How to repair minor damage to the lawn mower yourself

How to repair minor damage to the lawn mower yourself

Repairing spark plugs on the lawnmower works like this

If the engine of a gasoline mower does not start after repeated tightening, it is very likely that it has 'drowned' as a result of unburned fuel in the carburetor and cylinder. In this case, experienced hobby gardeners first check whether the tank is possibly empty. If this shortcoming can be ruled out, proceed as follows:

  • Bring the throttle to the 'stop' position and pull it through completely
  • Let the engine cool down first and only then pull off the spark plug connector
  • Remove the spark plug with the special spark plug wrench
  • Dry and clean the spark plug or get a new one
  • Do not reuse candles with cracked ceramic parts

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Screw the new spark plug into the thread by hand without using force. Then tighten an eighth to a quarter turn with the wrench to compress the plug sealing ring. Finally, put on the spark plug connector. If you turn on the engine now, it should work smoothly.

Sharpen dull lawnmower blades yourself

Unless sharpening is integrated into the maintenance program, frayed blades of grass indicate a dull lawnmower blade when mowing. You can either transport the mower to a specialist workshop or you can grind the mower blade yourself. Follow these steps:

  • Thick work gloves, sturdy clothing and protective goggles are mandatory
  • Depending on the mower model, pull out the spark plug connector or the power cable or remove the battery
  • Use a block of wood to prevent the knife from turning and remove the knife bar
  • Fix the lawnmower blade in a vice and sharpen it with a file
  • Sharpen both sides equally while maintaining the original cutting angle
  • Completely remove the residual burr with a whetstone

Before the sharpened lawnmower blade is reinstalled, it should be checked for imbalance. To do this, hang it on the center hole on a nail or screwdriver. If one side drops, the balance is restored in another sanding pass.

Experts advise against sanding with a flex

In order to skillfully sharpen lawnmower knives, the experts also use workshop files. With this tool you have the grinding process better under control. Under a flex, the knife heats up so much that it creates an uneven cut. In addition, much more material is removed from the sheet than is necessary. This shortens the life of the lawnmower blade and causes an undesirably large imbalance.


Already knew? China mows Germany. Of the 3.3 million lawnmowers imported in 2014, 1.6 million were made in the Middle Kingdom. The United Kingdom follows in second place on the import rankings with 920,000 mowers.

Repair clogged air filter yourself - instructions

If the engine performance is steadily reducing, the cause is usually a clogged air filter. The carburettor is no longer supplied with sufficient air, so that the filter must either be cleaned or replaced. How to handle it right:

  • Remove the cover of the air filter housing by removing the screw
  • Remove, separate and check the filter element
  • Damaged filters must be replaced
  • Dirty foam filters can be washed out with hot water and washing-up liquid
  • Do not clean the paper filter wet, but tap it out or clean it with the suction nozzle of the vacuum cleaner

Place the air filter back in the housing and screw the cover tight. If the engine smokes when it starts, there is still too much oil in the foam filter.

Readjust Carburetor - How To Do It Right

If a petrol lawnmower keeps stuttering, the carburetor setting is not the right one. In older models, the fuel-air mixture for high speeds is set using a screw. This screw is often located near the throttle body. To readjust the carburetor:

  • Let the engine warm up for about 5 minutes with the throttle valve half open
  • Put the throttle in the 'slow' position
  • Use a screwdriver to turn the gasoline / air mixture adjusting screw so that the highest speed is reached
  • Then adjust the screw in the opposite direction until the motor runs at the desired speed

Check this setting by moving the throttle. If the engine does not accelerate smoothly now, the mixture screw must be adjusted again.

What to do if the electric lawnmower wears down

While a performance problem with a petrol-powered lawnmower can be resolved by replacing the spark plugs or adjusting the carburetor, the issue is more problematic with an electric lawnmower. Here the engine is operated with a capacitor. If this is defective, the capacity drops dramatically.

A defective capacitor can no longer be repaired. New operating capacitors are available from specialist retailers for less than 10 euros. You should only replace the part yourself if you are an experienced do-it-yourselfer. To be absolutely sure that you are installing the new capacitor precisely, take photos of the individual steps involved in removing it. When installing, simply proceed in reverse order.


One of the most common defects on the electric lawnmower is the 'sewn' power cable. You can effectively prevent this damage by using a bright red cable.