Nice day to work on this. Went down in the 30's last night and was still in the 40's when I got out there. So we are working with a freshly charged battery today and just a reminder it is a 12v conversion with a 12v coil.
First thing I did was run a jumper from the ignition side of the battery to the battery side of the coil. There was no noticeable attempt to start when cranked a few times.
Second I grounded the wire from the coil to the distributor (at the distributor) and, with a meter on the battery side of coil gave it a few cranks. Before cranking there was 12v, this dropped to 5v when cranked. Not even close to the 10v +/- I was looking for.
Third I inspected the wires and the knife switch that is "in line" on the battery positive side and found a couple of connections that MIGHT be an issue but probably not. I took the starter side of the switch off and took it directly to the battery, no change.
Lastly, I put my meter on the battery itself and gave a couple of cranks. 12v went down to 5v when cranking.
I have some ideas, but if I knew anything the tractor would be running already. I am interested in YOUR ideas and opinions. Any and all appreciated! :)