Do you want me to guess at this, or try to guide you? No matter what I do here, you are my eyes and ears, as I am not there to see the engine for myself. So I have to ask you detailed specific question, and I need detailed specific answers back to those questions. If this was in front of my I would have simply jumped 12V right to the trim motor to see if it was dead or not 1/2 an hour ago.
I'm also going on the premise that you have more than 1 thing wrong, and that those more than 1 things wrong are related. Because you do have more than 1 problem. You have a dead trim system and a not starting engine.
This can littlerally something as simple as loose/corroded battery cables. Or something extremely difficult. So I try to narrow things down via questions back to you so we are not wasteing time testing things that do not need to be tested.
Believe me I am not trying to give you a hard time at all, I am trying to help, but I am in the business, and I know your options right now.
So let me ask you this. Have you pulled and sanded down the battery cable ends, and battery posts, and tightened it all back down yet to see if it helps or not?