Evinrude Lark 3 - replaced everything and STILL no spark

[Gas Giant]

Engine is a '61 Evinrude Lark 3, Model Number 35524. (No generator)

Okay, as the title says I have no spark on either cylinder. I won't go into huge detail, (unless asked to) but here is the condensed version.

Work done:
-Replaced points and condensers, set points to 0.020"
-Replaced coils, adjusted coils as best I could using a straightedge per the manual I have.
-Replaced spark plug wires
-Replaced ALL engine wiring with new tin-coated copper conductor marine wire
-Replaced ALL the boat wiring with the same tin-coated conductor wire
-Replaced engine battery cables, and boat-side battery cables

How the tests were performed:
-Checked for spark using an automotive style adjustable spark tester. I don't remember what the gap was set at, but it wasn't very far
-Also checked for spark by grounding a spark plug to the block with the spark plug wire on the spark plug.
-Also checked for spark by sticking a screwdriver in the spark plug wire end and holding it near the block
-Several attempts were made using the electric starter. Despite the new wiring, the starter did not want to turn the engine very well. Not sure why, it did turn it over nicely a few weeks ago. Since it turned the engine so slowly, I didn't bother with many tests using the electric starter. NOTE: I'll worry about the slow starter later, mainly worried about spark for now (Its probably the Ford starter solenoid....)
-Most attempts were made using the pull starter. I did this several times with the wiring harness still connected and the key set to run, and several times with the wiring harness disconnected.
-It should be noted that the engine crankshaft turns over freely with pulled with the pull starter. I mean it obviously has compression, but its not locked up or binding or anything.

The only thing left I can think of is the vacuum switch mentioned in the manual....I am not positive, but I think this is it:

The post in it is loose. I disconnected the wiring from it (except for one white wire that I cranked the nut down on too tight), thinking it may have been throwing off the tests, but it made no difference - no matter what I did, I never got spark.

So, at this point, I have no clue at all what the problem could be. Any advice is greatly appreciated; I'm really tired of pulling the flywheel off and reinstalling it (done it 3 times now) and I just want this thing to spark so I can move onto lower unit and carburetor frustrations

 

[nwcove]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

out of my league, but will bump you up . (kinda seems like you have a wiring issue....grounding out, like a kill switch)

 

[freddyray21]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

the vacuum switch will only cut off spark to one cylinder not both. You do have the key on? There are two black wires coming out from under the flywheel. these are your kill wires. If the key is off they ground out each set of points and it will not spark. You can also just unhook the wiring harness and it will have the same effect at the key being on.

 

[Gas Giant]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

nwcove - thanks for the bump.

freddyray, I tested it both ways, with the key in the switch set to Run, and with the harness disconnected - still nada. But thanks for the info on it only killing one cylinder - when I think about the wiring, that makes sense as only one cylinder is wired to the vacuum switch.

I wouldn't rule out a wiring issue, I'm open to ANY ideas at this point.

 

[Daviet]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

Disconnect the wire from under the flywheel to the cut out switch and the other black wire from under the flywheel. If you still don't have spark the problem has to be under the flywheel. Double check all the wires under the flywheel and make sure they did not get shorted out somehow.
http://www.maxrules.com/graphics/omc/wiring/61_66_40HP.jpg

 

[Gas Giant]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

Daviet - will do. Now can I disconnect the other black wire from under the flywheel at the other end, or should I yank the flywheel and disconnect it at the flywheel end? (Actually never mind - the wire is already disconnected at the other end - I guess its off with the flywheel again!)

 

[freddyray21]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

check the points with an ohm meter to make sure they are working as supposed to. also make sure they are clean. even new points need a little cleaning.

 

[Gas Giant]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

freddyray, I'll do that. Any particular resistance value to look for, or am I just making sure they aren't open?

 

[freddyray21]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

with the points open and mounted the needle should not move. With the points closed and mounted you should peg the needle. just to see if they are not shorted out.

 

[Gas Giant]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

Ahh ok. Got it.

 

[lindy46]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

Did you replace the kill wires which attach to the points? If they are old they may short out and cause the no spark situation. Did you set the points when they were riding at the "top" mark on the cam? Did you mount the coils flush with the mounting bosses? If they are in too far, they may not spark properly. Did you screw the plug wires into the coils or just push them in? That's about all I can think of.

 

[Gas Giant]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

Lindy, to answer your questions:

1) Yes, I replaced the kill switch wires. They're brand new.
2) Yes, I set the points when they were riding on the "Top" mark.
3) Coils are mounted flush with the bosses, did it with a straightedge per the manual I have.
4) I did "twist" the wires back and forth when I installed them, but I wouldn't say I "screwed" them in. I'll look into that also when the flywheel is off.

Thanks for the replies so far. Any and all advice is appreciated.

 

[Gas Giant]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

More findings: (See end of post for the summarized version)

Pulled the flywheel again today and did some checking with a multimeter.

To make a long story short, both sets of points had continuity across them with the points wide open (at 0.020"). After my process of elimination, I determined that it was the wire from the coils that was causing this. If the coil wire was left disconnected (leaving the kill and condenser wires still connected to the points), the points weren't continuous with them wide open, and were continuous with them closed. As normal.

The same was true for both sets of points, oddly enough.

So I pulled the coils out, and ran some continuity checks on them.

One coil had no continuity at all between the ring terminals and the spark plug wire needle (is that what its called? The needle the spark plug wires "twist" or "thread" onto?). It was open. There was 0 ohms (as far as my Radio Shack multimeter is concerned...lol) between the ring terminals themselves, they were connected.

The other coil had about 1.7k ohms between the ring terminals and the spark plug wire needle. There was 0 ohms between the ring terminals themselves, they were connected.

I compared this to the old coils I removed, and they were similar to the one with 1.7k ohms. So, it appears as though I have one bad coil. (or 3 bad coils and one good one? lol)

But.......how would this affect the other set of points? Aren't they independent of each other? The kill wires were disconnected from the ignition switch at the connector and disconnected from the vacuum switch, and even when I tested the points with them all connected they didn't create the continuity across open points.

Summary:
-I have continuity across the points on both sets of points,) even with them as open as they can be, if the coils are connected. If they are disconnected the points act as normal as far as continuity goes.
-One coil has no continuity between the ring terminals and the spark plug wire needle, and one does.

Any ideas on what is causing this? Could a single bad coil cause that problem on both sets of points?

 

[Gas Giant]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

Just tried putting in two of the "good" coils - same result. Points are shorted when they are open IF a coil is connected to them. Take the coil wire out, and they are open (electrically) when open (physically).

It doesn't seem like its supposed to be like this. I've never had to go this in depth on a points-style ignition before. On my Bel Air, I'd just throw em in, gap em, and the car would fire right up no problems.

So, any ideas at this point are really appreciated.

 

[Gas Giant]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

Just some info I got, apparently my line of thinking was flawed in a way. When the points are physically open, I am reading a short because I am reading the continuity through the coil - so that is normal.

I also didn't have boots on the spark plug wires where they enter the coils - the engine didn't have them when I got it. So, when I put the coils back in, I used some M23053/5 heat shrink tubing to insulate the wires. Maybe they were shorting to the armature plate?

When I get it back together I'll post results.

 

[mark in new jersey]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

I'm most likely wrong, but I'll toss this out anyway...

If the magnet in the flywheel has become demagnetized (and that happens to old AlNiCo magnets all the time), you won't get a spark.

Ultimately, it is the magnet.....passing by the coil...that induces current in the coil's primary [the iron laminations]. This current, when induced, causes a huge voltage on the coil's secondary winding; it is that huge voltage which ultimately jump's the plug's gap.

But: No magnet = no current = no voltage = no spark = no run.

 

[Gas Giant]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

Mark,

You bring up a good point.

I did forget to mention that I tested the magnet the other day by dangling a steel screwdriver on a string around the inside of the flywheel. The magnet grabbed the screwdriver no problem, so I guess its still magnetized. Not sure how I'd measure the strength of the magnet, but it felt pretty strong.

 

[lindy46]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

Just some info I got, apparently my line of thinking was flawed in a way. When the points are physically open, I am reading a short because I am reading the continuity through the coil - so that is normal.

Correct. I think your coils are probably ok. You should have 0.9ohm resistance between the green and black coil wires and about 4000-8000ohms resistance between either wire and the spark plug wire spike. That's with the coils disconnected from the motor. I doubt if your flywheel magnet is the culprit - I've never seen one go bad. Have you tried disconnecting and taping off the kill wires from the points? Try that and see if you have spark. Do you have continuity at the spark plug boots back to the coil? I'm running out of ideas here!

 

[Gas Giant]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

lindy46 - I'm glad I'm not the only one running out of ideas!

I do have continuity between the spark plug boots and the coils, I did check that.

I haven't tried leaving the kill wires disconnected at at the points, but I have tried it with the kill wires disconnected at the other ends (one of them goes to the vacuum switch (and meets up with another that goes to the plastic connector that mates with the boat wiring), the other just goes goes to the plastic connector. Meaning I disconnected them at both the vacuum switch and plastic connector. You think possibly they are shorting out anyway, somewhere between the connector/vacuum switch and the points? They're new wires, but I suppose anything is possible.

I did put the flywheel back on last night, so I should be able to test again for spark tonight if the weather permits. I will post the results.

 

[lindy46]

Re: Evinrude Lark 3 - replaced everything and STILL no spark

Forgot they were new wires - so they shouldn't be grounding out.