That time of year again, spending the weekend doing the impellers on all the outboards.

I'm having trouble I've never experienced before with my 98 135 2-stroke. The lower unit came off easily enough, but will NOT go back in. Checking the underside of the powerhead with a flashlight reveals a loose ring or spacer moving around and blocking the hole in the powerhead. I can flip it around quite easily with a long cleaning rod, but it will not stay out of the way of the driveshaft when I try and install it. For the life of me I cannot figure a purpose for the thing. It looks for all the world like a loose piece just dropped from the motor. Nothing like it shows on the schematics.

Any ideas on what this thing is and how to get it out of the way? I've never had this difficulty before, is it a piece of a broken spacer or collet?  I REALLY do not want to pull the powerhead off this motor, any other way to access it?