JD A -bad rotor weak spark, time to go pertronix?

My 1950 A has not been getting a spark for a few months now and I think I figured it out today.

I could put a neon spark tester on the pug wires and it would light, but no spark on the plug gap.

When I took off the mag cover I noticed that the rotor was very loose and wobbly. The metal spring that tensions it on the shaft was broken on one side. I retensioned the one good side and this got it to run, but not very well.

So- do I just get a new rotor, or should I go to electronic ignition. And if I do, must I go to an alternator? I have a pertronix on my "56 ford 650 and it has been flawless for 15 years now.
 
Pertronix is not available for magnetos, to my knowledge. A Delco-Remy 1111558 distributor with separate coil can be converted to electronic, if that"s what you want.
 
makes more since to just buy new rotor and points for the mag. I really don't understand why people want to convert to expensive pertronix. I have a Case SC that has had the same set of points for 23 years. My 9n is going on nine years with the same points.

dad change his 67 Ford pickup over and it only lasted 11 years. he changed it back to points and they have been in it for 14 years.
 
Just replace the rotor and throw in a new set of points, as discussed, EI will not correct a rotor issue and I think you would need to change to a distributor.
 
I pretty much agree with the other gents.

Its cheap and easy to just get a new rotor, and if all else in the mag is okay including the rotor shaft bushings/bearing, a new rotor tip may have ya up n running just fine. While in there Id inspect the points and if burned or pitted Id replace them anyway. Its more often the points (dirty or oxide coated or burned) that cause a weak spark them most other problems.

If you insist on an EI you need to first convert to a Delco battery powered coil distributor ignition and install the elec switch inside of it.

John T
 
Thanks for the comments. I forgot that the pertronix unit still employs the distributor, so a rotor would be needed anyway. DUH!
And they apparently don't make a kit for a magneto system anyway, so I'll just keep it stock.
The points and condenser are not that old and the points look fine. I've ordered a new rotor. I have just never encountered a loose rotor like that on a distributor, but it makes sense that it could make for a flaky, intermittent spark. Hopefully this will solve the occasional spells of no spark that I've had over the years.
 
I bought a used mag and the rotor that was in it has one of the spring ears broke off and it fit loose on the shaft. I cut a small piece of tin and slid it in there and the rotor fit tight. My tractor has been running for 2 years without a miss with that piece of tin on the shaft. I was going to get a new one but if it works I ain't going to fix it until I have problems out of it .
 
Putting a tiny dab of silicone gasket sealer in the rotor works as well.

Set the rotor to the middle of it's loose travel, then let the silicone cure.

It's easy to pull it off at a later time, if that becomes necessary.
 

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