’79 9.9 OMC, Power pack CD2 question

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  • August 26, 2017 at 7:22 pm #8030
    Alan
    Participant

      Hello to all;
      My faithful 9.9, (w/ a 15 HP carb) is running, (remarkably well) on one cylinder. Pulled the top spark wire and it died immediately. Pulled the lower, and there was no difference. Testing w/ ohm meter shows lower coil is an open circuit; I’ll replace both w/ OMC/BRP coils. Unless someone wants to recommend otherwise.

      My question on the power pack CD. I know nothing about electronic ignition, but it looks like the corner got hot and crispy. The wire next to it looks fused on.

      Does this need to be replaced? If there is any doubt, out it will go. This motor has pulled my fat outta the fire twice now. Once, it got us back to the harbor when the main motor quit, several miles out on the Pacific. Don’t even want to think about how much a marine towing service would have charged.

      All opinions welcome.
      Many thanks and happy motoring to all.
      Alan

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      August 26, 2017 at 9:44 pm #63837
      johnyrude200
      Participant

        The first few years of this motor did not include a fiber washer between the pack and the exhaust bypass cover bosses. You should remove the pack and place fiber washers between that and the powerhead to reduce the melting risk. The ground can be put on the upper left exhaust bypass cover or another convenient location; be sure to use a star washer to insure a good ‘grab’ of the pack grounding wire.

        If the pack wire(s) are fused to the pack, replace them for obvious reasons, because you’re on borrowed time.

        If you’re SURE you have a bad coil, then just replace that coil and the pack. OR, you can swap leads from the pack to the coils to see if you have a 1/2 dead powerpack, which is fairly common. This will rule out a bad lower or upper coil.

        If you had NO SPARK, then you need to look at the pack or the charge coil (ohm it out). They are relatively simple ignition systems to figure out what is wrong.

        Keep in mind all you need is a bad or misconfigured ground for any of these components to shut off ignition power. Over the years people pull coils and don’t bother to replace components correctly. Stupid things such as that can stop the ignition system, or corrosion build up, mouse pee, salt, etc. Doesn’t take much to stop it but also doesn’t take much to correct it. Much easier to deal with than points, condensers, and coils in terms of diagnosing a problem. Fewer points to fail.

        Last food for thought: if that pack is melting down you should probably look at your cooling system. Use an electronic thermometer (laser type) and run the motor WOT for 5 mins. Check the top of the cylinders, and the sides of the cylinders (on the port side near the head). It shouldn’t be getting much above 150°. Make sure your thermostat isn’t stuck shut or the water pump has failed, or you might have a collapsed water tube grommet under the powerhead (unusual for that year because they switched to a more troublesome style in 1980 if memory serves correct). Possible to just flat out have a clog st tge thermostat too. Leaves, sand, salt, and random bad luck do funny things to the small motors.

        August 26, 2017 at 10:55 pm #63841
        Alan
        Participant

          Thanks Johnnyrude!
          I’m not sure how best to test stuff; guidance will be appreciated.

          Hmmm, I didn’t even know it had a, "charge coil". Since it runs remarkably well on the one cylinder, may I assume this is OK?

          If not; Marineengine.com says these are for rope start models. Mine has rope start, but electric start, too. Not sure what category I fall under. Assuming I have one; any pointers as to which wires to check w/ the ohm meter?

          All connections seem clean and tight, but I’ll re-check.

          I’ll try swapping the wires from the powerpack to the coils, to see if the outage follows. Although, since I get different readings on the coils themselves, I do suspect the lower one.

          Good idea to mount the powerpack w/ fiber washers. I wouldn’t be surprised if it got warm at some point, but it doesn’t look recent. I’ve replaced the impeller and both tube grommets; they were a bit swollen, but not as bad as some of the ones I’ve seen. I’ll certainly point the thermometer at it after a full warm up, at some point. Seems to be pumping fine, but I’ll keep the thermostat in mind and check the temp.

          All opinions welcome.
          Appreciated;
          Alan

          August 27, 2017 at 12:03 am #63848
          johnyrude200
          Participant

            With the cooling system, the overboard water indicator doesnt mean the motor is cooling. It only means the pump is working. You should see a decent amount of spray from the upper exhaust housing relief hole even when the motor is cold. Not a huge amount, but more than just a dribble. That is an indicator that the water is actually circulating.

            With the coil under the flywheel, Id buy a service manual if you plan to maintain the motor. If memory serves correct it should ohm out at 575 +/- 25. You have spark so I doubt that is the problem unless its a thin weak spark gapped at 1/2".

            The rest is clockwork in terms of figuring out the problem.

            Check my EDITS of my first post….

            August 27, 2017 at 3:24 pm #63901
            fleetwin
            Participant

              US Member

              Like JR says, that motor has been badly overheated at some point in its career, and that is why the powerpack wiring is melted that way, and that is why the paint is discolored as well.
              Was/is this engine used in salt water? 1979 was the first year of the faulty water tube grommet design, so the cooling system is definitely questionable unless you know for sure this work has been done already. You make it sound like this engine is used extensively, sometimes on open water. These are great engines, but like most machines, has its weak link, which is the upper water tube grommet. This is a big job, because the powerhead has to come off, rusted corroded hardware will create big headaches if the engine has been used in salt water.
              As for the engine running on one cylinder, the possibilities are many. Certainly replace the one bad coil if it has shown an open circuit, is this coil on the cylinder that is not firing? Keep in mind that the problem might be just the melted wiring as well, a shorted or open connection/lead might be all that is wrong. Check all connections, and grounds, using the low ohms scale.
              So, if you are planning to keep the engine, and want it to be trouble free, than I would urge you to get the cooling system overhaul done by someone with experience on these engines. The melted powerpack mount isn’t a big concern, but electrical components can surely be affected by excessive heat.
              Please let me know if you have any other questions or concerns, this is a great old engine, and is worth an investment in quality maintenance.

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