Small Engines (Lawn Mowers, etc.): STIHL FS 120 WEED EATER, weed eater, exhaust ports

Question
This unit works pretty well but after about 10 minutes, it begins to slowly bog down! I guess it does it after it gets hot!  I replaced the air filter and the plug! Can you help!

Answer
The first thing I'd do is remove the muffler and check the exhaust ports for carbon-plugging.  Also check the spark arrestor in the muffler.  If these are OK, try loosening the fuel cap slighty when it begins to die.  If this corrects it, the tank vent is likely plugged and will need to be cleaned.  Hope this helps.