89 3.0 points ignition...What else does grey wire go to tach and ...?

[andrewterri]

Hey guys it has been a little while. Helping on my old boat my friend bought. There was a no spark issue. Disconnected grey wire from negative side of coil. Boat got spark and started. Hook wire back up and disconnected from tac and no spark. While unhooking from tac and leaving hooked up to coil the wires get hot with key left on. Nothing gets hot if the grey wire is disconnected to coil. So where ever else the grey wire is attached to is causing the problem but can't seem to figure it out with diagram. Can someone please help? I think whatever else the grey wire is attached to have a bad ground connection and is causing the problem and just needs the connection cleaned. Thank you guys...

 

[andrewterri]

Sorry guys, the boat is an 89 3.0 mercruiser with a points ignition system

 

[nola mike]

Try running a new wire from the coil to the tach

 

[andrewterri]

What has me thinking that something else is ungrounded off that grey wire is with it unhooked the purple wires get hot, the power cable from the battery, the starter wire on the battery, and the purple choke wire and Blake ground wire on choke for carb. Seems like something else is ungrounded.

 

[andrewterri]

Do you know of anything else the grey wires runs too. I think I read it went to the shift interrupted switch but can confirm that

 

[Bt Doctur]

the grey wire goes to the tach, period the shift interrupter wire goes to the neg side of the coil with a points system
With the grey wire disconnected from the tach and with it connected to the coil you lose spark, the grey wire is grounded someplace.

 

[DanD34]

On my 88 the gray wire feeds both the tach and the shift interrupt switch and is what it shows on the wiring diagram.