Op: take s look at;
https://www.manualslib.com/manual/82...4.html?page=47

I was able to resolve this. I believe the key take away was that the Electronic Spark Timing on the distributor was not grounded properly to the distributor. Once grounded well I got spark. I also validated the shift detection cut off had proper voltage in.

Thanks for reporting your resolution. Too many folks never come back with the answer.

Where was the ground issue ? Screws holding down module ? Distributor clamp to dist or manifold ?

I believe it was the screws holding down the module.

I wanted to revisit this due to my experience. I've bounced back and forth from having spark to not with no consistent pattern. I'm currently ordering the pickup coil and will report back with results. At this point essentially everything has been replaced with the exception of the entire distributor (which includes the pickup coil) or the wiring harness. I've bypassed the shift interrupt (as described in the service manual for troubleshooting),verified voltage on purple wire into coil and disconnected the tachometer. The only thing not new is the pickup coil and the mechanical portions of the distributor.


I've replaced:
three EST modules
three ignition coils
rotor
plugs
wires
dist cap
coil/est harness

I wanted to post the definitive solution here.

This cable was not making contact on the EST side of the connection. There's no test for that. The test is to test this side for voltage, not to test the other for the digital signal coming from the EST as the dist turns. I realized that the female connections mating with the pins inside the EST we not making good contact. This test isn't easy or intuitive because the pins in the EST are very recessed and hard to grab with alligator clips. After mocking up a wire i could insure the connection was taking place inside the EST I was able to prove out this wire as the faulty point.


replace the two prong wire from the est to the coil

Thanks for letting us know. Glad you are back on the water.

Btw: i provided a link to you on this same issue and same fix on your other thread.

See my response here:
What is this Mercruiser 3.0 Wiring from coil to dist

and click on the link on that post.

Also see next post I made after that one. So see #7 and #8.