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    5.7L Black Scorpion running rough after warmed up

    Caddmann, my 89 Merc 5.7 started acting up over the weekend with the same symptoms. I had an issue like that a couple years back on which I found bad spark plugs to be the culprit. Now I've got inconsistent bogging at high power settings and occasional chugging / cutting out at idle. I was...
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    Motor Knock

    I had a sporadic, non rhythmic clatter a while back that I was concerned was engine knock. After some investigation, I found a bad water shutter to be the culprit.
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    Merc 5.7 High Temps on Intake Manifold

    Bondo, I appreciate the reply. That’s a relief, and surprising actually. I can’t find a good schematic for how the raw water routes through the engine block. So that I’m understanding correctly...the way it’s cooled/routed, there is no heat exchange in that portion of the block/intake manifold?
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    Merc 5.7 High Temps on Intake Manifold

    Hey all, I ran my 1989 Merc 5.7 Alpha One this morning after my post winter maintenance and noticed a little bit of smoke/steam rising from the starboard side of the intake manifold. This was after running it pretty hard for 5-10 min, with the boat running great and everything seemingly...
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