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Rebuilt Wico OC, intermittent spark

con-rad

Registered
Hey all,

Recently rebuilt two OC's with new coils and condensers. The first one I rebuilt will make a 5/8" spark reliably and usually jump a 3/4" gap. The second one I did will only jump 1/2", and even then won't fire every time. I cleaned and filed the points several times and re-adjusted the points gap so they just start to open with the armature 3/32" from the cores. All the electrical connections on the primary and secondary and wire brushed nice and clean and don't have excessive resistance as checked with a multimeter. Am I missing something, or perhaps the magnets are just a little weaker on this one?

Thanks,

connor
 

cobbadog

Registered
When you say you don't have 'excessive resistence' how much are you talking?
Is the magneto completely oil free inside and all wires insulated properly so that a spark cannot leak to ground?
What point gap are you using? SOmetimes like this when you work on identical magnetos they end up being totally different. Coils may be slightly different and then that makes a difference too. The same for condensors, might have a slightly different value and give different result.
I would start again and double check all your readings on the new parts and ensure they are within spec. Remove the points and clean under them and clean and re-clean the points and then gap them. Sometimes coils can be a bit faulty even from new and is why if possible they should be checked out on a test bench or use a machine to check the coil first, then heat it using power and re check after 5 - 10 minutes while the coil is warm. If there is a drop in readings or performance this is your problem.
 

Kirk Taylor

Registered
Hey all,

Recently rebuilt two OC's with new coils and condensers. The first one I rebuilt will make a 5/8" spark reliably and usually jump a 3/4" gap. The second one I did will only jump 1/2", and even then won't fire every time. I cleaned and filed the points several times and re-adjusted the points gap so they just start to open with the armature 3/32" from the cores. All the electrical connections on the primary and secondary and wire brushed nice and clean and don't have excessive resistance as checked with a multimeter. Am I missing something, or perhaps the magnets are just a little weaker on this one?

Thanks,

connor
Conner,

If you haven't done it already, either swap the cover from the "good" magneto or remove the cover and check the spark from contact to contact just in case you might have a bad high tension terminal. If the cover is off, you also may be able to see if it's sparking to ground from someplace it shouldn't.
 

mmcdonald

Sponsor
Last Subscription Date
04/13/2017
Haven't worked on one of those in awhile but if I'm thinking of the right mag the armature not breaking cleanly every time can cause intermittent spark similar to the EK mag. Slop in the slide pin/armature. Just another thought.
 

con-rad

Registered
By excessive resistance, i mean that each connection was no more than an ohm. All the wires inside are new and soldered on, with the exception of the factory screw terminals.

the points gap is adjusted so they just start to open with the armature 3/32" from the cores.

I checked the armature guide play, it is the same between the so-so mag and the good one.

Good thought on the cover, i'll try swapping them. I did clean the spring contacts, but i'll try changing it out anyway.

Connor
 

Mitch Malcolm

Sponsor
Age
65
Last Subscription Date
02/20/2018
Kirk beat me to it the lead out towers can leak off some voltage without being a complete path to ground same as the EK and PR Wico's and for a shameless plug they are available at and made by Lightning Magneto :D
 

Tony Page

Subscriber
Last Subscription Date
07/12/2019
Haven't worked on one of those in awhile but if I'm thinking of the right mag the armature not breaking cleanly every time can cause intermittent spark similar to the EK mag. Slop in the slide pin/armature. Just another thought.
Had an EK that was driving me crazy. Found that guide pin on the armature had a very slight bend.
 
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