I have a Troy Bilt TB90BC trimmer/brushcutter. The line spool head will not spin up to speed. It will work for a second or two, then stop spinning under power. It will still rotate freely, just not in a controlled fashion. Is it going to be the the Gearbox assembly or is it the clutch on the engine?
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix grass trimmers.