Hi, I have a 2004 Merc Opti 225. You can see in the photos that the trilobe keeps working itself out. It has never came out completely, but, I usually have to gently tap it back down into place with a hammer every 3 or 4 outings. Was looking at replacing it myself, and wondering if there were any pitfalls, things to watch out for, or tips on getting that out, since you can't tap from the back. Also wondering, should I replace the shaft the pin goes through? I was planning on trimming the motor all the way up, and putting the lock in place. Anything else I should know ? Thanks for any help.