Dies, wait, restarts

[kpdii]

This week we were about an hour out on my new to me 1977 Newport 28 w/original Atomic 4 and the engine suddenly dies. No warning, no sputter, it just dies. We attempted restart to no avail and spent the next hour grabbing the small amount of wind we could find to get somewhere.

Just after that hour filled with total frustration of getting nowhere, I tried the motor again and it fired right up. She ran smoothly at lower RPM's so we motored on (no wind) for about 4 hours at 3.5 knots. If I tried to increase the RPMs I occasionally thought that I would hear a miss so I backed it down and kept it low.

While she was running (in fresh water) the temp stayed near 150 the entire time. Ambient temp was 100.

My guess from dealing with cranky old cars is that it is ignition related, specifically coil or condenser due to the sudden nature of the engine stopping, and the restart once it cooled. When it was at higher RPMs, it was more like an intermittent miss than a sputter, so that leads me to think its not fuel. Does that sound right to everyone?

It looks like a tuneup is in order, if heat was a factor, what steps do people take to keep the ignition cool?

Thanks
Patton

[rewell6]

Sounds just like a heat related ignition problem. The coil should be fine if it gets hot. Just make sure it's not near the exhaust.

[sailhog]

Could be the coil. However, I've been told (by the Moyer people) that they don't fail very often.

[kpdii]

Originally Posted by sailhog

Could be the coil. However, I've been told (by the Moyer people) that they don't fail very often.

What else would you look to?

[cardiacpaul]

heres a redneck way of keeping the coil cool.
go to your local used computer dealer (electronic discount sales on abrams in arlington texas for those in the dfw area)
Wander over to the pallet of CPU fans (not case fans, those are 120 volt.. cpu fans are ... shocking, 12volt!) take one home with a couple of tie wraps for oh, all of 2.00. Wire the red to the hot side of the coil and black to the neg side, (don't wire the neg side to an independant ground, your coil won't work) and voila, cooled coil101. Wanna get fancy? grab a "great-big-o" (international southern unit of measurement) cpu heatsink & strap it on along with the fan.

[sailhog]

kpd,
I have a book on trouble-shooting the A-4, but it's on my boat. Let me get back to you tonight or tomorrow.

[kpdii]

Thanks Guys.
Patton

[capngregg]

If you are completely satisfied with the cleanliness and integrity of your fuel system (tank and pickup screen in particular), I think you will find that it is an ignition related problem and more than likely the coil itself. Not knowing the current status of your system I would investigate upgrading to a solid state (pointless) ignition system.

The upgrade is not expensive (depending on your budget I guess) and really performs much more reliably in the long run. Upgrade the coil as well.

For those windless days I have an '68 Century with a 285 HP, 390 cu.in. engine (industrial engine that rotates R/H) that I had problems with much the same as yours. Hard to start sometimes too, but it just never seemed to act like a big powerful engine until I upgraded the ignition and added a high performeance racing coil. The engine would only reach about 2700 RPM and then surge/"ping" if I tried to accelerate any further.

The coil looks and costs almost the same as a stock coil but the windings of course yield a much hotter spark. This sleepy engine came to life and really does put out the HP now.

Verify the fuel system integrity (especially the cleanliness of the standpipe pickup screen or your in-line fuel filter) then go for the ignition system upgrade.

Good Luck!

[sailhog]

KPD,
Here's the scoop from Moyer -- if indeed you have these symptoms...

If the engine shuts down very abruptly, as if someone had inadvertently turned off the ignition:

1. Loss of dependable 12v DC ppower to the positive terminal of the coil. The corrective action is to trace the 12v circuit in the boat's electrical system and repair faulty wires, connections or switches.

The second cause:
Broken lead between the negative terminal of the coil and the points assembly. The corrective actin is to replace the lead.

Here's an added note:
In many cases, loose or corroded terminals build up a small amount of heat during the final moments before failure. Wiothin a short time after failing (usually 15-30 min.) these terminals may again make a good connection after cooling. The engine may then appear to run normally, but seldom for more than an hour or so.


Sounds like your engine was running for four hours, so I don't know if that's the problem. Hope this helps.

[imagine2frolic]

Can you raise rpms with the choke is out? If so then rebuild the carb. Mine had this same reaction when my iron fuel tank started to deposit rust into my fuel.