My new Seafari
 

Well I just couldnt pass up this nice little 78 Seafari. It has a 175 Merc Black max and a 2010 Dual axel trailer. Its pretty nice for its age and the price was good. looking forward to some fishin and crusin Seafari style!

Nice score..looks to be in great shape and trailer is a perfect match!
-Fred

Great boat 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?

Is this covered under ACA for medical needs?

Mr. Shrimpin will be along shortly. Got a manual?

Nice find,
GFS

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

Thanks Denny!

http://issuu.com/cdielectronics/docs...044661/2001100

page 83-84

would be interesting to know if you have spark on any of the cylinders.

my guess is no.


do you have a kill switch lanyard on your control set? (have to ask this to cover all bases.)

I had a cdi box do something similar to this one time on a dirt bike, ran fine cold or till stopped then no fire to restart or really weak fire. Changed the cdi and fixed the problem. Just a guess? I also had a 1980 Johnson 70hp that had a no fire issue and it was the cdi box.

Check for spark at the plugs - all of them. Then trace backwards, i.e.; coils, switchbox/powerpack, trigger, etcetera.

Having happily lived with Mercs most of my life, and having undergone EXACTLY that scenario with a '92 XR4, my guess is trigger or switchbox. But that's only a guess.

My wife got rather upset when for the 2nd time we were 9-10 miles offshore and the motor wouldn't start 'til it cooled down completely. :-(

My motor had a bad trigger due to deterioration of the wiring insulation. During diagnostics, we discovered my switchbox wasn't very good, either. Changed those out and the motor ran perfectly another 5 years/300 hours before I repowered with a 90 Optimax.