Super M points

My Super M used to literaly purr. Recently the coil went bad. It was a 12 volt "no ballust required" coil on a 6 volt distributor. Since a new one was $80, I put on a 6volt coil with a resistor. She doesn't run as nice now...sputters a little. What should I have my points gapped at? Or is there something else I should look at?

I don't know where you are at, but a "12 Volt" coil (IC14SB) is only about $19.00 at NAPA. Got one nearby?

Distributor point gap is .020".

Sounds like you have cut your voltage in half. 12V "with no resister" means that it has an internal resister. Now you have a 6V with an external resister. I would go back to the 12V. That should give you a hoter spark.

You could have a coil and ballast mis match whereby the ballast is dropping too much voltage leaving less then 6 volts on the new 6 volt rated coil......

Put a voltmeter on the coils input (or low output side of ballast, same point electrically) and with ignition ON and a good set of points closed READ THE VOLTAGE it should be near 6 to 7 or so volts BUTTTTTTT if its real low like 4 or 5 the ballast resistance is too high which lowers the spark energy.

On that 12 volt tractor you need EITHER a 6 volt coil and a correct ohms ballast resistor which is approx the same ohms as the coils primary (50 50 voltage divider) OR ELSE a full ture 12 volt (some call them internally ballasted) coil NO ballast required.

NOTE A full ture 12 volt (some call internally ballasted) coil may be labeled "12 volts" OR "12 volts NOT for use with external ballast resistor"

HOWEVER a coil labeled "12 volts for use with ballast resistor" is in reality a 6 votl coil an dneeds a ballast JUST LIKE IT SAYS

Check the points to be sure they didnt get burned carboned or pitted and replace them if necessary. If theres any doubt for no more then they cost a new set of points and condensor and/or the correct sized ballast (if coil voltage too low per above) may cure the problem..

John T

You may have already done this, but make sure coil polarity is correct. If you have a positive ground system, the wire from the distributor goes to the positive coil terminal. It needs to be connected to the negative coil terminal if you have a negative ground.

Thanks for the help all...i'll check the voltage and resistance and make sure i've got at least 6 volts going to the coil. I initially replaced the coil with a straight 12 volt coil and it ran horribly. That's when I went out and got the 6 volt with the resistor. I'll try and pick up a new set of points and condensor also.