I have a 1979 Oday 28, with a 15hp OMC Zephyr Saildrive. This past weekend while motoring I started hearing this kind of metallic clicking sound, and the engine was stuttering in time with the clicking. I pulled off the companion steps to take a look at the engine and saw that the clicking sound was being made by the top coil arching to the lower coils mounting bolt. (The OMC is a two cylinder with each plug having it's own coil assembly mounted one above the other.) I unscrewed the bolt of the lower coil and found about 1/3rd of a plastic washer left that had hardened and broken apart. It looked as though the plastic washer was supposed to insulate the coil assembly from the block (although I don't understand why that would be needed), and when I looked at the parts list for the coil assemblies, it lists metal lock washers, not plastic washers. For the time being, I simply unmounted the lower coil from the block, letting it hang by it's plug connector, and that stopped the problem. I plan on picking up some plastic replacement washers to see if that actually does fix it, but I was wondering if maybe it's a problem with one of the coils themselves, and not the washer at all. Has anyone experienced anything like this before with coils? especially with an OMC engine?