Our JD 60 was rebuilt about 10 years ago, and at that time I replaced the coil with an aftermarket coil It ran well for quite some time although we didn't use it heavily. Recently, I started having problems with it burning points and/or condensers quite rapidly. In response to a previous post, I was told the aftermarket coil had windings that required an external resistor, or replacement of the aftermarket coil with a superior coil. I looked around and found the original coil from the JD 60, which I had replaced during the restoration for no good reason other than I was restoring the tractor. (When I say "original" I mean the coil that was on the JD 60 prior to restoration). I put the original coil back on, together with a set of points and condenser, and it ran real very well ... for about ten minutes, then it started sputtering so bad I could barely get it back in the shed. This is the same thing it's been doing very recently prior to putting the original coil back on, I'd replace the points and condenser and then it would run very well for about ten minutes, then sputter so bad you could barely limp it back to the shed. I've been told condensers these days are junk - but something else must be going on. Can anyone suggest anything that I might do to determine why this is happening? Would adding an external resistor resolve this issue? But if that were the case, why was it that I never had to use an external resistor with the original coil prior to restoration? This has got me stumped and its very frustrating. Thanks for any help.