Trimmer power-head maintenance is pretty straightforward stuff.
Assuming you have a standard two-cycle engine, getting the right mix of gas and oil is key. Equally important is keeping the gas and oil fresh. I never mix more than a gallon at a time, and that is for use on both my trimmer and my chainsaw.
Even then, it can get old, depending on the season. Old fuel tends to gum up the carburetor and cause trouble over time.
Concern for clean air may seem ironic, considering the pollution rate with most two-cycle engines. However, maintaining a clean and plentiful flow of air into the combustion chamber will actually reduce pollution flowing out. Fresh air ensures more complete fuel burn.
Check your manual for proper care of your air filter, and check it often. The dirtier the work you do with the trimmer, the more often the filter should be checked and cleaned.
Take a few minutes before you put the trimmer away and clean off any plant material build up. Take extra care around the gas cap.
Keeping it clean helps reduce the potential for a plug in the fuel line. If you get one, you’ll know it. Often the engine will idle, but when you open the throttle it will stall out. Then it is off to the shop and a delay in finishing that trimming you were going to do.
A quick wipe down saves money and cuts down on frustration. Combined with fresh fuel and clean air filters, a little maintenance goes a long way.