Another Mercruiser Digital Ignition with no spark

[starsnbars89]

Hi. I'm new here and don't know much about boats, but I'm pretty savvy with engines. Have an early-'90s Cobia Spirit here with the Mercruiser Alpha1 3.0L L4 engine. Has the digital ignition but won't spark. I've run the diagnostic tests given in other similar posts and my question is this: What terminals should be hot on the input connector for the spark amplifier. I know that the coil end should have two hot terminals and mine only has one putting out 10V. However, the input for the amplifier also only has one hot terminal putting out 10V as well while the other is putting out .38V?? This makes me think that it's not the amplifier at fault but a wiring harness issue. Would that be a fair assessment? All the fuses are good under the helm, the key switch is working, all the wiring LOOKS ok, juice is flowing fine everywhere else, just no spark! Trying to fix this thing cheaply so any help would be appreciated, thanks!

 

[Bt Doctur]

Re: Another Mercruiser Digital Ignition with no spark

at the 3 wire harness plug, NOT THE PLUG FROM DIST TO AMPLIFIERpurple is ign voltage, grey is tach .wht/green to shift interupt.

 

[Don S]

Re: Another Mercruiser Digital Ignition with no spark

Here are the troubleshooting procedures for the DDIS system.

View attachment DDIS.pdf

The parts are expensive, and a couple are NLA, what most people do with the DDIS is replace it with the EST distributor kit. It's the same as what Merc went after they stopped using the DDIS (Which wasn't that great) plus it's cheaper than a couple of the parts for the DDIS.
3.0L Delco Voyager EST Marine Electronic Distributor Kit

 

[starsnbars89]

Re: Another Mercruiser Digital Ignition with no spark

Alright, so if I'm correct, there is only one ignition input for the amplifier. The .38 on the other is simply just some residual current. The neutral switch wouldn't affect spark, would it? It only affects the key switch's cranking ability, no? Wouldn't make sense for the boat to stop running when put into neutral and it would make more sense that they wouldn't want the boat starting while in gear right? Thanks for all your help guys!

 

[Don S]

Re: Another Mercruiser Digital Ignition with no spark

Alright, so if I'm correct, there is only one ignition input for the amplifier.

There is only input voltage from the ignition switch powering the the ignition amplifier. That is the purple wire coming from the ignition switch shown in the picture (purple arrow). Do you have battery voltage on the purple wire.

The .38 on the other is simply just some residual current.

Have no idea what wire or wires (or terminals) you are referring to.

The neutral switch wouldn't affect spark, would it?

No it will not affect the purple wire, only the yellow/red in the harness.

 

[starsnbars89]

Re: Another Mercruiser Digital Ignition with no spark

Yeah, I think we're on the same page here. The .38V wire is the grey one for the tach so it's just meaningless residual current. I have 10V on the purple wire everywhere but no voltage on the second terminal to the coil pack so the amplifier must be bad. We're just gonna bite the bullet and swap out the ignition system I think. Thanks for the help!