Al, I was out yesterday and double checked this. When the boat and running, and out of gear, the relay showed the batteries were combined - and when she went into gear, sure enough, the LED started blinking, indicating the SI circuit was closed. So, I pulled the in-line fuse that I have in the SI line from the starter to the relay, and it combined the batteries like it should, both in and out of gear.

Thanks for catching this, and it makes sense now why I was having battery depletion problems last year as well. I couldn't figure it out - but since my stereo bettery was isolated and never getting a charge when the boat was in gear, it makes total sense!

For now, I'll just leave the in-line fuse out, but sooner than later I'd like to try to find the right wire to use from the ignition switch - but it'll be a few weeks before I tackle that. Unless someone else out there can find it!!