Re: idle pulley bearing, locked up....
I replaced the Clutch "v-belt" idler with a pulley from tractor supply. I think it was 3in or 3-1/2in in diameter. It did need a bushing to reduce the bore to 3/8, but that was for sale also from TSC. (I actually drove the old bushing out of the old pulley and reused it.)
If you are describing the "flat idler pulley (used to adjust the clutch height), IDK if TSC can help.
Used parts are often avail on ePay, but it's used so YMMV