My Merc 500 has 3 original coils and one that had been replaced, recently that same newer coil failed again. To my knowlege, this is just one of those things that can happen and I can think of almost nothing that would cause it. The coil failed with a hole burnt in the side where it arced out of the insulated encapsulation to the aluminum shield that holds the coil in.
The motor has been sitting for 12 years and I recently started running it again, the newer coil could have been installed who knows, 12-15 years ago, but it still looks new. This one cylinder also has a funky connector where the plug wire goes up into the coil, and it had a bad plug wire. It looks like someone in the past tried to adapt an automotive connector instead of that cap looking thing that this outboard uses. I'm wondering if the loss of secondary connection would cause the coil to go into meltdown? This coil was good when I checked it 2 weeks ago, since that time the plugs were changed and the plug wire was broken. It was run for a few minutes before I discovered the broken plug wire. Actually some yahoo had replaced that one wire with a solid spark plug wire, they're all new now.
This is a Thunderbolt ingition and I would think that the cylinder either is told to fire or its not. After all, its nothing but a switched voltage into a coil, right?
The motor has been sitting for 12 years and I recently started running it again, the newer coil could have been installed who knows, 12-15 years ago, but it still looks new. This one cylinder also has a funky connector where the plug wire goes up into the coil, and it had a bad plug wire. It looks like someone in the past tried to adapt an automotive connector instead of that cap looking thing that this outboard uses. I'm wondering if the loss of secondary connection would cause the coil to go into meltdown? This coil was good when I checked it 2 weeks ago, since that time the plugs were changed and the plug wire was broken. It was run for a few minutes before I discovered the broken plug wire. Actually some yahoo had replaced that one wire with a solid spark plug wire, they're all new now.
This is a Thunderbolt ingition and I would think that the cylinder either is told to fire or its not. After all, its nothing but a switched voltage into a coil, right?
