6 or 12 v coil ???

If the engine had stopped with the breaker points "open", it would be normal to have 12 Volts at the coil.

If you "jog" the engine over a bit, so the points close, and primary ignition current is flowing, about half of the battery voltage will be "dropped" across the resistance, and half across the coil's primary winding, giving you about 6 Volts at the igntion switch side of the coil.

Are you Sure its a 6 volt coil????? ?

NOTE a full true 12 volt coil will be labeled "12 volts" or "12 volts NOT for use with external ballast resistor" HOWEVER if labeled "12 volts for use with external ballast resistor" its in reality a 6 volt coil and needs external ballast!!!!! But since yours is marked 6 volts we have to assume thats correct IN WHICH CASE I strongly suggest you add an external ballast to extend points life even if running warm hasnt harmed the coil as of yet..... Id also insure any start by pass system is functioning n wired correct such as an extra lil I terminal on the starter solenoid or an extra terminal on the push to start switch used to feed hot unballasted voltage to the coil ONLY while cranking.

If it had a discrete or part of switch ballast perhaps it went bad and it was by passed?? BUT if so and you use 12 full time on a 6 volt coil it will simply run hotter and the points burn up sooner.

Until the coil overheats (if it ever does???) or the points burn up the spark ought to be plenty strong in the meantime lol

John T

There isn't a heck of a lot of difference between 6 volt and 12 volt.

Allan

A generic tractor starter is a series wound DC motor with the armature n field wired in series and a 6 volt starter will have different current ratings then one designed for use on 12 volt. As we all know, however, you can use 12 volts on a 6 volt starter n provided you dont let it crank too long n overheat thay can last a long time other then perhaps premature bendix wear from the higher kick in torque. HOWEWVER if you use 6 on a 12 volt starter she wont work worth a dern lol.

A 6 volt coil IS NOT same as a 12 volt coil. A typical 6 volt will have around 1.5 ohms of primary resistance as measured between its lil + and - terminals while a 12 volt coil (some call internally ballasted) will have more like 3 ohms. If you use 12 volts on a 6 volt coil it will run too hot and the points burn up soon and likewise, if you only use 6 volts on a 12 volt coil it will yield a weaker spark. There is some truth in your statement since a coil is more of a current then a voltage device. Its the current passing through the primary winding that develops a magnetic field in which energy gets stored and why (GIVEN the correct current) a 6 volt coil can develop a spark of sufficient energy just the same as a 12 volt coil can.....

Moral of story, they reallyyyyy yy arent the same.

Hope this helps, God Bless n yall take care now

John T

With POINTS OPEN - 12 volts at both + and - terminals of the coil and both sides of resistor.

With POINTS CLOSED you should see near 0 volts at distributor side of coil, 6 volts at battery side of coil and output of resistor and 12 volts at input to the resistor.

This is because with points open there is no current flow and you see battery voltage on coil, but with points closed the circuit is completed and is designed to drop 6 volts across coil and 6 volts across resistor.

Bob

• Hobby farm

Poor spark or fouling plugs can come from carbon instead of copper plug wires and from running Champion plugs. Seems like the modern Champion tractor plugs can't be cleaned when they get dirty either by engine operation or a spark plug cleaner.

Plugs may be fouling from oil or from running rich. The float needle and seat get worn from decades of vibration and don't seal off gas making the engine run rich.

Gerald J.