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Re: MD7A overheating - update

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  • Sid
    Thought I would provide an update. Never did discover the source of the noises, but all the easy fixes failed, so I had to remove the exhaust manifold... R&R
    Message 1 of 7 , Jun 24, 2013
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      Thought I would provide an update. Never did discover the source of the noises, but all the easy fixes failed, so I had to remove the exhaust manifold... R&R was a terrible, messy, toxic job (don't think I could have done it with gloves, so I probably took a few years off my life expectancy), but there were severe blockages in the passages there, and after cleaning out the muck and reassembling stuff (worse than disassembly, you need at least 6 arms), I am happy to report that the engine is running extremely cool now. I haven't actually done any motoring, but running for about 1/2 hour at up to 2200 rpm, the engine temp barely got into the green.

      I made pretty good use of the profanasaurus, but it does give one a great feeling to take an engine apart, put it back together, and it starts right up!

      Sid
      Passing Fancy
      S28-II #319

      --- In Sabresailboat@yahoogroups.com, Dave Lochner <davelochner@...> wrote:
      >
      > Sid,
      >
      > Dive on your keel, see if there is a scrape mark. You might have hit some semi-submerged object, like a waterlogged chunk of wood.
      >
      > Dave
      >
      >
      > On Jun 17, 2013, at 8:09 PM, Sid wrote:
      >
      > > Thanks Dave...
      > >
      > > That was going to be my next step. I did the easy stuff first. I did noticed a bit of leakage around the strainer, as well as around the Speedseal, so I replaced the strainer gasket (there was a bit of crud in the strainer), and the o-ring and impeller. The result of the above was - maybe - a little improvement, but I guess I will have to tackle the thermostat next.
      > >
      > > Last time I removed the thermostat housing, two years ago, there was so much crud in there that I found orifices I didn't even know were there. Cleaning that out did produce a great improvement at that time, so I hope that will do the same this time as well. I assume there is crud in the interior of the engine as well that can only be removed with a full engine flush.
      > >
      > > I am quite puzzled. though, about what the clunk I heard might have been. It certainly sounded ominous.
      > >
      > > Sid
      > >
      > > --- In Sabresailboat@yahoogroups.com, DAVID LOCHNER <davelochner@> wrote:
      > > >
      > > > Sid,
      > > >
      > > > Check the thermostat and the thermostat housing for crud. If the thermostat is not opening you will over heat the engine. There is a bypass in the cooling system that allows water to by pass the engined when he thermostat is closed.
      > > >
      > > > Dave
      > > >
      > > >
      > > > On Jun 17, 2013, at 9:14 AM, Sid <xawdisney@> wrote:
      > > >
      > > > > Was motoring along the other day, and noticed the engine running a bit warmer than usual, when suddenly we heard a thud from down below. Sounded like transmission jumping out of gear, but there was no change in our motion, or and noticeable changes in engine speed or any additional sounds out of the ordinary.. As we continued along, I noticed that the engine temp was approaching the red, so I shifted to neutral to let it cool back down which it did, slowly, but couldn't keep it in gear very long at a time.
      > > > >
      > > > > This is a raw water cooled engine, and there was a reasonable flow out the back, though when I reached down to touch it, the exhaust water was only lukewarm. I expected it to be a bit warmer.
      > > > >
      > > > > Any ideas?
      > > > >
      > > > > Sid
      > > > > Passing Fancy
      > > > > S-28 II #319
      > > > >
      > > > >
      > > >
      > >
      > >
      >
    • christopher
      Sid, Good job. The MD7A is an excellent engine. Keep it cool and it will serve you well. Install fresh water cooling and it could outlast the rest of the
      Message 2 of 7 , Jun 25, 2013
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        Sid,
        Good job. The MD7A is an excellent engine. Keep it cool and it will serve you well. Install fresh water cooling and it could outlast the rest of the boat.

        --- In Sabresailboat@yahoogroups.com, "Sid" <xawdisney@...> wrote:
        >
        > Thought I would provide an update. Never did discover the source of the noises, but all the easy fixes failed, so I had to remove the exhaust manifold... R&R was a terrible, messy, toxic job (don't think I could have done it with gloves, so I probably took a few years off my life expectancy), but there were severe blockages in the passages there, and after cleaning out the muck and reassembling stuff (worse than disassembly, you need at least 6 arms), I am happy to report that the engine is running extremely cool now. I haven't actually done any motoring, but running for about 1/2 hour at up to 2200 rpm, the engine temp barely got into the green.
        >
        > I made pretty good use of the profanasaurus, but it does give one a great feeling to take an engine apart, put it back together, and it starts right up!
        >
        > Sid
        > Passing Fancy
        > S28-II #319
        >
        > --- In Sabresailboat@yahoogroups.com, Dave Lochner <davelochner@> wrote:
        > >
        > > Sid,
        > >
        > > Dive on your keel, see if there is a scrape mark. You might have hit some semi-submerged object, like a waterlogged chunk of wood.
        > >
        > > Dave
        > >
        > >
        > > On Jun 17, 2013, at 8:09 PM, Sid wrote:
        > >
        > > > Thanks Dave...
        > > >
        > > > That was going to be my next step. I did the easy stuff first. I did noticed a bit of leakage around the strainer, as well as around the Speedseal, so I replaced the strainer gasket (there was a bit of crud in the strainer), and the o-ring and impeller. The result of the above was - maybe - a little improvement, but I guess I will have to tackle the thermostat next.
        > > >
        > > > Last time I removed the thermostat housing, two years ago, there was so much crud in there that I found orifices I didn't even know were there. Cleaning that out did produce a great improvement at that time, so I hope that will do the same this time as well. I assume there is crud in the interior of the engine as well that can only be removed with a full engine flush.
        > > >
        > > > I am quite puzzled. though, about what the clunk I heard might have been. It certainly sounded ominous.
        > > >
        > > > Sid
        > > >
        > > > --- In Sabresailboat@yahoogroups.com, DAVID LOCHNER <davelochner@> wrote:
        > > > >
        > > > > Sid,
        > > > >
        > > > > Check the thermostat and the thermostat housing for crud. If the thermostat is not opening you will over heat the engine. There is a bypass in the cooling system that allows water to by pass the engined when he thermostat is closed.
        > > > >
        > > > > Dave
        > > > >
        > > > >
        > > > > On Jun 17, 2013, at 9:14 AM, Sid <xawdisney@> wrote:
        > > > >
        > > > > > Was motoring along the other day, and noticed the engine running a bit warmer than usual, when suddenly we heard a thud from down below. Sounded like transmission jumping out of gear, but there was no change in our motion, or and noticeable changes in engine speed or any additional sounds out of the ordinary.. As we continued along, I noticed that the engine temp was approaching the red, so I shifted to neutral to let it cool back down which it did, slowly, but couldn't keep it in gear very long at a time.
        > > > > >
        > > > > > This is a raw water cooled engine, and there was a reasonable flow out the back, though when I reached down to touch it, the exhaust water was only lukewarm. I expected it to be a bit warmer.
        > > > > >
        > > > > > Any ideas?
        > > > > >
        > > > > > Sid
        > > > > > Passing Fancy
        > > > > > S-28 II #319
        > > > > >
        > > > > >
        > > > >
        > > >
        > > >
        > >
        >
      • jack horner
        I understand Christopher , when i removed my manifold it was 30 years shoot !  I went to home depot and made one from black iron parts.  I had it  ceramic
        Message 3 of 7 , Jun 27, 2013
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          I understand Christopher , when i removed my manifold it was 30 years shoot !  I went to home depot and made one from black iron parts.  I had it  ceramic coated on the inside and 8 years later  its still in great shape. Small money compared to SS from Volvo !
           Lee Nicholas   MD7A  S 28   fla


          From: christopher <cercole@...>
          To: Sabresailboat@yahoogroups.com
          Sent: Tuesday, June 25, 2013 9:59 AM
          Subject: [SabreSailboat] Re: MD7A overheating - update

           
          Sid,
          Good job. The MD7A is an excellent engine. Keep it cool and it will serve you well. Install fresh water cooling and it could outlast the rest of the boat.

          --- In Sabresailboat@yahoogroups.com, "Sid" <xawdisney@...> wrote:
          >
          > Thought I would provide an update. Never did discover the source of the noises, but all the easy fixes failed, so I had to remove the exhaust manifold... R&R was a terrible, messy, toxic job (don't think I could have done it with gloves, so I probably took a few years off my life expectancy), but there were severe blockages in the passages there, and after cleaning out the muck and reassembling stuff (worse than disassembly, you need at least 6 arms), I am happy to report that the engine is running extremely cool now. I haven't actually done any motoring, but running for about 1/2 hour at up to 2200 rpm, the engine temp barely got into the green.
          >
          > I made pretty good use of the profanasaurus, but it does give one a great feeling to take an engine apart, put it back together, and it starts right up!
          >
          > Sid
          > Passing Fancy
          > S28-II #319
          >
          > --- In Sabresailboat@yahoogroups.com, Dave Lochner <davelochner@> wrote:
          > >
          > > Sid,
          > >
          > > Dive on your keel, see if there is a scrape mark. You might have hit some semi-submerged object, like a waterlogged chunk of wood.
          > >
          > > Dave
          > >
          > >
          > > On Jun 17, 2013, at 8:09 PM, Sid wrote:
          > >
          > > > Thanks Dave...
          > > >
          > > > That was going to be my next step. I did the easy stuff first. I did noticed a bit of leakage around the strainer, as well as around the Speedseal, so I replaced the strainer gasket (there was a bit of crud in the strainer), and the o-ring and impeller. The result of the above was - maybe - a little improvement, but I guess I will have to tackle the thermostat next.
          > > >
          > > > Last time I removed the thermostat housing, two years ago, there was so much crud in there that I found orifices I didn't even know were there. Cleaning that out did produce a great improvement at that time, so I hope that will do the same this time as well. I assume there is crud in the interior of the engine as well that can only be removed with a full engine flush.
          > > >
          > > > I am quite puzzled. though, about what the clunk I heard might have been. It certainly sounded ominous.
          > > >
          > > > Sid
          > > >
          > > > --- In Sabresailboat@yahoogroups.com, DAVID LOCHNER <davelochner@> wrote:
          > > > >
          > > > > Sid,
          > > > >
          > > > > Check the thermostat and the thermostat housing for crud. If the thermostat is not opening you will over heat the engine. There is a bypass in the cooling system that allows water to by pass the engined when he thermostat is closed.
          > > > >
          > > > > Dave
          > > > >
          > > > >
          > > > > On Jun 17, 2013, at 9:14 AM, Sid <xawdisney@> wrote:
          > > > >
          > > > > > Was motoring along the other day, and noticed the engine running a bit warmer than usual, when suddenly we heard a thud from down below. Sounded like transmission jumping out of gear, but there was no change in our motion, or and noticeable changes in engine speed or any additional sounds out of the ordinary.. As we continued along, I noticed that the engine temp was approaching the red, so I shifted to neutral to let it cool back down which it did, slowly, but couldn't keep it in gear very long at a time.
          > > > > >
          > > > > > This is a raw water cooled engine, and there was a reasonable flow out the back, though when I reached down to touch it, the exhaust water was only lukewarm. I expected it to be a bit warmer.
          > > > > >
          > > > > > Any ideas?
          > > > > >
          > > > > > Sid
          > > > > > Passing Fancy
          > > > > > S-28 II #319
          > > > > >
          > > > > >
          > > > >
          > > >
          > > >
          > >
          >



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