Shift cutout switch not working even after replacement

[Capt. Obvious]

I have an old 3.0L Mercruiser Alpha One. I recently replaced the carb and although it ran much better, I found shifting back into neutral almost impossible in the water. (This made for quite the adventure on a boat ramp with a lot of water current.) Anyway, I got home and tested the shift interrupt (shift cutout) switch and it didn't work at all. I bought a replacement switch assembly and installed it. Testing the new one, it still didn't work. I'm wondering now if I have a loose wire somewhere. Any ideas? I'm not very good at the wiring aspect so not even sure where it goes.

 

[dubs283]

Have you tested the old or new switch for continuity?

Possible there is a damaged/unconnected wire somewhere. Depending on the vintage and style of ignition system on your motor the wire could go to either the coil or distributor

 

[Capt. Obvious]

Have you tested the old or new switch for continuity?

Possible there is a damaged/unconnected wire somewhere. Depending on the vintage and style of ignition system on your motor the wire could go to either the coil or distributor

Thanks. It strange that it happened after a carb replacement but then again, it is a boat and things like to break.

 

[alldodge]

Which distributor?

 

[achris]

How are you testing the new switch?

 

[Capt. Obvious]

How are you testing the new switch?

Multimeter but also pushing the button down while the engine is running does nothing.

 

[alldodge]

Which distributor?

You said old 3.0 which could mean may things. Could be points Dizzy or TB Dizzy. Points uses a ground to make the motor stumble and TB uses 12V.

Do you know if the other end of the shift interruptor actually connects to a ground or 12V?

 

[achris]

Multimeter but also pushing the button down while the engine is running does nothing.

Then you have either a faulty switch, or a wiring problem... If the multimeter shows the switch closing, then it's a wiring issue...

Chris...

 

[Capt. Obvious]

Then you have either a faulty switch, or a wiring problem... If the multimeter shows the switch closing, then it's a wiring issue...

Chris...

The switch is good, both of them actually. The wiring is hard to find because it's an insulated bundle. It's been so dang hot here in Mississippi, I haven't been up for taking the time to trace it down yet. I have no idea where the wires run at this point.

 

[alldodge]

I haven't been up for taking the time to trace it down yet. I have no idea where the wires run at this point.

Knock knock , hello

Which distributor

No need to trace wiring unless there is something wrong with it. To find out what it should be we need to know if you have points or some kind of electronic type