HELP..Mercruiser 7.4L in water for over 2 months...

Discussion in 'Propulsion' started by investorsc, Oct 26, 2007.

  1. investorsc
    Joined: Oct 2007
    Posts: 1
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: PA

    investorsc New Member

    Hello all.....:(

    Our Crownline was found to have approx. 12" of water above the floor level. Boat was run in early MAY, and covered (Plug In).... Pump Switch was on and Battery Maintainer was plugged in. Heavy Rains this summer and center poles went down thus rain into boat. GFI at building tripped sometime, ending the battery charging. Boat uncovered after Labor Day for some fall visits to the lake.

    This resulted in a waterline at the engine of approx. the bottom edge of the rocker arm covers. The motor was sitting in water to this level for at LEAST 2 months. Boat is totally dead electrical with new batteries. Marine Surveyor said boat itself is pretty much toast- the only variable is the motor.....

    Lower Pulley, Power Steering Pump are VERY rusty. Alternator is "faded and slight rust" "(Above water line). Boat was covered the whole time, keeping a virtual 100% humidity inside the boat and engine comparment for June?,July, August, and half of September....

    Oil Level is showing about 2 inches above full, but not milky (Of course motor has not been run). Dipstick does not appear to have a definate oil/water line. There is light corrosion on the upper (bare) areas of the dipstick. Engine has only 125 Hours on it from New.

    What should we look for to determine the status of the motor, or to determine it's condition relative to the boat? Whether the boat is totaled or not propbably hinges on this item..... I know the engine was mint.... Now has rust around the top of the intake near the heads, on any exposed machine areas (Block corners at block/hear interface)... Along the entire underside of the water jackets on both sides for Exhaust...Etc.

    Any advice, experience, or ideas are appreciated and welcome....


  2. StianM
    Joined: May 2006
    Posts: 593
    Likes: 23, Points: 18, Legacy Rep: 114
    Location: Norway

    StianM Senior Member

    can you turn it? Doubt it.

    Replace the electrical parts and fill the cylinders with coke and let it stand for 1/2 hour and then try turning it. if you have large quanetys of water in your sump check the bearings, if not your probartly lucky.
  3. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 488, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    It's very unlikely that you don't have a anchor living in your engine bay. Engines can survive short submerging, if attended shortly after getting the water out, but two months means the engine is locked up tight and suitable only as a mooring weight. Don't try to turn it, just pull one of the heads, which frankly will be a waste of time, but you'll find the rings welded to the cylinder walls, the cylinder walls covered in rust and further disassembly will reveal lifters rusted to the cam, rods rusted to the crank, etc. If you don't turn the engine, which will do more damage, the block may be salvageable for a rebuild, depending on how deep the rusting is on the machined surfaces. Some of the internal piece may also be salvageable with re-machining. In all honesty, unless the engine has some special value to you, it's done and not worth rebuilding. If it is a special engine for what ever reason then all things can be made right, though much of the internals will need to be replaced. Bolt on accessories, like the starter, pumps, alternator, etc. are all rebuildable also, but it's not worth the effort, when a new unit can be had and bolted on. Sorry about your misfortune.

  4. Frosty

    Frosty Previous Member

    1 day/ change oil fuel, fresh battery, starter alternator --start it.

    2 months---not very likely, cheaper to buy a new one.

Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.