Coil or fuel: New Ignition, dies after 20 minutes, runs and dies

[mgraham49]

New super cool electronic ignition. No good deed goes unpunished. did not replace coil. When cold overnight, starts, runs 10 - 15 minutes, then dies like no gas. If let sit 5 minutes, will run for 30 seconds. If crank with key off, can see wet fuel (not puddle, it drains out the scavenge tube) in throat when choked.

Have replaced fuel filter, cleaned bowl for mechanical fuel pump, pulled drain from bottom of carb, all seems to work well.

But it starts and runs and dies as if running out of gas, not an all or nothing like I thought ignition problem would be. But when it does restart, it starts instantly, not after cranking a while (which I would think would be the case if it were fuel were being starved then delivered).

I read all the threads on this, I didn't hold the coil wire to the block, but I did pull a plug and ground it to the block, it is sparking. But is it possible to get spark but it isn't strong enough from marginal coil breaking down with heat?

Also, don't know if this is issue (will post separately) but #2 cylinder has about 20 pounds of compression. Other three range 90 to 110. I see the posts about MMO. Do I just put it directly into the cylinder with plug out? I see Don's sticky about what it is, but could not find guidance sticky about how to use, how much in gas tank, how much directly in cylinder. And could the one open cylinder (I assume stuck valve) be related to start stop above? I don't think so.

Sorry for long post. I have owned this boat and this A-4 for 35 years, and this is the first time it has failed me.

Mike Graham - Bali Hai- Pearson 10M, Hull 14

[sastanley]

Hi Mike,

Is the coil original? My 32 year old coil failed right after I went to electronic ignition last year.

Coils are about $35-40.

Will wait for your other thread to comment on the other stuff, but yes, squirt it right in the spark plug hole and then turn the engine over a few times (by hand or with the starter) to mix it around and let it sit.

Oh, and welcome to the forum..as the single owner of your A-4 I'd be interested to hear about your experiences with it over the years and pictures, etc..

[ArtJ]

You can squirt some MMO directly into the plug hole. The valves are towards
the manifold side. You should be able to see at least one valve thru
the plug hole. Squirt a generous amount into the cylinders and the valves.
Remove all plugs and turn the engine over by hand. You should see the
valves moving up and down. If one is stuck, you can sometimes free it with
a allen wrench inserted carefully into the plug hole.

Let it soak a while and repeat, soak over night. The MMO can says how
much to add to gasoline.
I bellieve Don mentions elsewhere an amount which
is double that on the can to use.

If a few days of repeating the above don't yield results, another
scenario that works quite well is to drain all the regular oil, and refill
crankcase with 3 to 4 qts as required of MMO. Run the engine at no
more than a idle for several hours a day. Measure compression again,
repeat this for several days. Be sure not to run the engine above 1k rpm
in neutral.
When done drain oil and replace at least once, possibly twice to remove
mmo

Good Luck

Art

[mgraham49]

Coil is original (1974). Little rust on the sides, boat was in salt water for 15 years, then fresh water for last 20 years. But does a coil partially fail, where if you let it sit for 5 minutes, it starts, sounds fine, then after 30 seconds, begins to miss, then dies while stumbling? It is not a clean start stop. But it does restart instantly if it is going to restart.

If I could get a coil locally in an auto shop, I would go to boat and install tonight. I buy everything from MM, but not sure I can wait several days for new coil to be delivered. But don't want to screw up by buying wrong coil.

Mike

[sastanley]

Mike,
Yes, your coil symptoms sound very similar to mine when my 1977 coil failed last summer. Mine stumbled in such a way that I thought it was a fuel problem. Each time the engine restarted, it would run for 30-40-50 seconds, and then it would eventually not start at all. Wait 15 minutes and varoom! The final test was to mount the new coil and when the engine died after a 45 minute run, I switched the wires to the new coil and had the engine running in 5 minutes and it never failed again. I left the old coil on the engine as my 'spare' figuring I can at least limp home with it if my new one ever gave up.

I like to also buy A-4 parts from Moyer when I can, but sometimes it is simply more economical to buy locally.

I have the chrome () Flamethrower brand coil #40501 with 3 ohms resistance if I recall. As far as I can tell, the model Moyer sells on this site is the Pertronix #40611 (Epoxy filled black).

Link to coil --> IGLM_05.1_395

[mgraham49]

At the risk of showing how dumb I am, do coils come in different ohms, etc? What do I tell the local auto store if I want to try tonight?

[sastanley]

Apparently they do, & I don't know much about them either, except that I got one with the same specs as what was available thru the Moyer store. I think it is mostly about the internal resistance number (in ohms), but that is where I'll stop since that is all I know.

I find that the parts store chains (AutoZone/Advance, etc..) usually have employees that are pretty clueless when it comes to trying to help with marine engines. I think most of the chain store employees can't even change the battery in their own car.

Sometimes the local NAPA guys can help out, and a few of them have even heard of the A-4.

[hanleyclifford]

To get the idiot-proof result, tell the clerk you want a coil with its own internal resistor - if you start talking about ohms with these people you will lose their attention.

[roadnsky]

This from Don...

What coil is recommended for the Atomic 4?
Most coils with an internal resistance of 3 to 4 ohms should work very well in the Atomic 4.

In the unlikely event that your boat has had an external ballast resistor installed in its primary ignition circuit (somewhere between the ignition switch and the coil), you should select a coil with a lower internal resistance (approximately 1.5 ohms). The ballast resistor is a rather large porcelain device measuring about 4” long by 3/4” square, and it provides the additional 1.5 to 2 ohms necessary to bring the resistance within the primary circuit back up to 3 to 4 ohms. Coils which have a ballast resistor providing some of the required resistance externally tend to operate a bit cooler than coils with internal resistance. We have always been assured by manufacturers, however, that coils are designed to withstand the additional heat of internal resistance.

Manufacturers also point out that traditional metal-covered, oil filled coils tend to transfer heat somewhat more efficiently than solid epoxy coils. The fact that oil filled coils may feel quite hot to the touch is clear evidence that they are indeed transferring a lot of heat to the atmosphere (and to your fingers).

Unless coils are subjected to extremely high heat, physical damage, or oil leaks, they should have a life expectancy of many years. In many cases, coils last practically indefinitely. Some folks from very hot climates report that they have been able to improve their coil life somewhat by moving them outside of their very hot engine compartments. Prior to relocating their coils, they would have to replace them every year or two.

The increased dwell time provided by electronic ignition systems (approximately twice that of conventional systems) can cause coils to run somewhat hotter than those on engines with points and condensers. However, we have no evidence from our experience to indicate that coils used in electronic ignition systems fail significantly faster than those in conventional systems, nor do we have any indication that any good oil-filled coil (with at least 3 ohms internal resistance) will not work satisfactorily with electronic ignition systems.

Maybe buy a cheap one from the Auto Parts store to get you going and order a "good" one from MMI.
Then you'd have a spare?

[ndutton]

I just went through this.

The critical factor in coil selection for the electronic ignition upgrade is the internal resistance of the coil. As I recall, it needs to be 3 - 4 ohms. Be careful, different coils have different resistances.

I got mine at a local old skool auto parts store but I specified exactly which Pertronix Flamethrower model number I wanted (thanks Shawn, your info was immensely helpful). If you go to the neighborhood auto parts boutique (Auto Zone, et al) they'll look at you like you're from outer space, then ask what brand and model car it's for. Without that, they're lost.

Mine was special ordered by my auto parts store, took them 3 hours to get it in.

The safest approach is Moyer, beyond that you'll need to get specific.

[mgraham49]

I just ordered my oil filled coil from MM. Safety in getting the right one, even though I am inpatient to see if this fixes the issue. So I get the new coil in Thursday, will put on this weekend. Hope that fixes it. I also got some MMO from the local store, now I need to do some reading about how to get some pressure in #2 cylinder, and I am a little nervous about the posts about hitting the valve through the spark plug hole with something that has been described as like an allen wrench. Back to reading the posts.

Thank you to all of you. Mike

[sastanley]

Mike, you might be able to see if the valve is stuck with a bright flashlight and someone turning the engine over while you observe thru the plug hole. If it doesn't move you might be able to see it. Alternatively, you could pull the valve cover, but that is under the carb & fuel pump.

It took my suspected sticky valve about 2 months to free up...MMO treatments, as they've been called here, can also drip down the rings on the pistons and free them up as well, which could get sticky and cause compression problems.

[mgraham49]

Success. I ordered and installed an oil filled coil from MM (thanks Ken) and when installed, the engine has run fine (in gear in slip for 30 minutes and then across harbor) without a cough.

It seemed so much like fuel I almost don't believe it. I always thought that either a coil worked or it didn't. But apparently with heat the coil can begin to break down and give inconsistent spark. Let it sit for even a few minutes, and it will restart and then die. Doesn't make sense to me, but there you are.

So now if I can just get the stuck valve in #2 to start working, and have a 4 cylinder instead of 3, boy will I be happy. If the MMO doesn't get it to work after a month, can I free the valve without pulling the engine? And can the valves be ground without pulling the engine?

All my best, and thank you to everyone.

Mike

[sastanley]

Mike,

I agree 100% that the coil problem seemed like fuel..my experience is that they get hot and slowly fade..give it a minute and it will get you going again only to die in a few minutes...after about 5 of these episodes, it fails to start & run.
To your other Q's, Yes to all of the above...keep at those MMO treatments in the cylinders....every time you use the motor if you can. If it doesn't work, some of the valves you can manually tap free with a little creative work thru the spark plug hole...well documented here on the forum. Otherwise, you might have to pull the head..but, nothing so drastic just yet...