Small Engines (Lawn Mowers, etc.): Stihl FS80 String Trimmer, air mixture, holzworth

Question
John, I have a Sthil FS 80 string trimmer that is about 4 years old. It runs really strong when I first start it, but after a few minutes and once it get hot, it will shut off on me. Before it shuts off, it sounds like it kinda bogs down for a split second and then it quits running. I can get it to fire back up for a second but then it dies again and won't crank back up. The engine seems like it gets really hot for the short time that the trimmer actually runs. My dad told me that he thinks it might be the coil. Just wondering if you had any suggestions?

Thanks,

Matt Holzworth

P.S. I read some answers that you gave about cleaning the screen by the exhaust and was able to get my other FS80 back up and running at full strength after it seemed to be losing a lot of its' power. Thanks for the help!!

Answer
Hello Matt:

Thanks for the Good Words and I am Glad I can Help. If the Exhaust Port is Clear on this Unit, then the Running Hot can be; 1- the Carburetor Air Mixture Screw for Full Throttle (H) is Set Too Lean. Turn the Full Throttle Air Mixture Screw Counter Clockwise 1/4 Turn and See if the Engine Runs Cooler. Repeat this Process Until the Engine Run Cool or No Longer Revs Properly. Once it No Longer Revs Properly, then Turn the Mixture Screw 1/2 Turn and Leave it. 2- If the Air Mixture Screw Setting Did Not Correct the Running Hot Problem, then Increase the Oil in the Oil/Gas Ratio. 3- If the Engine Runs Too Hot, the Ign Module/Coil will Short Out and the Plug Stops Firing. Once the Engine Cools, then Engine will Restart. If you have the Running Hot Problem Corrected, then Operate the Unit. If it Runs and Quits, then Check for Fire as Soon as the Engine Quits. If No Fire, then the Ign Module/Coil is Bad. If you Hit a Snag or this Does Not Correct the Problem,  I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Thanks.

Respectfully

John