Dead 9n, new information

Make you measurements with the tractor not running and the Points Closed. The method of measuring each point to Ground (one probe on the Frame) is less accurate (you can be mislead because all grounds are not equal) than simply measuring the Voltage Drop across each component by connecting one probe on each side. You can do it both ways and then it should become obvious that the voltage drop is the number that has meaning and simplifies trouble shooting.

# = Probes, Ballast = Dash mounted oem,
RU100 = additional added Resistor RU100 or Equiv.

A. Top of Coil (#1) to frame of Distributor #2
B. Top of Coil (#1) to Battery Ground POST #2
C. One side of Ballast(#1) other side of Ballast #2
D. One side of RU100 (#1) other side of RU100 #2

With Points open:
E) One side of RU100 (#1) other side of RU100 #2

Voltage Results: for front mount 6 volt coil with 12V Batt System
A. 2.4V to 3.5 Volts : ideal = 2.7V
B. Same as A (2.4V to 3.5V) ideal = 2.7V
C. 2.0V to 3.9 V (typical = 3.65V)
D. 5.2V to 7.1 V (typical = 6.15v)
E. 0.000V (ZERO)

The Sum of B+C+D “MUST” equal Battery Voltage.

Hope this Helps,

That is the infamious "ballast resistor" and it is doing exactly what it is suppost to be doing. Reducing the voltage to the other resistor and finally getting the volts to the coil to 8.8 volts. Marginally low, but workable.

Leave everything alone, you should be good to go. All your voltage make sense and are in the ballpark..... ..Dell