Shift Interlock?

[Caveman Charlie]

I'm converting my breaker point ignition over to Pertronx HEI on my 73 Silverline I/O with mercrusier 140. One wire from the negative- side of the coil goes to the points. But, There are two extra wires coming off the negative - side of the coil. One goes the the tachometer. No problem there. But, the other one (according the the wiring diagram) runs to a shift interlock and then to a ground. What does this shift interlock do? Should I just leave it hooked up? Or, would it be best to unhook it now that I'm running a new 12 volt positive wire from the ignition switch back to the positive + side of the coil.


(This is not a neutral safety switch. That is in a different place.)

 

[Bondo]

Re: Shift Interlock?

Ayuh,........

If you disconnect it,.....
The Outdrive will Not come out of Gear.......

It's the Shift Interupt Switch...........

 

[Caveman Charlie]

Re: Shift Interlock?

Well, it's printed as Shift Interlock Switch. And it doesn't seem to wired into the Trim control at all. There is a Reverse Interlock Switch that is wired into the trim control. But, this is a totally different switch.

There does not seem to be any shift interrupt switch on this boat. Although the directions that came with the pertronix unit did say that some OMC boats have such a switch. Whatever that is. What's a OMC boat?

 

[Silvertip]

Re: Shift Interlock?

OMC = Outboard Marine Corporation (as in Johnson/Evinrude - boats, snowmobiles, outdrives, etc.) until they went belly up and acquired by BRP = Bombardier Recreational Products with only Evinrude and Johnson outboards as survivors. A shift interrupter switch momentarily drops the ignition while shifting to reduce drive train strain and hence ease the shifting process.