New alternator, now no power to the engine

[dwkfym]

I installed a new 65amp alternator, now I have no power to the engine.

The way my wiring is done is as follows: alternator ignition goes to coil pos, then another wire from coil pos goes to ignition switch, then to the ammimeter, then back down to a fuse bus bar pos, then on the bus bar to the battery selector. The other accessories on the bus bar include galley pump, depth finder, and VHF.

I installed an inline fuse from the line that goes to the battery switch to the bus bar. Prior to installing the new alternator, the 30a fuse here kept popping.

The event that lead me to replace the alternator was that my coil kept burining out. My engine bay got flooded and after I replaced the oil 8 times to get the water out, I started her up. Didn't notice that my 12v lighter socket voltimeter was reading 14+a (which it never did before.. always high 12's even when charging) and after 20 minutes, the engine quit. Coil was hot to the touch. This might have had something to do with it -- if my ammimeter was burnt out when this happened, would this kill the circuit?

Thanks in advance. I'm getting really frustrated with the season closing fast. (located in Deale, MD)

[ndutton]

OK, let's get started.

The description is appreciated but has a few holes that need to be cleared up before we can help and be assured, this can be solved. First, an accurate and detailed drawing would be of immense help. It need not be professionally engineered on a CAD program, a hand drawing is just fine as long as it's accurate. Important details that should be included are exactly which terminal the various wires are connected to on the ignition switch, ammeter, coil, alternator, etc. and their color. What brand of alternator? Exactly what coil is installed, what was its internal resistance? If these questions seem daunting, no problem. Report back with questions of your own and we can walk it through step by step.

There is no need to include anything other than engine related connections to the buss bar at this time.

The forum has pretty good electrical guys so with accurate information from you we can solve this.

[dwkfym]

Thanks. I'm gonna go by the boat again and trace the wires.

Alternator is an internally resisted Arco 0065. Modified to close out the sensing wire and tested at the shop to make sure it worked.

Coil is a Echlin IC64 (now IC14)

[joe_db]

Please do supply a diagram! That setup does not sound right. Also what kind of alternator?

[ndutton]

I believe dwkfym meant the coil rather than the alternator had internal resistance (both the Echlin IC64 and IC14 are 3Ω coils = good) and the alternator is actually an Arco 60065. Looking forward to the drawing.

[dwkfym]

You are correct, I made a mistake. Internally regulated alternator, internally resisted coil

I did my best, I hope this is a correct representation

https://imgur.com/a/vkZs8 Link to image

[ndutton]

Oh yeah, there are problems. Before we go deep we should double check a few things on the drawing for accuracy:

• The - post on the coil goes to the distributor, NOT an engine ground. Don't be misled by the - sign. If in fact it goes to the ground it explains the overheated coil in spades.
• Ignition switch wiring (as drawn) is several layers of wrong. Pleased revisit it carefully including terminal labeling (B for battery, I for ignition and S for starter solenoid) on the switch itself. One of the wires, probably heavy gauge red, should go from the large starter post to the B terminal on the ignition switch (not shown on the drawing).

That was a good effort on the drawing and it really helps. Let's double check these few things and we'll really get down to business.

[dwkfym]

Thanks. Let me check the coil post tomorrow. Just to be clear, we aren't talking about the ignition cable (looks like a spark plug cable) that goes to the distributor cap, correct? You are talking about the negative post?

Also, my ignition switch is sealed from the back. I see four wires coming out of it each with a label. I think I have it right.. I took some photos of the gauges attached below

Note - loose nuts and such is from me taking them off while working on the wiring.

[ndutton]

Not to worry dwk, we'll get through this even if it's one wire at a time. For starters, let's talk about the coil connections. You are correct, we are not talking about the large "secondary" wire that comes from the big center snoot on the coil but rather the wires that attach to the small posts marked + & -.

The coil takes modest 12V and boosts it up to somewhere between 25,000 and 40,000 volts, enough to cause a tiny lightning bolt across the spark plug gap. The 12V input voltage is delivered through those two small posts on the coil. There may be a number of wires on the + post but for simplicity we'll only talk about the one, hopefully purple if of the proper color, that comes from the I terminal on the ignition switch. That wire provides 12V+ to the coil when the ignition switch is on.

As we know, we need a complete circuit so the coil also gets a 12V- wire connected to the small post marked - but here's the important part: that wire is NOT a solid ground. It is switched on and off by the points under the plastic distributor cap. That's the reason the wire connected to that post comes from the distributor. For this discussion, it's the ONLY wire connected to the - post. (Note: if your instruments include a tachometer there may be a sensing wire to it that's connected to the same - post on the coil so if there are two, confirm one goes to the coil, the other to the tachometer) Any other wires on the coil - post are wrong, wrong, wrong.

You might want to keep the attached wiring diagram handy while we are chasing this down. It may not be exactly how your boat is wired but the basic engine wiring will need to end up as in the drawing.

[dwkfym]

I'm at the boat. Negative post on the coil does go to the distributor.

[ndutton]

Did we determine whether or not you have electronic ignition? Is there one wire (typically black) coming out of the side of the distributor or two (red and black)?

[dwkfym]

It has points.

Here is the corrected wiring diagram.

[HOTFLASH]

Gauge -

Thanks for the diagram. Print is small for my eyes, so I cannot see some of the labels and have not followed each wire. But at first glance I did notice that the G( -) wires from the gauges one to another do not seem to be connected to a (-) ground bus or other wire to ground. Am I missing something?

Mary

[ndutton]

In addition to the missing ground Mary noticed, I see no 12V+ path from the battery switch common to the ignition switch and I'm having real problems with the ignition switch terminals (Ign, Blo, Ign. Blo) when every ignition switch I've ever seen has Battery, Ignition, Start and maybe Accessory terminals. I see no wire to the starter solenoid, required to actually start the engine and I see no sender wire for the oil pressure gauge.

Until we sort out the ignition switch connections we can't deal with the ammeter and everywhere those wires go. That your engine was running prior to this episode indicates there are still inaccuracies with the drawing because with what is missing, there's no way it could start and run. Sorry to be a pain, just trying to get the best information so we can give the best advice.

In the meantime, carefully examine the wire from the points inside the distributor to the coil - post for damage and a short to ground, especially where it exits the distributor, and check to be certain the points open and close as the distributor shaft rotates.

[Marian Claire]

" I'm having real problems with the ignition switch terminals (Ign, Blo, Ign. Blo)"

I think the Off/Blower/Ign+Blower/Ign switch is like the one that came on the MC. The same one that failed and I eliminated. One thing it does is forces you to pass thru the blower only setting before you can start the engine. Kind of reminds you the run the blower before you start the engine. Then you can have the blower running and start the engine. The last setting allows you to use all battery power to start the engine.
Dan S/V Marian Claire