Every year for the last 3 years I've replaced the carb on my Sthil weed eater.  They've told me that it was cheaper to replace the carb than overhaul it. 

Last year at the end of the season I put Stabil in the fuel and ran the engine for a while.  I then emptied the tank and ran it until it stopped.

This year I put a product in the tank first, the product is called Start from the same company that makes Stabil.  Then I put in fuel, pumped the primer and after 3 or 4 pulls it started.  Not only that but it ran and idled.