Pre 1979 battery ignition inline , how does it kill the ignition

[Jdeanie]

Hello I replaced ign switch in control box and am having a dandy of a time trying to gather information on what actually kills the power to ignition while running.
I have all my wires traced back from boat to the engine .
I installed a CDI engine wire harness and am using all of the wires except the orange , that orange traced back to my control box to the M post on old ign switch.
Now it's just a open wire at engine .
It's hard to find wiring info that dosent expect me to know more than I do .
I keep reading about two magneto lines that ground out to kill engine, well wtf is a magneto cause I have all kinds of other parts but nothing called a magneto .
I hope I give someone a chuckle with my lack of knowledge.
I'm working on getting photos uploaded.
1978 900 90 hp
I believe original design ign switch was a 5 post , I have a 6 post that I'm replacing with another 6 post .

 

[alldodge]

Howdy Jdeanie

It appears you have another thread going on here which is basically asking the same questions. Did notice in this other thread you said it had a distributer and therefore would be a 1978, but here your saying its a 1979.
http://forums.iboats.com/forum/engi...boards/10177615-inline-90-900-78-79-no-ground

If it is a 1979 then I'll provide the following as a non-expert on your outboard
To kill the motor the ignition switch is turned off, which connects pins E and D together.
E=Orange switch boxes
D=Black ground

Connecting E and D together grounds E and kills the spark.

Now if you have a 1978 with a distributer I'll provide this
To kill the motor the same pins E and D will connect together
Again the orange wire E is grounded, only issue with this drawing is the Pin E is missing on the motor side which is also at pin E






I drew in a connection between missing pin E and the switch box. Also note the Mercury switch, this is here if the motor flips over it to will kill the motor.
To install a kill switch on the throttle control, it uses the Orange wire and the Black ground


Hope this helps

 

[Chris1956]

Throughout the 70s Merc switched the ignitions on their engines from battery CDI with a distributor to ADI ignition with 1 coil per cylinder. Merc wanted to use a universal boat wiring harness, so they made a harness that provided power to the white wire for ignition for battery CDI distributor ignitions and grounded the orange wire to kill the spark on ADI ignitions. Both orange and white wires were therefore connected to the ign switch.

The engine harnesses were all the same as well, but only the necessary wires for the particular ignition type were connected. The white and orange wires were not connected to the same ignition module, at least not by the factory.

Your motor switched over to ADI ignition in mid 1979. So the question is what type of ignition do you have?

 

[Jdeanie]

I have battery CDI distributor type. It's a 1978 900 90 hp, I've replaced or rebuilt all but power head.
I never have had a Mercury switch on it, seems people agree it's not nessesary.
I hope this helps

 

[Chris1956]

OK, so the orange wire is unused. Spark is provided by power on the white wire, which is next to the red wire on the switchbox. When the keyswitch is turned off, there is no more power on the white wire, killing the spark. The red wire on the switchbox is always "hot".

The mercury switch can also kill the spark by grounding a terminal on the switchbox. You might test the mercury switch for proper operation.