I have a 2008 Magic Scepter 28’. It has a 525efi S/N:OM959932. I have codes: EST1 Open Circuit, EST2 Open Circuit, EST3 Open Circuit, and EST4 Open Circuit. Engine won’t start at all, and verified no spark by removing cylinder #8 spark plug. I’m confused because shouldn’t it show EST8 Open circuit if it has no spark? Please help, don’t know if it’s the ignition coils, wiring harness break, circuit breaker failure, or ECM failure.. I already checked all the fuses and tested the lanyard switch and the neutral shift switch.

your gonna have to break out the voltmeter and start probing.get a wiring diagram too.

does the tach move at all when cranking?

Yes the tach moves. This morning I checked for 12v at the ignition coils plugs and the red wires have power. Would that mean the coils are bad?

As with all the PCM motors, to find out what the issues are you need a scanner and a manual
https://www.rinda.com/marine/marinemenu.htm

I bought the Rinda Scanner. That’s how I got those codes. EST 1,2,3,4. Don’t know how to diagnose that

Need the Diagnostic manual 8M8021131

I have same issue, have twin 2023 250HP Verado and have to have "all" the manuals to figure out what is happening, which I just bought
https://www.mercruiserparts.com/bam/.../31347/13369/0

Same, I looked through the parts diagram and can’t figure it out. All fuses and relays are good. Scratching my head here