Merc Ignition/Questine

[BRIAN73]

Hello Everyone:

I have a friend who just bought a 1988 Minx. It has a 350 mag with an alpha one. Yesterday he changed the stock merc ignition system over to a HEI. He want's to know what to do with the shift interrupter wire. How does he connect the Hei to the throttle to utilize that interrupt capabilty.
I have no experience at all with mercs, so I'm no help.
The local mechanic said that without the interrupter connected you will not be able to shift the boat into reverse. He claims that the purpose of this interrupter is to kill power to a couple of cylinders, so you can shift into reverse.
Can anyone out there help me with this problem.

Thank You In Advance.

Brian Englert

[Rootsy]

i donno exactly how you'd do it without tracing the wire to the source i do know that it grounds out the ignition itself... the shift interrupter momentarily kills the ignition system, ie shuts the motor off for a split second (like turning off the key and then back on in your car really quickly), when the small switch in the linkage is depressed. this unloads the gears in the sterndrive so that you can more so take it out of gear than putting it in gear, this applies both to forward and reverse shifting.

[GeneD]

This is tricky.
For one, I would like to know why he changed out the Thunderbolt ignition for an HEI? The Thunderbolt is an HEI to begin with. An '89 Merc should have a Thunderbolt IV. It puts out a ton of spark, has computerized timing, it's the best!
As for the shift interrupter, you will not be able to get out of forward gear without it.
Anyone who was at the Sanford Donzi Gathering a few years ago witnessed my problems with shifting. I couldn't get the damn thing to go INTO gear, due to the SS drive's inability to treat me right...anyway, I had to disconnect the shift interrupter to use the boat, and I had to shut the motor off to get it out of forward. Pain in the butt.
So, what to do?
The shift interrupter will ground out the ignition. You need to run a wire from the positive lead of the coil to the shift interrupter switch. This will cure the ailment.
But...seriously, put the old stuff back on. It was fine the way it was. Of course, if there is some mitigating circumstances on why he changed it out...