Shift Interrupter Wiring (Red Or Rich)

[fireman24mn]

 Got the new motor installed in the 18 and got if fired up this morn. I need to get the shift interrupter wired and working properly it never did before. I am thinking that in Pic 1 the empty screw in the lower Right of the pic. Should this terminal be wired to the +Positive terminal on the distributor. Does the other wiring look right or is it all messed up. Like I said it has never worked in this boat. The other 2 wires that are not orange are just ground wires.

[scott r bishop]

Wish I could be of help with the wiring, but if you're gonna be out on the lake at all tonight testing her out let me know, I plan to get out there about 7 or so.

[Rich_V174SS]

There should only be two wires on the switch, the two that complete a circuit when the switch is pressed. Use an ohm meter to determine which two that will show continuity when the switch is pressed. For standard points ignition one terminal of the switch goes to engine ground and I think you've got that situated on the left side of the first pic. The other switch terminal goes to the negative post of the ignition coil, not the positive post or else that's a direct short to ground. The negative terminal of the coil should also have the grey wire on it that goes to the tachometer and a black wire that goes to the points terminal in the distributor. Because you've got aftermarket ignition I think this setup may still apply. If you had Mercruiser Thunderbolt IV or V ignition with the optical sensor then the non-grounded terminal of the switch goes to the white/green wire terminal of the sensor in the distributor.

[OleRed]

That is GM automotive distributor, with a vacumn advance, one hot wire activates it, and the tach wire is there also, and it's not a bad thing to use it in a boat, in my opinion, as long as the blowers are used as recomended, or it could be dangerous. just because of the open space in the distributor housing around the vacumn advance mechinism,  the detent switch with that ignition only requires one wire from the NEGITIVE side of the coil, to the detent switch, connected to the ungronded side of the terminal block, the other side, coming out of the little terminal block, comes from the detent switch, it is grounded when activated, to the shift plate, causing an interuption in current when the shift plate requires the interuption.

[fireman24mn]

If i am understanding this correct I need to attach the wire from the interrupter to the negative on the coil?
The 2 orange wires do they look correct? or do you think that the one on the Rh side of the pic should be hooked to the Dis. negative.
Last on this distrubutor there is only a power and a tach lead. Do i need to cut one of the other wires and hook into that or do i splice into the power/positive feed. Thanks

[Rich_V174SS]

Of the two orange wires connected to the switch one needs to connect to a ground terminal, the other needs to be tied into the negative of the ignition coil. That wire can be connected to the tachometer wire connection. Do not connect anything to the positive feed for the coil.

But first you need to check that right-hand screw on the small terminal block is not in contact with ground on the shift plate. If it is then you need to remove the ground wires from the left-hand screw and put them on the right-hand screw. Then connect the left-hand orange wire to the negative/tach wire terminal of the coil. The tach wire and switch wire connected together need to be isolated from the engine ground, that's why that screw hangs over the edge of the shift plate. I see two wires on that left-hand screw, one black and the other (?). Where do those wires connect to? If they are connected to engine ground then take them off that screw and put them on the other side of that terminal block, on the other screw. Make sense?

[fireman24mn]

One of the wires was the tach feed so I hooked that up to the tach wire so now my tach works. So if I understand I need to figure out what side interrupts and hook that to the tach wire.

[Rich_V174SS]

It doesn't matter which side of the switch the tach wire connects to. What matters is where the ground wires are connected. The tach wire and one orange wire need to be connected together on the isolated terminal screw screwed into plastic. The other orange wire and ground wire go on the other terminal screw that's screwed through the plastic and into metal. You also need to figure out if you've got the orange wires on the correct terminals on the switch or else it could operate backwards, you need an ohm meter to determine the correct screws by checking continuity with the switch closed.