Seized engine vs botched starter install

[traumamed]

Editing to save future readers from having to read a long and irrelevant story.

I originally posted about a starter vs seized engine issue. Turns out that both were the case, as the boat in question appears to have sustained storm-related damage in Hurricane Irma that is now becoming apparent: finding water in places it should never be able to get, water damage revealing itself in decks and upholstery, and electrical gremlins popping up everywhere. It would seem that wind-driven rain was able to compromise the intake and/or thru-hull exhaust system, driving water into the engine. An unrelated starter issue acted as a confounder.

Not something most people will probably have to deal with, as this no longer appears to have been a purely mechanical issue.

 

[tpenfield]

Theory #1

I'm thinking that the engine hydro-locked, which broke the original starter. During the hydro-lock a connecting rod (or two) may have bent.

I would see for yourself if you can turn the engine with a breaker bar in either direction. If it hits a point in the rotation where it does not want to go any further, then it may be proof positive. If it is 'stuck' in that one position where the mechanic left it, the 'bent' connecting rod could be bound up against the cylinder wall within the engine.

All theory at this point, but your description sounds like a hydro-lock that damaged the engine.

Theory #2
Would be that whatever broke off of the starter is wedged within the flywheel housing.

 

[traumamed]

Theory #1

I'm thinking that the engine hydro-locked, which broke the original starter. During the hydro-lock a connecting rod (or two) may have bent.

Yikes. I hope you're wrong, but you might be right. I'm hoping for Theory #2.

I am just shocked that a hydro lock is even within the realm of possibility on a 4-year-old engine with barely 150 hrs on it and manifolds and risers with only 12 months and 50 hours on them. But it is what it is I guess. If it does end up being a hydro lock, I would sure love to know how to prevent this in the future, because I really maintained this thing well.

In any case, I will try to turn the engine over myself as you suggest rather than take the mechanic's word for it. How much resistance should I expect before I give up? I have a 3-foot breaker bar but I've never tried to turn a 7.4L over by hand before.

 

[alldodge]

Verified prop spun freely in neutral

Pull the drive before you get to evolved. The prop could spin in neutral even if there is damage in the upper housing

 

[Scott Danforth]

Pull the plugs and check for water and rust

 

[traumamed]

Pull the plugs and check for water and rust

Plugs are already out, no water or rust.

 

[Bt Doctur]

before you break the bolt in the crankshaft ,remove the drive first. Then if you must turn the engine, remove the nose bolt and the 3 bolts for the pully, remove pully and reinstall the 3 bolts and use then and a bar to try and turn the engine