[Bushwacker]

The plug fouling problem you're having most likely signals a weak ignition. Had the same thing happen on my old 1975 V-4 when power pack was going out. It was a magneto type CD system with single power pack. Put in fresh plugs in Green Turtle Cay, Bahamas just before return trip. Put it on plane and stayed there for about 4 hrs, all the way to Mangrove Cay, where we stopped for lunch. As soon as I dropped off plane, it started running rough. Had lost both cylinders on one bank. Changed those 2 plugs, put it back on plane, and ran on to West End where I installed spare power pack and changed those same 2 plugs. (once they're fouled, they won't fire, even with new power pack!)

Suggest you make up a simple spark checker which will check entire ignition system in about 5 seconds! Got the idea from a tool in the OMC manual. Gather materials as follows:
1. Large PVC cap (I used 2.5" for my V-4; probably should go larger for V-6)
2. Seven 1/4-20 SS machine screws, approx. 3" long; could be shorter for a V-4.
3. One 1/4-20 nut.
4. ~1' length of 12-14 ga solid copper wire with alligator clip on one end.
5. Adult beverage of choice.

Drill hole in center of cap, tap for a 1/4-20 thread. Spray inside of cap with flat black paint. Thread a screw into cap with a ground wire under screw head on outside of cap. This will be your ground electrode extending inside the length of the cap; I used the heavy solid wire because it helps support cap on engine. Now install 6 more equally spaced threaded holes around circumference of cap, pointing at the center electrode. Holes should be about 1/2" from end of cap. Cut the heads off the remaining 6 screws and install in cap. Use the nut to set a 7/16" gap between each radial screw and center electrode. Need to have at least 1.25" of threads sticking out of cap. Can also use a nut on each stud to lock it's position/gap in cap.

To use, simply connect a plug lead to each of the 6 "studs" and attach center electrode wire to a good ground on engine. I used the lifting ring attached to top of block on my V-4. If boat is not in water, hook up flushing attachment and turn on water. (Never even crank the engine with a dry water pump if you want good life from the pump!) Now have an assistant crank the engine (or turn on ignition and use a remote starter switch to jump solenoid) and watch for a spark between each of the 6 studs and center electrode. (Keep your hands away from cap during this test! A healthy system puts out about 40,000 volts!) If no spark at one or more wires, start checking for tight connections, bad coils, bad power pack, or bad sensor or charge coils in stator assembly. Now celebrate finding the problem by enjoying adult beverage!

Like Fr. Frank, I bought the entire ignition system off a blown motor and carried the parts as spares on my Bahama trips. The spec in the OMC book called for a 7/16 gap, but a healthy system should jump a 1/2" gap. The black paint inside cap makes it easier to see the sparks in bright sunlight! Enjoy! Denny