Re: ’79 9.9 OMC, Power pack CD2 question

[Don]

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.