1987 Mercruiser 350 Mag

Discussion in 'Gas Engines' started by HipGnosis, Mar 21, 2014.

  1. HipGnosis
    Joined: Mar 2014
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    Location: Leucadia

    HipGnosis New Member

    Considering buying a boat with a fairly clean looking 350. What else should I test before I lay out the dough?
  2. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Welcome to the forum.

    Drive the boat. If you can't test drive the boat, it's value should be half'd, simply because you can't tell what you have.

    Walk around inside the boat feeling for soft spots under foot. If there are any, half the price, because the sole and likely the stringers are rotten. Turn on and operate every device on the boat. Check the fuses or breakers and look for shoddy wiring repairs (very common and indicative of the boat's care history). If you can splash the boat, insist on lower the drive into a garbage can full of water and fire the puppy up. It should fire right up, no smoke and it should engage in forward and reverse without any grinding, clanking, etc. Check for tilt/trim hose and line leaks. Hows the pump sound. The general condition of the boat should give you a clue about the owner and in turn the care the boat has seen. If it look terrible, it probably is.

    Take someone along that knows boats, has owned several and is knowledgeable about drives to.
  3. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Also check the steering. It should be smooth. If it has power steering, you need to fire the engine to make it move without a lot of effort. Also, shake the outdrive side to side and up and down to check for play. If it is a salt water boat, consider taking a riser off to check for corrosion.
  4. Westfield 11
    Joined: Apr 2008
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    Location: Los Angeles

    Westfield 11 Senior Member

    Do a leak down compression test, not a pumping compression test. That will tell you the condition of both valves and the rings. All you need is an air source and the tester. This way you test the engine and not the battery and starter. Pull the dipstick and look for water, open the valve cover breather and look for water there too. if possible bring a new oil filter and take the old one home. Cut it open swirl the contents in gas, solvent or diesel and filter through a coffee filter, look for metal flakes.

    Take the top off the outdrive and inspect the oil for water. Check the oil in the gearbox for water.

    If the engine is warm walk away and come back the next day when it is cold. If the Filter and oils are brand new you have to wonder what they are trying to hide.....

  5. HipGnosis
    Joined: Mar 2014
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    Location: Leucadia

    HipGnosis New Member

    Thanks all for the great advice.
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