No voltage to ignition coil

ReedonGSL

Recruit
Joined
Jun 8, 2020
Messages
3
I have a 1998 Chaparral, 4.3 Mercruiser that no voltage to the ignition coil. There is continuity through the purple wire to the ignition control module, the alternator and oil pressure switch. There is no continuity to the ignition switch (which has 12v to the purple line when in 'Run' position.
If we jumper 12v from battery to ignition coil when we start the boat it runs without issue. My assumption is there is a corroded or bad connection in one of the wire plugs between the dash and the engine.
​​​​​ Does the lanyard switch only interrupt the ignition wire? If the lanyard was faulty would the boat run with our 12v jumper being applied to the ignition coil?
I believe we just need to trace the ignition wire from the engine to the dash and find where we are losing continuity but would love to hear other opinions. Thanks in advance.
 

Attachments

  • photo332536.jpg
    photo332536.jpg
    296.1 KB · Views: 0

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
51,357
first, check the MOB switch which is in the ignition supply line (purple) between the motor and the key switch. then check the key switch.

and yes, if the lanyard switch was bad, and you jumpered it at the coil bypassing the dash switch and the lanyard, it would run.
 

ReedonGSL

Recruit
Joined
Jun 8, 2020
Messages
3
OK thanks. Is the MOB switch life the connector shown in the diagram i posted? 10 pins or is it just on the ignition wire?
Ignore that question. I didn't know what MOB meant but I googled it and I do now.
We know the key switch is good. Thank uou.
 
Last edited:

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
51,357
the MOB switch is the lanyard. its simply a switch to kill the ignition. the OEM ones have two connections that are NOHC (normally open, held closed) for I/O's and NCHO (Normally Closed, Held open) for the outboards with magneto ignition the aftermarket ones have 2 sets of contacts
 
Top