New to me 18 hp Evinrude.

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Crosbyman

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coils points condensers are all the same....standard mag since early 50s onward.
strand copper or just plain metallic is usually available in bike shop or lawnmower shops. Carbon fiber is for cars to prevent static noise on the AM band because metallic cable would radiate high static noise
 
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Bman2895

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Yeah not fixed. It was okay for run but then went back to missing and then to not running on the second cylinder again.
 
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racerone

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Need to look at some videos on maintaining this simple magneto.----You overlooked something.----Like removing magplate and screwing new wires into the coils BEFORE putting coils in position.---Factory offered a special ring to place coils in position.
 
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Bman2895

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Thata definitely my next step. Getting some solid core wires and replacing them the correct way.
 
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Bman2895

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So the wires are solid core. I compared them to a set of wires I have off an old armature plate that are original wires and they're exactly the same as far as the copper and the thickness.

And as far as screwing the wire in the coil just has a spike where the wire goes in it's not like a coil on say a motorcycle where it does screw in?

Only things I saw when I took the armature plate off that stood out was there's a ground that goes from the armature plate to the block and it was in pretty bad shape. And the little screw that holds all the wires to the points with slightly loose. seems as though it's stripped when I tightened it and it never really tightened down.
 
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Mc Tool

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Bman2895 said:
So the wires are solid core. I compared them to a set of wires I have off an old armature plate that are original wires and they're exactly the same as far as the copper and the thickness.

And as far as screwing the wire in the coil just has a spike where the wire goes in it's not like a coil on say a motorcycle where it does screw in?

Only things I saw when I took the armature plate off that stood out was there's a ground that goes from the armature plate to the block and it was in pretty bad shape. And the little screw that holds all the wires to the points with slightly loose. seems as though it's stripped when I tightened it and it never really tightened down.
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Some coils do just have the spike , put some goo on the lead and shove it in and let the goo set . A bad earth is in the troublesome area so that would be a good fix , and with the points screw , take it out and have a look might be the screw thats stripped if your lucky, then you just gotta find another screw :)
 
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Bman2895

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Yeah the one newer coil had the screw in type wire. I changed one of the plug wires and it wasn't sure if it was solid or not. So I know both wires are solid copper. Fixed the ground. I took out the kill wires completely. The switch is bad and the wires cut already so I just removed them. I have a good spare set to throw on once I figure this out. Fixed the screw with a un stripped screw. Re assembled.

It's back to missing/dropping out on the top cylinder. It'll pop and cough on that cylinder too. Now when I swapped the coil the last time to the current coil on it ran much better without the missing until I ran it on the water for a few then back to dropping that cylinder. Two bad coils? It's got nice bright blue spark when testing it.
 
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Bman2895

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Did some more testing and honestly I'm just more confused. Spun up with a drill and the plugs out to see the spark. Both plugs sparked great. Even when spun up to speed. One thing I did notice was the top cylinder the faster I spun it over the spark got brighter and brighter. Where as the bottom cylinder the spark stayed the same as far as strength goes and just got faster.
 
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Bman2895

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Its simple enough I'm gonna swap coils around and see if the problem follows the coil. If it does then I'll have confirmed the coil issue. If it doesn't then I'll check condensers and points.
 
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racerone

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Condensers should be tested ( MERC-O-TRONIC ) magneto analyzer.----Often test OK when cold.-----Fail when warmed up.
 
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Crosbyman

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Visit the AOMCI western site ( link posted above) for great docs covering condensers, testing, repairs and if you plan working oldies there is a great little condenser test box you can build. You can ask mr.Mohat to send you the diagram. (read his article ). His basic model without this dial works great.
1756297440624.png
 
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Bman2895

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This is the issue. Figured I'd upload a video. In this video I only have the top cylinder plug wire on. It does this. Then on the water it seems it just gets worse until it's missing entirely.
 
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Bman2895

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So swapping the coils the spark still looks great at the plugs. However the bottom cylinder still ran without missing and the issue stayed on the top cylinder so I can rule out that coil. And you can still here it cut in and out. Gonna swap condensers and recheck tomorrow. I don't get alot of time in the evening to mess with it.
 
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racerone

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Seems to be an issue with throttle.-----Need to set up throttle so it opens closes at the correct time.-----May not be a spark issue at all.
 
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Bman2895

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One coil just didn't spark well at all at slower speeds. Put one in that did better but not perfect. So I'm just gonna need new coils. Any recommendations on brand?

I also swapped around the condensers and initially assumed there was no change as spark visually looked the same, but when I started it up this morning the top cylinder now runs smooth and the bottom cylinder now coughs and sputters. So im gonna swap another condenser in and re test. If it's not that then the coils are simply the issue.
 
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Crosbyman

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Coils available today are dirt cheap (Amazon) & seem to have a wide range of secondary resistance values ...sometimes 4K sometimes I have seen some at 8-9 Kohms . Try to stick with OEM $$$$

8-9Kohms may mean more turns to induce move volts or it may simply mean cheaper China wiring or wires so small that resistance increases with no real benefits. I suspect extra thin wires may become more prone to failure from internal arcing or heat deterioration .

Condensers... well they go bad incl new ones and must be tested under load be it Merc-o-tronic or Mohat boxes.

SPARKING IS VERY SUBJECTIVE..... I have rarely seen strong " snappy & blue sparks" and all my oldies work fine. maybe you have other issues to resolve.
 
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Bman2895

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Well currently spark is a nice blue "strong" spark. it does seem to jump roughly a 3/8 gap to the block. I may have been chasing partially a fuel issue. I think the cutting out was in fact spark related. But the coughing and sputtering I believe I've got that solved. I fired it back up today without changing anything I did last night. Let it warm up in the bucket to the point that it would have started missing before and it never did start cutting the cylinder out. It would still cough and sputter and I noticed if I slightly held the choke down it stopped. So I just opened up the mixture screw a little and that took care of it. It still doesn't want to idle down low. But it's low enough you can put it in gear without tearing things up.
 
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geoffwga1

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Bman2895 said:
You do? I've always had luck just popping them out and if needed snipping the end of the plug wire and putting it back in. But then again. I've done say 6 of these older Johnson/Evinrudes with the points ignition so I may just be getting lucky.

Are those adjustable spark gap testers suitable? And where can i get ahold of wires with the solid copper core? It does infact have two much newer (guessing hi resistance) plug wires on it. And never knew about the goo. May need to do that.
Click to expand...
Motor bike shop is your best bet,
 
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