Quote:
Originally Posted by Ryan
Thanks guys. Here's my only problem, it starts an runs like a top untill its runs between 20 minutes to an hour if I shut it off it won't restart. It's got fuel and spark but won't start. Put it on the trailer, and the next day starts right up, runs great, shut it off, won't start? Any thoughts?
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Ryan,
I'm no Merc expert, and Big Shrimpin may chime in with a better solution, but this scenario sounds a bad coil, although that motor should have one coil per cylinder, so it's unlikely all 6 coils would be bad. The general scenario for a bad coil is that they work fine when cold, but as they heat up and expand, small cracks in the coil winding's open up and no longer transmit current, giving you a weak or no spark. The OMC motors, and probably Mercs also, had trigger or sensor coils in the stator assembly; magnets in the flywheel would trigger a current/voltage in those sensor coils on every revolution which was used to fire the CD ignition system. If those sensor coils opened up when hot, it would probably shut down the whole ignition system. I'd get a manual and check continuity and resistance on those sensor coils after they're warmed up, and also check 'em for shorts to ground.
I once had an old 1958 Johnson 50 hp V-4 with a magneto ignition system. It had a bad coil in the magneto which developed enough voltage at high speed that it ran fine even when fully warmed up, but if you slowed down to idle, the voltage would drop, motor would die and refuse to start until it cooled down. A friend had a slightly later V-4 with a conventional battery/single coil/points/distributor ignition system. His coil died several miles offshore, but he made it back in by taking cover off motor and packing ice around the coil!
Nice find BTW! Looks like a very clean rig! Notice you have the gas tank hatch off. The fuel tank is so easy to remove on a Seafari that it's worth doing, if for no other reason than to check condition of the hoses and to make sure there are no imminent problems. I pulled mine when I first got the boat which was only 3 years old at the time. Discovered that the aluminum tank was resting on top of a brass nut that had evidently been dropped into the gas tank area at the factory before the tank was installed! Galvanic action was starting to eat away at the tank under the nut, but I caught it, repaired it before it had gone too far, and painted entire tank w/epoxy. Thanks to that inspection, I'm still running the original tank, almost 39 years later! Denny