Give it a try and see what happens. Unless of course it shreds and takes out a bunch of wiring when it goes. BTDT
You may be surprised how long that belt runs anyway. Half way through last year I noticed the same thing on the MoCo. Finished the year and did half if this year before I replaced it. The worry about it is the worst to me.
If I was going to do it I would use super glue. Put it in where the belt is gapped the most and then roll the pulley until it is closed.