‘94 454XL help

So recently I rebuilt the carbs on my motors. Bolted all back up and all was well. Ran them for a while and shut her down. Went and got everything together to get the idle mixture screws right and my starboard motor wouldn’t start. It turned over without a pop. I ended up getting the port motor adjusted and left for a while. Came back down and hit the key and she fired right up. Got the carb adjusted and all was well. I turned it off and on repeatedly without any issues. I guessed maybe I had flooded it somehow even though I couldn’t see how but who knows.

I left town town for a few days went down last night and it won’t start. Just turns over. I pulled a plug wire and checked for spark and nothing. Tinkering around I see that the coil has no power and the ignition relay on the manifold isn’t clicking on that motor. I tested wires, looked for chaffs and all and see nothing. Just no power. I fooled with it for a while then heard my engine breaker pop. Reset the breaker and 10 seconds after turning the key to run it pops again. The ignition switch was very warm. So now on top of no fire to the coil it seems I now have a short somewhere. Mind you I’ve been checking over things for hours and this just started it seems out of nowhere (the breaker situation).

My my question is does anyone have a general schematic for Crusader 454’s and also any input on this would be much appreciated. For reference the ignition system has the MSTS system. Believe it’s Delco Parts.

The generic 454 schematic won't help you much as the MSTS stuff adds a lot of wires and sensors.

Overall they are pretty reliable....when they fail, most people eliminate the ecu and use the EST distributor in module mode....

The ignition switch getting warm suggests power dissipation....I'd start with looking for a voltage drop across the switch....

In general, the introduction of electronic controls usually adds sensors and relays....and, to some extend offers internal diagnostics - though you typically need a scan tool to read them....