I need some help installing a shift interrupt on a multi port and multi coil engine , I have a switch that can be used on a momentary open or closed circuit ,but not sure what to attach it to any help would be grateful. Thanks Jeff

What drive?

Are you using an Alpha drive? The Alphas only good to about 300HP. With a 496, your going to be putting at least 375HP through it. That said, you would need not just the switch but the whole shift bracket and assembly.

As far as what to connect the switch to...the only thing I can think of is to have it open up the crank sensor circuit, which will generate a crank sensor fault code and an audio alarm every time the switch is activated.

Dave

Dave, its an alpha drive until next years upgrade , I messed around with a GM Van with a 8.1 disconnected the cam senser and the motor made no change at all except for the check engine light that came on. I know the delfi system uses a interrupt system but not sure how or what they are opening. Thanks Jeff

Does your 496 use a mefi or mototron?

Dick,
It's a Motorola ECM

Jeff,
At this time there are no multicoil (DIS) marine engines that use a shift interrupt switch. The current Mercruiser 5.0 and 5.7 engines are a single coil design that use a three wire interrupt switch that is powered by the 5 volt sensor circuit and sends a signal directly to the ECM.

There is an "Emergency Stop" circuit that goes from the CANbus connector to pin B23 of the ECM (Yel/Blk wire). Not sure exactly how, but maybe it could be used for interrupting.

Dave

Thinking along Dave_N's lines, if you can turn the boat off with a single wire kill switch or ignition switch then that seems like it could be worked into the shift interupt for the temporary delay you need. Don't worry about your Alpha, use a low pitch three blade prop and let it rev and plane off easy and you'll be fine, it could last years with easy treatment. Bravo upgrade is an easy job tho.

Dave is this circuit used while serviceing and do they ground pin 23 , I was thinking of opening one coil from each bank or opening the cam and crank together. I know mefi 4 have a shift interrupt for a 496 but can't get any info on what they are doing. If you have any leads on someone that maybe able to help it would be grafeful. Thanks Jeff