Stihl Trimmer won't start when hot.

[GLC]

I have a Stihl commercial trimmer, can't recall the model off hand, but it starts on the first or second pull when cold and runs great. After it warms up to operating temperature and I shut it off to fuel or put on more trimmer line, it absolutely will not start no matter what I do. Let it cool for an hour and it starts right up and runs great until shut off again.

I'm thinking the coil may be getting weak and failing when hot.

Any ideas?

 

[Bird]

The manual for my Stihl recommends 89 minimum octane gas; says the 87 will run hotter, so yours might be overheating if you are running regular, but I don't think that should keep it from starting if it turns alright when you pull the starter rope.

 

[GLC]

Good thought but I always run 93 octane gas in all my power tools, saws, trimmers, etc.

 

[Furu]

I had a similar issue with a Stihl chainsaw couple of years back. Tried several different things, the Stihl dealer thought the coil was the issue but eventually found a comment on another site and played with the idle mixture. When cold there was no indication of any problem but when warm just as you describe . I could wait 5-10 minutes and then would start.
Bottom line after taking the low speed mixture high speed mixture and idle screw and resetting the problem went away. Give it a try might be your problem and an easy fix. Your manual will describe how.

 

[JOE G]

If it is a 4 Mix Engine it could also be a valve adjustment issue.