Snap,

Why have the switch, then? By the time you discover a dead battery, they're both dead. I have been told by literally everybody with even the slightest opinion on the matter that you NEVER put the switch on both unless both batteries are too soft to drive the starter, and you're HOPING that the two of them combined will get you started, then you immediately switch to whichever battery you think is weaker to charge it.

Just because something else might get you first, doesn't mean you don't mitigate the risk of a relatively easily avoidable problem.

Thanks. Brad.

Where do you pull power for the stereo.

Wildman,

A breaker panel that is fed from the center lug of the switch; whichever battery the switch is set to. The ACR prevents the stereo from drawing from both batteries.

Thanks. Brad.

Someday, you're going to wish you put this much thought into adding real steering, instead of battery isolation...

MadFlavors,

Maybe. But we've been running this boat in the mid- to high 70, and the boat has yet to even hint at a desire to get out of shape. I am very careful when I run it hard. If the boat had been a handful beforehand, I'd have a different approach. If I find that it seems to have learned a new trick as we surpass prior-to WOT speeds, I'll stay out of it until the steering can be properly addressed. I fully understand the implications.

That said.... Business has been slow this whole time since we had the piston failure. This has been a good thing for getting things done, but bad for paying for the effort. The steering is still on my radar, and may yet happen before spring. But, for the moment, it's a want, not a need, as far as the checkbook is concerned. I am working out issues that don't hit like a truck in the budget area in the meantime.

Thanks. Brad.

with 1985 wires it would take 2 batteries to start a single engine in the cig. Lots of time I`d leave it on ALL most of the time. Same thing in the baja .. easy to start but I liked having both batterries while starting ... anyway that has never ever left me stranded either.
The chances of one battery taking out the other is close to 0 .. well in my case over the last 15 years anyway .
That`s the last thing I ever worried about .. the relay is a good idea thou either way
Edit: I would run a negative cable from one engine to the other also .

generally you do not run on both if you have twin engines as the two alternators can fight each other and cause issues. on a single engine with two batteries running on both is fine. if you have a concern that one battery is low you can start on the other and switch it to both and it will be fine.

All this is well and good, but not still doesn’t solve the problem of the risk of the battery the ECM is connected to taking a sh!t and leaving us dead in the water. No matter how you slice it, if THAT battery decides to fail, you’re done. Period. Even with the switch set to “ALL”, the failed battery will drain the other in short order and there you’ll be, needing a tow. The ACR solves the problem of charging both batteries regardless of which one the switch is set to, which is great. But setting the switch to all solves nothing, and only invites an additional problem. I have personally witnessed the phenomenon of a failed battery draining a good battery. Took about fifteen minutes with the engine running, and the alternator was so hot you could hardly even look at it.

I’m going to call BlueSea and make a suggestion for a new product. I doubt it will get us anywhere, but a phone call is free, and they are probably the only people that would be interested in developing such a product.

In the meantime, I am working on finalizing the electrical in the engine well with the best configuration the market has to offer.

Thanks. Brad.

Guys,

On other fronts…. Heads are done. Block is done at the machine shop. Cam is on order. Mods to intake manifold is all but complete. Fuel and oil line fittings and hose are in. Moving forward.

Interestingly, the builder happens to mention that there were no valve seals on the valve stems when he disassembled the heads. And we weren’t burning any perceivable amount of oil. We were losing a bit over time, but I attributed that to the PCV being part of the intake manifold, and the ProCharger pushing oil out the dipstick. Weird, right?

Thanks. Brad.

I dont put valve seal springs on the exhaust.. I thought some guys leave em off all together , More lubrication.