Lawn mower does not start - tips on causes and immediate help

Lawn mower does not start - tips on causes and immediate help

Cause: No fuel or no electricity

Surveys among the largest lawnmower manufacturers brought it to light. When the mower won't start, an empty tank is one of the top 3 most common causes. You should therefore first check the amount of fuel available so that you can add fresh petrol if necessary. If the engine has become hot as a result of repeated starting attempts, wait until it has cooled down before filling it.

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The electric lawnmower cannot run out of fuel. However, an electric mower will not respond if the plug is not properly connected to the socket. If you can rule out this cause, check in the fuse box whether the associated fuse has blown out. In most cases, a defective power cable has triggered the short circuit and must be completely replaced.

Cause: Spark plug dirty or defective

If the spark does not jump over, the lawnmower does not make a sound. Take a close look at the spark plug, because this is one of the most common causes of the engine not starting. If you are not familiar with the position of the spark plug, the operating instructions will provide detailed information. How to solve the problem:

  • Trigger the spark plug according to the manual
  • Take a dry rag
  • Carefully wipe the spark plug and contacts
  • Do not use water or other liquids

Reinstall the clean spark plug. If the lawnmower still does not start, the spark plug is defective and should be replaced with a new one.

Cause: Air filter clogged

The engine of your lawnmower is equipped with an air filter so that dirt particles do not clog the carburetor or enter the engine. The filter should be cleaned at fixed intervals of 25 operating hours. If maintenance fails, the air filter clogs so severely that the engine will no longer start. Most filter elements are made of foam or paper. How to get your lawnmower working again:

  • Remove the air filter according to the instructions in the manual
  • Knock out the paper filter or clean it with compressed air
  • Never use compressed air in close proximity to the motor
  • Clean the foam filter with hot water or detergent (not a solvent)
  • Rub dry with a rag

Reassemble the clean air filter and install it according to the instructions for use. Various manufacturers use dual air filters, consisting of an upstream foam element and a paper filter. You can dispose of this paper filter when it is completely dirty. Foam air filters, on the other hand, are designed for around 100 operating hours and also work without paper, so cleaning with water and a fat-dissolving agent is worthwhile.

Cause: Cutter bar blocked

On the lawnmower there is a close connection between the cutter bar and the engine, which only becomes apparent at second glance. If the starter rope is activated while the cutter bar is blocked, the engine cannot start. This problem often occurs after previously cutting wet lawns. Clumps of grass form and get caught between the blades. But stones or branches can also get caught. To get your lawnmower going:

  • Important: first pull the ignition plug on the petrol mower or the mains plug on the electric mower
  • Tilt the lawnmower backwards
  • Alternatively, tilt the device with the air filter upwards
  • Put on gloves
  • Remove grass residues, branches and other impurities
  • Clean the housing with a stiff brush

Before starting cleaning, please double-check whether the engine has been reliably prevented from starting up unintentionally. For reasons of safety, we recommend that you fix the spark plug cable on the petrol lawnmower so that it is at a sufficient distance from the spark plug.

Cause: dirty carburetor

Regular contact of the engine with grass, leaves, twigs and soil can lead to deposits. It is not uncommon for impurities that have accumulated in the carburettor to hopelessly clog the fuel and air lines. In the end, the lawnmower won't start at all. How to properly approach the problem:

  • Remove the spark plug cable and spark plug
  • Put a teaspoon of fuel directly into the cylinder
  • Reinstall the cable and spark plug

Start the engine. If it starts for a short time and goes out again immediately, the carburetor should be cleaned. It is often not necessary to remove the carburetor. You can purchase carburetor cleaning agents as sprays from specialist retailers, with the help of which external dirt is removed.


Does the lawnmower start and switch off again after a short time? Then there is a high probability that the fuel is too old. If the gasoline in the tank is more than a month old, important components can gum up and the cold start capability gradually decreases. Replace the fuel, fill up with fresh gasoline or spray a little start-up spray on the intake port (operating instructions).