My clutch housing just free wheels. Troybuilt told me to drop a rope in then plug hole to stop the piston close to
TDC - my problem is my clutch housing just free wheels - its not connected to the motor driveshaft at rest.

It doesn't appear to have any serviceable fastener in the cluch shaft receptical (where the main driveshaft of the weed eater connects. I am stupmed. Any ideas?

This is for a starter assembly replacement. Item 35 is what free wheels, and is the last step to get the starter housing off.

http://www.ereplacementparts.com/troybilt-tb70ss-41adt70c711-gas-trimmer-parts-c-26780_27267_27463.html

Thanks in advance

There is probably a torx scew inside the end . Probably T10 or T15.
Luck

DG - It was a T20 - your right - Thanks!

Your welcome.