A few months ago my brother-in-law and I were fishing (salt water) downs here in St. Pete. Both of us enjoy both fresh and saltwater fishing and have quite a few rods and reels. A youngster was fishing next to my BIL with a Zebco outfit. The first cast and he got nasty backlash. My BIL spent 10 minutes undoing the damage. Three casts later the same thing happened. My BIL being a nice guy fixed that problem too. In the end we gave the kid a spinning outfit to use and he had no problems.
Now, I don't know if this was an issue just with the kids reel or happens frequently with Zebco outfits. But, it made me leery about ever buying one.
P.S.: I use spinning, baitcasting, and conventional reels and can use a fly rod but it's not one of my favorites.
I bet the reel was overfilled.
Phil