I have recovered a few motors that have been sunk. The last being a suzuki df140 rinsed everything with fresh water then Salt Away which supposedly displaces the salt. Pulled the plugs and got all the saltwater out then sprayed with wd40.
Had the engine running again in 2 hours... I then sprayed all the connections with Boeshields T-9 which is an anti corrosion spray. Everything was fine for about 2 weeks of regular use, then starter and the solenoid then packed it in. I replaced both and the engine ran beautifully for another 2000 hours.
I had no problems with the cpu and any other electrics.
At the boatyard that I work at we have a old honda 4 stroke 40 that has been sunk 3 times that I know of and each time it has been salvaged and is still running although a little rough starting