On my flight home with my 231 last October, I got the throttle stuck in initial climb at about 32". For a while, I was afraid I was going to have to do an intentional shutdown and deadstick landing, but I finally got it freed up, took the friction lock off/apart, saw the problem (the little leather washer that's the heart of the friction adjuster gets pinched between the throttle control shaft and its housing), and learned how to avoid repeating my "mistake" (advancing power via vernier action with the friction lock in a relatively high state).
I've operated other vernier engine controls in other airplanes since the 1970's without any trouble whatsoever.
Since then, I've had no serious issues operating with this glitch, but today I began some formation instruction in preparation to fly in Caravan 2021, and really had trouble with the frequent power changes necessary. My instructor said he recommends I not attempt to fly formation any more until I get the issue corrected.
Suggestions most appreciated!
My mistress is a well maintained '85 231 with a ModWorks 262 conversion (252 FWF).