Small Engine Troubleshooting Problems? Ask a Mechanic Now.
I have a Troy Bilt 4-Cycle Gas Trimmer (TB525 EC) and how do I replace the line?
On this one you don't remove the spool. Just line up the arrows and feed it from the outside. However, to remove the bump knob, you press the tabs from the side. I'm linking to a manual below with instructions on page 5. Putting the new one on is illustrated on page 6.
Hope this helps! Let me know if anything isn't clear.