A few things....
First, don't double post. It just confuses things.
Second, you have to give it a little time. There are only a few guys who know the Merc engines.
Third... did you check the compression? I know you are saying it has no sprak... but we should check all the basics.
Generally, the kill to the CDI will be a ground, but on some CDI units (such as the seadoo 800 engines) it is a digital signal.
On that Merc CDI... there can be a few things. The Electronic control module may be sending the CDI a "Kill" via a ground, or, there may be an open coil in the stator (but that would probably kill one bank) or, the trigger plate has gone bad.
This is assuming that there are no mechanical issues like cut wires, or melted plugs.
The Merc ignition is very complex. You need to get the service manual, and follow the testing procedure step by step.
If you become a premium member, you can down load it.