Ignition systems

[Woodrunner (Göran kindervall)]

Ok, a little follow up on my coil modification.

The re-wind coil get a outer layer of electrical insulation tape.

And then a layer of textile reinforced tape, this is ok because this coil is only low tension by now (this textile tape could collect some moisture). I prefer big heat-shrink tubing, but couldn’t find any in my stuff.

Coil in place, some rubber-shoe sole repair glue keeps the wires steady in the coil ends.

The enameled copper wire needs thorough cleaning, easiest is to heat it with a cigarette lighter, and scrape off the burned enamel.
The left side wire is soldered together with the orange wire, and connected to the condenser/points.
The orange wire is wired to the outside coil +.

The other end is cleaned, and grounded, this is often soldered to the coil core, in this case connected to a ground screw.

[Woodrunner (Göran kindervall)]

Next steps, separate coils could be found cheap, they are sturdier, because they dont have the space limitations as a flywheel coil.

Separate/freestanding coil, with 2 terminals, marking + and -, mostly they have no markings, in that case, no matter how they are connected.
With only one terminal, coil is grounded through the core.

Now to the sad part: i forgot to snap a pic of how i mounted the coil, i tend to get a little excited when it comes to get old stuff running, sorry
So, i put the flywheel, and the shroud back before i remembered.
Anyways it’s located below the flywheel and magneto, bolted in one of the intake bolts, and grounded in the same.
A short piece of high tension plug wire, to the plug.

Time for test: dmn! Has anyone tried to photo a ignition spark? Not the easiest, but i got it after some attempts.
I used a spring-clamp to hold the plug, im not very found of the “tickling sensation” that could be the case when testing spark.

And: Finally! It runs! This must be the machine from ***, it thinks it’s some kind of jet-powered pogo stick, i felt like Wile e Coyote (he thats never gets the Road-runner) it jumps up and down, and shakes, until it revs up, then it behaves more like a rock-drill.
And the sound! The roar coming from the straight 1 3/4" exhaust sounds more like a ,50cal machine gun… and the smoke… well, i guess i start it outdoors next time.

This is the Hand-crank starting device, very nice when it back-fires, really don’t want to loose the grip then, and got hit on the wrist, which even happens if i stop it, whit the crank in place, it’s last breath seems to go backwards…

[giorgio (giorgio pastore)]

göran, great work!! it would be urgently needed a kind of webcam in your workshop to see all what you construct !!

[Tone (Tone Šuštarič)]

Goran, excellent work, how do you think the power of the spark?
The old Cobra is again ready for action, drilling, breaking and “torturing” a person, an hour of work with this machine is a better training than an afternoon at the gym.

[Woodrunner (Göran kindervall)]

Thanks Giorgio
A webcam? Well that would be some fun

[Woodrunner (Göran kindervall)]

Thanks Tone, i haven’t “analyzed” the spark, only with my senses, it’s a “fat” blue spark, and if i turn it slowly i can hear the spark snap.
With original coil the spark was thinner, pale, and no “snap” it managed 7mm in my spark-tester though, and that would be sufficient.
Well, i believe the old coil shorted when the voltage raised, when the motor fired and started turn faster, not unusual on old machines.
And yes, this machine is a beast, i prefer the Cobra when it comes to real working, this oldtimer, made 1938, is more of a museum piece, i still going to use it though.

[Woodrunner (Göran kindervall)]

Got my hands on this coil-tester, got an homemade already, but this one is a little more “professional”.

Got a lot of functions, and are able to test most point-type ignitions, both coils on the bench, and ignition systems mounted in place, and some magnetos.
Upper is two adjustable spark-gaps, upper right is a rheostat, upper left is built in points, visible, to be able to see heavy sparking when testing capacitors in place.
Lower is amp and volt- meters.
Hopefully going to make a video in the future.

[giorgio (giorgio pastore)]

göran, i need some didactic help…
our neighbours bcs mower, what we make run again fine in february, now not gives spark more…we controlled all electric connections, breaker contacts, and also tested with a wire direct from coil to housing mass if there is spark…but nothing.
on the fingers can be felt some electricity…
i think the coil is not more good…
or can it also be the condensator?
what happens if the condensator is not more good?
makes spark though, only the braker contacts suffer?
or with damaged condensator also not makes spark more?
ciao giorgio

[Woodrunner (Göran kindervall)]

Hi Giorgio, most older ignition systems make a weak spark, but often enough to run, if condenser is bad.
If condenser is shorted-no spark att all.
If its easy to test, one may test with condenser disconnected.

But as you describe it, i think it’s probably the coil, the thin, secondary winding, these often go bad, breaks or some turns shorted out.
Often spark disapears, and only some hundreds of volts can be felt if holding the plug wire.
If the coil is of the old “mummy”-style (wrapped in fabric, and varnished) this happens all the time.

[giorgio (giorgio pastore)]

göran, thank you for your quick response…
the coil is from the old style you describe…there are yet spare parts available, but cost is 124 to 148 euro…
who loves his old engine will sacrify this money for getting it run again (motor yet very strong, clutch will also come earlier or later, they have never changed the disc), but my neighbour has always money for cigarillos…will see if he will sacrify for the mower…?

[Woodrunner (Göran kindervall)]

You may build it for separate coil, like i do in this thread, a spool of 0,65-0,7mm enameled copper wire, and a universal 6volt coil (10-25euro)
About 170-240 turns would do it.

[giorgio (giorgio pastore)]

this what you have done with the coil i will study again…can always be important…if it is worth to do this work for the neighbour, is another question…a person who not appreciate much the things, important only zero cost if possible…i have made the work in change with another mower from him in bad conditions, i have made my part of the deal, a lot of time going there by foot and bringing with me the tools and some old spare parts, soldering completely new the well of the gasoline tank, what was clogged up completely, and making a new gasoline lid for the old lost one ( actually lost now again!)…
so i am a bit tired with him…when he buy a new coil i will do the work for him for a “thank you”, but if not i will not invest more time , he is a person what not likes to learn a bit about the things he use. important for him they run , and this with bad maintenance…

[Woodrunner (Göran kindervall)]

In that case, it seems he didn’t apreciates your work much, he shoud buy a new coil.

[SteveUnruh]

GiorgioP. I have now two of these similar type men in my Life now. Within one year of moving to this new area.
Both men last Spring on their rider mower lawn mowers had the same brand of engine fail to be able to crank over to start.
Same-same problem. The weighted finger exhaust valve lifters on the cam shafts had broken off. A design weakness. Cranking compression then too high for their electric starters.
Both men can talk my ears off in different ways but neither can remove the engine; crack the engines cases to install a new camshaft.
Sad. Sad. Simple simple engines. Learning teenager’s work.
I have learned from previous with them that ME helping does not actually help; but in their eyes obligates me again and again for different of their problems.
One I did make his set aside for eight years push mower work again. Enough. The other I loaned out my own, old-old now rider lawn mower. Once. Twice.
He then got a consumer pay-monthly loan on a new much less powered rider mower. Just this last week repossessed by the equipment company for lack of payments.

When person chooses to live down a holes of despondency; and debts; and bad habits . . . do not jump down into that hole with him keep him company.

Regards
Steve Unruh

[giorgio (giorgio pastore)]

the next thing will be the roof- in very bad conditions will falling down on the mower. we have had suspect to work under the roof there. some parts are just fallen down and this is the garage