I'll put down $5 that it's the ignition. Generally speaking, electronics can work fine until strong continuous current warms them up exposing a fault, and MSD hasn't had the best track record here.

I'd open the hatch and wait the amt of time it takes you to replace the plugs. No shorter. And then try to restart and run.

plugs look dark enough. I don't know

I have read about the bad rap on MSD. Not saying anything good or bad, other than both acting up in the same way at the exact same time doesn't make sense to me, and more than one occasion.

I basically did this. After changing plugs in one engine, I started it to make sure that was the problem. Then I tried to start the other and still had the problem.

I can certainly try this. May try putting the plugs back in one engine just for the hell of it and see what happens.

Did the carbs get rebuilt lately? I did a dominator once put the wrong gasket in and when I shut it off it would siphon the carb dry. changed igniting on it drove me crazy.

One carb is new only apart to change jets, the other was on the boat/engine when I got it.

Thanks for the input!

coil weak or mounted on hot motor , check ignition with fine tooth comb

Ignitions have common power source and ground? There may be something going on there. The po of my boat ran a 20g wire to the coil when it required a 12g and it was at idle that noticed a significant difference.

Have you tried changing out the brand of beer that you consume when yelling at it? I've found that to be as effective as anything else troubleshooting boat problems.

Have you tried a different brand of plug? ( Champion RV9YC )

it,s hard to tell but it looks like the center electrode is burnt off of # 1&2.also reversion will cause the exact symptoms you described.