If the lawn mower no longer runs smoothly, jerks and jerks, you cannot avoid a repair. Instead of taking the money to a specialist workshop, you can sometimes repair your lawn mower yourself. You can find out how to do this here.
How can I repair my lawn mower myself?
Repairing your lawn mower yourself is possible by changing the spark plugs, sharpening the blade, cleaning the air filter or adjusting the carburettor. On electric lawnmowers, you can replace the capacitor to improve performance.
Repairing spark plugs on the lawnmower works like this
If the engine of a petrol mower does not start after repeated tightening, it is most likely 'drowned' due to unburned fuel in the carburettor and cylinder. In this case, experienced hobby gardeners first check whether the tank is perhaps empty. If this shortcoming can be ruled out, proceed as follows:
- Put the throttle lever in the 'Stop' position and pull it fully in
- First let the engine cool down and only then remove the spark plug connector
- Remove the spark plug with the special spark plug wrench (€9.00 on Amazon)
- Dry and clean the spark plug or get a new one
- Do not reuse candles with cracked ceramic parts
Turn the new spark plug into the thread by hand until it stops, without using force. Then tighten the wrench an eighth to a quarter of a turn to compress the spark plug sealing ring. Last but not least, attach the candle cap. If you start the engine now, it should work smoothly.
Sharpen a blunt lawnmower blade yourself
If sharpening is not integrated into the maintenance program, frayed blades of grass when mowing indicate a dull lawnmower blade. You can either transport the mower to a specialist workshop or grind the mower blade yourself. Follow these steps:
- Thick work gloves, robust clothing and safety glasses are mandatory
- Depending on the mower model, pull the spark plug connector or the power cable or remove the battery
- Prevent the knife from turning with a wooden block and remove the knife bar
- Fix the lawnmower blade in a vice and sharpen with a file
- Sharpen both sides evenly while maintaining the original cutting angle
- Use a grindstone to completely remove the remaining burrs
Before the sharpened lawnmower blade is reinstalled, it should be checked for imbalance. To do this, hang it from the center hole on a nail or a screwdriver. If one side sinks, the balance is restored in another grinding pass.
Experts advise against sanding with a flex
In order to skillfully sharpen lawn mower blades, experts also use a workshop file. With this tool you have better control of the sanding process. The knife heats up so much under a flex that an uneven grinding pattern is created. In addition, much more material is removed from the blade than necessary. This shortens the lifespan of the lawnmower blade and causes an undesirably large imbalance.
Tip
Did you know? China mows Germany. Of the 3.3 million lawn mowers imported in 2014, a whopping 1.6 million units come from the Middle Kingdom. The United Kingdom follows in second place in the import rankings with 920,000 mowers.
Repair a clogged air filter yourself – instructions
If the engine performance is constantly reduced, the cause is usually a clogged air filter. The carburettor is no longer supplied with enough air, so the filter must either be cleaned or replaced. How to handle it correctly:
- Remove the air filter housing cover by removing the screw
- Remove, separate and check the filter element
- Damaged filters must be replaced
- Contaminated foam filters can be washed out with hot water and detergent
- 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 starting, there is still too much oil in the foam filter.
Readjusting the carburettor - how to do it right
If a petrol lawnmower keeps stuttering, it means that the carburettor is not properly adjusted. In older models, the fuel-air mixture is adjusted for high speeds using a screw. This screw is often located near the throttle body. How to readjust the carburetor:
- Let the engine warm up for about 5 minutes with the throttle valve half open
- Move the throttle to the 'slow' position
- Use a screwdriver to turn the fuel-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, the mixture screw should be adjusted again.
What to do if the electric lawn mower gives out?
While a performance problem with a gasoline-powered lawn mower can be solved by replacing the spark plugs or adjusting the carburettor, the matter is more problematic with an electric lawn mower. 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. However, you should only replace the part yourself if you are an experienced DIY enthusiast. To be absolutely sure that you install the new capacitor precisely, take photos of the individual steps of the removal. When installing, simply proceed in reverse order.
Tip
One of the most common defects on electric lawnmowers is the 'mowed' power cable. You can effectively prevent this damage by using a bright red cable.
