I have examined the parts list of your furler on "Spare Parts List Furlex 200 S & 300 S - Seldén" site and think that the problem could be two things: 1-One or many seat(s) for the ball bearings is(are) broken, or: 2-The forestay has broken strands inside the extrusions which stops the swivel from turning at regular angle in both directions. The second option is probably most probable.
Unfortunetely, you will have to dismantle the whole unit to examine, but the good news is that you may have saved your mast from dismantling because if strands are broken,your forestay could have failed under heavy winds.
To remove the whole unit without taking down the mast, you have to tie the jib halyard tight to the front deck or balcony and then remove the entire unit. Remember: Have the mast secured good to the front before taking off the forestay with the furler, and put two halyards if you can to be double secure!
I have seen the top swivel seized and the furler would move at the bottom as the extrusion would twist. If no movement at the spool the problem must be in the lower bearings.
Still check the forestay while doing the work.
So a tip here: If you're going to disconnect your forestay you'll likely find it impossible unless you slack off some standing rigging.
- Drop your jib and get it off the foredeck.
- Use your jib halyard and preferably another spare halyard to hold the mast upright in lieu of the forestay, and tighten them up before the next step.
- Loosen whatever standing rigging is necessary on your particular boat to release the tension on the forestay (e.g. backstay). But relieve only just enough tension to allow you to remove whatever hardware is bolted in place to keep your forestay attached. Count your turns as you slack off so you know exactly how many to put back on.
- Do whatever is necessary to fix your problem. If it has to be sent away, reconnect your forestay and retension appropriately. The halyards should just be used temporarily.
It might seem a bit harrowing, but think things through first, get someone to help (controlling the forestay and furling mechanism will be a handful), and take it slowly. I managed to pull my furler off by myself last year and send it out to be repaired, but its a lot easier with a second person.