The number 1 reason for burning up a front coil is leaving the key on.
The number 2 reason is cheap-azz off-shore replacement coils.
The absence of the oem ballast resistor on a front coil will not cause it to burn up in a few minutes of run time.
But, how did you determine the coil is defective?
Iíve always found it best to determine if a part is actually defective before I buy a new one.
About 5 years ago, my neighbor proudly told me about fixing his 8N. Seems like it wouldnít start, so he replaced the coil. Tractor started, problem solved. I asked him if I could have the old coil. He gave it to me. I put it on one of my 8Nís where it has been ever since.
I do not know why his tractor would not start. I do not know why it did start and ran fine after he put a new coil on it. Sure, I can make a lot of guesses, but we will never know for sure.
But I do know he did not have a bad coil.
Think about this the next time you are inclined to just start replacing parts w/o determining if the part is defective.