12 volt coil in 6 volt system

Axtell · Dec 28, 2014

Hello all,

I am looking over a 6 volt 8N and notice the previous owner (deceased) had cut the generator wires to the regulator and uses a 12 volt coil. The starter and switch have also been replaced/rewired. I flushed out the old fuel, cleaned out the carb and was able to crank it fairly easy. Since the charging circuit would appear to be removed, I would like to reconnect it, but wonder if this would cause a problem using the 12 volt coil. I do not know why this was done.

Thoughts appreciated,
Thanks!

old · Dec 28, 2014

Front or side mount distributor can make a difference. If it is in fact a TRUE 12 volt coil on a 6 volt system the spark will be weak. The ignition system and the charging system are not hooked up to each other as such other then the battery so it being unhooked does not have any thing to do with the coil

Charles Krammin · Dec 28, 2014

Maybe the PO was in the process of adding a 12 volt alternator and didn't get around to it and just used a 12 volt charger to charge a 12 volt battery.
You can do the same to fire it up.

How did you determine if the coil is in fact a "12 volt coil" (3.25 ohms with a digital tester)?

Charles Krammin SW MI

NOXJohn · Dec 28, 2014

I would suspect that the PO cut the generator
wires to the regulator and installed a 12 volt
coil because he was using a 12 volt battery to
start and run the tractor. That is something a
lot of people have done for many reasons. A 12
volt battery will start and run an N tractor
for hours before needing to be recharged. If
you go back to a 6 volt system you need to
replace the coil with a 6 volt unit or the
tractor most likely will not start due to a
very poor spark. I would have the 6 volt
generator and regulator checked before
reconnecting and buying a 6 volt battery. The
PO made the change for some reason which may
have been not charging. Or he may have just had
an extra 12 volt battery.

Dell (WA) · Dec 28, 2014

Axtell..........um? How do you know it is a 12-volt coil? How do you know it is an 8N? Do NOT reconnect enny of the wiring without checking the wiring schematics in the I&T FO-4. ($25, cheap) Electricity is funny stuff, 6-volts on a 12-volt coil will produce 1/2 the sparkies that a 6-volt coil will. ...ie... a 6-volt coil will produce 20-killovolts and 12-volt coil will produce just 10-kilovolts. And finally, since I flunked mind reading (just ask my ex-wife) byte the bullet and gitta NEW wiring harness from our host YesterdaysTractor. Pay attention, there are 2-different harnesses. 1-fer the weird 4-nipple front mount dizzy and 1-fer the 5-nipple side mount dizzy. The wiring harnesses wires are color coded and surprizingly enuff the correct lengths and correct terminals. BTW, the weird 4-nipple dizzy was also used on the 3-speed 9N/2N's. 8N's are 4-speed trannys and can have either the 4-nipple dizzy ...or... 5-nipple dizzy. The carburetor is the same M/S carbie.

Final lesson, the 8N came from the factory 6-volt positive (+) ground. While the battery don't care positive (+) or negative (-) ground, you CARE. You need to correctly polarize yer 6-volt genny to match yer battery polarity. Just "arc-spark" the side-by-side BAT and ARM terminals of the square can voltage regulator. Simple, eh? ........the amazed electrical Dell

Bruce (VA) · Dec 28, 2014

Front or side distributor?

As others have asked....how do you know it's a 12v coil?
75 Tips

Bruce (VA) · Dec 28, 2014

" How did you determine if the coil is in fact a "12 volt coil" (3.25 ohms with a digital tester)?"

Only if it's a round coil.

If it's a square coil, 2.5 ohms or more for 12v.
75 Tips

Axtell · Dec 28, 2014

(quoted from post at 10:39:20 12/28/14) Front or side mount distributor can make a difference. If it is in fact a TRUE 12 volt coil on a 6 volt system the spark will be weak. The ignition system and the charging system are not hooked up to each other as such other then the battery so it being unhooked does not have any thing to do with the coil

Side mount. The coil has label that reads 12 volts.

Axtell · Dec 28, 2014

Hmmm.., that's interesting. Thanks! The coil has a 12V label on it.

Axtell · Dec 28, 2014

Interesting you say that. When I took the tractor there was no battery in it. Reading and surfing I discovered from the factory they were 6 volt from the factory. It took the 6 volt battery out my cub and tried to crank it. It turned over but failed to fire. The next day after further reading I discovered the 8N was positive ground. I swapped the battery cables and it fired right up. As far as the coil, it had a 12 volt label on it.

Axtell · Dec 28, 2014

(quoted from post at 11:26:55 12/28/14) Axtell..........um? How do you know it is a 12-volt coil? How do you know it is an 8N? Do NOT reconnect enny of the wiring without checking the wiring schematics in the I&T FO-4. ($25, cheap) Electricity is funny stuff, 6-volts on a 12-volt coil will produce 1/2 the sparkies that a 6-volt coil will. ...ie... a 6-volt coil will produce 20-killovolts and 12-volt coil will produce just 10-kilovolts. And finally, since I flunked mind reading (just ask my ex-wife) byte the bullet and gitta NEW wiring harness from our host YesterdaysTractor. Pay attention, there are 2-different harnesses. 1-fer the weird 4-nipple front mount dizzy and 1-fer the 5-nipple side mount dizzy. The wiring harnesses wires are color coded and surprizingly enuff the correct lengths and correct terminals. BTW, the weird 4-nipple dizzy was also used on the 3-speed 9N/2N's. 8N's are 4-speed trannys and can have either the 4-nipple dizzy ...or... 5-nipple dizzy. The carburetor is the same M/S carbie.

Final lesson, the 8N came from the factory 6-volt positive (+) ground. While the battery don't care positive (+) or negative (-) ground, you CARE. You need to correctly polarize yer 6-volt genny to match yer battery polarity. Just "arc-spark" the side-by-side BAT and ARM terminals of the square can voltage regulator. Simple, eh? ........the amazed electrical Dell

Thanks for the info!
The coil has a 12 volt label on it and the tractor is a 4 speed. Isn't that the upgrade to the 8N? From a previous reply to a post I did try to crank it with the battery hooked bass awkward. After I figured that out she fired right up. I'll be mindefull of the polarization. Thanks again!

Axtell · Dec 28, 2014

Side distributor. The coil has a 12 volt label on it.

Axtell · Dec 28, 2014

The coil has a 12volt labe on it. I'll grab my ohmeter and check it to be sue. Great stuff guys! I appreciate it. I'll see if I can snap a pic and let you know what it read..

Bruce (VA) · Dec 28, 2014

" I swapped the battery cables and it fired right up. "

That's what's called a coincidence.

Polarity had nothing to do w/ it failing to start. You probably had a loose cable/dirty ground.

And yes, a 6v battery w/ a 12v coil will get you a weak spark.

You probably won't notice it until it gets cold or the battery gets run down a bit though.
75 Tips

Axtell · Dec 28, 2014

Thanks! I sure don't want a weak spark. I'll pick up a 6V coil and connect the gen and reg.

Thanks everyone!

Bruce (VA) · Dec 28, 2014

Make sure you wire it correctly or you will let the smoke out of the v/r.

Google "wiring diagrams JMOR" and find the correct one for your tractor.
75 Tips

old · Dec 28, 2014

A coil can have that but it can also have wording like 12 external resister needed or 12 volt no resister needed or some such wording

12 volt coil in 6 volt system

Axtell

Member

old

Well-known Member

Charles Krammin

Member

NOXJohn

Member

Dell (WA)

Well-known Member

Bruce (VA)

Well-known Member

Bruce (VA)

Well-known Member

Axtell

Member

Axtell

Member

Axtell

Member

Axtell

Member

Axtell

Member

Axtell

Member

Bruce (VA)

Well-known Member

Axtell

Member

Bruce (VA)

Well-known Member

old

Well-known Member

Similar threads