IH 444 Coil

[Paul J.]

I am not able to get the tractor to start and I
suspect I have a coil issue. I checked my books
for specs and cannot find any. I have a couple of
questions;

1 - What is the primary ohm reading supposed to
be?

2 - what is the secondary ohm reading supposed to
be?

3 - Is this supposed to be a 12 volt or a 6 volt
coil? I am getting a 12 volt reading the primary
coil.

Thanks,

Paul

 

[Bob M]

Paul - A good 12 volt coil primary will show between about 3 and 5 ohms; a 6 volt coil's primary resistance will be half that.

Secondary resistance for both 6 and 12 volt coils is generally between about 2.5K and 4K ohms. (Individual coil resistances may vary outside this range...)

Now if you read either a dead short (0 ohms) or an open (infinite resistance) in either coil winding you know the coil is bad. HOWEVER a coil can still be bad even when both windings' resistance values are within tolerance.