OT--String Trimmer Won't Idle Long

[GaTrapper]

I'm sorry if this is a little off topic.

I have a Stihl FS131 string trimmer.  Its maybe 2-3 years old. It gets used frequently during the growing season and chills out during the winter.  I only run non-ethanol in the machine. During the winter I crank it up every 2 weeks and let it run for a bit.

Currently, it cranks up easily and runs great. The issue involves idling. If I'm trimming and need to set the trimmer down for a minute, the machine will shut off within a minute or so. I changed the air filter and I am still experiencing this problem.

How can I correct this?

[sawguy21]

Try turning up the idle speed to just below where the head starts turning. The idle mix may need to be leaned out a bit as well.

[tawilson]

A plugged up spark arrestor has been the culprit for me a couple times.

[btulloh]

Amen on the spark arrestor. Easy to overlook but can cause all sorts of symptoms. 

[Tom King]

The spark arrester screen is held in the muffler outlet with one screw.  Take it out, and holding it with an old pair of pliers, heat it red hot with a propane torch.  Let it cool, and rub the ash off with an old glove on your hand.  Put it back in, and it should run like a new one.

[sawguy21]

That is worth checking out but a plugged arrestor won't allow it to rev up and develop full power. 

[joe_indi]

This would be a 4 Mix engine (four stroke running on 2 stroke fuel). If the valves have not been ever adjusted that could be the reason. Several years ago I made a How To kind of video and uploaded it to YouTube, it might be of some help.
The carbs on these engines are a bit 'fussy' 

My video