Swapped Engine and Electrical Issues

[mounty95]

So let me start by saying, that I accepted a Pearson 30 sailboat for Sea Scouts with an A4. I had to replace the A4 after a corroded heat left me with a 1x2 inch opening for water to flow. I replaced the A4 and she runs like a top, well aligned, nice and solid transmission.

My issues:
1. The 12 volt system (nav lights, VHF radio, etc) only works when the engine is running.
2. The new engine came with an ignition that I have mounted down below giving me the convenience of being able to start and work on the engine without having to jump up into the cockpit, but that doesn't seem safe or convenient to not be able to start the engine from the helm. In other words the ignition (which I believe I was told was electric ignition) in the cockpit does not work now.

Again, I accepted this boat last October and have been learning all of it's idiosyncrasies, but the engine swap has me perplexed. It seems that the running A4 completes the circuit for the 12V system and the minute I shut the engine down, everything turns off. For additional points and it only confuses me more is that the new ignition has 3 positions (similar to a car) but it doesn't matter what position the key is in the 12 V does not come on.

When I swapped the engine, I was told I could not connect both ignitions and so I went with the ignition that came with the new engine. I am good at following directions and researching these kinds of things, but I am not sure that I am googling or searching for the right terms.

Any help or guidance or pointing me in the right direction would be greatly appreciated.

[ndutton]

The ignition switch has three terminals: B (battery), I (ignition) and S (start).
It's possible the 12V distribution panel is supplied power from the I terminal. If this is the case, simply move the wire that supplies the distribution panel to the B terminal.

[nyvoyager]

It's your lucky day
Here's the dc schematic for the P30
I'm in the middle of this so let's see....
There is a red wire to the alternator
A white to the starter solinoid
A purple...hmmm it goes to the lectric fuel pump but also somewhere else.
There should be an 8 ga green wire to the bolt on the gear case - just behind the waterpump. this is the common ground and if it is disconnected nothing will work

[JOHN COOKSON]

It seems that the running A4 completes the circuit for the 12V system and the minute I shut the engine down, everything turns off.
Any help or guidance or pointing me in the right direction would be greatly appreciated.

At a minimum the blower, radio, and other electronics, such as the depth sounder should operate whether the engine is running or not.
If I can it to attach here's wiring diagram from my original A4 manual.

TRUE GRIT

[Al Schober]

You need to trace your present wiring and find out what you have and where it goes. Your present system isn't right.
Numerous ways to wire a boat - find one that works for you.
I've changed my system over the years. Originally had an A/B/BOTH switch, and got rid of that. Went to two separate battery banks - one for the engine (a Group 24) and one for the rest of the boat (whatever you need - 2 of Group 27 worked for me, Group 31s were too heavy). Each bank controlled by it's own ON/OFF switch.
Final configuration had the alternator output going to the boat bank. When it came up to voltage, a VSR (voltage sensitive relay) sent alternator output to the engine battery too.