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The brushcutter is a useful tool, whether it's finishing mowing the lawn or clearing hard-to-reach areas. But what do you do when the engine starts and then dies again?

In a nutshell

  • If the brushcutter goes out again immediately, the cause is usually a defective sprayer
  • The search for errors in the fuel supply promises help
  • Depending on the engine, a wide variety of causes can lead to a lack of fuel

One reason, many causes

The reason why the motor of the brushcutter starts first but then stops again is usually always the same. The engine initially receives enough fuel to cope with the starting process. However, there is then no sufficient follow-up flow, so that there is not enough fuel available for ongoing operation. The device turns off - it "dies". On the other hand, there can be numerous reasons why the fuel supply is too low:

The wrong attitude

The cause of a dying motor of the brushcutter does not have to be serious or even fatal. Even an unfavorable setting of the carburettor can result in the air-petrol mixture no longer being ignitable. Especially if too little fuel is allowed into the combustion chamber, the unit can start up at first, but then not take up any permanent function.


  • consult the operating instructions
  • Set the carburettor according to the manufacturer's instructions
  • If you lack specialist knowledge, visit a specialist dealer or workshop

Dirt in the fuel supply

A brush cutter causes a lot of dirt and dust during operation. It is not uncommon for some of this to end up in the fuel cycle as well. The dirt can then settle either in the lines, in the fuel filter or directly in the carburetor and impair the fuel passage and the functionality of the carburetor. Here, too, the most common consequence is a lack of fuel, which stands in the way of long-term operation.


  • Open the air filter and clean according to the manufacturer's instructions
  • Close the fuel tap
  • Remove fuel filter and lines and flush with mineral spirits or clean fuel
  • Blow out residual dirt with compressed air
  • Check the carburettor and, if necessary, clean it according to the manufacturer's instructions
  • Reinstall lines and filters
  • Check device for function

Notice: If the problems recur, the gasoline itself may also be contaminated. Then dirt keeps getting into the system. In this case, you should carry out comprehensive maintenance on the brushcutter or have it carried out by a specialist.


In addition to contamination, damage or signs of wear can of course lead to the fuel supply in the combustion chamber being restricted. Above all, the carburetor and the air filter should be named as possible causes.


  • Remove air filter
  • Check for damage
  • If there are holes, defects, etc., replace the filter
  • Remove and open carburettor
  • Depending on the model, check the membrane or carburetor needle for function and damage
  • If necessary, repair or replace with a replacement part
  • If in doubt, visit a specialist workshop

The wrong oil in the petrol

The last common reason for missing fuel can also be the wrong type of oil. Brushcutters generally use a two-stroke engine that relies on a petrol-oil mixture. If, for example, bio-oil is used, it can become viscous or even completely solid during longer periods without the use of equipment. As a result, lines can become clogged and the carburettor mechanism blocked.


  • Dismantle the fuel system
  • Clean components
  • Prevention through suitable oils without "gummy"

Notice: There is absolutely nothing against the use of bio-oils. However, if it is foreseeable that the device will be idle for a long time, you should use alternative mixed oils to prevent the problems mentioned.

frequently asked Questions

How do I recognize a defective air filter?

Whether permanent or replaceable filter, you should always replace it when the material changes. Signs can be changed structures, loosening particles or a general declining integrity.

Does every Sense use two-stroke engines?

Today, more and more smooth-running four-stroke engines are used. However, small combustion engines in particular are often built with the more powerful two-stroke engines. If there is no separate tank for engine oil, it is a two-stroke engine. If in doubt, refer to your user manual.

Can a blocked mower also cause the unit to go out?

If the aggregate dies off again immediately, i.e. without accelerating, a stuck mechanism cannot be the decisive factor. Because only when you accelerate does the mower engage and act on the engine.

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