John Deere EK Igniter Test

[storl-a]

I need some help With my John Deere "EK" engine. It's very similar to the hit and miss "E" engine, but runs on kerosene.
I have repaired the ignitor, and want to test it. The manual "Instructions for servicing magneto and igniter on John Deere engines" says: "To test igniter for spark, remove igniter an Place on engine as shown in figure 2 using one cap screw." But the Picture is so bad, I can't see how this is done! Have anyone a better Picture of this? Or a better copy?

I got some sparks when I drag the sparkwire on the engine, but it might be too weak. I would really like to test the Whole Assembly.

And: If it turns out to be too weak, where is the best Place to have the coil rewound?

[storl-a]

Picture cut from this forum, I got the same quality in my manual

[old sparky]

First try to recharge magnet ,then double ck timing mark they must be timed!

[storl-a]

The magnet is new, timing is set. The problem is how to bolt on the igniter so it can be tested.

[cobbadog]

Ignitors also must be well insulated when installed in the engine and must make a good seal so that you do not get compression back past it.
There are a list of good repairers on this site and can be found under the 'sponsors' tag at the top of the page.
If you feel that you need a coil buy one but be certain that you need a new coil before buying it. Csrry out all the tests to work out your problem. If you are unsure send the complete magneto to a repairer and then you can be certain you have spark and plenty of it.

[Chester]

[QUOTE=cobbadog;1580907]Ignitors also must be well insulated when installed in the engine

not correct, why do you suggest that?

[Mitch Malcolm]

OK here goes nothing First of all forget about testing the igniter by bolting it to the block (stupidest thing I have ever seen tried ) after lapping in the movable shaft and replacing the mica assemble the ignitor the points should be closed ! hold the igniter in your left hand points away from you then press down on the hammer with your right thumb that has to open the points .040 - .060 and the points have to close on there own when you let up . That's it. disconnect the mag and hook up a battery and low tension coil and immediately start the engine do not leave the coil hooked up over 1 minute. as soon as it starts and you adjust the mixer and choke disconnect the coil and hook up the mag with it running hopefully it will pickup and run it. Now be sure to have fuel and water in the engine do not shut it off for at least a couple hours the more hours you put on these engines the better they run and start . If it doesn't run on the mag obviously you have mag trouble or more likely timing issues. Simply line up the timing marks on all 3 gears the crankshaft gear with the cam gear and the cam gear and mag gear all at the same time . Start there and report back,,

[storl-a]

Originally Posted by Mitch Malcolm

First of all forget about testing the igniter by bolting it to the block (stupidest thing I have ever seen tried )

More stupid than insulate the igniter? "cobbadog" probably ment make a good seal.

Sounds like you Mitch have tried what I asked for, or at least seen someone try. It might be stupid, but: I have worked on various engines, and think if I could have seen the spark from the points I would have a pretty good idea of what condition the magnetos windings was in. Just by the look of the spark.
I'm aware of the startup metod Mitch describe, I would have tried this if I had a low tension coil.
I might have to buy one, startup on the Kerosene engines might be more fiddly, since you have to deal With two types of fuel.
If

[mmcdonald]

Besides what's been said(and excuse me if it was and I missed it).....if the wire from the mag will produce sparks dragging it around with flywheel turning at hand cranking speed it should work. That kero version should not be any higher compression than the gas models. The momentum of the hammer springing back(after being tripped) is what opens the ignitor points. I have seen a lot put together wrong or severely worn or tight. Clamp the mounting in a vise and trip it yourself with a screwdriver just like the engine would. Set up a light behind the points if you need to. You should be able to see them operate. One crucial timing point besides the gears which I saw mentioned is the trip timing to the mag. Having the ignitor trip at the perfect moment in relation to the magneto armature position will do wonders for cranking ease. Adjust by sliding trip on push rod if necessary. Also the ignitor base must be electrically connected to the magneto housing. Typically this isn't an issue but I have seen a few times when it was. If there is no return path for electricity there it will not work. If you disconnect wire and open ignitor points there is infinite resistance between them right...... Good luck.

[Andrew Mackey]

An auto coil for a GM car built in the 1960s should work fine for a low tension source. battery to coil, coil to points (no condenser), ignitor body back to battery (or engine block if mounted). Polarity does not matter. If out of the engine, you should get a good flash as the points open. As others have stated, if you are getting a spark as you drag the power wire, as you are cranking the engine, the mag should be strong enough to fire the engine. If you do not get spark across the points with battery and coil, either the grounded point has poor contact or the insulated point is shorting or is open. Make sure there is no carbon on the mica insulation on the isolated fixed point. If there is carbon, it may short under compression. Clean with a good carb cleaner like Berkbile 2+2 (available at a good auto supply), and a fine brass wire brush, and dry thoroughly. Make sure the points themselves mate evenly when closed. The more face contact the better the flash and 'hotter' spark. After cleaning, be sure there is no debris on the point faces. The points should be shiney and not pitted.

A low tension ignition system is 'electrically simple, mechanically complicated'. Everything must be 'just so' when dealing with low tension, especially one that has a magneto for a power source. The points MUST break at exactly the right time, or spark will be diminished. If there are not scribe marks on the mag armature, ground the mag power wire and turn the magneto. It should virtually stop when it reaches the point of peak magnetic flux. Turn the engine until the ignitor JUST trips, and install the magneto, making sure the gear does not turn. You should be set. If the engine has timing marks, set as nescessary.

[storl-a]

Originally Posted by mmcdonald

if the wire from the mag will produce sparks dragging it around with flywheel turning at hand cranking speed it should work.

That's good news! Maybe I try to start it With the magneto as it is.
Have done some research on low tension coils, looks like almost anything will work. Maybe even from a old moped? Got lots of them.

[Mike Monnier]

Disconnect the mag if you use a coil. A John Deere igniter is a little different from most since the points are normally closed. This will rapidly drain the battery if you choose to run a battery and coil unless you unhook the outboard igniter spring. Generally you can wipe the igniter wire across the main spring while cranking. If you see blue sparks the magneto is hot enough to fire the engine. Just be sure that the timing marks are correct. I would initially just put gasoline in the main tank to get it running. You won't hurt anything if you later decide to use kerosene to run the engine.

[cobbadog]

Hi Chester, I say that as they are insulated where they are fitted through the engine so the spark does not earth out and travels to the points. Well, that's my interpretation of how they work.
The points are inside the cylinder and the spark is attached on the outside of the engine so the ignitor must be insulated and I have read many times about what type of insulator is used to replace the old style mica.

Stated by Andrew Mackey "Make sure there is no carbon on the mica insulation on the isolated fixed point." this is the insulation I was mentioning and also to have a good seal from the points to the outside of the engine.

This is why I said what I did, sorry if it is misleading.

[storl-a]

Originally Posted by Mike Monnier

I would initially just put gasoline in the main tank to get it running.

That's a great tip! Would simplify the startup a lot.
Think I buy some kind of coil, just to get i started. Any tip of a cheap coil I can buy online (ebay), would be appreciated.

[storl-a]

Ok, here's a update:

As I could not find a cheap coil, I decided to try to start the engine With the magneto before I made a coil. The spark was weak when I dragged the wire on the engine, but unable to test the spark from the ignitor (my question in this post), I just had to try. After some fiddling With the fuelmixture it started!

https://www.youtube.com/watch?v=OJ02vu2rrrE

In first half of the video it runs on petrol, the second half on kerosene. The RPM i 550-600, any lower and it will stop. I do not fully understand how the Governor and throttle Works together yet, just have to try I Guess. A manual for the EK would be helpfull, but I havent found one yet.