By Stuart Robinson

Many people are put off by modern technology, believing it’s unnecessary and more trouble than it’s worth. This may be true with some things, but Stihl’s M-Tronic system, fitted to several of their hand-held gardening products, works extremely well, with a lot of advantages. Like these M-Tronic garden tools: brushcutters and chainsaws.

I’ve found that many of our customers worry that it’ll cause problems, whereas it actually helps prevent problems and should make the machine more reliable. Most of the time it’s a simple case of the customer not understanding what it actually is and how it works.

This is how it works

Very simply, the carburettor has a solenoid valve which is controlled by the engine management system (the ignition module). The valve opens and closes to allow more or less fuel through the jets; it will only allow sufficient fuel to pass through to achieve the requirement for that exact moment. The engine management system constantly evaluates the engine speed and external temperature and adjusts the valve as required. This makes it a self-tuning, very efficient carburettor. Apart from the solenoid valve, the carburettor is virtually the same as any other found on similar products. The management system also regulates the ignition timing.

M-Tronic engine management systems

The advantages

Easy starting: The M-Tronic system has the ability to distinguish between warm or cold starts and therefore takes the decision-making away from the operator.

No more manual carburettor adjustments: all the settings are controlled by the system. High or low altitude, outside temperature and different fuel qualities are all compensated for.

Superb acceleration: The M-Tronic system reacts incredibly quickly, providing the perfect amount of fuel required, when it’s required.

I’ve also found the solenoid valve helps protect the tiny fuel-ways and jets from blocking with dirt when the user hasn’t been too careful adding fuel. This often means that changing the valve remedies the running fault instead of having to replace a costly carburettor.

The M-Tronic technology has a memory function, it remembers the settings from the last time it was used and is restored when restarting, meaning unless conditions have changed the machine is set up ready. The memory function also records hours used and important information that can be used by Stihl dealers, if there’s a problem.

What you need to remember

As the carburettor is virtually the same as a standard carb., you should remember that it’s a serviceable part and at some point, it will probably require attention. It still has wearable diaphragms, an internal filter as well as moving parts.

It’s still very important to use good clean fuel or preferably an alkylate fuel as problems will still arise if you don’t (see Aspen blog).

Regular servicing or at least changing the fuel filter and cleaning out the tank, will help look after the carburettor, also make sure the air filter is kept clean.


I hope this blog helps to reassure you and don’t forget, here at John Miller’s we have the equipment, knowledge and expertise to take care of your garden machinery.


The content of this blog reflects the author’s knowledge and personal opinions and doesn’t necessarily represent the views or policies of the author’s employer, the manufacturer or organisations mentioned. For confirmation and clarity of the information within this blog, please contact the manufacturer or organisation directly.