after four hour run engine suddenly lost spark and died.

[afsam94]

I installed electronic ignition two years ago to replace points and new ignition system performed flawlessly until now.

In the absence of good sailing air we motored steadily yesterday for about 20 miles. The engine ran smoothly until suddenly rpm dropped and engine stopped entirely over a period of 2 seconds.

Engine turns over but will not start.
Fuel pump has good pressure to float bowl.
Emptied float bowl and refilled.
I should note that I removed a spark plug to examine it and it was certainly not flooded and in fact seemed dry but I think the biggest problem is that:
When I hold plug wire close to plug and crank there is no spark
There is no spark between the coil and distributor doing the same test.

Somebody else installed the electronic ignition a two years ago and with my limited ignition knowledge I was reluctant to start digging under the distributor cap (on the open water) to tinker with stuff I don't understand well.

I'm back safely in home port and was wondering what additional tests I can or should do.

Thanks again in advance to the Afourians

Al

[tenders]

I am 85% certain a new Moyer coil will get you fired right up again. Would guess that the electronic ignition stressed the old coil over a multi-hour run, and burnt it out. Sometimes when that happens, but apparently not in your case, the coil simply overheats and will run the engine again for a while when it cools down. But in those situations it is definitely failing.

It's also possible that the little wire in the electronic ignition that runs under the cap chafed through and grounded out. You'll be pleased when you remove the two screws holding the cap onto the distributor - it's easy to look at, and not very complicated under there. Just make sure that little wire doesn't get crimped when you put the cap back on. There's a notch for it to fit into.

Other more distant possibilities: the rotor cracked and isn't turning properly, the cap has too much carbon built up around the contacts to be effective, the electronic ignition itself failed (highly unlikely).

What I really recommend you do is buy a new coil, cap, and rotor from Moyer and replace them all. It's a ten-minute fix, plus the time you spend admiring it as you assemble/reassemble it, which could be considerable. Strongly suggest you carefully label where each plug wire goes onto the new cap, by looking at the old cap, before you pull those wires off the old cap.

[Al Schober]

Agree fully - sounds like a classic dead (or overheated - comatose) coil issue. Cap and rotor if they're due (I know mine are, and probably the wires).

[Mo]

I agree as well...sure sounds like a coil.

[afsam94]

thanks again to all

Will replace coil cap and rotor. As suggested this engine started to run again the following day after the engine had cooled down. I agree the coil is likely on it's last legs.

Once again you guys are making this too easy.

Will order from Moyer ASAP

I will post an update to this after make this upgrade and take her out for a test later in the month

Thanks

Al

[CalebD]

Coil. Definitely.

Also make sure you are running your engine "room" fan and that it is working efficiently. 4 hours of running puts a lot of heat into the surroundings in the engine room. I believe that the problem is that the coil can "overheat" and no longer produces sufficient spark at X degrees and has to be cooled off a bit before it will work again. The better your engine room circulation the less likely this is to be a problem.
Experienced this coil issue on a Tartan 34' under similar circumstances. The engine room circulation on that Tartan 34' was compromised imho, hence overheating eventually.

[afsam94]

Thanks - Late or Early? My Grampian's A4 is 1970

I want to order a coil and other parts. How do I know whether it's a late or early engine please

Also CalebD I take your point on engine room circulation. I have a blower that ventilates for CO but I still think it is getting hot in there so I may add a fan.

[afsam94]

Thanks - Late or Early? My Grampian's A4 is 1970

I want to order a coil and other parts. How do I know whether it's a late or early engine please

Also CalebD I take your point on engine room circulation. I have a blower that ventilates for CO but I still think it is getting hot in there so I may add a fan.

[Don Moyer]

Early/late model

Here's a link to early model/late model info. Don

https://moyermarine.com/faqemorlm/

[ndutton]

Also CalebD I take your point on engine room circulation. I have a blower that ventilates for CO but I still think it is getting hot in there so I may add a fan.

Take care here. Under no circumstances do you want air blowing into the engine space. For safety reasons the flow must draw air out of the space and safely overboard to be replaced by fresh air via aspiration.

Imagine a fuel leak of any size. The last thing you need is a fan blowing explosive gasoline fumes all over the boat.

[afsam94]

Thanks to Don for the early/late link. Will continue to rely on blower (sucker)

So will continue to rely on blower (sucker) to draw any any noxious fumes/heat out.

[afsam94]

Additional questions

i received the new coil and distributor cap.

In discussions with Ken he suggested the coil I currently have installed which I obtained from NAPA auto parts may be less than adequate for my atomic 4. He also said the one Moyer was providing (resistor not required) is different and better.

I have a couple questions please as follows:

• Instructions with the new coil say "Do not install these coils on 12 volt systems equipt with a resistor or with resitance built into the wiring harness." Do I have to worry that my atomic four may have such a resistance component currently?
• Why is this coil better and is it less likely to drop spark than my current coil?
• Directions with this coil say "If the negative battery post is grounded the coil terminal marked - must be connected to the distributor. If the positive post is grounded connect the coil terminal marked + to the distributor. Please help me understand what I need to be aware of here.

thanks
Al

[joe_db]

i received the new coil and distributor cap.

In discussions with Ken he suggested the coil I currently have installed which I obtained from NAPA auto parts may be less than adequate for my atomic 4. He also said the one Moyer was providing (resistor not required) is different and better.

I have a couple questions please as follows:

• Instructions with the new coil say "Do not install these coils on 12 volt systems equipt with a resistor or with resitance built into the wiring harness." Do I have to worry that my atomic four may have such a resistance component currently?
• Why is this coil better and is it less likely to drop spark than my current coil?
• Directions with this coil say "If the negative battery post is grounded the coil terminal marked - must be connected to the distributor. If the positive post is grounded connect the coil terminal marked + to the distributor. Please help me understand what I need to be aware of here.

thanks
Al

The A4 does not have resistance in the wiring harness. Do not worry about that.

You might have a ballast resistor. This would normally be a ceramic piece a couple of inches long with two wires connected to it. It would go on the + terminal of the coil. If you have one now, you can get rid of it. The Moyer coil has enough resistance on its own.

If the negative battery post is grounded the coil terminal marked - must be connected to the distributor A4s are negative ground engines, so connect the coil this way.

Why the Moyer coil is better - A4s are very hard on coils and doubly so with electronic ignition. Coils need resistance to keep too much current from going through them and causing them to overheat and fail. Aftermarket random coils from car parts shops might have the correct resistance and they might not. So....it is MUCH easier to just buy a coil we know works with just about any A4 setup than experiment with various car parts. The time and aggravation saved is worth a few $.

[afsam94]

coil and cap replaced w Moyer stuff.

She fired up instantly without a cough.

Forgot rotor and I have a used spare if that problem arises but will order new one with my next order to save shipping.