• Sounds like the freewheel pawls aren't engaging. You could always try spraying some GT-85 or something similar into any small openings you can find on the freewheel body, and seeing if that'll get the pawls moving consistently again. Otherwise new freewheel body needed (typically remove the old one by undoing a 10mm allen bolt (you'd need to remove the axle to access it); or hub/rebuild; or wheel...

About