I recently purchased a 1985 Mercury 115hp motor that was attached to a boat that was submerged completely for 2 days in saltwater. The motor itself had the entire lower unit and 4 inches of the powerhead submerged. All of the plugs look perfect except the very bottom one. There is a generous amount of corrosion on some of the lower wiring and on the carburetor. I spole to a local maring engine mechanic and he advised me to do the following:
1. Trim the motor as far horizontal as possible
2. Remove the Plugs and wires
3. Rotate the flywheel and attempt to expel any saltwater in the powerhead (if flywheel locked proceed to step 4)
4. Pickle the block with Marvel Mystery Oil (Pour entire quart into spark plug holes)
5. Let set until finished all boat wiring (wee to month)
6. Remove all corrosion from powerhead wires, carburetor, etc.
7. Rotate flywheel again to expel the Marvel Mystery oil
8. Put plugs and wires back in
9. Attach muffs and wires
10. Crank her up
Can anyone verify this informaton or offer any additional steps that we may have missed. I am planning to do this later tomorrow and would like some additional input. Thanks!
If it was my engine....this is first aid ( to be done five minutes after the engine are on dry land !!!, do NOT wait )
Get the engine up on dry land.
Remove all plugs
Disconnect all electrical connectors
Flush the entire engine ( inside/outside with fresh water, lots off it )
Turn the engine by hand while continuing flushing.
ALL salt water must be removed before the next step.
Then turn the engine by hand so the water can find it's way out
Then drain ALL fuel hoses/oil hose/carburetor/fuel pumps.
It's now time for lubrication, especially inside the engine ( crank/rods/cylinders ), spray the engine on the outside too..
Remove and open up the starter, flush it good under rinsing fresh water, dry and lubricate it the you can put it back together ( an untreated starter WILL fail within 3 mounts ... ).
And so it's time to get the engine running again...
New fresh gas, double the oil on the first tank...
Flush tru the whole fuel system with new fuel...
Start the engine, if it starts... let it run for some time..
If you got the slightest suspicion about any sand/gravel from the water can have entered the engine, you must disassemble the whole engine .
Got a engine with the same history....but on my engine they didn't remember to get oil inside the crankcase.....electronics and cylinders were very well lubricated....Still got the crankshaft and rods...nice paper weights...