Motors do not get "stuck" for no reason. What I have seen, is a few definite possibilities. Incorrect winterizing procedure. Improper maintenance of Elbows and manifolds, specially on raw water cooled motors. And keep in mind All the work you just did. Make sure the motor is not stuck due to any thing you just worked on.Got all the work done to only find I got a stuck starboard motor..... LOL
So we are pickling her in Marvel Mystery Oil to see if we can free her up....
Frustrating to say the least. But its not the end of the world, even if I need to replace I can do all the work myself, just may decide to do a proper restoration, replace tanks and paint bilge.
So far we have MMO in her soaking, going to go back Thursday and see if she budges, even if she does will pickle her again in MMO cut with ATF, then drain, do a compression test and test fire.