I've owned this trimmer for 3 years now. The 2nd year I replaced the magneto and this year looks like I need another one. Seems a bit odd. I work as an auto tech so these matters aren't totally foreign to me. Any insight?
Try the spark test first. If its good move to carb if not replace. If you have spark dump a tea spoon of gas down the carb and PULL with no choke and full throttle until it starts for a sec and dies. Then take the carb apart and check the needle and seat that they work. If all this fails then go for a carb rebuild