Trimmer Maintenance

Like Stihl’s other handheld equipment, Stihl trimmers are easy to maintain because they use two-cycle motors (or the 2/4 hybrid 4-MIX motors) that take a 50:1 gas/oil mix. You can mix this yourself, or use Stihl’s Motomix, a pre-mixed and stabilized fuel with a long shelf life.

If your Stihl gas-powered trimmer is not running properly (or at all), Tech Check is the recommended procedure for diagnosing any engine problems. This comprehensive procedure was developed by Stihl to identify and isolate any possible mechanical failure, and should be performed on any Stihl gas-powered units not running correctly. 

Tune Up is routine for working units with no complaints, or for the trimmer that may not be exhibiting problems, but has not been maintained for a while.

Valve Adjustment is for units equipped with the 4-MIX motors and should be performed around the 100-hour mark of the blower’s run time. New units do get a static valve adjustment at the factory, but it is not practical for the manufacturer to fully break in these motors. After 100 hours of run time, fine tuning of the valves is needed to ensure continued smooth operation. This is a one-time adjustment; under normal circumstances it should not need to be repeated.

Repair or Replace

We are well equipped to service everything we sell, but unlike the larger equipment, some of the smaller, less expensive trimmers might not be cost effective to repair should they require more than a tune-up. Such machines are generally cheaper to replace outright. As there’s no market for used parts on these machines, worn out units are sent for recycling.

Attachment Safety

Beware aftermarket attachments for your trimmer, particularly flail attachments meant to save the trouble of replacing trimmer line. They may not be suitable for the power of your machine, and swinging a heavier blade or a wider radius could overheat the motor. Flails can also break off and pose a safety hazard to the operator and passersby. The same can be said for defeating the rear guard in order to release a longer cutting line; for both warranty and safety reasons, it’s a bad idea.

Your operating manual will give you specifics; try and be one of the exceptional folks who actually reads it! You’ll do well to maintain a written log of your usage in order to keep your maintenance on schedule.