Well I’d say if it’s screwed on nearly all the way you have matching threads so maybe bottom threads just need a thread file or needle file run over them just a tad as slight bruising may have occurred along the way..or a little grinding paste so you can work the freewheel back & forth so it...
Weren’t yellow head tubes like this destined for the US Markets? I’m probably completely wrong but heard this back in the day…
My first proper bike was a scruffy second hand 76 5 speed Raleigh Europa