Did have only one cylinder firing, now have neither

[mr-asa]

My ’54 Gale 12D10, pretty much just the typical OMC ignition system.

When last I worked on it I had one cylinder sparking nice, fat, and blue. The other cylinder got me nothing. I got tired of futzing with it, so I put it aside for a couple months while I worked on my Fleetwin and enjoyed getting it out on the water.

I’ve got a couple reasons to get a more powerful motor running, so I turned back to my 12HP to see what I could see.
Pulled the flywheel to see what was what. Realized that the point set opposite the cam was not normally closed so I adjusted it so that it was. Rotated the crank through and saw that it opened. Ran a little bit of sand paper over the contacts, made sure everything was good that I could see and buttoned it back up then used a spark tester and saw…. nothing.

I have one of Frank’s timing ring sets and used it, the entire ignition system is new with the green coils, plugs are clean and have the correct gap according to the manual Garry gave me (I don’t remember the setting, but I remember doing that when I put everything back together last,) and like I said before I put it up a couple months back I had a nice fat spark on one cylinder.

Well?

[Doug Wilson]

double check the points and make sure they are wired right. make sure the plug wires are in the coils good may also crank the throttle a little further open than start have seen the timing get off a little. my uncle gave up and sold his 58 18hp johnson after replacing the coils guy that bought it opened throttle more started on first pull then would idle down never figured out why

Doug

how is it motors multiply when the garage lights get
turned off?

[mr-asa]

Points are wired correctly, I didn’t pull anything apart other than the flywheel to do adjustments, so nothing there changed except the settings.
I’m not trying to start it, the fuel lines aren’t even hooked up, right now I am just checking for spark. I tested it in all positions of the timing plate’s adjustment.

[frankr]

If you haven’t already, take the points completely out and polish each contact shiny bright. Trying to do it while on the plate is almost futile. Then reassemble and set the gaps correctly. I’m betting you will have fire.

And what’s this about the set opposite the cam not closing? That’s weird, unless they were gapped way too wide when open.

[chris-p]

^^^^What he said.

Dirty points, almost always. OR, debris between them, like sand from the sandpaper. Fingerprints can limit spark, they must be clean!

I polish them, install, then dip a business card or paper stock in acetone, and run that through to clean. You will be amazed at the dirt on the paper.

[fleetwin]

OK, seems like you are saying that you have replaced all the ignition parts on the dead cylinder, and there is still no spark, correct? Keep in mind that just because they are new parts, doesn’t mean they are any good. But, it seems like more than a coincidence that there was no spark before you replaced the ignition parts.
The only other thing left is the plug wire for that cylinder. Maybe it is shorted to ground or broken, do you hear any arcing?

[johnyrude200]

Many times I find the plug boot terminal is faulty. After you do the things mentioned above, pull the boot off, check for continuity from both ends of the wire. If the wires are original it may not be a bad idea to just swap them out. Granted, it’s another 30 mins of work, but if there are any pinholes in the wires (or if they are unflexible due to age, that could easily indicate they might be the culprit), the voltage can arc out anywhere along the line.

You could always pull the motor over with the lights off, a dark room. You’ll be able to see if it’s arcing somewhere else fairly easily. You might want to use a rope instead of the manual starter because you’ll have more cranking speed (in general, more voltage if it’s a weak system), and can stand in a place where your vantage point to observe different parts of the motor is easier to control instead of at the bow end of the motor.

I think the 10th edition service manual states it best – electrical current is like a pipe with water. If there are leaks, you get less at the end of the pipe, so you have to trace it back to the source step by step. Trial and error can be pretty frustrating, the magnetos aren’t as complicated as they might seem but can be a bit tedious at times.

And I agree with what was said before – if all else fails, swap out your point set completely, again. There seems to be some points which simply don’t work or are not compatible. If you don’t have a merctronic to test the components (in particular, coils and condensers), it can be pretty frustrating and time-consuming figuring out what the faulty component is.

[mr-asa]

quote FrankR:

And what’s this about the set opposite the cam not closing? That’s weird, unless they were gapped way too wide when open.

I thought it was weird as well. I took that one off and realized it was not a 90 degree angle between the bottom and the side, so I bent it back to where it should be and it closed up when I reinstalled it.

quote fleetwin:

OK, seems like you are saying that you have replaced all the ignition parts on the dead cylinder, and there is still no spark, correct?

I replaced all the parts months ago when I broke the motor down completely and rebuilt it, so literally everything in the ignition system except for the mounting plate and the flywheel is new. Plug wires are included in that list so I don’t believe they are the culprit, I didn’t hear or see any arcing.

[fleetwin]

Well, we must be missing something. Have you checked the offending cylinder’s points with an ohm meter to be sure they are closing fully and making complete contact to ground (with coil/condenser leads disconnected). Perhaps the points are binding on the pivot pin and not closing fully or slowly. You should see an ohm meter reading as close to zero as possible when the points are closed and the meter is calibrated to its lowest scale.
Next, I would just try swapping the ignition parts, one at a time, between cylinders. It just seems like too much of a coincidence that this cylinder did not spark before, and still does not spark with all new components. But, crazier coincidences have surely occurred. I am assuming this engine does NOT have any sort of stop switch set up and the mag plate is not sloppy from side to side.

[mr-asa]

I’m not sure how that would help, as I don’t have good spark on either cylinder right now? I can go through and check everything individually, but I’m not sure what known, good values of everything would be.

I haven’t ohm’d anything out yet as yesterday I just went to replace a couple broken parts and double-check the ignition. I will, however.

The closest this has to a stop switch is the timing adjustment bar that is adjusted independently of the throttle. Not a whole lot of play in the motor, in general.

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