Coil problems

I have a problem burning out coils on our IH M after we switched it from a generator to a 1wire alternator. Do i need to put a resistor on it or could it be something else burning them out cause it gets real hot and splits the top open on them sometimes?

If you went from 6 to 12 volts it will need a resister or 12 volt coil.

Yes, it is important to use the correct coil.

The NAPA number is ECH IC14. That is a true 12 volt, no resistor needed coil.

The wrong coil will also result in short points life. They may be damaged from running the wrong coil.

But any coil can overheat if the ignition is left on and the points happen to be closed. Also try to mount it away from exhaust heat.

When you do buy the coil, be sure to match the part number on the coil itself to the number on the box. Coils of that style are dinosaurs now, often they get traded around from store to store, reboxed. The safest way to be sure you are getting a true 12v coil is to check the resistance across the + and - terminals. It should be around 3 ohms. If down around 1.5 ohms, it needs a resistor.

When you switched from a Generator to an Alternator did you happen to switch from 6 to 12 volts ???????????? Is it a 6 or 12 volt tractor??????

If so (changed from 6 to 12 and kept old coil) you need to EITHER add an in line (between ignition switch and coils input) series voltage dropping (12 down to 6) ballast resistor orrrrrrrrrrrrrr toss the old 6 volt coil and install a new full true 12 volt rated coil no ballast required. If you use a 6 volt coil at 12 volts it will overheat badly plus the points will burn quickly.

If you did not change voltage you might want to check the alternator to insure its wired correct and its NOT producing too high voltage and overcharging the battery. If the voltage regulation circuitry is working properly and the battery is okay at fast RPM a good alternator might raise battery voltage to at least 13 up to 14 + volts would be normal and okay. However if its approaching 15 or more for extended times the battery will overcharge, coil draw excess current, and points burn sooner.

If its overheating so bad the top splits off it must be drawing excess current caused by too high voltage or its a 6 volt coil being operated at 12 volts THAT NEEDS FIXED take a volt meter and see what voltage the battery is with tractor running and insure you have the correct coil and/or coil and ballast if required. MAKE SURE THE ALTERNATOR IS WIRED CORRECT AND ISNT PRODUCING TOO MUCH VOLTAGE

John T

Yes, we switched to 12 volt when we put alternator on. I picked up a true 12 coil yesterday and will give that a try tomorrow and see what happens.