Merc I6 Trigger Testing?

[79 Silverline]

Sorry if this question overlaps the previous two I've asked, but I'm looking for specific info on the trigger (schematics, diagrams, specs, test procedures - none of this stuff shows up in my repair manual).<br /><br />As stated before, I'm running a 78 or 79 inline 6 90 HP merc. Switchbox and coil have been replaced with the CDI 2986 type box/coil assembly. Switchbox/Coil is 2 weeks old. Timing light on coil wire shows I'm getting missing spark at idle, which becomes really bad once I try to get on the power. I need to know anything I can about the trigger assembly. Everybody tells me that they either work fine, or die completely, but I'm thinking mine is dropping pulses to the switchbox. I need to confirm before shelling out 250 for another trigger.<br /><br />Trigger is a 393-3736, what can you tell me about it? Thanks!

 

[Laddies]

Re: Merc I6 Trigger Testing?

Before changeing the trigger remove all connections and clean them, make sure you have 12 volts on the white switch box termanal, 9 volts on the brn trigger wire, if you have a DVA 3 volts between the blk and white trigger wires, while they are hooked up, lower voltage means a bad trigger

 

[timmathis]

Re: Merc I6 Trigger Testing?

Verry rare to see A trigger do that. They mostly die! I had to replace mine. I just bought A used one$100.00

 

[79 Silverline]

Re: Merc I6 Trigger Testing?

Yeah, you'd think it'd just die or work? I'm about to tear down my entire wiring harness and run new fresh wire. I've just discovered a few minutes ago that my missing ignition seems to coincide with when the timing starts advancing... Hmm. Though I'm not sure why advancing the timing would suddenly stop the switchbox from firing? It's currently idling at 0 degrees advance, which I think spec is. Still have to do more troubleshooting. Repair manual is pretty much useless here.<br /><br />BTW, where did you manage to find a trigger for 100 bucks? I'm new to the boating world and don't know about where to find used parts and such. I was considering a Rapair rebuild unit, but that costs 250 bucks.