atomic 4 coil problem

[srizzoa4]

45 minutes into my maiden voyage in my new to me 1969 Bristol 29, the engine slowly lost rpms then died entirely. I hoisted sails and coninued. 10 minutes later, there was smoke commng from the wires of the ignition swith wires. I found the battery and disconneded the positive. another 10 minutes went by and smoke was billowing up out of the engine compartment below. I didn't know there was a second bank of batteries. I disconnected them. epoxy was spewing out ot the coil. The coil is 29650 "use with external resistors". I notice in your inventory of coils for "early model" a 4 engines that they are internal resistor coils. Should I purchase this one from you and swap it or stick with external resistor type? I have to re-wire all melted wires first and I'm just starting the project. thanks in advance for your advice.

[ndutton]

Do your wiring repairs as planned paying close attention to wire gauge, colors too if you want to do it right and make future troubleshooting easier. Absolutely purchase your new coil (recommend purchasing a spare too) from Moyer Marine. It is an internal resistance type and oil filled (more heat tolerant than epoxy filled). No external resistor is required unless you have electronic ignition. If that is the case, search “Rule of 2011” on this forum for what, if anything, you need to do additionally.

The simple fact is you had the wrong coil installed. I suspect you left the ignition switched on after the engine quit too. A Moyer Marine alarm system helps avoid that error.

[ronstory]

... and welcome to the forum.

[Al Schober]

45 minutes into my maiden voyage in my new to me 1969 Bristol 29, the engine slowly lost rpms then died entirely..

This is not the sign of a classic coil failure. The 45 min part is good, but when the coil dies, the engine dies like you flicked off the switch - DEAD.

Glad you didn't burn down the boat!

[ndutton]

The 45 min part is good, but when the coil dies, the engine dies like you flicked off the switch - DEAD.

Al, that has not been our experience. If there is a failure of the ignition system such as a wiring connection or keyswitch failure, then it does quit instantly as you describe. However, coil failure caused by overheating often mimics fuel starvation with a brief slowing and stumbling before shut down.

That is what made it so perplexing to troubleshoot back when EI related coil failures were common.

[srizzoa4]

replaced coil, still no spark

I bought a new coil from Moyer Marine. Replaced it, re-wired engine according to diagram. I have 12 volts at the coil (pos terminal) when ignition is on. Center wire held near engine block (1/4 " from ground) has no spark. Center coil wire has 12K Ohms resistance which seems normal. I'm not sure how the center wire will spark when turning over as it is not connected to the distributor at this point except the negative coil terminal to coil ground.

[Dave Neptune]

Are you holding the coil or the cap end close to the block. Should be the cap end with the coil end still in place.

Dave Neptune

[ndutton]

. . . . it is not connected to the distributor at this point except the negative coil terminal to coil ground.

Please explain this in detail. Extreme, minute detail.

[JOHN COOKSON]

I read the thread. Maybe I missed it. Do you have points or an EI?

ex TRUE GRIT

[GregH]

The Moyer video about the coil shows clearly how they tested for spark off the center plug (that would be the end that would attach to the distributor )

Watch "Atomic 4 - Coil Check" on YouTube

https://youtu.be/IlmvMWf_1o8

[srizzoa4]

Dave Neptune, I had the end off of the distributor. NDutton, I have points and condensor. Here's what I finally found: I was getting no spark because of a ground. After a lot of hunting around, I found that the points were shorted out to ground. Even when they were open, it was a grounded circuit. I also found that the wire from the neg terminal of the coil to the condensor had high resistance, so I replaced it too. The engine fired up for the first time since the maiden voyage. It stalled after 15 or 20 seconds, but still I was proud of myself. Now that I have spark, I have something to work with. I will set the points using a feeler gague tomorrow (I just threw the new one in there before tonight's research on how to set it) BTW, do I turn the distribotor to open the points or use a hand crank with ignition off to set points to max open where I gague it to 0.020? I guess i will then turn the distributor for max rpm (timing) with the engine warm and in gear. Ken at Moyer Marine has been most helpful as have people on this thread. Thanks all.

[JOHN COOKSON]

(A) It stalled after 15 or 20 seconds, but still I was proud of myself.

(B)BTW, do I turn the distribotor to open the points or use a hand crank with ignition off to set points to max open where I gague it to 0.020? I guess i will then turn the distributor for max rpm (timing) with the engine warm and in gear. .

(A) Maybe to quick or to slow pushing the choke in after starting? Sounds like a fuel problem.

(B)Turn the engine with the hand crank to set the points.
You can power time the engine by turning the distributor when the engine is warmed up.

ex TRUE GRIT

Do you have a copy of the MMI A4 maintenance & repair manual?

[srizzoa4]

I"m not sure if I should now move over to a timing thread, but here's what's going on now: I gapped the points, changed and gapped the spark plugs, changed the fuel filter. She fired right up and seems to be running pretty smooth both in neutral and in gear against the dock lines. I loosened up the retaining nut on the distributer so that I can power tune it. I can not budge the distributer. I was hesitant to put a big pair of channel locks on it. I sprayed it with PB blaster and will try again tomorrow.

When changing the plugs, I found top dead center by manually turning the flywheel. When cylender one (nearest the fly wheel) was at TDC, the distributer was pointing directly towards the block. From my view this is the 3:00 poosition with 12 being stern, 3 being port, 6 being bow and 9 at starboard. It rotates clockwise. The spark plug wire that goes to cylinder number one was at the 6:00 position. From there it is 1,2,4,3. I thought from some of my reading that the distributer would point towards the block (3:00) as it was at TDC, but that is where spark plugh wire number one whould be. I moved the wires so that this would be 1 and then went on to the 2,4,3. It would not start and I got a ton of blow back or misfire. I put it back and it seems to run fine.

How should I attempt to free up the distributer or should I just leave well enough alone? I don't know how to use a timing light and I don't know where the marks are, so I can't check it that way.

I started more research when I got home and on the video that Don Moyer did about placing the distributer, he said that the distributer should line up pointing away from the block (which would be my 9:00 position). THis is 180 degrees off of where I am now. I seem to be getting closer to nailing this, but then now my research is confusing me worse. Any advise appreciated.

[JOHN COOKSON]

You're Doing Fine......

The stock set up is to have #1 spark plug fire when the rotor is pointing away from the engine. The rotor will be pointing at 3 o'clock or 9 o'clock when #1 plug fires depending on whether the rotor is viewed from the front or back of the engine. Is this the way your distributor is set up? If the distributor is turned #1 spark plug will fire when the rotor is not pointing away from the engine ie 9 or 3 o'clock.

ex TRUE GRIT

[roadnsky]

Here is a graphic that may help...