Scott,
I had a similar issue with my 1450.
Instead of those nuts working loose, I didn't get the snap ring on correctly.
This happened after I had adjusted everything after a resto\repair of everything I found needing attention on a wore-down 1450.
This was my first attempt at anything on a cub.
On my maiden voyage, feeling how much better everything worked, I opened her up ran out and around the pasture a time or two.
Feeling pretty darn smug at my mechanical prowess, turned her towards the shop. Still going full speed, got almost to the door and hit the brakes, knowing full well I just put on new pads and that it would stop on a dime. It didn't stop and continued on into the shop and hit the rear wall. But not before running over the Grand daughters new bike first. Post crash evaluation revealed the snap ring had come off and the cam assembly apparently bounced off the shaft, giving me no control over a runaway hydro.
Total cost of damages: Grandaughters replacement bike, $150.00. My 1450 just some scratched up paint, no cost. My ego and pride, a total loss.
Brad