Alpha 1 Gen II - Shift cutout switch -how does it work

[big zeke]

Can someone please explain when I should and should not have continuity on this switch...the switch is new and the engine shifts smoothly into and out of gear but I thought this was supposed to interrupt the ignition momentarily when I come out of forward gear ( I`m assuming that means momentary continuity coming out of gear and no continuity otherwise). My switch has no continuity until I am about 25% throttle in forward and then it has full continuity from 24 - 100% in fwd. I`m testing continuity by disconnecting both sides of the switch, connecting a 2 amp source on the white wire and checking with a test light on the black wire for when the switch is continuous.

The boat seems to run fine, more of a curiosity than anything.

Thanks in advance for any replies
Zeke

 

[Don S]

Re: Alpha 1 Gen II - Shift cutout switch -how does it work

It's not a "Kill" switch, it's a shift interrupt switch, and here is what it's supposed to do.
HOW TO: How the Shift Interrupt system works*/ 288089

What engine do you have?

 

[ktbarrentine]

Re: Alpha 1 Gen II - Shift cutout switch -how does it work

If it aint broke...don't mess with it.... But it is good to get the intel from here, for when it does give you fits later (if ever). Are you trying to test this thing in or out of the water?

 

[Don S]

Re: Alpha 1 Gen II - Shift cutout switch -how does it work

My switch has no continuity until I am about 25% throttle in forward and then it has full continuity from 24 - 100% in fwd. I`m testing continuity by disconnecting both sides of the switch, connecting a 2 amp source on the white wire and checking with a test light on the black wire for when the switch is continuous.

Not exactly sure how you are testing continuity, or what the throttle has to do with it.

You test continuity by using an ohm meter, one test lead on each lead of the switch. When off, it will show no resistance and the switch is open. When you activate the switch you should see very low near 0 ohms.

 

[Another retired guy]

Re: Alpha 1 Gen II - Shift cutout switch -how does it work

The switch is normally in the "open" position allowing 12v power to the coil. When shifting from forward to neutral, the switch "closes" momentarily by grounding the circuit. This effectively stops the engine, thus removing thrust from the drive and allowing the clutch to disengage easily. This all happens so quickly that the brief interruption of power is not noticed.
If you have disconnected the wires from the switch and placed a tester between them, then you should be seeing 100% continuity.

 

[Don S]

Re: Alpha 1 Gen II - Shift cutout switch -how does it work

The switch is normally in the "open" position allowing 12v power to the coil. When shifting from forward to neutral, the switch "closes" momentarily by grounding the circuit.

Not exactly, it does not "Allow" 12 V to the coil, and is not in the purple wire to the coils + terminal.

On some systems it grounds the negative side of the coil, on some it puts power to the ignition module.

 

[big zeke]

Re: Alpha 1 Gen II - Shift cutout switch -how does it work

Sorry abt that...it's a 1993 4.3 V6 4bbl with a thunderbolt 4 ignition. In my testing I have disconnected both wires on the switch, then hooked up a 2 amp source with the + to the white wire, connected the - from the source to the clamp on my test light and connected the black wire to the light. When the light comes on then the circuit is continuous and the switch is made (with little or no resistance), as long as the light is off the circuit is not made (with infinite resistance...it's open).

 

[achris]

Re: Alpha 1 Gen II - Shift cutout switch -how does it work

2 amp ... You have likely blown the switch. They are designed for about 500mA...

The way it works is that the switch is connected to ground and the white/green wire on the distributor sensor. When the switch closes it grounds that line on the sensor, and no sensor pulse is detected by the ignition amplifier...and no spark (until the switch opens and the pulse is available form the sensor again).....

Chris........