Mercruiser 3.0 only stays running with key engaged?

[alldodge]

Right, so if the KS is jumpered closed, and there is an open someplace else in the circuit, wouldn't it behave as though the kill switch was tripped? (Able to run in start, but not run on run).
Or if the OP removed the KS from the equation by disconnecting the wires from the switch and leaving the circuit open would also be the same.

Correct

 

[Bszakaly97]

Right, so if the KS is jumpered closed, and there is an open someplace else in the circuit, wouldn't it behave as though the kill switch was tripped? (Able to run in start, but not run on run).
Or if the OP removed the KS from the equation by disconnecting the wires from the switch and leaving the circuit open would also be the same.

Not left unplugged, purple wire goes into switch and comes out... cut them both and spliced together as if switch isn’t even there.. believe that’s correct but if not please correct me!

 

[Bszakaly97]

Hello new here so I’ll do my best to explain everything and hopefully I’m in the right place, I have a mercruiser 3.0 in a 99 sea ray 180. Just swapped in a new motor with points... hooked up main harness plug and motor only starts and runs with key engaged. 12v at coil when starter is engaged but with just key on have nothing. When hit wire to + side of coil runs great. Tried replacing ignition simply because I had one round that I knew worked and didn’t change anything. Gauges work along with everything on the dash, also should mentioned I jumped pin 5 &6 on engine harness plug and had constant power to coil.. only used the test light but nothing lights up under the ignition so should I be following purple wire all the way back to main plug? Also already bypassed KS thanks for any help in advanced. Also using a deep cycle battery if that matters... just bought the boat so I also do not know it it worked properly with last motor but the motor in it now I had running and idling fine in last boat with no problems

So I’ve come to a conclusion... going to have to be a winter project problem, for now wired up a accessory switch with 12v hooked up to a 2 ohm resistor to the coil. I believe it’s a change in wiring from the older points motor harness to the harness made for electronic ignition so will end up switching entire harness over from the boat it came out of... thanks for everyone’s help!

 

[Pruno]

I believe it’s a change in wiring from the older points motor harness to the harness made for electronic ignition so will end up switching entire harness over from the boat it came out of...

this very well could be, and I would be way in over my head.

If this boat was sitting in my driveway a few simple things I’d check to eliminate them as possible sources…if you can get to your splice, I would expect to see voltage there with the key in run position. And/or check for voltage at the purple terminal on the back of the key. You could have something as simple as a bad key switch, or maybe the wire came disconnected. Good luck to you.