Not sure if you have checked this or not, but I was trying to start an old welder a while back. Would some times spit, backfire then just crank with no response.
The owner had installed new points, cap, rotor, plugs and wires.
Found I had no spark. Adjusted points, would get a spark or two, then nothing.
I finally took the new point set out, and they were tight enough that they would not close with the spring pressure to pull them shut.
I found the old points and they worked freely. Filed them to clean them up and got the welder started.
