Merc 4 stroke sank

[Agnewman]

My 20 hp merc 4 stroke sank. The water got up to the bottom of the carburetor. I drained the boat and there was an oil slick in the boat. The lower end of the motor had been bouncing on the sand bottom of the lake.
When I tried to start the engine with a fresh battery it would only ‘click’. When I tried pulling the start cord I was unable to. It seemed to be locked and the cord wouldn’t move at all.
Any ideas what would cause this and what I might do myself. Should I just bite the bullet and take it in for servicing.
I am fairly mechanical but lack experience on outboard engines.
John

 

[alldodge]

If motor sank and was immediately drained, flushed with fresh oil it might be ok. Sounds like yours spent some time with water in it, so it will need to be taken apart

How long did it spend with water?

 

[Mad Dog 2]

Have you removed the spark plugs and rolled the engine over and slowly by hand. That will push the water out if it is hydraulically locked up.
The engine should roll over unless the gear shifter is in forward or reverse engaging the safety lock. Gear shifter and linkages need to be in neutral and the prop spin freely both directions.
Sinking in a fresh water lake there should be no permanent damage.
Need to drain the carb, put oil down the spark plug holes, drain the sump, fresh oil, roll the engine over by hand this will stabilize and lubricate the engine.
The best thing is to get the engine running, keep checking the engine oil for water/bubbles/milk shake as you run it.
U Tube should have good videos.
As the post above says it could be rusting up. If it is that you need soak the cylinders and gently work the flywheel back and forth.