Motor damage on mercruiser 350?

Discussion in 'Powerboats' started by dogfish, Sep 2, 2007.

  1. dogfish
    Joined: Sep 2007
    Posts: 2
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    Location: florida

    dogfish New Member

    This boat was uncovered for a week and a half with rain water pouring into the bilge. At some point the batteries died( or shorted out) and the water started to fill up. When I drained the bildge today, the water level was above the first pulley and I assume the starter will be done. I am curious what I should look for before trying to run the motor. The fluids look good, but a trickle charger flashes a "check connection" light which will display on completely dead batteries that are hooked up correctly. Everything is drying out now for now and I will look at it in the morning. Thanks in advance for any advice!
  2. tuantom
    Joined: Jan 2005
    Posts: 182
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    Location: Chicago

    tuantom Senior Member

    I was in a similar spot once when a plastic bag found its way into the bilge so it could be sucked into the pump. Water was pretty much at the same level by time I got to it, though my batteries and electronic components stayed dry(ish). I changed the fluids (no sign of water though) and just opened up the starter and set it in the sun for a day or so - All was well. I can't speak first hand as to whether your batteries will come back or not; but I'd think they're toast.
  3. Frosty

    Frosty Previous Member

    Put a fresh battery on it. Its all you got to start it with, even if you could revive the old one which is possible, you may get stranded some place you dont want to be.
  4. dogfish
    Joined: Sep 2007
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    Location: florida

    dogfish New Member

    Thanks guys. I've got two batteries and I had previously wired in a trickle charger, but it will not charge completely dead batteries. so I had to use my jeep to get some juice in them and now they are charging on the boat. I should find out where I'm at in about an hour.

  5. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    This isn't that uncommon a problem and there are several things you should do to insure you don't damage things in an attempt to start her.

    Remove the starter, remove the covers (not the end plate unless you're familiar with reinstalling brushes) and squirt some "tuner cleaner" in each hole you find. Tuner cleaner is an electrical cleaner, that removes moisture, cleans contacts and doesn't leave a residue when dry, it's also non-conductive, unlike many penetrating oils (like WD-40). It's available at Radio Shack, electric supply shops and possibly from the big box stores. Reassemble the starter and mount it back on the engine.

    Check the oil, by backing off the drain plug, but do so slowly and watch carefully as the first thing that will come out (if water got into the block) will be water (oil floats). If there is any sign of water, you may want to take other actions, like "pickling the engine" which is filling it (completely) with oil, which forces water to the lower portions of the crankcase, where it can be drained off.

    In most cases, even if there's a little water in the oil, an oil (and filter) change will solve the problem. I usually R&R the oil and filter, then start up the engine, letting it run at around 1,200 RPM for several minutes to get plenty of heat in the motor. Shut down, drain and change the oil and filter again, then run the motor for 20 minutes to burn off any remaining moisture.

    Water can get in through a few different locations, a common one is the dip stick tube. If this is an I/O you may want to check the tilt/trim hydraulic fluid container, which is mounted low on the transom in most cases. It's amazing how water can seep into places, check everything you can find that may have been touched or covered by the water.
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