How do I remove the clutch on a stihl fs44 trimmer?

Hi,
There is a tool for that. Have you got the drum off? It requires a T-27 down through the spot where the shaft fits. There is a marking on the clutch itsef for Off and an arrow. You must remove the spark plug and block the piston. In a pinch a length of starter rope looped and inserted through the plug hole will do it. A punch and hammer used carefully to loosen the clutch if the tool is not available.
Peace,
Clarke
PS And good luck!