Stop running in forward after warming up but can run in reverse with assistance
I'm still new to these live steam locos and I was running mine on the rolling road to get some practice as well as to help it run in abit more. on the 7th steam up it ran without issue or needing assistance, at this time is started to be able to turn its wheels more freely making me think its definitely getting a good. But now it would slow down to a stop but in reverse once i got its wheels to turn it would run without issue tho it would stop sooner than it did before. I did look on the forums to see if someone elts had the same issues 1 said about seals expanding after service, and the engine did have one before I received it, while another mentioned it being out of timing. I don't want to assume its one or another before I attempt to inspect it directly and I would raver take the more likely option first then work from there. Any advice would help me a lot. The wheels still turn freely without abnormal resistance, while both hot and cold and I haven't herd or smelled anything out of the ordinary if that help with diagnosis.
The video clearly shows that just as David described the timing mechanism has slid forwards along the shaft a little and the the brass tag is not engaging with the brass reversing gear to alter the timing. Again, as David says the fix is not difficult but is very awkward whist in situ.
The same result (not reversing) was discussed in the thread you mentioned but the causes are different (https://www.oolivesteam.com/forum-1/technical/mallard-having-issues-with-forward-reverse-and-red-light)
I will contact you by phone to discuss your options.