Ain't them 1425's one of them late model xt throwaway lawn mowers?
I could be mistaken tho'
Remembering a long time ago them early JC penny lawnmowers
made by MTD, had a belt drive with a forward-N-Rev. lever that sometimes didn't work, or hung up.
They also had a problem with the drive pulley on the transaxle.
but prolly not this fellers problem.
If the belt from the engine is turning the drive pulley on the gear box, maybe it is in neutral but I'm not much help, as I've not had the displeasure of seeing one of those models.
sorry.