side and check the blades for free movement, remove foreign bodies
The user manual
In some minds, the opinion still persists that a real man, even as a gardener, must have all the skills and knowledge. The urge to find and fix errors intuitively and without further help may therefore be overly pronounced, especially among male users of lawn mowers. However, a look at the operating instructions is almost always worthwhile. Because the manufacturers of lawnmowers are also interested in ensuring that operation is as trouble-free as possible and provide specific help on common errors and how to rectify them in the instructions specifically for the associated product.
