Main engine breaker blowing on my x45 why?

We were doing great all day switch to surfing port side .check engine buzzer goes off I shut it off .
Start riding engine dies the little red button on engine pops . We empty the ballast reset button boat runs fine so we surf starboard side switch back to port and the button blows
Long winded I know but what cause this thing to pop

That's a very high draw to pop that breaker. Is there a lot of water in the bilge, or a sack pushing on wiring when the boat is on the port side? One of the first places I'd look would be with stereo wiring.

Thanks I will look at that,when the switch was blown ignition and stereo were the only things without power

It could just be a coincidence when you switched back it blew again. I had the breaker go bad in my 97 Nautique. It would just blow at random times and it happened frequently when I was just pulling into my lift at the end of the day. I couldn't figure out what was causing it to blow, so I replaced the breaker and it has been fine ever since. They are fairly cheap. Might want to give that a try before you spend to much time and money chasing the problem.

Thanks I will see if I can find one I am on the road in Chico Ca

Apparently MC computer systems are hyper-sensitive, in that if you start the boat say, by jumping the batteries, or if your wiring connections are in any way weak, it goes into "limp mode" where the alarm sounds, check engine light goes on, then the computer prevents you from getting any power out of your throttle to protect the engine.
pain in the rear, cuz without the computer to reset the system or diagnose the problem, you'll end up taking it in just for that. Ah, technology!

and i say this only because it happened to us this past week.