I know it's too late, but for next time. I have a set of really long and narrow needle nose pliers. I grab the straight middle section of the retainer. If you twist the retainer clockwise (as pictured) as you try to press it into the hole, the friction will spiral the retainer into the hole.
It runs like s*** and won't idle, but at least it starts. I figure once I get the air cleaner and everything else on maybe it'll run better. (I hope.)