63 Johnson 18 hp ignition mystery

racerone

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It has 2 seperate ignition units and it is hard to believe both would fail.-------The shut off system is common to both and worth investigating.
 

HighTrim

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Yeah unless oil somehow contaminated both set of points at the same time, the likelihood of both new coils failing at the same time are about zero. I would look to the kill wire first.
 

twocyclemania

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As for the kill switch: I've tried with it disconnected; both wires. The points were 'again' dressed with sandpaper (wet type - fine) and a flat needle file and than cleaned. There is no chance of oil contamination. ???
 

racerone

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Remove the flywheel.---Next is to disconnect the kill switch wires at the points.----------Test for spark again.----OK I started working on these magnetos over 40 years ago and I consider them to be very simple !
 

bwkre

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I still say check the points with a meter or continuity tester. Disconnect the wire and verify that the points actually close. Like racerone says double coil failure ( or capacitor failure ) would be very rare and the only other common part is the kill switch. Eliminate the "human" error by verifying point closure, looks can be deceiving.
 

Evoil

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I'm assuming you've checked or replaced the plug wires, I know it's unlikely that they're both gone. but it's an old motor. and uh, as others have mentoned. check everything with a meter for shorts and open circuits that shouldn't be open. is the gap between the coil and magnet corrent?
 

twocyclemania

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Thanks for the hints! As for the points opening and closing: I've watched them as I turned the prop (in gear) with the flywheel off. They do open and close in sinc with the cam. As for the coil gap; I wasn't aware that there's an actual measurement if indeed there is one. I have them mounted visually so the flywheel turns. There's not much of a tolerance one way or the other. I have not replaced the ignition wires but I did trim both ends and had no problem with spark on day one; after that nothing. I'm going to try disconnecting the kill switch wires at the points. I had them disconnected at the connectors. I really don't think this is going to do it but I'll give it a try.
 

racerone

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When you find out what is wrong you will say -" why did I not look at that last week "----And yes the coils need to be in the correct position relative to the magnets.---The system is called a MAGNETO for a reason.
 

HighTrim

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Have the coils laminations flush with the edge of the mounting boss. you don't want to be able to catch your nail on it when you run it up the embossed edge. If too far back though, spark is limited or dead. Too far out and it will hit the magnets.
 

twocyclemania

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Checked the coil laminations and they were perfectly lined up with the casting on the mag plate. Done this many times and this one is no different. I also disconnected the the kill switch wires at the points - still no spark. I think I"m going to have to pull the mag plate and replace the ignition wires; only thing left. An antique car shop near me sells the metal core wire by the foot. Unless anyone else has any suggestions I think (and thank) all the responders and I'll be sure to let you know when this one is solved. Like I said I've worked on many motors; the ignition system is simple and I've never had a problem. (For the time being I'm not going to allow its cousin, my 63 10 Johnson (which runs like a clock) anywhere near this motor as I don't want it to catch what this one has).
 

twocyclemania

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Forgot to mention: I also ran a ground wire from the mag plate as suggested previously and no difference.
 

AlTn

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not sure how you're testing for spark, but I have had a bad grounding spot for the clip of the open gap air tester leave me scratching my head
 

twocyclemania

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Tested it three different ways: with in in-line tester (bulb that lights up); holding the plug to the block for grounding while cranking it; and the failsafe method - having the kids hold the end of the plug while I crank it over. - No spark or kids jumping.
 

geoffwga1

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Are you sure you have those coils wired up right.The one on top of the coil goes to ground on the coil retaining screw and all others go to the points(green wire from under coil and one from the capacitor.
 

HighTrim

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If you are going to work on outboards, you need to invest in a adjustable spark tester, and for the Magneto Ignition set the gap to about 1/4" or so. It needs that gap to properly test the ignition system. All methods you mentioned also rely on the spark plug functioning to provide spark. Sometimes even new plugs out of the box are bad.
 

tblshur

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please dont get mad at me for i know very, very little about what you talk about but should the hot side of points read open circuit on ohnm meter:confused::joyous:
 

twocyclemania

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I believe I have the wires hooked up correctly. There are two wires emanating from the coil. One is to the ground screw and the other to points mounting. As for the spark plugs I've used at least three different plugs: the correct champions that were on the motor; a brand new pair (for a later 15 evinrude that I had handy) and even a lawn mower plug. As for testers and ohm readings; sorry but I don't have them nor am I electrical testing literate. I just replace.
 

racerone

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OK, you need to take the time to learn how to use a simple ohmeter.----When you see the points closed in your magneto they need to be ELECTRICALLY CLOSED.-----A visual check is not good enough.--Any dirt on them and they will be ELECTRICALLY OPEN all the time .
 

twocyclemania

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Here's the latest! I pulled the mag plate and basically stripped it and cleaned everything. I checked the kill switch wires underneath (tried with them connected and without). Checked the ignition wires for continuity; they were okay. Reassembled everything (remember the coils and condensers are new). Cleaned and set the points. Coils are mounted flush with the casting on the mag plate. I trimmed the existing ignition wires and extended them so they would be sure to contact the coils. After I was done I had spark to both cylinders. The next day I went over everything and mounted the flywheel. No spark. I pulled the flywheel and cleaned the shaft taper and the flywheel contact area. I had put a small smear of grease on it but read in my Glenn outboard manual that that was a no-no. Reinstalled the flywheel and I'm getting a 'shock' on the lower cylinder (but no spark) and there's nothing coming from the upper cylinder. Thought I'd let everyone know since I'm really appreciative of the support and suggestions thrown my way. As for now I'm back to square one. I'm going to replace the ignition wires and have the coils/condensers checked. Any suggestions in the meantime are appreciated.
 

tomhath

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Dec 5, 2007
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Did you check the resistance from the points to ground (where the condenser and kill wire attach)? You should see a small but measurable drop in resistance to ground when the points close. There won't be much resistance when the points are open because the coil only has a couple of ohms. If you don't see a change when the points open and close you need to track down why (either the points aren't making contact or there's a short somewhere). A cheap multimeter is good enough (maybe $10 at any hardware store).
 
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