Buddy has a nitro that has electrical issues

[NY29T]

Buddy has a nitro with some electrical issues and need some guidance

1. Engine wouldn’t start at all. Buddy had to take the key out and put it back in to get it to start.
2. once he get the engine started if he hit the trim button the engine would turn off.

im thinking it’s some sort of short just not sure where to start looking .

thanks for any help!

[Sun Fish]

Id check with the Mercury forum for help on this one. Doesnt sound boat related but motor related.