12 volt coil

robertw

Member
I bought a farmall m that was converted from 6 to 12 volts it has a new 12 volt coil that doesn't require a external resistor that what is says on it the problem is that it's gets hot you can't touch it with your hands hasn't quit yet had it at a pull this week end and the motor run out of power at 156 feet there were some tractors 5 or 6 that was over 200 out of 24 in the class 222 won it this was in the 6500 lbs. class it has 150 lbs. compresson on all four cyl. was wondering if that coil is working right thats on reg. gas thought it should have done better then that runs good
Thanks for any help
 
A coil getting real hot a lot of times is saying hey I am going bad replace me. Yes a coil should be warm but not super hot.
 
A full 12 volt coil may be labeled "12 Volts" or "12 Volts NOT for use with ballast" or "12 Volts no ballast required" etc. Im talkin typical old farm tractor points and condenser ignition coils NOT after market or high performance or high voltage or high energy coil or Accell or Mallory racing coils etc SOME OF WHICH may still require some external ballast.

Under normal running conditions Id expect a stock correct voltage coil to get warm but NOT so hot you cant keep your hand on it.

John T
 
dito wht was said.

What 12v coil was it?

I'd reccomend a napa IC14SB..

beware. some manufacturers label a coil as 12v, then in flyspec print vaugely make reference to serial resistance.
 
My old coil was getting hot and I replaced it with the Napa IC14SB and it still gets hot. Still have not figured it out.
 
Between the normal operating temperature and heat generated from the engine the coil could get hot enough that you would not want to keep your hand in it. That is about 150° F. An engine under full load is going to running at about 200° F so it is hard to tell if it is overheating by touch. If it is hot enough to boil water it might well be too hot.
 
in addition to what's been said,
put a voltmeter on it while it's running to
check alternator/generator output.
too many volts will mess up the resistance-coil-resistor calculations, and make lots of coil heat.

Since you have the IC14SB, it is probably good to spec.
I'd like to add to SG's post about off brand stuff.
I usually use the IC14SB, but came across some deals on
import 'no resistor needed' 12v coils.
junk, they ohm out much too low.
I labeled them and threw them on the shelf until the next 6 volt tractor comes in.
 
(quoted from post at 19:06:01 06/26/14) Between the normal operating temperature and heat generated from the engine the coil could get hot enough that you would not want to keep your hand in it. That is about 150° F. An engine under full load is going to running at about 200° F so it is hard to tell if it is overheating by touch. If it is hot enough to boil water it might well be too hot.

Mine is definitely not hot enough to boil water and may very well be as hot as the engine itself. The heat I worry about when I try to start it and it is hard to start , it gets quite hot then
 

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