At one point yesterday, I actually did hear what sounded like an alternator bearing growling upon start up. It went away as soon as I raised hatch. Alternator always seems to be charging ok, but today I did notice some black residue around the front of the alternator housing. I pulled the belt and alt feels fine, spins freely. The belt was pretty loose, so that could have been the black residue (belt slipping).

I doubt that is the problem. It would run bad all the time, not just when hitting a wave. That's seconday voltage jumping across there, and it takes some pretty heavy corrosion to prevent 30 or 40 thousand volts from making it across.

My bet is on the main harness connection, even though it looks and feels good.

I had a tach circuit corrode and loosen up and start grounding out the ignition circuit on an old outboard runabout one time. It was a real bugger to sort out and I went thru the same crap you are. I decided to take the tach apart since it was the only guage dying and what do you know, there was the wire dangling off the circuit board touching the metal guage body, effectively grounding out the ignition circuit. A dab of solder and it was back in business.

Hey, I can dream can`t I ???


I`m really not expecting that to fix it. I hope to find the problem while running it on the hose tomorrow.

Any chance a neutral safety switch going bad could cause this?

What he said -or, shift interrupt vibrate out of place and cutting power?

Not telling you what to do at all....just making sugestions...but if it were me, I would try these things one at a time when you can run it on the hose. The main thing obviously is that you get it fixed, but for piece of mind, I would want to know what the problem was. Also I would use a nice heavy gauge jumper wire to test grounds as some wires may appear fine on the outside but be corroded on the inside.

Is this the device that the shift cable goes to , on top of the port-side valve cover ?

After sleeping on this , I think I`ll run it on the hose today after work and thoroughly check out these things.
I`d definately like to know for sure what the culprit is .

Unless it's an Alpha drive, there is no shift interrupt.