I think the Tecumseh coil will not work on the Victa Norm and Vm as looking at the width it's 32 mm so is too long for the Victa core centre.
The thing is the Tecumseh coil should fit a Villiers torque major or Kirby but will not be a simple swap. It looks like the Tecumseh coil is molded onto the core or molded onto two metal tabs that are spot welded to the core.
Might have to see if this Tecumseh coil will work on the Villiers motor , don't throw out the coils Norm if you throw out the Tecumseh motors as they might be usable on a few motors.
Originally Posted by vint_mow
Max, this is probably the dumb question of the day, but instead of reversing the coil, why not simply reverse the wiring? So use the earth wire for the positive and the positive wire for the earth? The reason I ask is that if I test an external Victa flywheel coil with the multimeter, I get the same reading in KOhms through the earth wire as the positive wire. Wouldn't reversing the wiring be the same as reversing the coil and using the same wiring?
Yes I was thinking about that Vm, but don't think the coil would work properly, coils are made to work one way.
Generally I would say no you can't reverse the primary windings polarity ,I have seen car coils wired backwards on oscilloscopes and the spark is completely wrong even though the engine will run.
Does it matter which way an ignition coil is wired? The coil will work efficiently and put out the same voltage either way it is hooked up, but the spark plugs are more sensitive when it comes to polarity, hence our second and more important definition. Coil polarity should be such so as to provide negative polarity to the spark plugs center electrode.
With a car coil , Coil Polarity (In relation to spark plugs) Coil polarity should be such so as to provide negative polarity to the spark plugs center electrode.
It has been found that it takes approximately 15% less voltage to form an arc at the plugs, if the hotter center electrode is negative, and the cooler (by comparison) ground electrode is positive. The center electrode is hotter since heat transfer from the tip must make its way through the porcelain insulator past the sealing gaskets to the shell block and then to the water jackets.
If your center electrode is positive, your car will probably still run fine until, with its 15% handicap, it exceeds the coil output. If you live where temperatures dip down to 0° you may not get your car started. Driving with a full load and accelerating hard up a hill may cause an ignition miss. If your ignition system is well-worn to where you have various voltage losses, you could get a miss.
I know you can test the polarity on a car coil and I guess the same test should work on a mower coil but you will need an old needle volt meter.
Hooking up a mower to an oscilloscope would show straight away the effect of reversing the primary windings polarity, but I think the volt meter test would be a quicker test.
First Video is how the coil works and the other two show what the spark should look like on an oscilloscope.
