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Another coil question
https://slantsix.org/forum/viewtopic.php?t=64470
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Author:  wjajr [ Fri Mar 27, 2020 9:46 am ]
Post subject:  Re: Another coil question

Slantfin a ways back:
Quote:
I managed to test for spark at the coil, and have a yellow-orange spark coming from the wire that would go to the center of the distributor cap.
The way I read this is coil wire was not inserted into coil. and a ground was passed near the coil's tower.

If that is the case, it could be coil to distributor wire is faulty.

Can a good blue-white spark be produced from grounding a plug or is it still yellow? If a yellow spark is the case voltage is down, and not able to jump the gap under compression pressure in cylinder. It takes two full revolutions of crank to fire a plug once.

There are two circuits in play during starting and running engine. Start circuit bypasses ballast resistor feeding nominal 12V to coil. Once key is released from start, returning to run, current passes through ballast resistor reducing 12V to around 5 volts to coil.

Author:  slantfin [ Sat Apr 04, 2020 12:27 pm ]
Post subject:  Re: Another coil question

Thanks again for your attention on this. I took the wire from the coil that usually inserts to the center of the cap and stuck a spark plug into it and the grounded the threads of the plug to the alternator body. I'm going to check it again with a more simple approach of just taking the same wire and arcing it to the frame. I'll check the individual plugs for spark quality as well. I'll let you know the result.

Author:  slantfin [ Mon Apr 06, 2020 8:20 am ]
Post subject:  Re: Another coil question

OK, got serious last evening and once it got to dark-thirty went out and took a good look at the spark. Good white spark off the distributor end of the coil wire; good spark at the plug end of the distributor wires out. I don't have an excuse for my earlier attempts except that it was light out and it was always snowing/raining/I was in a hurry. Got all the time in the world just now, lol.
I'm calling the spark adequate, and am going to take a look at vacuum/carb today. If that doesn't work, I'll take this to the engine page. Thanks again wjajr, Lou, Reed and others who took time to help!

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