Mercruiser shifting problem. Help please.

[nes-cv23]

After pulling the motor out of blue and rebuilding it.. It all went back together great and runs awesome. The problem I have is the shifting must be out of place or something I've misaligned. The shifter goes in and out or forward and reverse very well and with a spin of the prop (by hand) I can tell it locks in gear good, also with the motor running on muffs in the driveway it goes in and out of gear well also, the problem is when I went for a test drive on the lake it went into gear well and ran great, but when I came in to the dock it would not come out of gear until I shut the motor off and then popped out of gear and was able to start it again and the same thing happens when I put it back in gear.. Would not come out of gear until I shut off motor again.   What do I have wrong that would cause it to not go to neutral until the motors not running?    Idle set at around 600.   Chev v-8 with mercruiser  outdrive.   

[75starflight]

Your shift cable adjustment is off and not engaging the shift interrupt switch. I had the same problem with phoenix last year.

[Rich_V174SS]

Your shift interrupter switch must have gotten disconnected in the removal/reinstallation process. It's the switch mounted on the shift plate in the engine bay where the shift cables are connected to each other with a lever. The switch causes a momentary stall of the engine when tension on the shift cable is produced, tension caused by trying to disengage the gears while there's water resistance on the prop. Of the two wires that go to the switch, one is a ground and the other connects to the negative terminal of the ignition coil.

[nes-cv23]

That makes more sense.. I upgraded the distributor to a msd brand hei and removed the old points and coil.... What would I have to do to get it to work again?  Connect that switch to the new distributor  somehow?

[dorelse]

Yes you will.  I'm running an MSD Streetfire, and you'll need to complete that circuit.

[Rich_V174SS]

You have to find the negative terminal on the new coil that connects to your tachometer, this will be your connection point for the shift interrupt switch.

[nes-cv23]

It is also a msd street fire dist.   And all I have to do is connect the switch to the tac. Wire And that will interrupt it long enough to work?  ...   One wire of the switch to ground and the other wire to the tac. Wire on the new dist.? Do I have that right?

[Rich_V174SS]

Yes. These wires should already be part of the engine wire harness. I would have thought connecting the tach wire lead to the HEI would also have connected the shift interrupt, they're normally connected together within the harness bundle. Perhaps only on the later ones.

[dorelse]

Your MSD will have a (+) and (-) take off and should have had the pigtails included with it.    On mine, I had 3 wires, the tach, interrupt switch and (-) off the MSD.  Connected them together and it all works.

[nes-cv23]

I get it now.   I separated those wires so it would only go to the tac.  I'll reconnect it and see what happens   Thanks for the help, I knew you guys would know what to do... Any more talk would be great if anyone else thinks of something else, thanks again!

[Plugcheck]

    My drive system connects the interrupt directly to the coil negative.  In any case, you're simply inhibiting any spark being made from the coil.   Back when I raced, we tied the oil pressure switch to the coil negative.  No oil pressure=no spark.