Stihl Trimmer Won’t Start When Hot

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Your weed eater engine needs consistent airflow to keep it working. If not, it might result in overheating.

Stihl is one of the popular trimmer brands available on the market. They come with two-cycle and four-cycle engines. When you use a Stihl string trimmer with two strokes, the engine of your trimmer has to pass through some processes that involve constant airflow and fuel.

However, it has to be a balanced process and when this is interrupted, it might cause overheating problems which may make your string trimmer stop working. BUT, you don’t have to worry because there are ways to fix this problem without going to a repairer’s shop.

Stihl String Trimmer Troubleshooting: String Trimmer Overheating


In this section, you will learn the troubleshooting tips in fixing your Stihl String trimmer:

Restoring Proper Air Circulation

Proper air circulation is important for a smooth-running engine process. However, the airflow of your equipment can be stopped for some reasons. Generally, if the air muffler or filter is dirty or the vents get blocked, your weed eater stops working.

The real reason for this is that the air is not rightly circulated through the engine system of your trimmer and there won’t be a free fuel supply. This will affect the engine parts because they will be forced to function harder to maintain balance. This may make the trimmer cease working.

The easiest way to handle this issue is to ensure regular maintenance of your trimmer. This will make several engine parts like the carburetor last long.

Check Gas Cap and Fuel Filter


Dirty fuel filters can result in inconsistent fuel supply and airflow, causing an overheating issue. Inspect the fuel filter and clean up any debris. Fuel filters are affordable, it is better to replace dirty ones than to clean them. You can also replace it around every forty hours of operation.

Furthermore, inspect the gas cap to confirm if the trimmer’s air vent is clogged.  Remove it halfway and run your string trimmer.

Inspect the Carburetor


If your Stihl trimmer won’t start when hot, the problem could arise from the diaphragm of your fuel pump. This means that it won’t ensure a proper flow of fuel and it will prevent your Stihl trimmer from operating.  

This might not be the only problem with its carburetor, it might arise as a result of the inlet lever not staying in its right position.  When you detect this problem, it is advisable to engage the services of a professional to help you out.

Maintain Fuel Supply

Always ensure that the fuel filter remains unblocked for the fuel to flow in a free manner. If the fuel lines aren’t kept clear, it might cause the diaphragm to overheat and this might make your Stihl trimmer stop working when hot. Also, the inner parts might overheat if the air vents get obstructed.

Check For Air Leak

If air leaks out of the power system, there may be some issues. It can cause interruption which will make the trimmer overheat. 

Air leak could develop in several places, it might be in the fuel lines, fuel tank, gaskets or connecting valves that leads to the carburetor.

Engage the Services of an Expert

If you have tried the above points and you realize that there are still some issues with your Stihl trimmer, it might be a serious issue that requires the services of a professional. The expert will assess, service or change any faulty component of your gas grass trimmer.

Maintenance Tips

If your Stihl trimmer doesn’t start when hot, the perfect thing to do is to carry out proper maintenance on your trimmer. 

Some of the steps to take involve cleaning some components of your trimmer like filters, fuel lines and air vents.  

Also, there are other maintenance tips that you can take note of:

  • Replace parts such as filters, spark plug and trimmer line regularly.
  • Ensure that you check parts for damage. Make sure that you turn off your weed eater and remove the spark plug to prevent accidental start-ups.
  • Make sure that the idle speed is always correct. If the trimmer stalls when idle, all you need to do is to adjust it and install the spark plug. While doing this, you should make use of protective gear.
  • With four-cycle engines, homeowners don’t have to bother about the mixture of oil and fuel. All you need to do is just add the oil separately and it should be topped up.
  • Keep your Stihl trimmer in a well-ventilated and dry area.


It is a common problem for Stihl string trimmers to overheat. If you notice that it ceases to work when hot, we have provided several troubleshooting tips to guide you. 

Most of these tips can help you solve the Stihl trimmer problem yourself. If you have tried the tips and there are still problems then consider seeking professional help.