Ive read that same thing all the years i had an Opti. Most failures are from cold seizure. The metal heats up at different temps and causes the issues. There is mountains of info from Merc Techs online about it. My opti had 870 hours when i got it and i put over 250 on it. I always let mine warm up too. Mine was also a 75hp which didnt have near the issues as the 150+engines
That being said i was always scared mine was going to pop from all the stories you here, coils, air compressors, oil pumps, and the list goes on.