Yamaha 115 just stopped

Took my 2003 Yamaha 115 (175 hours) out Tuesday..started right up. Motored around for about 1/2 hour, then as soon as I tried to adjust the trim, the engine stopped.
When I tried to restart it, it just "clicked" as though the battery was dead. I tried to tilt the engine, but that just clicked as well. Had to get towed back.
About an hour later, I tried to tilt the engine again and it worked, but the engine still just clicked.
Started to write this post Wednesday and decided to check the transmission, figuring if it slipped in/out of gear, maybe it wouldn't start. It's on the same control as the trim...just a guess. Anyway, I went down to the boat, put the key in, and it started right up.
I can't trust this to have self-remedied, but have no idea what to check. The only facts I really have are 1) Boat started; batteries were good. 2) the instant I pressed the trim control, the engine died. (Coincidence??) 3) Nothing was done to the boat or batteries or engine (except a quick washdown) after it got back at dock.
Is it possible for a running engine to stop due to some electrical malfunction, perhaps a problem with the trim?
Any help/suggestions/advice would be most welcome! Thanks.

You have a bad connection on the battery cables. Check all of the connections, engine and battery.

I agree with Dockside. Are you using wing nuts on your battery connections? Many do... Including me 'cause they are easy. They will vibrate lose and if you are going to use them, at least place a lock washer under them. Standard flat washer... They'll vibrate lose and sometimes you'll have power from a weak connection that will run some lights and such but try to draw serious amps on start-up... Clicking.

i would replace the wing nuts if you have them with standard nuts...and throw an old or cheap box end wrench in the battery compartment..then when you are back there charging batteries etc check them for tightness as part of the routine...use anti corrosive on the terminals and you are set to go...good battery connections prevent all kind of potential problems such as wire crystallization etc...