Re: 1998 5.0 merc.I/0
Man, do I remember a customers NEW boat that did the same thing.
Every 9 to 10 hours, it didn't matter if it was all in one day or over a 2 month period. The coil burned out.
We replaced every battery cable to the next size bigger, new distributor, new alternator, new engine wiring harness, new starter, new circuit breakers, many new OEM coils, and it still did it. The boat did have an AC system, and it was checked and was never used on the boat anyway.
Finally the lawyers got involved.
Everybody got sued.
Mercrusier finally gave him a new engine (EFI not carbed) new outdrive, new transom shield, new trim system. Boat Manufacurer replaced the complete engine harness and all instrument's, controls, cablels, switches etc.
Problem cured.
Now the fun part. Merc didn't want the engine/drive back (shipping from Alaska they didn't like). So we put it in another boat the shop had and used it for a work boat. and all of us ran the boat for 2 years and it never lost a coil.
To this day, we have no clue what cured the problem. But everything on the engine was the same as when we pulled it out of the original boat.
