Farmall spark problem?

[randerson]

we have a old Farmall M and had a short and the wiring burnt up so I ordered a new harness and installed it and have no luck getting it started. It has been converted to 12Volt. Well today I started doing some troble shooting after my dad and brother tried new wires new plugs and a new coil. I also tried some new points condenser and rotor. with no such luck I have been working on this all day finally I grabbed a test light and started check each location from ammeter on well low and behold I have power in and out of ammeter but no power to ignition switch so I swapped out the wire and now I have power from the ignition switch threw the ballast resistor and to the coil + side but cant get the light to light when I turn the engine over. I'm going to try the old coil right now but have really been stumped it ran fine till I shut it off when wiring burnt up...

[highlife4me]

Did you check to see if the rotor spins when the motor is cranked over?

[randerson]

yes it is spining I have power to the + side of the coil but not on the - side I don't have spark at the points

[jmd1]

sounds like you are missing a ground someplace. do you have lights on this machine? do they work? i think i would be looking hard for a ground wire that is not connected or misconnected. good luck

[highlife4me]

Is the new coil a 12V or 6V? I know you can get them either way. If you have a 12V coil you would not need the external resistor. Not sure if this would cause no power coming out of the coil though.

[randerson]

I actually have one of both 6v and 12 volt the 12 volt one says right on it to use the resistor.

I disconected the lights but they were single wire lights that ground themselves

[JollyJoker]

Is this a positive ground system?

[randerson]

no when its converted to 12 volt its changed to a negative ground system