New here, an intro and questions

[ndutton]

Okay, I'll bite. How much voltage is too much?

[hanleyclifford]

I don't know that we actually settled on a specific figure suitable for all, but in my case if I see more than 12 volts at coil+, I put in a resistor. I have run as low as 10 volts with no ill effects.

[ndutton]

And there you've hit on the problem I have using coil input voltage alone as a diagnostic.

There are so many different internal resistance values with the coils found on A-4's that a single voltage or even voltage range alone can't say one way or another. We've seen coils of 1.5, 3, 3.3, 4, 4.5, and up to 10 ohms internal resistance reported on our forum.

For example, let's say my alternator output is 14.7 volts (it used to be) and my wiring system imparts a 0.2 voltage drop (it does) so I'm 14.5 volts at the coil + and there's no external resistor. Do I have a problem?

Well, maybe but we don't know for sure. If my coil is a 3 ohm, there's a problem (14.5V/3ohms=4.83 amps, 20% higher than the allowable 4 amp maximum specified by the electronic ignition manufacturers). If my coil is a Moyer 4.5 ohm, I'm good (14.5V/4.5 ohms=3.22 amps, 20% below the threshold).

I'm not saying the input voltage isn't important but we need the coil resistance too for a meaningful conclusion.

[hanleyclifford]

Agreed, the ohm value is an important piece. My coils are all around 3 ohms so the 12 volt figure is good for me. You are right, ohm value should be known before the volts at coil + figure can be meaningful.

[ndutton]

James,

Welcome to the forum and congratulations on the purchase of your 'new' boat. We got into this electronic ignition - coil business last year and you may find the thread informative. It's lengthy but worth the time I think.

The thread is found here.

[sastanley]

James, Anytime there is a coil discussion, myself, Neil and Hanley get in a tizzy. Do not be overwhelmed by our 'off-topic coil discussion' as we hijack your thread with our passions.

As you become more familiar with the engine, you'll learn idiosyncrasies you never thought you would have to deal with.

Like you, I bought my boat for the 'right price' with no knowledge of the A4, other than as a kid, it ran Ok and I spent many hours sleeping inside the genoa on deck, under power, out of the sun.. It is a resilient beast and we'll help you get it running more reliably.

I still highly recommend the Moyer Manual..it far surpasses any crap Universal published, which I found on my boat as well, and have since removed.

[marthur]

James,

I live aboard a Catalina 27 cruising the great lakes (especially in the North Channel of Lake Huron during the summer). I am very happy with our C-27 and it A-4.

Let me suggest a test for the coil / ignition. At the next shut down, remove the wire from the coil to the distributor. Hold it close the engine block and crank the engine. You should get a big blue spark. If there is no spark or a tiny yellowish spark (like static electricity in the winter) you have a problem with the coil or electronic ignition.

That said, I would preemptively replace the coil and keep the old one as a spare. If the problem is solved, chuck the old coil and get another spare. If not solved, you have one of the things I carry as "essential onboard spares." The quotes are because I carry more than just the essentials--I believe in traveling light, I just don't do it : )

Your original post was focused on fuel / cooling. The reasoning of the others probably goes something like this: A bad in-line fuel filter or the occasional piece of grit in the main jet of the carb can do funny things, but those problems are not usually sudden shutdowns. A blocked or partially blocked air vent to the fuel tank can cause a pretty abrupt shut down, but that will not usually resolve if you open the engine room. A coil, on the other hand will act this way if it going bad and overheating. If you have the factory original hot section (or an exact replacement) your coil is right near the hot section of the exhaust and the additional cooling air would definitely lower the temperature of the engine compartment.

Good luck!

Mike

[TAftw]

Hi everyone, thank you for all the information. Although this is a little overwhelming, I appreciate all the help.

I thought the engine was overheating and because of this I opened the hatch to allow for more airflow. I guess that airflow kept the coil cool and kept it from overheating? I don't know, that seems to make sense to me. For the short term it worked, but now I want to fix the issue. It now sounds like I don't have a cooling problem, but rather an electrical problem.

FWIW, the deck above the engine was getting abnormally hot, which is why I thought the engine was overheating. I'm used to powerboats with lots of insulation on the hatches to the engine room, so not being able to stand on the deck above the engine scared me a little. I know nothing about sailing, this is my first sailboat so I don't know what's normal and what's not! .

Is there any other coil I could buy at an auto parts or marine store that would work? I know about not mixing auto and marine parts, I'm just trying to figure out a way yo have the boat seaworthy by Tuesday. Mailorder might not be an option.

I'm leaving to work on the boat in a couple hours, I'll have pics up by tomorrow night!

[JOHN COOKSON]

James
Here's another coil test: Carefully feel the coil after the engine has been running for a while or after a shut down. If it is super hot order a new one from Moyer - they're compatible with electronic ignitions. Coil heat damage is cumulative and irreversible.

If you need help with the gauges let us know. There are a lot of experts in the forum. I rebuilt the wiring on my gauges so I'm familiar with it. With two gauges out, off the top of my head, it sounds like a power supply problem to the two gauges.

I've owned my 1979 Catalina 27 for 31+ years. It's the perfect boat for me - at least the way I use it.

Welcome aboard.

TRUE GRIT

[JOHN COOKSON]

Is there any other coil I could buy at an auto parts or marine store that would work? I know about not mixing auto and marine parts, I'm just trying to figure out a way yo have the boat seaworthy by Tuesday. Mailorder might not be an option.

See FAQs on the web site, ignition system, #8.

TRUE GRIT

[sastanley]

James..the distributors on our late model (post 1968-ish) A4's are made by Delco..so there is a slight mix of automotive & marine stuff going on with the Atomic 4 already. When I bought my boat, I found spares for various ignition parts from NAPA all over the place.

Back to the discussion about your coil, the problem is it is hard to find a coil in a brick & mortar store with enough internal resistance to meet what is recommended by Moyer. The coil Moyer sells is over 4 ohms (like 4.5 I think) - I went to an Advance Auto, and the best they had was a 1.5 ohm coil. It lasted about 45 minutes. John's recommendation to check out that FAQ entry is great! edit - here is a link, http://www.moyermarine.com/faq/4.2.html

There are alternatives, which is part of the off-topic discussion between Hanley, Neil and myself. Some of us have put a ballast resistor in line in front of the coil..that provides extra external resistance which lowers the incoming voltage to the coil..In short, the coil does not need 12 volts to power the spark plugs. In fact, on a good operating electrical system, the voltage may be near 14.0 if the alternator is working well. The coil definitely doesn't need 14 volts..Generally, coil failure seems to primarily be a problem on boats with electronic ignition, the details and theory of which I will not bore you with at the moment..

So, in theory you could get a 1.5 ohm internally resisted coil from your local auto boutique, and add external resistors in front of it to get up to Moyer's recommended resistance. I will warn you however, most auto boutique 'sales associates' will look at you cross-eyed if you start asking for specs on the internal resistance of the two or three coils they may have behind their parts counter, & most of them have probably never heard of a ballast resistor..you'll need to do the research yourself ahead of time.

Keep in mind, these are all suggestions and not necessarily recommendations. I do not currently run with a Moyer recommended coil, but there's other modifications I've made as well, and I've been tinkering and experimenting for over a season now. I am currently running a 3 ohm internally resisted Pertronix Flamethrower coil with a 1.8 ohm external resistor in front of it to keep my coil cool & happy.

By the way - the engine 'room' does get hot. I ran for 7+ hours a couple weeks ago & pulled the cushions & boards just to help promote air flow. Powerboats move at speed and even though they have insulated engine spaces, often are vented too, further aided from moving along at 20+ knots. Poor Atomic 4's are almost like boilers in the bowels of a big ship, so it is easy to assume you were overheating, especially without a functioning temp gauge. Some of us have picked up those $25 infrared thermometers to pinpoint engine component temps..talk about getting geeky!

[Jesse Delanoy]

One other thought. If your engine has an oil pressure safety switch (shuts off power to the fuel pump if oil pressure drops below a certain level) try bypassing it electrically when you have a shutdown, and see if the engine starts right back up. As you don't have an oil pressure gauge, this could evidence a serious oil pressure problem.

[marthur]

Unlike SStanley, I had no trouble getting a coil in the auto parts store when mine failed. They only carried one or two that would work but they were in stock. I am running electronic ignition with a BWD E502P oil filled coil from Advance Auto Parts in Cheyboygan, MI and it runs well. This is the third year with no problems in sight. My notes indicate that I paid $31.15 after tax.

I usually order from Moyer, but if you need to go to the parts counter, have them try to match / cross reference one of these:
Echlin IC64
Delco 070FLX
Niehoff DR-180 or UN171
Standard UC-15
BorgWarner E40BAP or E502P
NAPA: IC6450 (Canadian NAPA # is IC14)

Let the parts person know that you need 3-4 ohm internal resistance and the primary winding is 12 V and have them confirm the spec on their computer. FYI: I only have experience with the bold parts numbers.

On another note, here is the deal with your very warm cockpit floor: the C-27 has a very nice hot section to the exhaust. That would be the galvanized or black pipe that comes off the exhaust manifold. It loops way up and I have never heard of a water intrusion problem with this installation. That is a way cool thing.

However, the hot section runs right beneath the cockpit floor and unless it is really well insulated, it will heat that fiberglass right up. A poorly insulated hot section will make the cockpit floor uncomfortably hot in that area.

And don't forget: when the engine conks out you can always sail : )

Mike

[Carl-T705]

Are people confusing ohms and volts? A delco auto ignition operates at about 9-10 volts. That's why they run a ballast resistor to drop voltage not ohms. A delco ignition only sees 12 volts while the starter motor is engaged. The positive side of the coil has 2 hot wires, one from the resistor and one from the starter solinoid. Why Universal didn't copy this when switching to the Delco system is puzzling to me.

[hanleyclifford]

Are people confusing ohms and volts? A delco auto ignition operates at about 9-10 volts. That's why they run a ballast resistor to drop voltage not ohms. A delco ignition only sees 12 volts while the starter motor is engaged. The positive side of the coil has 2 hot wires, one from the resistor and one from the starter solinoid. Why Universal didn't copy this when switching to the Delco system is puzzling to me.

Actually Universal did enable the starting override circuit on some models using the "R" terminal on the (Delco) solenoid (energized only during cranking). You are right about the resistor lowering volts, not ohms, but the ohm rating of the coil must be known so as not to exceed the amp rating of the coil. Please be careful and don't get Neil rattled again on this.