Hey Joe....no I have not done that test yet. I did just run out to the barn though and check the voltage of both batteries and the port battery was 12.38 and the starboard was 12.59. Wondering if like what SB said that it is the alternator. What I can tell you is that when hooking a jumper back to the port battery and leaving it on for a few minutes while running the engine would continue to run. Then after being charged in the slip overnight it was fine the next day. When the boat is at home I always turn the battery switches off. Thinking next step is to go to the pond and see what output there is. Thoughts?

What was wrong with the weather pack connector and what did you do to fix it? Did it cause a draw?

i would check alt output and main alt wire connector,i have seen the connector break.

Perform the checks above too.....but, running two alternators into the same connected system can fuk them up.

You need to seperate them.

One alternator per engine and that engine's batteries.

Boat manufacturers will let you tie them together so you can jump start one engine to the other without using jumper cables.

I normally run my switches on 1 and 2 , but have ran them both on "both" many times. My alternators positive wires go right to the starter main stud, I would assume yours do as well. I cant see running it that way hurting anything, heck, alot of heavy equipment stuff run dual alternators.

I do know the MSD boxes, are pretty voltage sensitive.The specs on the 6560 marine box, is 12 to 18V required. Where as, the daytona box, is 6 to 20 volt, and the cranes were 6 to 18 volts.

It could very well be a charging issue. The box gets its voltage requirement from the heavy gauge wires, so I don't think the purple wire having low voltage, would shut the box down, unless it had NO voltage, as in, a break in the connection, as that is used for a turn on lead only.

I'd probably start ONLY the troubled engine, and put a meter on the box's power source, and ground. The heavy gauge wires. With the engine running, you should see 13.5 plus volts there. If you don't get that, then check the voltage at the battery, and at the back of alternator.

A bad alternator not charging properly, allowing that sides battery to constantly drain down repeatedly, will kill the batterys life.

I do believe the stock alternator, NEEDS a 12 volt signal to the back of it, to charge. So, before you replace it, make sure the small wire going into the alternator, does in fact get power. If there was a break in that purple wire somewhere, the alt wont charge.

I had the same problem 3 years ago, I fought it all summer checking everything I could find, long story short,,my MSD would run or not run when it wanted due to internal problem inside the ignition box, I finally installed a new box and problem solved, has run perfect since then,, I wasted many hours looking for other problems that were not there.
Just saying that was my problem.
Good Luck

I have had an issue with the voltage regulator on the altenator go bad. It would charge and when it got hot it would stop charging. But everyone I would start the boat after sitting it would charge. My voltage gauge would go from 14 volts down to 12. It would jump back and forth when it tried to work while running. I could see it on my gauge I don't know if you can see anything like that or not. Or if both of your switches being on both would give you gauges a false reading. After that issue I got the altenator that charges after it revs past 1500rpm and doesn't have the built in regulator.

Put a screwdriver on the center back of the altanator and see if it is magnetic. If it is not , it's not charging